ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.232 by root, Thu Jul 9 01:08:22 2009 UTC vs.
Revision 1.396 by root, Sat Mar 10 17:36:24 2012 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	event loops.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
340	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
		432	attaching callbacks to signals in a generic way, which is a pity,
		433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
		435	means in some cases, signals will be delayed. The maximum time
		436	a signal might be delayed is 10 seconds by default, but can
		437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
		438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
		439	section for details.
		440
		441	All these problems can be avoided by installing the optional
		442	L<Async::Interrupt> module, which works with most event loops. It will not
		443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		444	(and not with L<POE> currently). For those, you just have to suffer the
		445	delays.
		446
375	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
376		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
377	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
378		452
379	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
383		458
384	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	461	callback arguments.
387		462
…		…
403		478
404	This means you cannot create a child watcher as the very first	479	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	480	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
		483
		484	As most event loops do not support waiting for child events, they will be
		485	emulated by AnyEvent in most cases, in which case the latency and race
		486	problems mentioned in the description of signal watchers apply.
408		487
409	Example: fork a process and wait for it	488	Example: fork a process and wait for it
410		489
411	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
412		491
…		…
424	# do something else, then wait for process exit	503	# do something else, then wait for process exit
425	$done->recv;	504	$done->recv;
426		505
427	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
428		507
429	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		509
434	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		512
438	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
441		525
442	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	527	program is otherwise idle:
…		…
459	});	543	});
460	});	544	});
461		545
462	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
463		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
464	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
467		556
468	AnyEvent is different, it expects somebody else to run the event loop and	557	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
470		559
471	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	561	they represent a condition that must become true.
		562
		563	Now is probably a good time to look at the examples further below.
473		564
474	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	567	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	568	becomes true, with the condition variable as the first argument (but not
479	the results).	569	the results).
480		570
481	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	574	->send >> method).
485		575
486	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	578
489	another way to call them is transactions - each condition variable can be	579	=over 4
490	used to represent a transaction, which finishes at some point and delivers	580
491	a result.	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
		582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
492		599
493	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
509		616
510	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
515		622
516	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	625	for the send to occur.
519		626
520	Example: wait for a timer.	627	Example: wait for a timer.
521		628
522	# wait till the result is ready	629	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
524		631
525	# do something such as adding a timer	632	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
527	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
530	after => 1,	637	after => 1,
531	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
532	);	639	);
533		640
534	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
535	# calls send	642	# calls ->send
536	$result_ready->recv;	643	$timer_fired->recv;
537		644
538	Example: wait for a timer, but take advantage of the fact that	645	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	646	variables are also callable directly.
540		647
541	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	649	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	650	$done->recv;
544		651
…		…
550		657
551	...	658	...
552		659
553	my @info = $couchdb->info->recv;	660	my @info = $couchdb->info->recv;
554		661
555	And this is how you would just ste a callback to be called whenever the	662	And this is how you would just set a callback to be called whenever the
556	results are available:	663	results are available:
557		664
558	$couchdb->info->cb (sub {	665	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	666	my @info = $_[0]->recv;
560	});	667	});
…		…
578	immediately from within send.	685	immediately from within send.
579		686
580	Any arguments passed to the C<send> call will be returned by all	687	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	688	future C<< ->recv >> calls.
582		689
583	Condition variables are overloaded so one can call them directly	690	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	692	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		693
592	=item $cv->croak ($error)	694	=item $cv->croak ($error)
593		695
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
596		698
597	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
598	user/consumer.	700	user/consumer. Doing it this way instead of calling C<croak> directly
		701	delays the error detection, but has the overwhelming advantage that it
		702	diagnoses the error at the place where the result is expected, and not
		703	deep in some event callback with no connection to the actual code causing
		704	the problem.
599		705
600	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
601		707
602	=item $cv->end	708	=item $cv->end
603		709
…		…
605	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
607		713
608	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
613		720
614	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		724
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	747	sending.
641		748
642	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	751	begun can potentially be zero:
645		752
646	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
647		754
648	my %result;	755	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
650		757
651	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
652	$cv->begin;	759	$cv->begin;
653	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	761	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	779	doesn't execute once).
673		780
674	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	785	call C<end>.
679		786
680	=back	787	=back
…		…
687	=over 4	794	=over 4
688		795
689	=item $cv->recv	796	=item $cv->recv
690		797
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	800	normally.
694		801
695	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	803	will return immediately.
697		804
…		…
699	function will call C<croak>.	806	function will call C<croak>.
700		807
701	In list context, all parameters passed to C<send> will be returned,	808	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	809	in scalar context only the first one will be returned.
703		810
		811	Note that doing a blocking wait in a callback is not supported by any
		812	event loop, that is, recursive invocation of a blocking C<< ->recv
		813	>> is not allowed, and the C<recv> call will C<croak> if such a
		814	condition is detected. This condition can be slightly loosened by using
		815	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		816	any thread that doesn't run the event loop itself.
		817
704	Not all event models support a blocking wait - some die in that case	818	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	819	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	820	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
711		825
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
726	waits otherwise.	829	waits otherwise.
727		830
728	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
734		837
735	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	839	replaces it before doing so.
737		840
738	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
742		846
743	=back	847	=back
744		848
745	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
746		850
…		…
749	=over 4	853	=over 4
750		854
751	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
752		856
753	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
754	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
755	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
756	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
757		861
758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
759	AnyEvent::Impl::Event based on Event, very stable, few glitches.
760	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
761		864
762	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
763		866
764	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
765	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
766	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
767	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
768	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
769		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
770	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
771	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
773	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
		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).
