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Revision 1.394 by root, Thu Jan 12 06:27:44 2012 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	event loops.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	200	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<ENVIRONMENT VARIABLES>
		439	section for details.
		440
		441	All these problems can be avoided by installing the optional
		442	L<Async::Interrupt> module, which works with most event loops. It will not
		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		444	(and not with L<POE> currently). For those, you just have to suffer the
		445	delays.
		446
375	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
376		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
377	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
378		452
379	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
383		458
384	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	461	callback arguments.
387		462
…		…
403		478
404	This means you cannot create a child watcher as the very first	479	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	480	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
		483
		484	As most event loops do not support waiting for child events, they will be
		485	emulated by AnyEvent in most cases, in which case the latency and race
		486	problems mentioned in the description of signal watchers apply.
408		487
409	Example: fork a process and wait for it	488	Example: fork a process and wait for it
410		489
411	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
412		491
…		…
424	# do something else, then wait for process exit	503	# do something else, then wait for process exit
425	$done->recv;	504	$done->recv;
426		505
427	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
428		507
429	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		509
434	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		512
438	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
441		525
442	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	527	program is otherwise idle:
…		…
459	});	543	});
460	});	544	});
461		545
462	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
463		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
464	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
467		556
468	AnyEvent is different, it expects somebody else to run the event loop and	557	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
470		559
471	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	561	they represent a condition that must become true.
		562
		563	Now is probably a good time to look at the examples further below.
473		564
474	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	567	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	568	becomes true, with the condition variable as the first argument (but not
479	the results).	569	the results).
480		570
481	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	574	->send >> method).
485		575
486	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	578
489	another way to call them is transactions - each condition variable can be	579	=over 4
490	used to represent a transaction, which finishes at some point and delivers	580
491	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
492		599
493	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
509		616
510	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
515		622
516	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	625	for the send to occur.
519		626
520	Example: wait for a timer.	627	Example: wait for a timer.
521		628
522	# wait till the result is ready	629	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
524		631
525	# do something such as adding a timer	632	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
527	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
530	after => 1,	637	after => 1,
531	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
532	);	639	);
533		640
534	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
535	# calls send	642	# calls ->send
536	$result_ready->recv;	643	$timer_fired->recv;
537		644
538	Example: wait for a timer, but take advantage of the fact that	645	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	646	variables are also callable directly.
540		647
541	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	650	$done->recv;
544		651
…		…
550		657
551	...	658	...
552		659
553	my @info = $couchdb->info->recv;	660	my @info = $couchdb->info->recv;
554		661
555	And this is how you would just ste a callback to be called whenever the	662	And this is how you would just set a callback to be called whenever the
556	results are available:	663	results are available:
557		664
558	$couchdb->info->cb (sub {	665	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	666	my @info = $_[0]->recv;
560	});	667	});
…		…
578	immediately from within send.	685	immediately from within send.
579		686
580	Any arguments passed to the C<send> call will be returned by all	687	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
582		689
583	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		693
592	=item $cv->croak ($error)	694	=item $cv->croak ($error)
593		695
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
596		698
597	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
598	user/consumer.	700	user/consumer. Doing it this way instead of calling C<croak> directly
		701	delays the error detection, but has the overwhelming advantage that it
		702	diagnoses the error at the place where the result is expected, and not
		703	deep in some event callback with no connection to the actual code causing
		704	the problem.
599		705
600	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
601		707
602	=item $cv->end	708	=item $cv->end
603
604	These two methods are EXPERIMENTAL and MIGHT CHANGE.
605		709
606	These two methods can be used to combine many transactions/events into	710	These two methods can be used to combine many transactions/events into
607	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
608	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
609		713
610	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
611	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
612	>>, 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
613	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
614	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.
615		720
616	Let's clarify this with the ping example:	721	You can think of C<< $cv->send >> giving you an OR condition (one call
		722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		724
		725	Let's start with a simple example: you have two I/O watchers (for example,
		726	STDOUT and STDERR for a program), and you want to wait for both streams to
		727	close before activating a condvar:
617		728
618	my $cv = AnyEvent->condvar;	729	my $cv = AnyEvent->condvar;
619		730
		731	$cv->begin; # first watcher
		732	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		733	defined sysread $fh1, my $buf, 4096
		734	or $cv->end;
		735	});
		736
		737	$cv->begin; # second watcher
		738	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		739	defined sysread $fh2, my $buf, 4096
		740	or $cv->end;
		741	});
		742
		743	$cv->recv;
		744
		745	This works because for every event source (EOF on file handle), there is
		746	one call to C<begin>, so the condvar waits for all calls to C<end> before
		747	sending.
		748
		749	The ping example mentioned above is slightly more complicated, as the
		750	there are results to be passwd back, and the number of tasks that are
		751	begun can potentially be zero:
		752
		753	my $cv = AnyEvent->condvar;
		754
620	my %result;	755	my %result;
621	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
622		757
623	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
624	$cv->begin;	759	$cv->begin;
625	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
626	$result{$host} = ...;	761	$result{$host} = ...;
…		…
641	loop, which serves two important purposes: first, it sets the callback	776	loop, which serves two important purposes: first, it sets the callback
642	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
643	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
644	doesn't execute once).	779	doesn't execute once).
645		780
646	This is the general pattern when you "fan out" into multiple subrequests:	781	This is the general pattern when you "fan out" into multiple (but
647	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
648	is called at least once, and then, for each subrequest you start, call	783	the callback and ensure C<end> is called at least once, and then, for each
649	C<begin> and for each subrequest you finish, call C<end>.	784	subrequest you start, call C<begin> and for each subrequest you finish,
		785	call C<end>.
650		786
651	=back	787	=back
652		788
653	=head3 METHODS FOR CONSUMERS	789	=head3 METHODS FOR CONSUMERS
654		790
…		…
658	=over 4	794	=over 4
659		795
660	=item $cv->recv	796	=item $cv->recv
661		797
662	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
663	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
664	normally.	800	normally.
665		801
666	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
667	will return immediately.	803	will return immediately.
668		804
…		…
670	function will call C<croak>.	806	function will call C<croak>.
671		807
672	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,
673	in scalar context only the first one will be returned.	809	in scalar context only the first one will be returned.
674		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
675	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
676	(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
677	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
678	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
679	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
680	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,
681	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
682		825
683	Another reason I<never> to C<< ->recv >> in a module is that you cannot
684	sensibly have two C<< ->recv >>'s in parallel, as that would require
685	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
686	can supply.
687
688	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
689	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
690	versions and also integrates coroutines into AnyEvent, making blocking
691	C<< ->recv >> calls perfectly safe as long as they are done from another
692	coroutine (one that doesn't run the event loop).
693
694	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
695	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
696	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
697	waits otherwise.	829	waits otherwise.
698		830
699	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
705		837
706	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
707	replaces it before doing so.	839	replaces it before doing so.
708		840
709	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
710	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
711	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
712	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.
713		846
714	=back	847	=back
715		848
		849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		850
		851	The available backend classes are (every class has its own manpage):
		852
		853	=over 4
		854
		855	=item Backends that are autoprobed when no other event loop can be found.
		856
		857	EV is the preferred backend when no other event loop seems to be in
		858	use. If EV is not installed, then AnyEvent will fall back to its own
		859	pure-perl implementation, which is available everywhere as it comes with
		860	AnyEvent itself.
		861
		862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		864
		865	=item Backends that are transparently being picked up when they are used.
		866
		867	These will be used if they are already loaded when the first watcher
		868	is created, in which case it is assumed that the application is using
		869	them. This means that AnyEvent will automatically pick the right backend
		870	when the main program loads an event module before anything starts to
		871	create watchers. Nothing special needs to be done by the main program.
		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		875	AnyEvent::Impl::Tk based on Tk, very broken.
		876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
		879	AnyEvent::Impl::IOAsync based on IO::Async.
		880	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		881	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
		882
		883	=item Backends with special needs.
		884
		885	Qt requires the Qt::Application to be instantiated first, but will
		886	otherwise be picked up automatically. As long as the main program
		887	instantiates the application before any AnyEvent watchers are created,
		888	everything should just work.
		889
		890	AnyEvent::Impl::Qt based on Qt.
		891
		892	=item Event loops that are indirectly supported via other backends.
		893
		894	Some event loops can be supported via other modules:
		895
		896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		897
		898	B<WxWidgets> has no support for watching file handles. However, you can
		899	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		900	polls 20 times per second, which was considered to be too horrible to even
		901	consider for AnyEvent.
		902
		903	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		904	backend, so it can be supported through POE.
		905
		906	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		907	load L<POE> when detecting them, in the hope that POE will pick them up,
		908	in which case everything will be automatic.
		909
		910	=back
		911
716	=head1 GLOBAL VARIABLES AND FUNCTIONS	912	=head1 GLOBAL VARIABLES AND FUNCTIONS
717		913
		914	These are not normally required to use AnyEvent, but can be useful to
		915	write AnyEvent extension modules.
		916
718	=over 4	917	=over 4
719		918
720	=item $AnyEvent::MODEL	919	=item $AnyEvent::MODEL
721		920
722	Contains C<undef> until the first watcher is being created. Then it	921	Contains C<undef> until the first watcher is being created, before the
		922	backend has been autodetected.
		923
723	contains the event model that is being used, which is the name of the	924	Afterwards it contains the event model that is being used, which is the
724	Perl class implementing the model. This class is usually one of the	925	name of the Perl class implementing the model. This class is usually one
725	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
726	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
727		928	will be C<urxvt::anyevent>).
728	The known classes so far are:
729
730	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
731	AnyEvent::Impl::Event based on Event, second best choice.
732	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
733	AnyEvent::Impl::Glib based on Glib, third-best choice.
734	AnyEvent::Impl::Tk based on Tk, very bad choice.
735	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
737	AnyEvent::Impl::POE based on POE, not generic enough for full support.
738
739	# warning, support for IO::Async is only partial, as it is too broken
740	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
741	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
742
743	There is no support for WxWidgets, as WxWidgets has no support for
744	watching file handles. However, you can use WxWidgets through the
745	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
746	second, which was considered to be too horrible to even consider for
747	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
748	it's adaptor.
749
750	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
751	autodetecting them.
752		929
753	=item AnyEvent::detect	930	=item AnyEvent::detect
754		931
755	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
756	if necessary. You should only call this function right before you would	933	if necessary. You should only call this function right before you would
757	have created an AnyEvent watcher anyway, that is, as late as possible at	934	have created an AnyEvent watcher anyway, that is, as late as possible at
758	runtime.	935	runtime, and not e.g. during initialisation of your module.
		936
		937	The effect of calling this function is as if a watcher had been created
		938	(specifically, actions that happen "when the first watcher is created"
		939	happen when calling detetc as well).
		940
		941	If you need to do some initialisation before AnyEvent watchers are
		942	created, use C<post_detect>.
759		943
760	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
761		945
762	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
763	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
		948
		949	The block will be executed I<after> the actual backend has been detected
		950	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		951	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		952	other initialisations - see the sources of L<AnyEvent::Strict> or
		953	L<AnyEvent::AIO> to see how this is used.
		954
		955	The most common usage is to create some global watchers, without forcing
		956	event module detection too early, for example, L<AnyEvent::AIO> creates
		957	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		958	avoid autodetecting the event module at load time.
764		959
765	If called in scalar or list context, then it creates and returns an object	960	If called in scalar or list context, then it creates and returns an object
766	that automatically removes the callback again when it is destroyed. See	961	that automatically removes the callback again when it is destroyed (or
		962	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
767	L<Coro::BDB> for a case where this is useful.	963	a case where this is useful.
		964
		965	Example: Create a watcher for the IO::AIO module and store it in
		966	C<$WATCHER>, but do so only do so after the event loop is initialised.
		967
		968	our WATCHER;
		969
		970	my $guard = AnyEvent::post_detect {
		971	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		972	};
		973
		974	# the ||= is important in case post_detect immediately runs the block,
		975	# as to not clobber the newly-created watcher. assigning both watcher and
		976	# post_detect guard to the same variable has the advantage of users being
		977	# able to just C<undef $WATCHER> if the watcher causes them grief.
		978
		979	$WATCHER ||= $guard;
768		980
769	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
770		982
771	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
772	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
773	the event loop has been chosen.	985	after the event loop has been chosen.
774		986
775	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
776	if it contains a true value then the event loop has already been detected,	988	if it is defined then the event loop has already been detected, and the
777	and the array will be ignored.	989	array will be ignored.
778		990
779	Best use C<AnyEvent::post_detect { BLOCK }> instead.	991	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		992	it, as it takes care of these details.
		993
		994	This variable is mainly useful for modules that can do something useful
		995	when AnyEvent is used and thus want to know when it is initialised, but do
		996	not need to even load it by default. This array provides the means to hook
		997	into AnyEvent passively, without loading it.
		998
		999	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1000	together, you could put this into Coro (this is the actual code used by
		1001	Coro to accomplish this):
		1002
		1003	if (defined $AnyEvent::MODEL) {
		1004	# AnyEvent already initialised, so load Coro::AnyEvent
		1005	require Coro::AnyEvent;
		1006	} else {
		1007	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1008	# as soon as it is
		1009	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1010	}
		1011
		1012	=item AnyEvent::postpone { BLOCK }
		1013
		1014	Arranges for the block to be executed as soon as possible, but not before
		1015	the call itself returns. In practise, the block will be executed just
		1016	before the event loop polls for new events, or shortly afterwards.
		1017
		1018	This function never returns anything (to make the C<return postpone { ...
		1019	}> idiom more useful.
		1020
		1021	To understand the usefulness of this function, consider a function that
		1022	asynchronously does something for you and returns some transaction
		1023	object or guard to let you cancel the operation. For example,
		1024	C<AnyEvent::Socket::tcp_connect>:
		1025
		1026	# start a conenction attempt unless one is active
		1027	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1028	delete $self->{connect_guard};
		1029	...
		1030	};
		1031
		1032	Imagine that this function could instantly call the callback, for
		1033	example, because it detects an obvious error such as a negative port
		1034	number. Invoking the callback before the function returns causes problems
		1035	however: the callback will be called and will try to delete the guard
		1036	object. But since the function hasn't returned yet, there is nothing to
		1037	delete. When the function eventually returns it will assign the guard
		1038	object to C<< $self->{connect_guard} >>, where it will likely never be
		1039	deleted, so the program thinks it is still trying to connect.
		1040
		1041	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1042	callback directly on error:
		1043
		1044	$cb->(undef), return # signal error to callback, BAD!
		1045	if $some_error_condition;
		1046
		1047	It should use C<postpone>:
		1048
		1049	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1050	if $some_error_condition;
		1051
		1052	=item AnyEvent::log $level, $msg[, @args]
		1053
		1054	Log the given C<$msg> at the given C<$level>.
		1055
		1056	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1057	to see whether the message will be logged. If the test succeeds it will
		1058	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1059	the L<AnyEvent::Log> documentation for details.
		1060
		1061	If the test fails it will simply return. Right now this happens when a
		1062	numerical loglevel is used and it is larger than the level specified via
		1063	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1064
		1065	If you want to sprinkle loads of logging calls around your code, consider
		1066	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1067	which can reduce typing, codesize and can reduce the logging overhead
		1068	enourmously.
780		1069
781	=back	1070	=back
782		1071
783	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
784		1073
…		…
795	because it will stall the whole program, and the whole point of using	1084	because it will stall the whole program, and the whole point of using
796	events is to stay interactive.	1085	events is to stay interactive.
797		1086
798	It is fine, however, to call C<< ->recv >> when the user of your module	1087	It is fine, however, to call C<< ->recv >> when the user of your module
799	requests it (i.e. if you create a http request object ad have a method	1088	requests it (i.e. if you create a http request object ad have a method
800	called C<results> that returns the results, it should call C<< ->recv >>	1089	called C<results> that returns the results, it may call C<< ->recv >>
801	freely, as the user of your module knows what she is doing. always).	1090	freely, as the user of your module knows what she is doing. Always).
802		1091
803	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
804		1093
805	There will always be a single main program - the only place that should	1094	There will always be a single main program - the only place that should
806	dictate which event model to use.	1095	dictate which event model to use.
807		1096
808	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1097	If the program is not event-based, it need not do anything special, even
809	do anything special (it does not need to be event-based) and let AnyEvent	1098	when it depends on a module that uses an AnyEvent. If the program itself
810	decide which implementation to chose if some module relies on it.	1099	uses AnyEvent, but does not care which event loop is used, all it needs
		1100	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1101	available loop implementation.
811		1102
812	If the main program relies on a specific event model - for example, in	1103	If the main program relies on a specific event model - for example, in
813	Gtk2 programs you have to rely on the Glib module - you should load the	1104	Gtk2 programs you have to rely on the Glib module - you should load the
814	event module before loading AnyEvent or any module that uses it: generally	1105	event module before loading AnyEvent or any module that uses it: generally
815	speaking, you should load it as early as possible. The reason is that	1106	speaking, you should load it as early as possible. The reason is that
816	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
817	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
818	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
819		1110
820	You can chose to use a pure-perl implementation by loading the	1111	You can chose to use a pure-perl implementation by loading the
821	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
822	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
823		1114
824	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
825		1116
826	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
839		1130
840		1131
841	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
842		1133
843	The following is a non-exhaustive list of additional modules that use	1134	The following is a non-exhaustive list of additional modules that use
844	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1135	AnyEvent as a client and can therefore be mixed easily with other
845	in the same program. Some of the modules come with AnyEvent, some are	1136	AnyEvent modules and other event loops in the same program. Some of the
846	available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
847		1141
848	=over 4	1142	=over 4
849		1143
850	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
851		1145
852	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
853	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
854		1148
855	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
856		1150
857	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
858	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
860		1154
861	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
862		1156
863	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
864	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
865	non-blocking SSL/TLS.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
866		1160
867	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
868		1162
869	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
870		1164
		1165	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1166
		1167	Implement event-based interfaces to the protocols of the same name (for
		1168	the curious, IGS is the International Go Server and FCP is the Freenet
		1169	Client Protocol).
		1170
871	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
872		1172
873	A simple-to-use HTTP library that is capable of making a lot of concurrent	1173	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
874	HTTP requests.	1174	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1175	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1176	file I/O, and much more.
		1177
		1178	=item L<AnyEvent::Filesys::Notify>
		1179
		1180	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1181	path changes (e.g. "watch this directory for new files", "watch this
		1182	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1183	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1184	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1185	fall back to blocking scans at regular intervals transparently on other
		1186	platforms, so it's about as portable as it gets.