774		882
775	=item Backends with special needs.	883	=item Backends with special needs.
776		884
777	Qt requires the Qt::Application to be instantiated first, but will	885	Qt requires the Qt::Application to be instantiated first, but will
778	otherwise be picked up automatically. As long as the main program	886	otherwise be picked up automatically. As long as the main program
779	instantiates the application before any AnyEvent watchers are created,	887	instantiates the application before any AnyEvent watchers are created,
780	everything should just work.	888	everything should just work.
781		889
782	AnyEvent::Impl::Qt based on Qt.	890	AnyEvent::Impl::Qt based on Qt.
783		891
784	Support for IO::Async can only be partial, as it is too broken and
785	architecturally limited to even support the AnyEvent API. It also
786	is the only event loop that needs the loop to be set explicitly, so
787	it can only be used by a main program knowing about AnyEvent. See
788	L<AnyEvent::Impl::Async> for the gory details.
789
790	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
791
792	=item Event loops that are indirectly supported via other backends.	892	=item Event loops that are indirectly supported via other backends.
793		893
794	Some event loops can be supported via other modules:	894	Some event loops can be supported via other modules:
795		895
796	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
809		909
810	=back	910	=back
811		911
812	=head1 GLOBAL VARIABLES AND FUNCTIONS	912	=head1 GLOBAL VARIABLES AND FUNCTIONS
813		913
		914	These are not normally required to use AnyEvent, but can be useful to
		915	write AnyEvent extension modules.
		916
814	=over 4	917	=over 4
815		918
816	=item $AnyEvent::MODEL	919	=item $AnyEvent::MODEL
817		920
818	Contains C<undef> until the first watcher is being created. Then it	921	Contains C<undef> until the first watcher is being created, before the
		922	backend has been autodetected.
		923
819	contains the event model that is being used, which is the name of the	924	Afterwards it contains the event model that is being used, which is the
820	Perl class implementing the model. This class is usually one of the	925	name of the Perl class implementing the model. This class is usually one
821	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
822	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
		928	will be C<urxvt::anyevent>).
823		929
824	=item AnyEvent::detect	930	=item AnyEvent::detect
825		931
826	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
827	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
828	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
829	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>.
830		943
831	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
832		945
833	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
834	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
		948
		949	The block will be executed I<after> the actual backend has been detected
		950	(C<$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.
835		959
836	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
837	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
838	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 ||= $guard;
839		980
840	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
841		982
842	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
843	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
844	the event loop has been chosen.	985	after the event loop has been chosen.
845		986
846	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
847	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
848	and the array will be ignored.	989	array will be ignored.
849		990
850	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.
851		1069
852	=back	1070	=back
853		1071
854	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
855		1073
…		…
866	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
867	events is to stay interactive.	1085	events is to stay interactive.
868		1086
869	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
870	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
871	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 >>
872	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).
873		1091
874	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
875		1093
876	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
877	dictate which event model to use.	1095	dictate which event model to use.
878		1096
879	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
880	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
881	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.
882		1102
883	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
884	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
885	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
886	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
887	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
888	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
889	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
890		1110
891	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
892	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
893	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
894		1114
895	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
896		1116
897	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
910		1130
911		1131
912	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
913		1133
914	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
915	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1135	AnyEvent as a client and can therefore be mixed easily with other
916	modules and other event loops in the same program. Some of the modules	1136	AnyEvent modules and other event loops in the same program. Some of the
917	come with AnyEvent, most are available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
918		1141
919	=over 4	1142	=over 4
920		1143
921	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
922		1145
923	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
924	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
925		1148
926	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
927		1150
928	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
929	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
931		1154
932	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
933		1156
934	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
935	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
936	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
937		1160
938	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
939		1162
940	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
941		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
942	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
943		1172
944	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
945	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.
946		1195
947	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
948		1197
949	Provides a simple web application server framework.	1198	A simple embedded webserver.
950		1199
951	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
952		1201
953	The fastest ping in the west.	1202	The fastest ping in the west.
954		1203
955	=item L<AnyEvent::DBI>
956
957	Executes L<DBI> requests asynchronously in a proxy process.
958
959	=item L<AnyEvent::AIO>
960
961	Truly asynchronous I/O, should be in the toolbox of every event
962	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
963	together.
964
965	=item L<AnyEvent::BDB>
966
967	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
968	L<BDB> and AnyEvent together.
969
970	=item L<AnyEvent::GPSD>
971
972	A non-blocking interface to gpsd, a daemon delivering GPS information.
973
974	=item L<AnyEvent::IRC>
975
976	AnyEvent based IRC client module family (replacing the older Net::IRC3).
977
978	=item L<AnyEvent::XMPP>
979
980	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
981	Net::XMPP2>.
982
983	=item L<AnyEvent::IGS>
984
985	A non-blocking interface to the Internet Go Server protocol (used by
986	L<App::IGS>).
987
988	=item L<Net::FCP>
989
990	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
991	of AnyEvent.
992
993	=item L<Event::ExecFlow>
994
995	High level API for event-based execution flow control.
996
997	=item L<Coro>	1204	=item L<Coro>
998		1205
999	Has special support for AnyEvent via L<Coro::AnyEvent>.	1206	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1207	to simply invert the flow control - don't call us, we will call you:
		1208
		1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
		1212
		1213	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1214	my $line = <STDIN>; # works for ttys
		1215
		1216	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1217	my ($body, $hdr) = Coro::rouse_wait;
		1218	};
1000		1219
1001	=back	1220	=back
1002		1221
1003	=cut	1222	=cut
1004		1223
1005	package AnyEvent;	1224	package AnyEvent;
1006		1225
1007	no warnings;	1226	# basically a tuned-down version of common::sense
1008	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	}
1009		1233
		1234	BEGIN { AnyEvent::common_sense }
		1235
1010	use Carp;	1236	use Carp ();
1011		1237
1012	our $VERSION = 4.801;	1238	our $VERSION = '6.14';
1013	our $MODEL;	1239	our $MODEL;
1014
1015	our $AUTOLOAD;
1016	our @ISA;	1240	our @ISA;
1017
1018	our @REGISTRY;	1241	our @REGISTRY;
1019		1242	our $VERBOSE;
1020	our $WIN32;	1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1021		1245
1022	BEGIN {	1246	BEGIN {
1023	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1247	require "AnyEvent/constants.pl";
		1248
1024	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1025		1250
1026	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1027	if ${^TAINT};	1252	if ${^TAINT};
1028	}
1029		1253
1030	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1031		1256
1032	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
1033		1259
1034	{	1260	# $ENV{PERL_ANYEVENT_xxx} now valid
		1261
		1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1263
1035	my $idx;	1264	my $idx;
1036	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
1037	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
1038	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1039	}	1268	}
1040		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($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
1041	my @models = (	1347	our @models = (
1042	[EV:: => AnyEvent::Impl::EV::],	1348	[EV:: => AnyEvent::Impl::EV::],
1043	[Event:: => AnyEvent::Impl::Event::],
1044	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1349	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1045	# everything below here will not be autoprobed	1350	# everything below here will not (normally) be autoprobed
1046	# as the pureperl backend should work everywhere	1351	# as the pure perl backend should work everywhere
1047	# 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
1048	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1355	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1356	# everything below here should not be autoloaded
1049	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1357	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1050	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1358	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1359	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1051	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1360	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1052	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1053	[Wx:: => AnyEvent::Impl::POE::],	1361	[Wx:: => AnyEvent::Impl::POE::],
1054	[Prima:: => AnyEvent::Impl::POE::],	1362	[Prima:: => AnyEvent::Impl::POE::],
1055	# IO::Async is just too broken - we would need workarounds for its	1363	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1056	# byzantine signal and broken child handling, among others.	1364	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1057	# IO::Async is rather hard to detect, as it doesn't have any	1365	[FLTK:: => AnyEvent::Impl::FLTK::],
1058	# obvious default class.
1059	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1060	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1061	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1062	);	1366	);
1063		1367
1064	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, $reset_ae] : undef;
		1385
		1386	_isa_set;
		1387	}
		1388
		1389	# all autoloaded methods reserve the complete glob, not just the method slot.
		1390	# due to bugs in perls method cache implementation.
1065	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1391	our @methods = qw(io timer time now now_update signal child idle condvar);
1066		1392
1067	our @post_detect;
1068
1069	sub post_detect(&) {	1393	sub detect() {
1070	my ($cb) = @_;	1394	return $MODEL if $MODEL; # some programs keep references to detect
1071		1395
1072	if ($MODEL) {	1396	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1073	$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"};
1074		1403
1075	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;
1076	} else {	1423	} else {
1077	push @post_detect, $cb;	1424	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1078		1425	}
1079	defined wantarray
1080	? bless \$cb, "AnyEvent::Util::postdetect"
1081	: ()
1082	}	1426	}
1083	}
1084		1427
1085	sub AnyEvent::Util::postdetect::DESTROY {	1428	# check for already loaded models
1086	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1087	}
1088
1089	sub detect() {
1090	unless ($MODEL) {	1429	unless ($MODEL) {
1091	no strict 'refs';	1430	for (@REGISTRY, @models) {
1092	local $SIG{__DIE__};	1431	my ($package, $model) = @$_;
1093		1432	if (${"$package\::VERSION"} > 0) {
1094	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1095	my $model = "AnyEvent::Impl::$1";
1096	if (eval "require $model") {	1433	if (eval "require $model") {
		1434	AnyEvent::log 7 => "autodetected model '$model', using it.";
1097	$MODEL = $model;	1435	$MODEL = $model;
1098	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1436	last;
1099	} else {	1437	} else {
1100	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1438	AnyEvent::log 8 => "detected event loop $package, but cannot load '$model', skipping: $@";
		1439	}
1101	}	1440	}
1102	}	1441	}
1103		1442
1104	# check for already loaded models
1105	unless ($MODEL) {	1443	unless ($MODEL) {
		1444	# try to autoload a model
1106	for (@REGISTRY, @models) {	1445	for (@REGISTRY, @models) {
1107	my ($package, $model) = @$_;	1446	my ($package, $model) = @$_;
		1447	if (
		1448	eval "require $package"
1108	if (${"$package\::VERSION"} > 0) {	1449	and ${"$package\::VERSION"} > 0
1109	if (eval "require $model") {	1450	and eval "require $model"
		1451	) {
		1452	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1110	$MODEL = $model;	1453	$MODEL = $model;