		1187
		1188	(I haven't used it myself, but I haven't heard anybody complaining about
		1189	it yet).
		1190
		1191	=item L<AnyEvent::DBI>
		1192
		1193	Executes L<DBI> requests asynchronously in a proxy process for you,
		1194	notifying you in an event-based way when the operation is finished.
875		1195
876	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
877		1197
878	Provides a simple web application server framework.	1198	A simple embedded webserver.
879		1199
880	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
881		1201
882	The fastest ping in the west.	1202	The fastest ping in the west.
883		1203
884	=item L<AnyEvent::DBI>
885
886	Executes L<DBI> requests asynchronously in a proxy process.
887
888	=item L<AnyEvent::AIO>
889
890	Truly asynchronous I/O, should be in the toolbox of every event
891	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
892	together.
893
894	=item L<AnyEvent::BDB>
895
896	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
897	L<BDB> and AnyEvent together.
898
899	=item L<AnyEvent::GPSD>
900
901	A non-blocking interface to gpsd, a daemon delivering GPS information.
902
903	=item L<AnyEvent::IGS>
904
905	A non-blocking interface to the Internet Go Server protocol (used by
906	L<App::IGS>).
907
908	=item L<AnyEvent::IRC>
909
910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
911
912	=item L<Net::XMPP2>
913
914	AnyEvent based XMPP (Jabber protocol) module family.
915
916	=item L<Net::FCP>
917
918	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
919	of AnyEvent.
920
921	=item L<Event::ExecFlow>
922
923	High level API for event-based execution flow control.
924
925	=item L<Coro>	1204	=item L<Coro>
926		1205
927	Has special support for AnyEvent via L<Coro::AnyEvent>.	1206	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1207	to simply invert the flow control - don't call us, we will call you:
928		1208
929	=item L<IO::Lambda>	1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
930		1212
931	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	1213	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1214	my $line = <STDIN>; # works for ttys
		1215
		1216	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1217	my ($body, $hdr) = Coro::rouse_wait;
		1218	};
932		1219
933	=back	1220	=back
934		1221
935	=cut	1222	=cut
936		1223
937	package AnyEvent;	1224	package AnyEvent;
938		1225
939	no warnings;	1226	# basically a tuned-down version of common::sense
940	use strict qw(vars subs);	1227	sub common_sense {
		1228	# from common:.sense 3.4
		1229	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1230	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1231	$^H |= 0x00000600;
		1232	}
941		1233
		1234	BEGIN { AnyEvent::common_sense }
		1235
942	use Carp;	1236	use Carp ();
943		1237
944	our $VERSION = 4.42;	1238	our $VERSION = '6.13';
945	our $MODEL;	1239	our $MODEL;
946
947	our $AUTOLOAD;
948	our @ISA;	1240	our @ISA;
949
950	our @REGISTRY;	1241	our @REGISTRY;
951		1242	our $VERBOSE;
952	our $WIN32;	1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
953		1245
954	BEGIN {	1246	BEGIN {
955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1247	require "AnyEvent/constants.pl";
		1248
956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
957		1250
958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
959	if ${^TAINT};	1252	if ${^TAINT};
960	}
961		1253
962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
963		1256
964	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
965		1259
966	{	1260	# $ENV{PERL_ANYEVENT_xxx} now valid
		1261
		1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1263
967	my $idx;	1264	my $idx;
968	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
969	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
970	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
971	}	1268	}
972		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($cb) = @_;
		1274
		1275	push @post_detect, $cb;
		1276
		1277	defined wantarray
		1278	? bless \$cb, "AnyEvent::Util::postdetect"
		1279	: ()
		1280	}
		1281
		1282	sub AnyEvent::Util::postdetect::DESTROY {
		1283	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1284	}
		1285
		1286	our $POSTPONE_W;
		1287	our @POSTPONE;
		1288
		1289	sub _postpone_exec {
		1290	undef $POSTPONE_W;
		1291
		1292	&{ shift @POSTPONE }
		1293	while @POSTPONE;
		1294	}
		1295
		1296	sub postpone(&) {
		1297	push @POSTPONE, shift;
		1298
		1299	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1300
		1301	()
		1302	}
		1303
		1304	sub log($$;@) {
		1305	# only load the big bloated module when we actually are about to log something
		1306	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1307	local ($!, $@);
		1308	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1309	# AnyEvent::Log overwrites this function
		1310	goto &log;
		1311	}
		1312
		1313	0 # not logged
		1314	}
		1315
		1316	sub _logger($;$) {
		1317	my ($level, $renabled) = @_;
		1318
		1319	$$renabled = $level <= $VERBOSE;
		1320
		1321	my $logger = [(caller)[0], $level, $renabled];
		1322
		1323	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1324
		1325	# return unless defined wantarray;
		1326	#
		1327	# require AnyEvent::Util;
		1328	# my $guard = AnyEvent::Util::guard (sub {
		1329	# # "clean up"
		1330	# delete $LOGGER{$logger+0};
		1331	# });
		1332	#
		1333	# sub {
		1334	# return 0 unless $$renabled;
		1335	#
		1336	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1337	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1338	# package AnyEvent::Log;
		1339	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1340	# }
		1341	}
		1342
		1343	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1344	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1345	}
		1346
973	my @models = (	1347	our @models = (
974	[EV:: => AnyEvent::Impl::EV::],	1348	[EV:: => AnyEvent::Impl::EV::],
975	[Event:: => AnyEvent::Impl::Event::],
976	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1349	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
977	# everything below here will not be autoprobed	1350	# everything below here will not (normally) be autoprobed
978	# as the pureperl backend should work everywhere	1351	# as the pure perl backend should work everywhere
979	# and is usually faster	1352	# and is usually faster
		1353	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
		1354	[Event:: => AnyEvent::Impl::Event::], # slow, stable
		1355	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1356	# everything below here should not be autoloaded
		1357	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
980	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1358	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
981	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1359	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1360	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
985	[Wx:: => AnyEvent::Impl::POE::],	1361	[Wx:: => AnyEvent::Impl::POE::],
986	[Prima:: => AnyEvent::Impl::POE::],	1362	[Prima:: => AnyEvent::Impl::POE::],
987	# IO::Async is just too broken - we would need workaorunds for its	1363	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
988	# byzantine signal and broken child handling, among others.	1364	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
989	# IO::Async is rather hard to detect, as it doesn't have any	1365	[FLTK:: => AnyEvent::Impl::FLTK::],
990	# obvious default class.
991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
994	);	1366	);
995		1367
996	our %method = map +($_ => 1),	1368	our @isa_hook;
		1369
		1370	sub _isa_set {
		1371	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1372
		1373	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1374	for 1 .. $#pkg;
		1375
		1376	grep $_ && $_->[1], @isa_hook
		1377	and AE::_reset ();
		1378	}
		1379
		1380	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1381	sub _isa_hook($$;$) {
		1382	my ($i, $pkg, $reset_ae) = @_;
		1383
		1384	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1385
		1386	_isa_set;
		1387	}
		1388
		1389	# all autoloaded methods reserve the complete glob, not just the method slot.
		1390	# due to bugs in perls method cache implementation.
997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1391	our @methods = qw(io timer time now now_update signal child idle condvar);
998		1392
999	our @post_detect;
1000
1001	sub post_detect(&) {	1393	sub detect() {
1002	my ($cb) = @_;	1394	return $MODEL if $MODEL; # some programs keep references to detect
1003		1395
1004	if ($MODEL) {	1396	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1005	$cb->();	1397	# the author knows about the problems and what it does to AnyEvent as a whole
		1398	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1399	# anyway.
		1400	AnyEvent::log fatal => "AnyEvent: IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1401	. "design, abuses internals and breaks AnyEvent - will not continue."
		1402	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1006		1403
1007	1	1404	local $!; # for good measure
		1405	local $SIG{__DIE__}; # we use eval
		1406
		1407	# free some memory
		1408	*detect = sub () { $MODEL };
		1409	# undef &func doesn't correctly update the method cache. grmbl.
		1410	# so we delete the whole glob. grmbl.
		1411	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1412	# a glob with an active sub. hrm. i hope it works, but perl is
		1413	# usually buggy in this department. sigh.
		1414	delete @{"AnyEvent::"}{@methods};
		1415	undef @methods;
		1416
		1417	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1418	my $model = $1;
		1419	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1420	if (eval "require $model") {
		1421	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1422	$MODEL = $model;
1008	} else {	1423	} else {
1009	push @post_detect, $cb;	1424	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1010		1425	}
1011	defined wantarray
1012	? bless \$cb, "AnyEvent::Util::postdetect"
1013	: ()
1014	}	1426	}
1015	}
1016		1427
1017	sub AnyEvent::Util::postdetect::DESTROY {	1428	# check for already loaded models
1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1019	}
1020
1021	sub detect() {
1022	unless ($MODEL) {	1429	unless ($MODEL) {
1023	no strict 'refs';	1430	for (@REGISTRY, @models) {
1024	local $SIG{__DIE__};	1431	my ($package, $model) = @$_;
1025		1432	if (${"$package\::VERSION"} > 0) {
1026	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1027	my $model = "AnyEvent::Impl::$1";
1028	if (eval "require $model") {	1433	if (eval "require $model") {
		1434	AnyEvent::log 7 => "autodetected model '$model', using it.";
1029	$MODEL = $model;	1435	$MODEL = $model;
1030	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1436	last;
1031	} else {	1437	} else {
1032	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1438	AnyEvent::log 8 => "detected event loop $package, but cannot load '$model', skipping: $@";
		1439	}
1033	}	1440	}
1034	}	1441	}
1035		1442
1036	# check for already loaded models
1037	unless ($MODEL) {	1443	unless ($MODEL) {
		1444	# try to autoload a model
1038	for (@REGISTRY, @models) {	1445	for (@REGISTRY, @models) {
1039	my ($package, $model) = @$_;	1446	my ($package, $model) = @$_;
		1447	if (
		1448	eval "require $package"
1040	if (${"$package\::VERSION"} > 0) {	1449	and ${"$package\::VERSION"} > 0
1041	if (eval "require $model") {	1450	and eval "require $model"
		1451	) {
		1452	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1042	$MODEL = $model;	1453	$MODEL = $model;
1043	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1044	last;	1454	last;
1045	}
1046	}	1455	}
1047	}	1456	}
1048		1457
1049	unless ($MODEL) {
1050	# try to load a model
1051
1052	for (@REGISTRY, @models) {
1053	my ($package, $model) = @$_;
1054	if (eval "require $package"
1055	and ${"$package\::VERSION"} > 0
1056	and eval "require $model") {
1057	$MODEL = $model;
1058	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1059	last;
1060	}
1061	}
1062
1063	$MODEL	1458	$MODEL
1064	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1459	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1065	}
1066	}	1460	}
1067
1068	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1069
1070	unshift @ISA, $MODEL;
1071
1072	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1073
1074	(shift @post_detect)->() while @post_detect;
1075	}	1461	}
1076		1462
		1463	# free memory only needed for probing
		1464	undef @models;
		1465	undef @REGISTRY;
		1466
		1467	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1468
		1469	# now nuke some methods that are overridden by the backend.
		1470	# SUPER usage is not allowed in these.
		1471	for (qw(time signal child idle)) {
		1472	undef &{"AnyEvent::Base::$_"}
		1473	if defined &{"$MODEL\::$_"};
		1474	}
		1475
		1476	_isa_set;
		1477
		1478	# we're officially open!
		1479
		1480	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1481	require AnyEvent::Strict;
		1482	}
		1483
		1484	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1485	require AnyEvent::Debug;
		1486	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1487	}
		1488
		1489	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1490	require AnyEvent::Socket;
		1491	require AnyEvent::Debug;
		1492
		1493	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1494	$shell =~ s/\$\$/$$/g;
		1495
		1496	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1497	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1498	}
		1499
		1500	# now the anyevent environment is set up as the user told us to, so
		1501	# call the actual user code - post detects
		1502
		1503	(shift @post_detect)->() while @post_detect;
		1504	undef @post_detect;
		1505
		1506	*post_detect = sub(&) {
		1507	shift->();
		1508
		1509	undef
		1510	};
		1511
1077	$MODEL	1512	$MODEL
1078	}	1513	}
1079		1514
1080	sub AUTOLOAD {	1515	for my $name (@methods) {
1081	(my $func = $AUTOLOAD) =~ s/.*://;	1516	*$name = sub {
1082		1517	detect;
1083	$method{$func}	1518	# we use goto because
1084	or croak "$func: not a valid method for AnyEvent objects";	1519	# a) it makes the thunk more transparent
1085		1520	# b) it allows us to delete the thunk later
1086	detect unless $MODEL;	1521	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1087		1522	};
1088	my $class = shift;
1089	$class->$func (@_);
1090	}	1523	}
1091		1524
1092	# utility function to dup a filehandle. this is used by many backends	1525	# utility function to dup a filehandle. this is used by many backends
1093	# to support binding more than one watcher per filehandle (they usually	1526	# to support binding more than one watcher per filehandle (they usually
1094	# allow only one watcher per fd, so we dup it to get a different one).	1527	# allow only one watcher per fd, so we dup it to get a different one).
1095	sub _dupfh($$;$$) {	1528	sub _dupfh($$;$$) {
1096	my ($poll, $fh, $r, $w) = @_;	1529	my ($poll, $fh, $r, $w) = @_;
1097		1530
1098	# cygwin requires the fh mode to be matching, unix doesn't	1531	# cygwin requires the fh mode to be matching, unix doesn't
1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1532	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1100	: $poll eq "w" ? ($w, ">")
1101	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1102		1533
1103	open my $fh2, "$mode&" . fileno $fh	1534	open my $fh2, $mode, $fh
1104	or die "cannot dup() filehandle: $!,";	1535	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1105		1536
1106	# we assume CLOEXEC is already set by perl in all important cases	1537	# we assume CLOEXEC is already set by perl in all important cases
1107		1538
1108	($fh2, $rw)	1539	($fh2, $rw)
1109	}	1540	}
1110		1541
		1542	=head1 SIMPLIFIED AE API
		1543
		1544	Starting with version 5.0, AnyEvent officially supports a second, much
		1545	simpler, API that is designed to reduce the calling, typing and memory
		1546	overhead by using function call syntax and a fixed number of parameters.
		1547
		1548	See the L<AE> manpage for details.
		1549
		1550	=cut
		1551
		1552	package AE;
		1553
		1554	our $VERSION = $AnyEvent::VERSION;
		1555
		1556	sub _reset() {
		1557	eval q{
		1558	# fall back to the main API by default - backends and AnyEvent::Base
		1559	# implementations can overwrite these.
		1560
		1561	sub io($$$) {
		1562	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1563	}
		1564
		1565	sub timer($$$) {
		1566	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1567	}
		1568
		1569	sub signal($$) {
		1570	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1571	}
		1572
		1573	sub child($$) {
		1574	AnyEvent->child (pid => $_[0], cb => $_[1])
		1575	}
		1576
		1577	sub idle($) {
		1578	AnyEvent->idle (cb => $_[0]);
		1579	}
		1580
		1581	sub cv(;&) {
		1582	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1583	}
		1584
		1585	sub now() {
		1586	AnyEvent->now
		1587	}
		1588
		1589	sub now_update() {
		1590	AnyEvent->now_update
		1591	}
		1592
		1593	sub time() {
		1594	AnyEvent->time
		1595	}
		1596
		1597	*postpone = \&AnyEvent::postpone;
		1598	*log = \&AnyEvent::log;
		1599	};
		1600	die if $@;
		1601	}
		1602
		1603	BEGIN { _reset }
		1604
1111	package AnyEvent::Base;	1605	package AnyEvent::Base;
1112		1606
1113	# default implementations for many methods	1607	# default implementations for many methods
1114		1608
1115	BEGIN {	1609	sub time {
		1610	eval q{ # poor man's autoloading {}
		1611	# probe for availability of Time::HiRes
1116	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1612	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1613	*time = sub { Time::HiRes::time () };
1117	*_time = \&Time::HiRes::time;	1614	*AE::time = \& Time::HiRes::time ;
		1615	*now = \&time;
		1616	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1118	# if (eval "use POSIX (); (POSIX::times())...	1617	# if (eval "use POSIX (); (POSIX::times())...