1111	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1112	last;	1454	last;
1113	}
1114	}	1455	}
1115	}	1456	}
1116		1457
1117	unless ($MODEL) {
1118	# try to load a model
1119
1120	for (@REGISTRY, @models) {
1121	my ($package, $model) = @$_;
1122	if (eval "require $package"
1123	and ${"$package\::VERSION"} > 0
1124	and eval "require $model") {
1125	$MODEL = $model;
1126	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1127	last;
1128	}
1129	}
1130
1131	$MODEL	1458	$MODEL
1132	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1459	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1133	}
1134	}	1460	}
1135
1136	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1137
1138	unshift @ISA, $MODEL;
1139
1140	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1141
1142	(shift @post_detect)->() while @post_detect;
1143	}	1461	}
1144		1462
		1463	# free memory only needed for probing
		1464	undef @models;
		1465	undef @REGISTRY;
		1466
		1467	push @{"$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/\$\$/$$/g;
		1495
		1496	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1497	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1498	}
		1499
		1500	# now the anyevent environment is set up as the user told us to, so
		1501	# call the actual user code - post detects
		1502
		1503	(shift @post_detect)->() while @post_detect;
		1504	undef @post_detect;
		1505
		1506	*post_detect = sub(&) {
		1507	shift->();
		1508
		1509	undef
		1510	};
		1511
1145	$MODEL	1512	$MODEL
1146	}	1513	}
1147		1514
1148	sub AUTOLOAD {	1515	for my $name (@methods) {
1149	(my $func = $AUTOLOAD) =~ s/.*://;	1516	*$name = sub {
1150		1517	detect;
1151	$method{$func}	1518	# we use goto because
1152	or croak "$func: not a valid method for AnyEvent objects";	1519	# a) it makes the thunk more transparent
1153		1520	# b) it allows us to delete the thunk later
1154	detect unless $MODEL;	1521	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1155		1522	};
1156	my $class = shift;
1157	$class->$func (@_);
1158	}	1523	}
1159		1524
1160	# utility function to dup a filehandle. this is used by many backends	1525	# utility function to dup a filehandle. this is used by many backends
1161	# to support binding more than one watcher per filehandle (they usually	1526	# to support binding more than one watcher per filehandle (they usually
1162	# allow only one watcher per fd, so we dup it to get a different one).	1527	# allow only one watcher per fd, so we dup it to get a different one).
1163	sub _dupfh($$;$$) {	1528	sub _dupfh($$;$$) {
1164	my ($poll, $fh, $r, $w) = @_;	1529	my ($poll, $fh, $r, $w) = @_;
1165		1530
1166	# cygwin requires the fh mode to be matching, unix doesn't	1531	# cygwin requires the fh mode to be matching, unix doesn't
1167	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1532	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1168		1533
1169	open my $fh2, "$mode&", $fh	1534	open my $fh2, $mode, $fh
1170	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1535	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1171		1536
1172	# we assume CLOEXEC is already set by perl in all important cases	1537	# we assume CLOEXEC is already set by perl in all important cases
1173		1538
1174	($fh2, $rw)	1539	($fh2, $rw)
1175	}	1540	}
1176		1541
		1542	=head1 SIMPLIFIED AE API
		1543
		1544	Starting with version 5.0, AnyEvent officially supports a second, much
		1545	simpler, API that is designed to reduce the calling, typing and memory
		1546	overhead by using function call syntax and a fixed number of parameters.
		1547
		1548	See the L<AE> manpage for details.
		1549
		1550	=cut
		1551
		1552	package AE;
		1553
		1554	our $VERSION = $AnyEvent::VERSION;
		1555
		1556	sub _reset() {
		1557	eval q{
		1558	# fall back to the main API by default - backends and AnyEvent::Base
		1559	# implementations can overwrite these.
		1560
		1561	sub io($$$) {
		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
1177	package AnyEvent::Base;	1605	package AnyEvent::Base;
1178		1606
1179	# default implementations for many methods	1607	# default implementations for many methods
1180		1608
1181	BEGIN {	1609	sub time {
		1610	eval q{ # poor man's autoloading {}
		1611	# probe for availability of Time::HiRes
1182	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 () };
1183	*_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.";
1184	# if (eval "use POSIX (); (POSIX::times())...	1617	# if (eval "use POSIX (); (POSIX::times())...
1185	} else {	1618	} else {
1186	*_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	;
1187	}	1683	}
1188	}	1684	}
1189		1685
1190	sub time { _time }	1686	sub _sig_del {
1191	sub now { _time }	1687	undef $SIG_TW
1192	sub now_update { }	1688	unless --$SIG_COUNT;
1193
1194	# default implementation for ->condvar
1195
1196	sub condvar {
1197	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1198	}	1689	}
1199		1690
1200	# 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;
1201		1694
1202	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;
1203		1700
1204	sub _signal_exec {	1701	my %signame2num;
1205	sysread $SIGPIPE_R, my $dummy, 4;	1702	@signame2num{ split ' ', $Config::Config{sig_name} }
		1703	= split ' ', $Config::Config{sig_num};
1206		1704
1207	while (%SIG_EV) {	1705	my @signum2name;
1208	for (keys %SIG_EV) {	1706	@signum2name[values %signame2num] = keys %signame2num;
1209	delete $SIG_EV{$_};	1707
1210	$_->() for values %{ $SIG_CB{$_} || {} };	1708	*sig2num = sub($) {
		1709	$_[0] > 0 ? shift : $signame2num{+shift}
		1710	};
		1711	*sig2name = sub ($) {
		1712	$_[0] > 0 ? $signum2name[+shift] : shift
		1713	};
1211	}	1714	}
1212	}	1715	};
1213	}	1716	die if $@;
		1717	};
		1718
		1719	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1720	sub sig2name($) { &$_sig_name_init; &sig2name }
1214		1721
1215	sub signal {	1722	sub signal {
1216	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.";
1217		1727
1218	unless ($SIGPIPE_R) {	1728	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1219	require Fcntl;	1729	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1220		1730
1221	if (AnyEvent::WIN32) {
1222	require AnyEvent::Util;
1223
1224	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1225	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1226	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1227	} else {	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 {
1228	pipe $SIGPIPE_R, $SIGPIPE_W;	1741	pipe $SIGPIPE_R, $SIGPIPE_W;
1229	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;
1230	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
1231		1744
1232	# 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...