1119	} else {	1618	} else {
1120	*_time = sub { time }; # epic fail	1619	*time = sub { CORE::time };
		1620	*AE::time = sub (){ CORE::time };
		1621	*now = \&time;
		1622	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1623	}
		1624	};
		1625	die if $@;
		1626
		1627	&time
		1628	}
		1629
		1630	*now = \&time;
		1631	sub now_update { }
		1632
		1633	sub _poll {
		1634	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1635	}
		1636
		1637	# default implementation for ->condvar
		1638	# in fact, the default should not be overwritten
		1639
		1640	sub condvar {
		1641	eval q{ # poor man's autoloading {}
		1642	*condvar = sub {
		1643	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1644	};
		1645
		1646	*AE::cv = sub (;&) {
		1647	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1648	};
		1649	};
		1650	die if $@;
		1651
		1652	&condvar
		1653	}
		1654
		1655	# default implementation for ->signal
		1656
		1657	our $HAVE_ASYNC_INTERRUPT;
		1658
		1659	sub _have_async_interrupt() {
		1660	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1661	&& eval "use Async::Interrupt 1.02 (); 1")
		1662	unless defined $HAVE_ASYNC_INTERRUPT;
		1663
		1664	$HAVE_ASYNC_INTERRUPT
		1665	}
		1666
		1667	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1668	our (%SIG_ASY, %SIG_ASY_W);
		1669	our ($SIG_COUNT, $SIG_TW);
		1670
		1671	# install a dummy wakeup watcher to reduce signal catching latency
		1672	# used by Impls
		1673	sub _sig_add() {
		1674	unless ($SIG_COUNT++) {
		1675	# try to align timer on a full-second boundary, if possible
		1676	my $NOW = AE::now;
		1677
		1678	$SIG_TW = AE::timer
		1679	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1680	$MAX_SIGNAL_LATENCY,
		1681	sub { } # just for the PERL_ASYNC_CHECK
		1682	;
1121	}	1683	}
1122	}	1684	}
1123		1685
1124	sub time { _time }	1686	sub _sig_del {
1125	sub now { _time }	1687	undef $SIG_TW
1126	sub now_update { }	1688	unless --$SIG_COUNT;
1127
1128	# default implementation for ->condvar
1129
1130	sub condvar {
1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1132	}	1689	}
1133		1690
1134	# default implementation for ->signal	1691	our $_sig_name_init; $_sig_name_init = sub {
		1692	eval q{ # poor man's autoloading {}
		1693	undef $_sig_name_init;
1135		1694
1136	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1695	if (_have_async_interrupt) {
		1696	*sig2num = \&Async::Interrupt::sig2num;
		1697	*sig2name = \&Async::Interrupt::sig2name;
		1698	} else {
		1699	require Config;
1137		1700
1138	sub _signal_exec {	1701	my %signame2num;
1139	sysread $SIGPIPE_R, my $dummy, 4;	1702	@signame2num{ split ' ', $Config::Config{sig_name} }
		1703	= split ' ', $Config::Config{sig_num};
1140		1704
1141	while (%SIG_EV) {	1705	my @signum2name;
1142	for (keys %SIG_EV) {	1706	@signum2name[values %signame2num] = keys %signame2num;
1143	delete $SIG_EV{$_};	1707
1144	$_->() for values %{ $SIG_CB{$_} || {} };	1708	*sig2num = sub($) {
		1709	$_[0] > 0 ? shift : $signame2num{+shift}
		1710	};
		1711	*sig2name = sub ($) {
		1712	$_[0] > 0 ? $signum2name[+shift] : shift
		1713	};
1145	}	1714	}
1146	}	1715	};
1147	}	1716	die if $@;
		1717	};
		1718
		1719	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1720	sub sig2name($) { &$_sig_name_init; &sig2name }
1148		1721
1149	sub signal {	1722	sub signal {
1150	my (undef, %arg) = @_;	1723	eval q{ # poor man's autoloading {}
		1724	# probe for availability of Async::Interrupt
		1725	if (_have_async_interrupt) {
		1726	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1151		1727
1152	unless ($SIGPIPE_R) {	1728	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1153	require Fcntl;	1729	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1154		1730
1155	if (AnyEvent::WIN32) {
1156	require AnyEvent::Util;
1157
1158	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1159	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1160	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1161	} else {	1731	} else {
		1732	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1733
		1734	if (AnyEvent::WIN32) {
		1735	require AnyEvent::Util;
		1736
		1737	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1738	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1739	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1740	} else {
1162	pipe $SIGPIPE_R, $SIGPIPE_W;	1741	pipe $SIGPIPE_R, $SIGPIPE_W;
1163	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1742	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1164	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1743	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1165		1744
1166	# not strictly required, as $^F is normally 2, but let's make sure...	1745	# not strictly required, as $^F is normally 2, but let's make sure...
1167	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1746	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1168	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1747	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1748	}
		1749
		1750	$SIGPIPE_R
		1751	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1752
		1753	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1169	}	1754	}
1170		1755
1171	$SIGPIPE_R	1756	*signal = $HAVE_ASYNC_INTERRUPT
1172	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1757	? sub {
		1758	my (undef, %arg) = @_;
1173		1759
1174	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1760	# async::interrupt
1175	}
1176
1177	my $signal = uc $arg{signal}	1761	my $signal = sig2num $arg{signal};
1178	or Carp::croak "required option 'signal' is missing";
1179
1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1762	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1763
		1764	$SIG_ASY{$signal} ||= new Async::Interrupt
		1765	cb => sub { undef $SIG_EV{$signal} },
		1766	signal => $signal,
		1767	pipe => [$SIGPIPE_R->filenos],
		1768	pipe_autodrain => 0,
		1769	;
		1770
		1771	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1772	}
		1773	: sub {
		1774	my (undef, %arg) = @_;
		1775
		1776	# pure perl
		1777	my $signal = sig2name $arg{signal};
		1778	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1779
1181	$SIG{$signal} ||= sub {	1780	$SIG{$signal} ||= sub {
1182	local $!;	1781	local $!;
1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1782	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1184	undef $SIG_EV{$signal};	1783	undef $SIG_EV{$signal};
		1784	};
		1785
		1786	# can't do signal processing without introducing races in pure perl,
		1787	# so limit the signal latency.
		1788	_sig_add;
		1789
		1790	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1791	}
		1792	;
		1793
		1794	*AnyEvent::Base::signal::DESTROY = sub {
		1795	my ($signal, $cb) = @{$_[0]};
		1796
		1797	_sig_del;
		1798
		1799	delete $SIG_CB{$signal}{$cb};
		1800
		1801	$HAVE_ASYNC_INTERRUPT
		1802	? delete $SIG_ASY{$signal}
		1803	: # delete doesn't work with older perls - they then
		1804	# print weird messages, or just unconditionally exit
		1805	# instead of getting the default action.
		1806	undef $SIG{$signal}
		1807	unless keys %{ $SIG_CB{$signal} };
		1808	};
		1809
		1810	*_signal_exec = sub {
		1811	$HAVE_ASYNC_INTERRUPT
		1812	? $SIGPIPE_R->drain
		1813	: sysread $SIGPIPE_R, (my $dummy), 9;
		1814
		1815	while (%SIG_EV) {
		1816	for (keys %SIG_EV) {
		1817	delete $SIG_EV{$_};
		1818	&$_ for values %{ $SIG_CB{$_} || {} };
		1819	}
		1820	}
		1821	};
1185	};	1822	};
		1823	die if $@;
1186		1824
1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1825	&signal
1188	}
1189
1190	sub AnyEvent::Base::signal::DESTROY {
1191	my ($signal, $cb) = @{$_[0]};
1192
1193	delete $SIG_CB{$signal}{$cb};
1194
1195	# delete doesn't work with older perls - they then
1196	# print weird messages, or just unconditionally exit
1197	# instead of getting the default action.
1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1199	}	1826	}
1200		1827
1201	# default implementation for ->child	1828	# default implementation for ->child
1202		1829
1203	our %PID_CB;	1830	our %PID_CB;
1204	our $CHLD_W;	1831	our $CHLD_W;
1205	our $CHLD_DELAY_W;	1832	our $CHLD_DELAY_W;
1206	our $WNOHANG;
1207		1833
1208	sub _sigchld {	1834	# used by many Impl's
1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1835	sub _emit_childstatus($$) {
		1836	my (undef, $rpid, $rstatus) = @_;
		1837
		1838	$_->($rpid, $rstatus)
1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1839	for values %{ $PID_CB{$rpid} || {} },
1211	(values %{ $PID_CB{0} || {} });	1840	values %{ $PID_CB{0} || {} };
1212	}
1213	}	1841	}
1214		1842
1215	sub child {	1843	sub child {
		1844	eval q{ # poor man's autoloading {}
		1845	*_sigchld = sub {
		1846	my $pid;
		1847
		1848	AnyEvent->_emit_childstatus ($pid, $?)
		1849	while ($pid = waitpid -1, WNOHANG) > 0;
		1850	};
		1851
		1852	*child = sub {
1216	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1217		1854
1218	defined (my $pid = $arg{pid} + 0)	1855	my $pid = $arg{pid};
1219	or Carp::croak "required option 'pid' is missing";	1856	my $cb = $arg{cb};
1220		1857
1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1858	$PID_CB{$pid}{$cb+0} = $cb;
1222		1859
1223	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1224
1225	unless ($CHLD_W) {	1860	unless ($CHLD_W) {
1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1861	$CHLD_W = AE::signal CHLD => \&_sigchld;
1227	# child could be a zombie already, so make at least one round	1862	# child could be a zombie already, so make at least one round
1228	&_sigchld;	1863	&_sigchld;
1229	}	1864	}
1230		1865
1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1866	bless [$pid, $cb+0], "AnyEvent::Base::child"
1232	}	1867	};
1233		1868
1234	sub AnyEvent::Base::child::DESTROY {	1869	*AnyEvent::Base::child::DESTROY = sub {
1235	my ($pid, $cb) = @{$_[0]};	1870	my ($pid, $icb) = @{$_[0]};
1236		1871
1237	delete $PID_CB{$pid}{$cb};	1872	delete $PID_CB{$pid}{$icb};
1238	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1873	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1239		1874
1240	undef $CHLD_W unless keys %PID_CB;	1875	undef $CHLD_W unless keys %PID_CB;
		1876	};
		1877	};
		1878	die if $@;
		1879
		1880	&child
1241	}	1881	}
1242		1882
1243	# idle emulation is done by simply using a timer, regardless	1883	# idle emulation is done by simply using a timer, regardless
1244	# of whether the process is idle or not, and not letting	1884	# of whether the process is idle or not, and not letting
1245	# the callback use more than 50% of the time.	1885	# the callback use more than 50% of the time.
1246	sub idle {	1886	sub idle {
		1887	eval q{ # poor man's autoloading {}
		1888	*idle = sub {
1247	my (undef, %arg) = @_;	1889	my (undef, %arg) = @_;
1248		1890
1249	my ($cb, $w, $rcb) = $arg{cb};	1891	my ($cb, $w, $rcb) = $arg{cb};
1250		1892
1251	$rcb = sub {	1893	$rcb = sub {
1252	if ($cb) {	1894	if ($cb) {
1253	$w = _time;	1895	$w = AE::time;
1254	&$cb;	1896	&$cb;
1255	$w = _time - $w;	1897	$w = AE::time - $w;
1256		1898
1257	# never use more then 50% of the time for the idle watcher,	1899	# never use more then 50% of the time for the idle watcher,
1258	# within some limits	1900	# within some limits
1259	$w = 0.0001 if $w < 0.0001;	1901	$w = 0.0001 if $w < 0.0001;
1260	$w = 5 if $w > 5;	1902	$w = 5 if $w > 5;
1261		1903
1262	$w = AnyEvent->timer (after => $w, cb => $rcb);	1904	$w = AE::timer $w, 0, $rcb;
1263	} else {	1905	} else {
1264	# clean up...	1906	# clean up...
1265	undef $w;	1907	undef $w;
1266	undef $rcb;	1908	undef $rcb;
		1909	}
		1910	};
		1911
		1912	$w = AE::timer 0.05, 0, $rcb;
		1913
		1914	bless \\$cb, "AnyEvent::Base::idle"
1267	}	1915	};
		1916
		1917	*AnyEvent::Base::idle::DESTROY = sub {
		1918	undef $${$_[0]};
		1919	};
1268	};	1920	};
		1921	die if $@;
1269		1922
1270	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1923	&idle
1271
1272	bless \\$cb, "AnyEvent::Base::idle"
1273	}
1274
1275	sub AnyEvent::Base::idle::DESTROY {
1276	undef $${$_[0]};
1277	}	1924	}
1278		1925
1279	package AnyEvent::CondVar;	1926	package AnyEvent::CondVar;
1280		1927
1281	our @ISA = AnyEvent::CondVar::Base::;	1928	our @ISA = AnyEvent::CondVar::Base::;
1282		1929
		1930	# only to be used for subclassing
		1931	sub new {
		1932	my $class = shift;
		1933	bless AnyEvent->condvar (@_), $class
		1934	}
		1935
1283	package AnyEvent::CondVar::Base;	1936	package AnyEvent::CondVar::Base;
1284		1937
1285	use overload	1938	#use overload
1286	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1939	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1287	fallback => 1;	1940	# fallback => 1;
		1941
		1942	# save 300+ kilobytes by dirtily hardcoding overloading
		1943	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1944	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1945	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1946	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1947
		1948	our $WAITING;
1288		1949
1289	sub _send {	1950	sub _send {
1290	# nop	1951	# nop
		1952	}
		1953
		1954	sub _wait {
		1955	AnyEvent->_poll until $_[0]{_ae_sent};
1291	}	1956	}
1292		1957
1293	sub send {	1958	sub send {
1294	my $cv = shift;	1959	my $cv = shift;
1295	$cv->{_ae_sent} = [@_];	1960	$cv->{_ae_sent} = [@_];
…		…
1304		1969
1305	sub ready {	1970	sub ready {
1306	$_[0]{_ae_sent}	1971	$_[0]{_ae_sent}
1307	}	1972	}
1308		1973
1309	sub _wait {
1310	AnyEvent->one_event while !$_[0]{_ae_sent};
1311	}
1312
1313	sub recv {	1974	sub recv {
		1975	unless ($_[0]{_ae_sent}) {
		1976	$WAITING
		1977	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1978
		1979	local $WAITING = 1;
1314	$_[0]->_wait;	1980	$_[0]->_wait;
		1981	}
1315		1982
1316	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1983	$_[0]{_ae_croak}
1317	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1984	and Carp::croak $_[0]{_ae_croak};
		1985
		1986	wantarray
		1987	? @{ $_[0]{_ae_sent} }
		1988	: $_[0]{_ae_sent}[0]
1318	}	1989	}
1319		1990
1320	sub cb {	1991	sub cb {
1321	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1992	my $cv = shift;
		1993
		1994	@_
		1995	and $cv->{_ae_cb} = shift
		1996	and $cv->{_ae_sent}
		1997	and (delete $cv->{_ae_cb})->($cv);
		1998
1322	$_[0]{_ae_cb}	1999	$cv->{_ae_cb}
1323	}	2000	}
1324		2001
1325	sub begin {	2002	sub begin {
1326	++$_[0]{_ae_counter};	2003	++$_[0]{_ae_counter};
1327	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2004	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1332	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2009	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1333	}	2010	}
1334		2011
1335	# undocumented/compatibility with pre-3.4	2012	# undocumented/compatibility with pre-3.4
1336	*broadcast = \&send;	2013	*broadcast = \&send;
1337	*wait = \&_wait;	2014	*wait = \&recv;
1338		2015
1339	=head1 ERROR AND EXCEPTION HANDLING	2016	=head1 ERROR AND EXCEPTION HANDLING
1340		2017
1341	In general, AnyEvent does not do any error handling - it relies on the	2018	In general, AnyEvent does not do any error handling - it relies on the
1342	caller to do that if required. The L<AnyEvent::Strict> module (see also	2019	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1354	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2031	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1355	so on.	2032	so on.
1356		2033
1357	=head1 ENVIRONMENT VARIABLES	2034	=head1 ENVIRONMENT VARIABLES
1358		2035
1359	The following environment variables are used by this module or its	2036	AnyEvent supports a number of environment variables that tune the
1360	submodules.	2037	runtime behaviour. They are usually evaluated when AnyEvent is
		2038	loaded, initialised, or a submodule that uses them is loaded. Many of
		2039	them also cause AnyEvent to load additional modules - for example,
		2040	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2041	loaded.
1361		2042
1362	Note that AnyEvent will remove I<all> environment variables starting with	2043	All the environment variables documented here start with
1363	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2044	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1364	enabled.	2045	namespace. Other modules are encouraged (but by no means required) to use
		2046	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2047	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2048	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2049	variables starting with C<AE_>, see below).
		2050
		2051	All variables can also be set via the C<AE_> prefix, that is, instead
		2052	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2053	case there is a clash btween anyevent and another program that uses
		2054	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2055	variable to the empty string, as those variables take precedence.
		2056
		2057	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2058	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2059	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2060	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2061	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2062	is set).
		2063
		2064	The exact algorithm is currently:
		2065
		2066	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2067	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2068	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2069
		2070	This ensures that child processes will not see the C<AE_> variables.
		2071
		2072	The following environment variables are currently known to AnyEvent:
1365		2073
1366	=over 4	2074	=over 4
1367		2075
1368	=item C<PERL_ANYEVENT_VERBOSE>	2076	=item C<PERL_ANYEVENT_VERBOSE>
1369		2077
1370	By default, AnyEvent will be completely silent except in fatal	2078	By default, AnyEvent will only log messages with loglevel C<3>
1371	conditions. You can set this environment variable to make AnyEvent more	2079	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2080	environment variable to a numerical loglevel to make AnyEvent more (or
1372	talkative.	2081	less) talkative.
1373		2082
		2083	If you want to do more than just set the global logging level
		2084	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2085	complex specifications.
		2086
		2087	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2088	the default logging settings.
		2089
1374	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2090	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1375	conditions, such as not being able to load the event model specified by	2091	unexpected conditions, such as not being able to load the event model
1376	C<PERL_ANYEVENT_MODEL>.	2092	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2093	exception - this is the minimum recommended level.
1377		2094
1378	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2095	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1379	model it chooses.	2096	chooses.
		2097
		2098	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2099	which optional modules it loads and how it implements certain features.
		2100
		2101	=item C<PERL_ANYEVENT_LOG>
		2102
		2103	Accepts rather complex logging specifications. For example, you could log
		2104	all C<debug> messages of some module to stderr, warnings and above to
		2105	stderr, and errors and above to syslog, with:
		2106
		2107	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2108
		2109	For the rather extensive details, see L<AnyEvent::Log>.
		2110
		2111	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2112	so will take effect even before AnyEvent has initialised itself.
		2113
		2114	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2115	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2116	using the latter saves a few hundred kB of memory until the first message
		2117	is being logged.
1380		2118
1381	=item C<PERL_ANYEVENT_STRICT>	2119	=item C<PERL_ANYEVENT_STRICT>
1382		2120
1383	AnyEvent does not do much argument checking by default, as thorough	2121	AnyEvent does not do much argument checking by default, as thorough
1384	argument checking is very costly. Setting this variable to a true value	2122	argument checking is very costly. Setting this variable to a true value
…		…
1386	check the arguments passed to most method calls. If it finds any problems,	2124	check the arguments passed to most method calls. If it finds any problems,
1387	it will croak.	2125	it will croak.
1388		2126
1389	In other words, enables "strict" mode.	2127	In other words, enables "strict" mode.
1390		2128
1391	Unlike C<use strict>, it is definitely recommended to keep it off in	2129	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1392	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2130	>>, it is definitely recommended to keep it off in production. Keeping
1393	developing programs can be very useful, however.	2131	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2132	can be very useful, however.
		2133
		2134	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2135
		2136	If this env variable is nonempty, then its contents will be interpreted by
		2137	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2138	replacing every occurance of C<$$> by the process pid). The shell object
		2139	is saved in C<$AnyEvent::Debug::SHELL>.
		2140
		2141	This happens when the first watcher is created.
		2142
		2143	For example, to bind a debug shell on a unix domain socket in
		2144	F<< /tmp/debug<pid>.sock >>, you could use this:
		2145
		2146	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2147	# connect with e.g.: socat readline /tmp/debug123.sock
		2148
		2149	Or to bind to tcp port 4545 on localhost:
		2150
		2151	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2152	# connect with e.g.: telnet localhost 4545
		2153
		2154	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2155	multiuser systems.