1233	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1746	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1234	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;
1235	}	1754	}
1236		1755
1237	$SIGPIPE_R	1756	*signal = $HAVE_ASYNC_INTERRUPT
1238	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1757	? sub {
		1758	my (undef, %arg) = @_;
1239		1759
1240	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1760	# async::interrupt
1241	}
1242
1243	my $signal = uc $arg{signal}	1761	my $signal = sig2num $arg{signal};
1244	or Carp::croak "required option 'signal' is missing";
1245
1246	$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
1247	$SIG{$signal} ||= sub {	1780	$SIG{$signal} ||= sub {
1248	local $!;	1781	local $!;
1249	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1782	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1250	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	};
1251	};	1822	};
		1823	die if $@;
1252		1824
1253	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1825	&signal
1254	}
1255
1256	sub AnyEvent::Base::signal::DESTROY {
1257	my ($signal, $cb) = @{$_[0]};
1258
1259	delete $SIG_CB{$signal}{$cb};
1260
1261	# delete doesn't work with older perls - they then
1262	# print weird messages, or just unconditionally exit
1263	# instead of getting the default action.
1264	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1265	}	1826	}
1266		1827
1267	# default implementation for ->child	1828	# default implementation for ->child
1268		1829
1269	our %PID_CB;	1830	our %PID_CB;
1270	our $CHLD_W;	1831	our $CHLD_W;
1271	our $CHLD_DELAY_W;	1832	our $CHLD_DELAY_W;
1272	our $WNOHANG;
1273		1833
1274	sub _sigchld {	1834	# used by many Impl's
1275	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1835	sub _emit_childstatus($$) {
		1836	my (undef, $rpid, $rstatus) = @_;
		1837
		1838	$_->($rpid, $rstatus)
1276	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1839	for values %{ $PID_CB{$rpid} || {} },
1277	(values %{ $PID_CB{0} || {} });	1840	values %{ $PID_CB{0} || {} };
1278	}
1279	}	1841	}
1280		1842
1281	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 {
1282	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1283		1854
1284	defined (my $pid = $arg{pid} + 0)	1855	my $pid = $arg{pid};
1285	or Carp::croak "required option 'pid' is missing";	1856	my $cb = $arg{cb};
1286		1857
1287	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1858	$PID_CB{$pid}{$cb+0} = $cb;
1288		1859
1289	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1290
1291	unless ($CHLD_W) {	1860	unless ($CHLD_W) {
1292	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1861	$CHLD_W = AE::signal CHLD => \&_sigchld;
1293	# child could be a zombie already, so make at least one round	1862	# child could be a zombie already, so make at least one round
1294	&_sigchld;	1863	&_sigchld;
1295	}	1864	}
1296		1865
1297	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1866	bless [$pid, $cb+0], "AnyEvent::Base::child"
1298	}	1867	};
1299		1868
1300	sub AnyEvent::Base::child::DESTROY {	1869	*AnyEvent::Base::child::DESTROY = sub {
1301	my ($pid, $cb) = @{$_[0]};	1870	my ($pid, $icb) = @{$_[0]};
1302		1871
1303	delete $PID_CB{$pid}{$cb};	1872	delete $PID_CB{$pid}{$icb};
1304	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1873	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1305		1874
1306	undef $CHLD_W unless keys %PID_CB;	1875	undef $CHLD_W unless keys %PID_CB;
		1876	};
		1877	};
		1878	die if $@;
		1879
		1880	&child
1307	}	1881	}
1308		1882
1309	# idle emulation is done by simply using a timer, regardless	1883	# idle emulation is done by simply using a timer, regardless
1310	# of whether the process is idle or not, and not letting	1884	# of whether the process is idle or not, and not letting
1311	# the callback use more than 50% of the time.	1885	# the callback use more than 50% of the time.
1312	sub idle {	1886	sub idle {
		1887	eval q{ # poor man's autoloading {}
		1888	*idle = sub {
1313	my (undef, %arg) = @_;	1889	my (undef, %arg) = @_;
1314		1890
1315	my ($cb, $w, $rcb) = $arg{cb};	1891	my ($cb, $w, $rcb) = $arg{cb};
1316		1892
1317	$rcb = sub {	1893	$rcb = sub {
1318	if ($cb) {	1894	if ($cb) {
1319	$w = _time;	1895	$w = AE::time;
1320	&$cb;	1896	&$cb;
1321	$w = _time - $w;	1897	$w = AE::time - $w;
1322		1898
1323	# 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,
1324	# within some limits	1900	# within some limits
1325	$w = 0.0001 if $w < 0.0001;	1901	$w = 0.0001 if $w < 0.0001;
1326	$w = 5 if $w > 5;	1902	$w = 5 if $w > 5;
1327		1903
1328	$w = AnyEvent->timer (after => $w, cb => $rcb);	1904	$w = AE::timer $w, 0, $rcb;
1329	} else {	1905	} else {
1330	# clean up...	1906	# clean up...