		2156
		2157	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2158
		2159	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2160	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1394		2161
1395	=item C<PERL_ANYEVENT_MODEL>	2162	=item C<PERL_ANYEVENT_MODEL>
1396		2163
1397	This can be used to specify the event model to be used by AnyEvent, before	2164	This can be used to specify the event model to be used by AnyEvent, before
1398	auto detection and -probing kicks in. It must be a string consisting	2165	auto detection and -probing kicks in.
1399	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2166
		2167	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2168	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1400	and the resulting module name is loaded and if the load was successful,	2169	resulting module name is loaded and - if the load was successful - used as
1401	used as event model. If it fails to load AnyEvent will proceed with	2170	event model backend. If it fails to load then AnyEvent will proceed with
1402	auto detection and -probing.	2171	auto detection and -probing.
1403		2172
1404	This functionality might change in future versions.	2173	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2174	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2175	the end of a string designates a module name and quotes it appropriately).
1405		2176
1406	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2177	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1407	could start your program like this:	2178	could start your program like this:
1408		2179
1409	PERL_ANYEVENT_MODEL=Perl perl ...	2180	PERL_ANYEVENT_MODEL=Perl perl ...
1410		2181
1411	=item C<PERL_ANYEVENT_PROTOCOLS>	2182	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1427	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2198	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1428	- only support IPv4, never try to resolve or contact IPv6	2199	- only support IPv4, never try to resolve or contact IPv6
1429	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2200	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1430	IPv6, but prefer IPv6 over IPv4.	2201	IPv6, but prefer IPv6 over IPv4.
1431		2202
		2203	=item C<PERL_ANYEVENT_HOSTS>
		2204
		2205	This variable, if specified, overrides the F</etc/hosts> file used by
		2206	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2207	from that file instead.
		2208
1432	=item C<PERL_ANYEVENT_EDNS0>	2209	=item C<PERL_ANYEVENT_EDNS0>
1433		2210
1434	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2211	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1435	for DNS. This extension is generally useful to reduce DNS traffic, but	2212	DNS. This extension is generally useful to reduce DNS traffic, especially
1436	some (broken) firewalls drop such DNS packets, which is why it is off by	2213	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1437	default.	2214	packets, which is why it is off by default.
1438		2215
1439	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2216	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1440	EDNS0 in its DNS requests.	2217	EDNS0 in its DNS requests.
1441		2218
1442	=item C<PERL_ANYEVENT_MAX_FORKS>	2219	=item C<PERL_ANYEVENT_MAX_FORKS>
1443		2220
1444	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2221	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1445	will create in parallel.	2222	will create in parallel.
		2223
		2224	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2225
		2226	The default value for the C<max_outstanding> parameter for the default DNS
		2227	resolver - this is the maximum number of parallel DNS requests that are
		2228	sent to the DNS server.
		2229
		2230	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2231
		2232	Perl has inherently racy signal handling (you can basically choose between
		2233	losing signals and memory corruption) - pure perl event loops (including
		2234	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2235	have to poll regularly to avoid losing signals.
		2236
		2237	Some event loops are racy, but don't poll regularly, and some event loops
		2238	are written in C but are still racy. For those event loops, AnyEvent
		2239	installs a timer that regularly wakes up the event loop.
		2240
		2241	By default, the interval for this timer is C<10> seconds, but you can
		2242	override this delay with this environment variable (or by setting
		2243	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2244	watchers).
		2245
		2246	Lower values increase CPU (and energy) usage, higher values can introduce
		2247	long delays when reaping children or waiting for signals.
		2248
		2249	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2250	polling (with most event loops).
		2251
		2252	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2253
		2254	The absolute path to a F<resolv.conf>-style file to use instead of
		2255	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2256	resolver, or the empty string to select the default configuration.
		2257
		2258	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2259
		2260	When neither C<ca_file> nor C<ca_path> was specified during
		2261	L<AnyEvent::TLS> context creation, and either of these environment
		2262	variables are nonempty, they will be used to specify CA certificate
		2263	locations instead of a system-dependent default.
		2264
		2265	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2266
		2267	When these are set to C<1>, then the respective modules are not
		2268	loaded. Mostly good for testing AnyEvent itself.
1446		2269
1447	=back	2270	=back
1448		2271
1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2272	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1450		2273
…		…
1508	warn "read: $input\n"; # output what has been read	2331	warn "read: $input\n"; # output what has been read
1509	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2332	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1510	},	2333	},
1511	);	2334	);
1512		2335
1513	my $time_watcher; # can only be used once
1514
1515	sub new_timer {
1516	$timer = AnyEvent->timer (after => 1, cb => sub {	2336	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1517	warn "timeout\n"; # print 'timeout' about every second	2337	warn "timeout\n"; # print 'timeout' at most every second
1518	&new_timer; # and restart the time
1519	});	2338	});
1520	}
1521
1522	new_timer; # create first timer
1523		2339
1524	$cv->recv; # wait until user enters /^q/i	2340	$cv->recv; # wait until user enters /^q/i
1525		2341
1526	=head1 REAL-WORLD EXAMPLE	2342	=head1 REAL-WORLD EXAMPLE
1527		2343
…		…
1600		2416
1601	The actual code goes further and collects all errors (C<die>s, exceptions)	2417	The actual code goes further and collects all errors (C<die>s, exceptions)
1602	that occurred during request processing. The C<result> method detects	2418	that occurred during request processing. The C<result> method detects
1603	whether an exception as thrown (it is stored inside the $txn object)	2419	whether an exception as thrown (it is stored inside the $txn object)
1604	and just throws the exception, which means connection errors and other	2420	and just throws the exception, which means connection errors and other
1605	problems get reported tot he code that tries to use the result, not in a	2421	problems get reported to the code that tries to use the result, not in a
1606	random callback.	2422	random callback.
1607		2423
1608	All of this enables the following usage styles:	2424	All of this enables the following usage styles:
1609		2425
1610	1. Blocking:	2426	1. Blocking:
…		…
1658	through AnyEvent. The benchmark creates a lot of timers (with a zero	2474	through AnyEvent. The benchmark creates a lot of timers (with a zero
1659	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2475	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1660	which it is), lets them fire exactly once and destroys them again.	2476	which it is), lets them fire exactly once and destroys them again.
1661		2477
1662	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2478	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1663	distribution.	2479	distribution. It uses the L<AE> interface, which makes a real difference
		2480	for the EV and Perl backends only.
1664		2481
1665	=head3 Explanation of the columns	2482	=head3 Explanation of the columns
1666		2483
1667	I<watcher> is the number of event watchers created/destroyed. Since	2484	I<watcher> is the number of event watchers created/destroyed. Since
1668	different event models feature vastly different performances, each event	2485	different event models feature vastly different performances, each event
…		…
1689	watcher.	2506	watcher.
1690		2507
1691	=head3 Results	2508	=head3 Results
1692		2509
1693	name watchers bytes create invoke destroy comment	2510	name watchers bytes create invoke destroy comment
1694	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2511	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1695	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2512	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1696	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2513	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1697	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2514	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1698	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2515	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1699	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2516	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1700	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2517	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1701	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2518	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1702	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2519	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1703	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2520	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1704	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2521	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1705	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2522	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1706		2523
1707	=head3 Discussion	2524	=head3 Discussion
1708		2525
1709	The benchmark does I<not> measure scalability of the event loop very	2526	The benchmark does I<not> measure scalability of the event loop very
1710	well. For example, a select-based event loop (such as the pure perl one)	2527	well. For example, a select-based event loop (such as the pure perl one)
…		…
1722	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2539	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1723	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2540	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1724	cycles with POE.	2541	cycles with POE.
1725		2542
1726	C<EV> is the sole leader regarding speed and memory use, which are both	2543	C<EV> is the sole leader regarding speed and memory use, which are both
1727	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2544	maximal/minimal, respectively. When using the L<AE> API there is zero
		2545	overhead (when going through the AnyEvent API create is about 5-6 times
		2546	slower, with other times being equal, so still uses far less memory than
1728	far less memory than any other event loop and is still faster than Event	2547	any other event loop and is still faster than Event natively).
1729	natively.
1730		2548
1731	The pure perl implementation is hit in a few sweet spots (both the	2549	The pure perl implementation is hit in a few sweet spots (both the
1732	constant timeout and the use of a single fd hit optimisations in the perl	2550	constant timeout and the use of a single fd hit optimisations in the perl
1733	interpreter and the backend itself). Nevertheless this shows that it	2551	interpreter and the backend itself). Nevertheless this shows that it
1734	adds very little overhead in itself. Like any select-based backend its	2552	adds very little overhead in itself. Like any select-based backend its
…		…
1782	(even when used without AnyEvent), but most event loops have acceptable	2600	(even when used without AnyEvent), but most event loops have acceptable
1783	performance with or without AnyEvent.	2601	performance with or without AnyEvent.
1784		2602
1785	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2603	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1786	the actual event loop, only with extremely fast event loops such as EV	2604	the actual event loop, only with extremely fast event loops such as EV
1787	adds AnyEvent significant overhead.	2605	does AnyEvent add significant overhead.
1788		2606
1789	=item * You should avoid POE like the plague if you want performance or	2607	=item * You should avoid POE like the plague if you want performance or
1790	reasonable memory usage.	2608	reasonable memory usage.
1791		2609
1792	=back	2610	=back
…		…
1808	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2626	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1809	(1%) are active. This mirrors the activity of large servers with many	2627	(1%) are active. This mirrors the activity of large servers with many
1810	connections, most of which are idle at any one point in time.	2628	connections, most of which are idle at any one point in time.