1331	undef $w;	1907	undef $w;
1332	undef $rcb;	1908	undef $rcb;
		1909	}
		1910	};
		1911
		1912	$w = AE::timer 0.05, 0, $rcb;
		1913
		1914	bless \\$cb, "AnyEvent::Base::idle"
1333	}	1915	};
		1916
		1917	*AnyEvent::Base::idle::DESTROY = sub {
		1918	undef $${$_[0]};
		1919	};
1334	};	1920	};
		1921	die if $@;
1335		1922
1336	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1923	&idle
1337
1338	bless \\$cb, "AnyEvent::Base::idle"
1339	}
1340
1341	sub AnyEvent::Base::idle::DESTROY {
1342	undef $${$_[0]};
1343	}	1924	}
1344		1925
1345	package AnyEvent::CondVar;	1926	package AnyEvent::CondVar;
1346		1927
1347	our @ISA = AnyEvent::CondVar::Base::;	1928	our @ISA = AnyEvent::CondVar::Base::;
1348		1929
		1930	# only to be used for subclassing
		1931	sub new {
		1932	my $class = shift;
		1933	bless AnyEvent->condvar (@_), $class
		1934	}
		1935
1349	package AnyEvent::CondVar::Base;	1936	package AnyEvent::CondVar::Base;
1350		1937
1351	use overload	1938	#use overload
1352	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1939	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1353	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;
1354		1949
1355	sub _send {	1950	sub _send {
1356	# nop	1951	# nop
		1952	}
		1953
		1954	sub _wait {
		1955	AnyEvent->_poll until $_[0]{_ae_sent};
1357	}	1956	}
1358		1957
1359	sub send {	1958	sub send {
1360	my $cv = shift;	1959	my $cv = shift;
1361	$cv->{_ae_sent} = [@_];	1960	$cv->{_ae_sent} = [@_];
…		…
1370		1969
1371	sub ready {	1970	sub ready {
1372	$_[0]{_ae_sent}	1971	$_[0]{_ae_sent}
1373	}	1972	}
1374		1973
1375	sub _wait {
1376	AnyEvent->one_event while !$_[0]{_ae_sent};
1377	}
1378
1379	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;
1380	$_[0]->_wait;	1980	$_[0]->_wait;
		1981	}
1381		1982
1382	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1983	$_[0]{_ae_croak}
1383	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]
1384	}	1989	}
1385		1990
1386	sub cb {	1991	sub cb {
1387	$_[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
1388	$_[0]{_ae_cb}	1999	$cv->{_ae_cb}
1389	}	2000	}
1390		2001
1391	sub begin {	2002	sub begin {
1392	++$_[0]{_ae_counter};	2003	++$_[0]{_ae_counter};
1393	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2004	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1398	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2009	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1399	}	2010	}
1400		2011
1401	# undocumented/compatibility with pre-3.4	2012	# undocumented/compatibility with pre-3.4
1402	*broadcast = \&send;	2013	*broadcast = \&send;
1403	*wait = \&_wait;	2014	*wait = \&recv;
1404		2015
1405	=head1 ERROR AND EXCEPTION HANDLING	2016	=head1 ERROR AND EXCEPTION HANDLING
1406		2017
1407	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
1408	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
…		…
1420	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2031	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1421	so on.	2032	so on.
1422		2033
1423	=head1 ENVIRONMENT VARIABLES	2034	=head1 ENVIRONMENT VARIABLES
1424		2035
1425	The following environment variables are used by this module or its	2036	AnyEvent supports a number of environment variables that tune the
1426	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.
1427		2042
1428	Note that AnyEvent will remove I<all> environment variables starting with	2043	All the environment variables documented here start with
1429	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
1430	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:
1431		2073
1432	=over 4	2074	=over 4
1433		2075
1434	=item C<PERL_ANYEVENT_VERBOSE>	2076	=item C<PERL_ANYEVENT_VERBOSE>
1435		2077
1436	By default, AnyEvent will be completely silent except in fatal	2078	By default, AnyEvent will only log messages with loglevel C<3>
1437	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
1438	talkative.	2081	less) talkative.
1439		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
1440	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
1441	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
1442	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.
1443		2094
1444	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
1445	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.
1446		2118
1447	=item C<PERL_ANYEVENT_STRICT>	2119	=item C<PERL_ANYEVENT_STRICT>
1448		2120
1449	AnyEvent does not do much argument checking by default, as thorough	2121	AnyEvent does not do much argument checking by default, as thorough
1450	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
…		…
1452	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,
1453	it will croak.	2125	it will croak.
1454		2126
1455	In other words, enables "strict" mode.	2127	In other words, enables "strict" mode.
1456		2128
1457	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>
1458	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2130	>>, it is definitely recommended to keep it off in production. Keeping
1459	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.
1460		2161
1461	=item C<PERL_ANYEVENT_MODEL>	2162	=item C<PERL_ANYEVENT_MODEL>
1462		2163
1463	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
1464	auto detection and -probing kicks in. It must be a string consisting	2165	auto detection and -probing kicks in.
1465	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
1466	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
1467	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
1468	auto detection and -probing.	2171	auto detection and -probing.
1469		2172
1470	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).
1471		2176
1472	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
1473	could start your program like this:	2178	could start your program like this:
1474		2179
1475	PERL_ANYEVENT_MODEL=Perl perl ...	2180	PERL_ANYEVENT_MODEL=Perl perl ...
1476		2181
1477	=item C<PERL_ANYEVENT_PROTOCOLS>	2182	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1493	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>
1494	- only support IPv4, never try to resolve or contact IPv6	2199	- only support IPv4, never try to resolve or contact IPv6
1495	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2200	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1496	IPv6, but prefer IPv6 over IPv4.	2201	IPv6, but prefer IPv6 over IPv4.
1497		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
1498	=item C<PERL_ANYEVENT_EDNS0>	2209	=item C<PERL_ANYEVENT_EDNS0>
1499		2210
1500	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
1501	for DNS. This extension is generally useful to reduce DNS traffic, but	2212	DNS. This extension is generally useful to reduce DNS traffic, especially
1502	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
1503	default.	2214	packets, which is why it is off by default.
1504		2215
1505	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
1506	EDNS0 in its DNS requests.	2217	EDNS0 in its DNS requests.
1507		2218
1508	=item C<PERL_ANYEVENT_MAX_FORKS>	2219	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1514		2225
1515	The default value for the C<max_outstanding> parameter for the default DNS	2226	The default value for the C<max_outstanding> parameter for the default DNS
1516	resolver - this is the maximum number of parallel DNS requests that are	2227	resolver - this is the maximum number of parallel DNS requests that are
1517	sent to the DNS server.	2228	sent to the DNS server.
1518		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
1519	=item C<PERL_ANYEVENT_RESOLV_CONF>	2252	=item C<PERL_ANYEVENT_RESOLV_CONF>
1520		2253
1521	The file to use instead of F</etc/resolv.conf> (or OS-specific	2254	The absolute path to a F<resolv.conf>-style file to use instead of
1522	configuration) in the default resolver. When set to the empty string, no	2255	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1523	default config will be used.	2256	resolver, or the empty string to select the default configuration.
1524		2257
1525	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2258	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1526		2259
1527	When neither C<ca_file> nor C<ca_path> was specified during	2260	When neither C<ca_file> nor C<ca_path> was specified during
1528	L<AnyEvent::TLS> context creation, and either of these environment	2261	L<AnyEvent::TLS> context creation, and either of these environment
1529	variables exist, they will be used to specify CA certificate locations	2262	variables are nonempty, they will be used to specify CA certificate
1530	instead of a system-dependent default.	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.
1531		2269
1532	=back	2270	=back
1533		2271
1534	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2272	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1535		2273
…		…
1593	warn "read: $input\n"; # output what has been read	2331	warn "read: $input\n"; # output what has been read
1594	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2332	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1595	},	2333	},
1596	);	2334	);
1597		2335
1598	my $time_watcher; # can only be used once
1599
1600	sub new_timer {
1601	$timer = AnyEvent->timer (after => 1, cb => sub {	2336	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1602	warn "timeout\n"; # print 'timeout' about every second	2337	warn "timeout\n"; # print 'timeout' at most every second
1603	&new_timer; # and restart the time
1604	});	2338	});
1605	}
1606
1607	new_timer; # create first timer
1608		2339
1609	$cv->recv; # wait until user enters /^q/i	2340	$cv->recv; # wait until user enters /^q/i
1610		2341
1611	=head1 REAL-WORLD EXAMPLE	2342	=head1 REAL-WORLD EXAMPLE
1612		2343
…		…
1685		2416
1686	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)
1687	that occurred during request processing. The C<result> method detects	2418	that occurred during request processing. The C<result> method detects
1688	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)
1689	and just throws the exception, which means connection errors and other	2420	and just throws the exception, which means connection errors and other
1690	problems get reported tot he code that tries to use the result, not in a	2421	problems get reported to the code that tries to use the result, not in a
1691	random callback.	2422	random callback.
1692		2423
1693	All of this enables the following usage styles:	2424	All of this enables the following usage styles:
1694		2425
1695	1. Blocking:	2426	1. Blocking:
…		…
1743	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
1744	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,
1745	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.
1746		2477
1747	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
1748	distribution.	2479	distribution. It uses the L<AE> interface, which makes a real difference
		2480	for the EV and Perl backends only.
1749		2481
1750	=head3 Explanation of the columns	2482	=head3 Explanation of the columns
1751		2483
1752	I<watcher> is the number of event watchers created/destroyed. Since	2484	I<watcher> is the number of event watchers created/destroyed. Since
1753	different event models feature vastly different performances, each event	2485	different event models feature vastly different performances, each event
…		…
1774	watcher.	2506	watcher.
1775		2507
1776	=head3 Results	2508	=head3 Results
1777		2509
1778	name watchers bytes create invoke destroy comment	2510	name watchers bytes create invoke destroy comment
1779	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
1780	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
1781	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
1782	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
1783	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
1784	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
1785	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
1786	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
1787	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
1788	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
1789	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
1790	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
1791		2523
1792	=head3 Discussion	2524	=head3 Discussion
1793		2525
1794	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
1795	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)
…		…
1807	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2539	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1808	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2540	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1809	cycles with POE.	2541	cycles with POE.
1810		2542
1811	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
1812	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
1813	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).
1814	natively.
1815		2548
1816	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
1817	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
1818	interpreter and the backend itself). Nevertheless this shows that it	2551	interpreter and the backend itself). Nevertheless this shows that it
1819	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
…		…
1867	(even when used without AnyEvent), but most event loops have acceptable	2600	(even when used without AnyEvent), but most event loops have acceptable
1868	performance with or without AnyEvent.	2601	performance with or without AnyEvent.
1869		2602
1870	=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
1871	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
1872	adds AnyEvent significant overhead.	2605	does AnyEvent add significant overhead.
1873		2606
1874	=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
1875	reasonable memory usage.	2608	reasonable memory usage.
1876		2609
1877	=back	2610	=back
…		…
1893	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
1894	(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
1895	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.