1811		2629
1812	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2630	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1813	distribution.	2631	distribution. It uses the L<AE> interface, which makes a real difference
		2632	for the EV and Perl backends only.
1814		2633
1815	=head3 Explanation of the columns	2634	=head3 Explanation of the columns
1816		2635
1817	I<sockets> is the number of sockets, and twice the number of "servers" (as	2636	I<sockets> is the number of sockets, and twice the number of "servers" (as
1818	each server has a read and write socket end).	2637	each server has a read and write socket end).
…		…
1826	a new one that moves the timeout into the future.	2645	a new one that moves the timeout into the future.
1827		2646
1828	=head3 Results	2647	=head3 Results
1829		2648
1830	name sockets create request	2649	name sockets create request
1831	EV 20000 69.01 11.16	2650	EV 20000 62.66 7.99
1832	Perl 20000 73.32 35.87	2651	Perl 20000 68.32 32.64
1833	IOAsync 20000 157.00 98.14 epoll	2652	IOAsync 20000 174.06 101.15 epoll
1834	IOAsync 20000 159.31 616.06 poll	2653	IOAsync 20000 174.67 610.84 poll
1835	Event 20000 212.62 257.32	2654	Event 20000 202.69 242.91
1836	Glib 20000 651.16 1896.30	2655	Glib 20000 557.01 1689.52
1837	POE 20000 349.67 12317.24 uses POE::Loop::Event	2656	POE 20000 341.54 12086.32 uses POE::Loop::Event
1838		2657
1839	=head3 Discussion	2658	=head3 Discussion
1840		2659
1841	This benchmark I<does> measure scalability and overall performance of the	2660	This benchmark I<does> measure scalability and overall performance of the
1842	particular event loop.	2661	particular event loop.
…		…
1968	As you can see, the AnyEvent + EV combination even beats the	2787	As you can see, the AnyEvent + EV combination even beats the
1969	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2788	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1970	backend easily beats IO::Lambda and POE.	2789	backend easily beats IO::Lambda and POE.
1971		2790
1972	And even the 100% non-blocking version written using the high-level (and	2791	And even the 100% non-blocking version written using the high-level (and
1973	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2792	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1974	large margin, even though it does all of DNS, tcp-connect and socket I/O	2793	higher level ("unoptimised") abstractions by a large margin, even though
1975	in a non-blocking way.	2794	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1976		2795
1977	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2796	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1978	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2797	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1979	part of the IO::lambda distribution and were used without any changes.	2798	part of the IO::Lambda distribution and were used without any changes.
1980		2799
1981		2800
1982	=head1 SIGNALS	2801	=head1 SIGNALS
1983		2802
1984	AnyEvent currently installs handlers for these signals:	2803	AnyEvent currently installs handlers for these signals:
…		…
1989		2808
1990	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2809	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1991	emulation for event loops that do not support them natively. Also, some	2810	emulation for event loops that do not support them natively. Also, some
1992	event loops install a similar handler.	2811	event loops install a similar handler.
1993		2812
1994	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2813	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
1995	reset it to default, to avoid losing child exit statuses.	2814	AnyEvent will reset it to default, to avoid losing child exit statuses.
1996		2815
1997	=item SIGPIPE	2816	=item SIGPIPE
1998		2817
1999	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2818	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2000	when AnyEvent gets loaded.	2819	when AnyEvent gets loaded.
…		…
2018	if $SIG{CHLD} eq 'IGNORE';	2837	if $SIG{CHLD} eq 'IGNORE';
2019		2838
2020	$SIG{PIPE} = sub { }	2839	$SIG{PIPE} = sub { }
2021	unless defined $SIG{PIPE};	2840	unless defined $SIG{PIPE};
2022		2841
		2842	=head1 RECOMMENDED/OPTIONAL MODULES
		2843
		2844	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2845	its built-in modules) are required to use it.
		2846
		2847	That does not mean that AnyEvent won't take advantage of some additional
		2848	modules if they are installed.
		2849
		2850	This section explains which additional modules will be used, and how they
		2851	affect AnyEvent's operation.
		2852
		2853	=over 4
		2854
		2855	=item L<Async::Interrupt>
		2856
		2857	This slightly arcane module is used to implement fast signal handling: To
		2858	my knowledge, there is no way to do completely race-free and quick
		2859	signal handling in pure perl. To ensure that signals still get
		2860	delivered, AnyEvent will start an interval timer to wake up perl (and
		2861	catch the signals) with some delay (default is 10 seconds, look for
		2862	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2863
		2864	If this module is available, then it will be used to implement signal
		2865	catching, which means that signals will not be delayed, and the event loop
		2866	will not be interrupted regularly, which is more efficient (and good for
		2867	battery life on laptops).
		2868
		2869	This affects not just the pure-perl event loop, but also other event loops
		2870	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2871
		2872	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2873	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2874	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2875	does nothing for those backends.
		2876
		2877	=item L<EV>
		2878
		2879	This module isn't really "optional", as it is simply one of the backend
		2880	event loops that AnyEvent can use. However, it is simply the best event
		2881	loop available in terms of features, speed and stability: It supports
		2882	the AnyEvent API optimally, implements all the watcher types in XS, does
		2883	automatic timer adjustments even when no monotonic clock is available,
		2884	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2885	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2886	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2887
		2888	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2889	then this module will do nothing for you.
		2890
		2891	=item L<Guard>
		2892
		2893	The guard module, when used, will be used to implement
		2894	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2895	lot less memory), but otherwise doesn't affect guard operation much. It is
		2896	purely used for performance.
		2897
		2898	=item L<JSON> and L<JSON::XS>
		2899
		2900	One of these modules is required when you want to read or write JSON data
		2901	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2902	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2903
		2904	=item L<Net::SSLeay>
		2905
		2906	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2907	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2908	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2909
		2910	=item L<Time::HiRes>
		2911
		2912	This module is part of perl since release 5.008. It will be used when the
		2913	chosen event library does not come with a timing source of its own. The
		2914	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2915	try to use a monotonic clock for timing stability.
		2916
		2917	=back
		2918
		2919
2023	=head1 FORK	2920	=head1 FORK
2024		2921
2025	Most event libraries are not fork-safe. The ones who are usually are	2922	Most event libraries are not fork-safe. The ones who are usually are
2026	because they rely on inefficient but fork-safe C<select> or C<poll>	2923	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2027	calls. Only L<EV> is fully fork-aware.	2924	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2925	are usually badly thought-out hacks that are incompatible with fork in
		2926	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2927	continue event-processing in both parent and child (or both, if you know
		2928	what you are doing).
		2929
		2930	This means that, in general, you cannot fork and do event processing in
		2931	the child if the event library was initialised before the fork (which
		2932	usually happens when the first AnyEvent watcher is created, or the library
		2933	is loaded).
2028		2934
2029	If you have to fork, you must either do so I<before> creating your first	2935	If you have to fork, you must either do so I<before> creating your first
2030	watcher OR you must not use AnyEvent at all in the child.	2936	watcher OR you must not use AnyEvent at all in the child OR you must do
		2937	something completely out of the scope of AnyEvent.
		2938
		2939	The problem of doing event processing in the parent I<and> the child
		2940	is much more complicated: even for backends that I<are> fork-aware or
		2941	fork-safe, their behaviour is not usually what you want: fork clones all
		2942	watchers, that means all timers, I/O watchers etc. are active in both
		2943	parent and child, which is almost never what you want. USing C<exec>
		2944	to start worker children from some kind of manage rprocess is usually
		2945	preferred, because it is much easier and cleaner, at the expense of having
		2946	to have another binary.
2031		2947
2032		2948
2033	=head1 SECURITY CONSIDERATIONS	2949	=head1 SECURITY CONSIDERATIONS
2034		2950
2035	AnyEvent can be forced to load any event model via	2951	AnyEvent can be forced to load any event model via
…		…
2065	pronounced).	2981	pronounced).
2066		2982
2067		2983
2068	=head1 SEE ALSO	2984	=head1 SEE ALSO
2069		2985
2070	Utility functions: L<AnyEvent::Util>.	2986	Tutorial/Introduction: L<AnyEvent::Intro>.
2071		2987
2072	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2988	FAQ: L<AnyEvent::FAQ>.
2073	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2989
		2990	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2991	(simply logging).
		2992
		2993	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2994	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2995
		2996	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2997	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2998	L<Qt>, L<POE>, L<FLTK>.
2074		2999
2075	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3000	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2076	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3001	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2077	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3002	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		3003	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
2078	L<AnyEvent::Impl::POE>.	3004	L<AnyEvent::Impl::FLTK>.
2079		3005
2080	Non-blocking file handles, sockets, TCP clients and	3006	Non-blocking handles, pipes, stream sockets, TCP clients and
2081	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	3007	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2082		3008
2083	Asynchronous DNS: L<AnyEvent::DNS>.	3009	Asynchronous DNS: L<AnyEvent::DNS>.
2084		3010
2085	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	3011	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2086		3012
2087	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	3013	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		3014	L<AnyEvent::HTTP>.
2088		3015
2089		3016
2090	=head1 AUTHOR	3017	=head1 AUTHOR
2091		3018
2092	Marc Lehmann <schmorp@schmorp.de>	3019	Marc Lehmann <schmorp@schmorp.de>

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