1896		2629
1897	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
1898	distribution.	2631	distribution. It uses the L<AE> interface, which makes a real difference
		2632	for the EV and Perl backends only.
1899		2633
1900	=head3 Explanation of the columns	2634	=head3 Explanation of the columns
1901		2635
1902	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
1903	each server has a read and write socket end).	2637	each server has a read and write socket end).
…		…
1911	a new one that moves the timeout into the future.	2645	a new one that moves the timeout into the future.
1912		2646
1913	=head3 Results	2647	=head3 Results
1914		2648
1915	name sockets create request	2649	name sockets create request
1916	EV 20000 69.01 11.16	2650	EV 20000 62.66 7.99
1917	Perl 20000 73.32 35.87	2651	Perl 20000 68.32 32.64
1918	IOAsync 20000 157.00 98.14 epoll	2652	IOAsync 20000 174.06 101.15 epoll
1919	IOAsync 20000 159.31 616.06 poll	2653	IOAsync 20000 174.67 610.84 poll
1920	Event 20000 212.62 257.32	2654	Event 20000 202.69 242.91
1921	Glib 20000 651.16 1896.30	2655	Glib 20000 557.01 1689.52
1922	POE 20000 349.67 12317.24 uses POE::Loop::Event	2656	POE 20000 341.54 12086.32 uses POE::Loop::Event
1923		2657
1924	=head3 Discussion	2658	=head3 Discussion
1925		2659
1926	This benchmark I<does> measure scalability and overall performance of the	2660	This benchmark I<does> measure scalability and overall performance of the
1927	particular event loop.	2661	particular event loop.
…		…
2053	As you can see, the AnyEvent + EV combination even beats the	2787	As you can see, the AnyEvent + EV combination even beats the
2054	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2788	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2055	backend easily beats IO::Lambda and POE.	2789	backend easily beats IO::Lambda and POE.
2056		2790
2057	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
2058	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
2059	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
2060	in a non-blocking way.	2794	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2061		2795
2062	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
2063	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
2064	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.
2065		2799
2066		2800
2067	=head1 SIGNALS	2801	=head1 SIGNALS
2068		2802
2069	AnyEvent currently installs handlers for these signals:	2803	AnyEvent currently installs handlers for these signals:
…		…
2074		2808
2075	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
2076	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
2077	event loops install a similar handler.	2811	event loops install a similar handler.
2078		2812
2079	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
2080	reset it to default, to avoid losing child exit statuses.	2814	AnyEvent will reset it to default, to avoid losing child exit statuses.
2081		2815
2082	=item SIGPIPE	2816	=item SIGPIPE
2083		2817
2084	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>
2085	when AnyEvent gets loaded.	2819	when AnyEvent gets loaded.
…		…
2103	if $SIG{CHLD} eq 'IGNORE';	2837	if $SIG{CHLD} eq 'IGNORE';
2104		2838
2105	$SIG{PIPE} = sub { }	2839	$SIG{PIPE} = sub { }
2106	unless defined $SIG{PIPE};	2840	unless defined $SIG{PIPE};
2107		2841
		2842	=head1 RECOMMENDED/OPTIONAL MODULES
		2843
		2844	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2845	its built-in modules) are required to use it.
		2846
		2847	That does not mean that AnyEvent won't take advantage of some additional
		2848	modules if they are installed.
		2849
		2850	This section explains which additional modules will be used, and how they
		2851	affect AnyEvent's operation.
		2852
		2853	=over 4
		2854
		2855	=item L<Async::Interrupt>
		2856
		2857	This slightly arcane module is used to implement fast signal handling: To
		2858	my knowledge, there is no way to do completely race-free and quick
		2859	signal handling in pure perl. To ensure that signals still get
		2860	delivered, AnyEvent will start an interval timer to wake up perl (and
		2861	catch the signals) with some delay (default is 10 seconds, look for
		2862	C<$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
2108	=head1 FORK	2920	=head1 FORK
2109		2921
2110	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
2111	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
2112	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).
2113		2934
2114	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
2115	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.
2116		2947
2117		2948
2118	=head1 SECURITY CONSIDERATIONS	2949	=head1 SECURITY CONSIDERATIONS
2119		2950
2120	AnyEvent can be forced to load any event model via	2951	AnyEvent can be forced to load any event model via
…		…
2150	pronounced).	2981	pronounced).
2151		2982
2152		2983
2153	=head1 SEE ALSO	2984	=head1 SEE ALSO
2154		2985
2155	Utility functions: L<AnyEvent::Util>.	2986	Tutorial/Introduction: L<AnyEvent::Intro>.
2156		2987
2157	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2988	FAQ: L<AnyEvent::FAQ>.
2158	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>.
2159		2999
2160	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3000	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2161	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>,
2162	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3002	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2163	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	3003	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3004	L<AnyEvent::Impl::FLTK>.
2164		3005
2165	Non-blocking file handles, sockets, TCP clients and	3006	Non-blocking handles, pipes, stream sockets, TCP clients and
2166	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3007	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2167		3008
2168	Asynchronous DNS: L<AnyEvent::DNS>.	3009	Asynchronous DNS: L<AnyEvent::DNS>.
2169		3010
2170	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3011	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2171	L<Coro::Event>,
2172		3012
2173	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3013	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2174	L<AnyEvent::HTTP>.	3014	L<AnyEvent::HTTP>.
2175		3015
2176		3016
2177	=head1 AUTHOR	3017	=head1 AUTHOR
2178		3018

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines