ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.238 by root, Thu Jul 16 03:48:33 2009 UTC vs.
Revision 1.408 by root, Thu Dec 6 12:04:23 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} = ...;
…		…
656	};	763	};
657	}	764	}
658		765
659	$cv->end;	766	$cv->end;
660		767
		768	...
		769
		770	my $results = $cv->recv;
		771
661	This code fragment supposedly pings a number of hosts and calls	772	This code fragment supposedly pings a number of hosts and calls
662	C<send> after results for all then have have been gathered - in any	773	C<send> after results for all then have have been gathered - in any
663	order. To achieve this, the code issues a call to C<begin> when it starts	774	order. To achieve this, the code issues a call to C<begin> when it starts
664	each ping request and calls C<end> when it has received some result for	775	each ping request and calls C<end> when it has received some result for
665	it. Since C<begin> and C<end> only maintain a counter, the order in which	776	it. Since C<begin> and C<end> only maintain a counter, the order in which
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	781	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	782	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	783	doesn't execute once).
673		784
674	This is the general pattern when you "fan out" into multiple (but	785	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	786	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	787	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,	788	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	789	call C<end>.
679		790
680	=back	791	=back
…		…
687	=over 4	798	=over 4
688		799
689	=item $cv->recv	800	=item $cv->recv
690		801
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	802	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	803	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	804	normally.
694		805
695	You can only wait once on a condition - additional calls are valid but	806	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	807	will return immediately.
697		808
…		…
699	function will call C<croak>.	810	function will call C<croak>.
700		811
701	In list context, all parameters passed to C<send> will be returned,	812	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	813	in scalar context only the first one will be returned.
703		814
		815	Note that doing a blocking wait in a callback is not supported by any
		816	event loop, that is, recursive invocation of a blocking C<< ->recv
		817	>> is not allowed, and the C<recv> call will C<croak> if such a
		818	condition is detected. This condition can be slightly loosened by using
		819	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		820	any thread that doesn't run the event loop itself.
		821
704	Not all event models support a blocking wait - some die in that case	822	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	823	(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	824	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	825	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	826	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	827	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	828	while still supporting blocking waits if the caller so desires).
711		829
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	830	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	831	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	832	time). This will work even when the event loop does not support blocking
726	waits otherwise.	833	waits otherwise.
727		834
728	=item $bool = $cv->ready	835	=item $bool = $cv->ready
…		…
734		841
735	This is a mutator function that returns the callback set and optionally	842	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	843	replaces it before doing so.
737		844
738	The callback will be called when the condition becomes "true", i.e. when	845	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	846	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	847	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	848	callback is called immediately when it is set. Calling C<recv> inside
		849	the callback or at any later time is guaranteed not to block.
742		850
743	=back	851	=back
744		852
745	=head1 SUPPORTED EVENT LOOPS/BACKENDS	853	=head1 SUPPORTED EVENT LOOPS/BACKENDS
746		854
…		…
749	=over 4	857	=over 4
750		858
751	=item Backends that are autoprobed when no other event loop can be found.	859	=item Backends that are autoprobed when no other event loop can be found.
752		860
753	EV is the preferred backend when no other event loop seems to be in	861	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	862	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	863	pure-perl implementation, which is available everywhere as it comes with
756	available everywhere as it comes with AnyEvent itself.	864	AnyEvent itself.
757		865
758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	866	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.	867	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
761		868
762	=item Backends that are transparently being picked up when they are used.	869	=item Backends that are transparently being picked up when they are used.
763		870
764	These will be used when they are currently loaded when the first watcher	871	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	872	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	873	them. This means that AnyEvent will automatically pick the right backend
767	when the main program loads an event module before anything starts to	874	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.	875	create watchers. Nothing special needs to be done by the main program.
769		876
		877	AnyEvent::Impl::Event based on Event, very stable, few glitches.
770	AnyEvent::Impl::Glib based on Glib, slow but very stable.	878	AnyEvent::Impl::Glib based on Glib, slow but very stable.
771	AnyEvent::Impl::Tk based on Tk, very broken.	879	AnyEvent::Impl::Tk based on Tk, very broken.
772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	880	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
773	AnyEvent::Impl::POE based on POE, very slow, some limitations.	881	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		882	AnyEvent::Impl::Irssi used when running within irssi.
		883	AnyEvent::Impl::IOAsync based on IO::Async.
		884	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		885	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
774		886
775	=item Backends with special needs.	887	=item Backends with special needs.
776		888
777	Qt requires the Qt::Application to be instantiated first, but will	889	Qt requires the Qt::Application to be instantiated first, but will
778	otherwise be picked up automatically. As long as the main program	890	otherwise be picked up automatically. As long as the main program
779	instantiates the application before any AnyEvent watchers are created,	891	instantiates the application before any AnyEvent watchers are created,
780	everything should just work.	892	everything should just work.
781		893
782	AnyEvent::Impl::Qt based on Qt.	894	AnyEvent::Impl::Qt based on Qt.
783		895
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.	896	=item Event loops that are indirectly supported via other backends.
793		897
794	Some event loops can be supported via other modules:	898	Some event loops can be supported via other modules:
795		899
796	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	900	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
821	Contains C<undef> until the first watcher is being created, before the	925	Contains C<undef> until the first watcher is being created, before the
822	backend has been autodetected.	926	backend has been autodetected.
823		927
824	Afterwards it contains the event model that is being used, which is the	928	Afterwards it contains the event model that is being used, which is the
825	name of the Perl class implementing the model. This class is usually one	929	name of the Perl class implementing the model. This class is usually one
826	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	930	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
827	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	931	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
828	will be C<urxvt::anyevent>).	932	will be C<urxvt::anyevent>).
829		933
830	=item AnyEvent::detect	934	=item AnyEvent::detect
831		935
832	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	936	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
833	if necessary. You should only call this function right before you would	937	if necessary. You should only call this function right before you would
834	have created an AnyEvent watcher anyway, that is, as late as possible at	938	have created an AnyEvent watcher anyway, that is, as late as possible at
835	runtime, and not e.g. while initialising of your module.	939	runtime, and not e.g. during initialisation of your module.
		940
		941	The effect of calling this function is as if a watcher had been created
		942	(specifically, actions that happen "when the first watcher is created"
		943	happen when calling detetc as well).
836		944
837	If you need to do some initialisation before AnyEvent watchers are	945	If you need to do some initialisation before AnyEvent watchers are
838	created, use C<post_detect>.	946	created, use C<post_detect>.
839		947
840	=item $guard = AnyEvent::post_detect { BLOCK }	948	=item $guard = AnyEvent::post_detect { BLOCK }
841		949
842	Arranges for the code block to be executed as soon as the event model is	950	Arranges for the code block to be executed as soon as the event model is
843	autodetected (or immediately if this has already happened).	951	autodetected (or immediately if that has already happened).
844		952
845	The block will be executed I<after> the actual backend has been detected	953	The block will be executed I<after> the actual backend has been detected
846	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	954	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
847	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	955	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
848	other initialisations - see the sources of L<AnyEvent::Strict> or	956	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
852	event module detection too early, for example, L<AnyEvent::AIO> creates	960	event module detection too early, for example, L<AnyEvent::AIO> creates
853	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	961	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
854	avoid autodetecting the event module at load time.	962	avoid autodetecting the event module at load time.
855		963
856	If called in scalar or list context, then it creates and returns an object	964	If called in scalar or list context, then it creates and returns an object
857	that automatically removes the callback again when it is destroyed. See	965	that automatically removes the callback again when it is destroyed (or
		966	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
858	L<Coro::BDB> for a case where this is useful.	967	a case where this is useful.
		968
		969	Example: Create a watcher for the IO::AIO module and store it in
		970	C<$WATCHER>, but do so only do so after the event loop is initialised.
		971
		972	our WATCHER;
		973
		974	my $guard = AnyEvent::post_detect {
		975	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		976	};
		977
		978	# the ||= is important in case post_detect immediately runs the block,
		979	# as to not clobber the newly-created watcher. assigning both watcher and
		980	# post_detect guard to the same variable has the advantage of users being
		981	# able to just C<undef $WATCHER> if the watcher causes them grief.
		982
		983	$WATCHER ||= $guard;
859		984
860	=item @AnyEvent::post_detect	985	=item @AnyEvent::post_detect
861		986
862	If there are any code references in this array (you can C<push> to it	987	If there are any code references in this array (you can C<push> to it
863	before or after loading AnyEvent), then they will called directly after	988	before or after loading AnyEvent), then they will be called directly
864	the event loop has been chosen.	989	after the event loop has been chosen.
865		990
866	You should check C<$AnyEvent::MODEL> before adding to this array, though:	991	You should check C<$AnyEvent::MODEL> before adding to this array, though:
867	if it is defined then the event loop has already been detected, and the	992	if it is defined then the event loop has already been detected, and the
868	array will be ignored.	993	array will be ignored.
869		994
870	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	995	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
871	it,as it takes care of these details.	996	it, as it takes care of these details.
872		997
873	This variable is mainly useful for modules that can do something useful	998	This variable is mainly useful for modules that can do something useful
874	when AnyEvent is used and thus want to know when it is initialised, but do	999	when AnyEvent is used and thus want to know when it is initialised, but do
875	not need to even load it by default. This array provides the means to hook	1000	not need to even load it by default. This array provides the means to hook
876	into AnyEvent passively, without loading it.	1001	into AnyEvent passively, without loading it.
877		1002
		1003	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1004	together, you could put this into Coro (this is the actual code used by
		1005	Coro to accomplish this):
		1006
		1007	if (defined $AnyEvent::MODEL) {
		1008	# AnyEvent already initialised, so load Coro::AnyEvent
		1009	require Coro::AnyEvent;
		1010	} else {
		1011	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1012	# as soon as it is
		1013	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1014	}
		1015
		1016	=item AnyEvent::postpone { BLOCK }
		1017
		1018	Arranges for the block to be executed as soon as possible, but not before
		1019	the call itself returns. In practise, the block will be executed just
		1020	before the event loop polls for new events, or shortly afterwards.
		1021
		1022	This function never returns anything (to make the C<return postpone { ...
		1023	}> idiom more useful.
		1024
		1025	To understand the usefulness of this function, consider a function that
		1026	asynchronously does something for you and returns some transaction
		1027	object or guard to let you cancel the operation. For example,
		1028	C<AnyEvent::Socket::tcp_connect>:
		1029
		1030	# start a conenction attempt unless one is active
		1031	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1032	delete $self->{connect_guard};
		1033	...
		1034	};
		1035
		1036	Imagine that this function could instantly call the callback, for
		1037	example, because it detects an obvious error such as a negative port
		1038	number. Invoking the callback before the function returns causes problems
		1039	however: the callback will be called and will try to delete the guard
		1040	object. But since the function hasn't returned yet, there is nothing to
		1041	delete. When the function eventually returns it will assign the guard
		1042	object to C<< $self->{connect_guard} >>, where it will likely never be
		1043	deleted, so the program thinks it is still trying to connect.
		1044
		1045	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1046	callback directly on error:
		1047
		1048	$cb->(undef), return # signal error to callback, BAD!
		1049	if $some_error_condition;
		1050
		1051	It should use C<postpone>:
		1052
		1053	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1054	if $some_error_condition;
		1055
		1056	=item AnyEvent::log $level, $msg[, @args]
		1057
		1058	Log the given C<$msg> at the given C<$level>.
		1059
		1060	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1061	to see whether the message will be logged. If the test succeeds it will
		1062	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1063	the L<AnyEvent::Log> documentation for details.
		1064
		1065	If the test fails it will simply return. Right now this happens when a
		1066	numerical loglevel is used and it is larger than the level specified via
		1067	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1068
		1069	If you want to sprinkle loads of logging calls around your code, consider
		1070	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1071	which can reduce typing, codesize and can reduce the logging overhead
		1072	enourmously.
		1073
878	=back	1074	=back
879		1075
880	=head1 WHAT TO DO IN A MODULE	1076	=head1 WHAT TO DO IN A MODULE
881		1077
882	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1078	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
892	because it will stall the whole program, and the whole point of using	1088	because it will stall the whole program, and the whole point of using
893	events is to stay interactive.	1089	events is to stay interactive.
894		1090
895	It is fine, however, to call C<< ->recv >> when the user of your module	1091	It is fine, however, to call C<< ->recv >> when the user of your module
896	requests it (i.e. if you create a http request object ad have a method	1092	requests it (i.e. if you create a http request object ad have a method
897	called C<results> that returns the results, it should call C<< ->recv >>	1093	called C<results> that returns the results, it may call C<< ->recv >>
898	freely, as the user of your module knows what she is doing. always).	1094	freely, as the user of your module knows what she is doing. Always).
899		1095
900	=head1 WHAT TO DO IN THE MAIN PROGRAM	1096	=head1 WHAT TO DO IN THE MAIN PROGRAM
901		1097
902	There will always be a single main program - the only place that should	1098	There will always be a single main program - the only place that should
903	dictate which event model to use.	1099	dictate which event model to use.
904		1100
905	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1101	If the program is not event-based, it need not do anything special, even
906	do anything special (it does not need to be event-based) and let AnyEvent	1102	when it depends on a module that uses an AnyEvent. If the program itself
907	decide which implementation to chose if some module relies on it.	1103	uses AnyEvent, but does not care which event loop is used, all it needs
		1104	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1105	available loop implementation.
908		1106
909	If the main program relies on a specific event model - for example, in	1107	If the main program relies on a specific event model - for example, in
910	Gtk2 programs you have to rely on the Glib module - you should load the	1108	Gtk2 programs you have to rely on the Glib module - you should load the
911	event module before loading AnyEvent or any module that uses it: generally	1109	event module before loading AnyEvent or any module that uses it: generally
912	speaking, you should load it as early as possible. The reason is that	1110	speaking, you should load it as early as possible. The reason is that
913	modules might create watchers when they are loaded, and AnyEvent will	1111	modules might create watchers when they are loaded, and AnyEvent will
914	decide on the event model to use as soon as it creates watchers, and it	1112	decide on the event model to use as soon as it creates watchers, and it
915	might chose the wrong one unless you load the correct one yourself.	1113	might choose the wrong one unless you load the correct one yourself.
916		1114
917	You can chose to use a pure-perl implementation by loading the	1115	You can chose to use a pure-perl implementation by loading the
918	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1116	C<AnyEvent::Loop> module, which gives you similar behaviour
919	everywhere, but letting AnyEvent chose the model is generally better.	1117	everywhere, but letting AnyEvent chose the model is generally better.
920		1118
921	=head2 MAINLOOP EMULATION	1119	=head2 MAINLOOP EMULATION
922		1120
923	Sometimes (often for short test scripts, or even standalone programs who	1121	Sometimes (often for short test scripts, or even standalone programs who
…		…
936		1134
937		1135
938	=head1 OTHER MODULES	1136	=head1 OTHER MODULES
939		1137
940	The following is a non-exhaustive list of additional modules that use	1138	The following is a non-exhaustive list of additional modules that use
941	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1139	AnyEvent as a client and can therefore be mixed easily with other
942	modules and other event loops in the same program. Some of the modules	1140	AnyEvent modules and other event loops in the same program. Some of the
943	come with AnyEvent, most are available via CPAN.	1141	modules come as part of AnyEvent, the others are available via CPAN (see
		1142	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1143	a longer non-exhaustive list), and the list is heavily biased towards
		1144	modules of the AnyEvent author himself :)
944		1145
945	=over 4	1146	=over 4
946		1147
947	=item L<AnyEvent::Util>	1148	=item L<AnyEvent::Util>
948		1149
949	Contains various utility functions that replace often-used but blocking	1150	Contains various utility functions that replace often-used blocking
950	functions such as C<inet_aton> by event-/callback-based versions.	1151	functions such as C<inet_aton> with event/callback-based versions.
951		1152
952	=item L<AnyEvent::Socket>	1153	=item L<AnyEvent::Socket>
953		1154
954	Provides various utility functions for (internet protocol) sockets,	1155	Provides various utility functions for (internet protocol) sockets,
955	addresses and name resolution. Also functions to create non-blocking tcp	1156	addresses and name resolution. Also functions to create non-blocking tcp
…		…
957		1158
958	=item L<AnyEvent::Handle>	1159	=item L<AnyEvent::Handle>
959		1160
960	Provide read and write buffers, manages watchers for reads and writes,	1161	Provide read and write buffers, manages watchers for reads and writes,
961	supports raw and formatted I/O, I/O queued and fully transparent and	1162	supports raw and formatted I/O, I/O queued and fully transparent and
962	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1163	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
963		1164
964	=item L<AnyEvent::DNS>	1165	=item L<AnyEvent::DNS>
965		1166
966	Provides rich asynchronous DNS resolver capabilities.	1167	Provides rich asynchronous DNS resolver capabilities.
967		1168
		1169	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1170
		1171	Implement event-based interfaces to the protocols of the same name (for
		1172	the curious, IGS is the International Go Server and FCP is the Freenet
		1173	Client Protocol).
		1174
968	=item L<AnyEvent::HTTP>	1175	=item L<AnyEvent::AIO>
969		1176
970	A simple-to-use HTTP library that is capable of making a lot of concurrent	1177	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
971	HTTP requests.	1178	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1179	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1180	file I/O, and much more.
		1181
		1182	=item L<AnyEvent::Filesys::Notify>
		1183
		1184	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1185	path changes (e.g. "watch this directory for new files", "watch this
		1186	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1187	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1188	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1189	fall back to blocking scans at regular intervals transparently on other
		1190	platforms, so it's about as portable as it gets.
		1191
		1192	(I haven't used it myself, but I haven't heard anybody complaining about
		1193	it yet).
		1194
		1195	=item L<AnyEvent::DBI>
		1196
		1197	Executes L<DBI> requests asynchronously in a proxy process for you,
		1198	notifying you in an event-based way when the operation is finished.
972		1199
973	=item L<AnyEvent::HTTPD>	1200	=item L<AnyEvent::HTTPD>
974		1201
975	Provides a simple web application server framework.	1202	A simple embedded webserver.
976		1203
977	=item L<AnyEvent::FastPing>	1204	=item L<AnyEvent::FastPing>
978		1205
979	The fastest ping in the west.	1206	The fastest ping in the west.
980		1207
981	=item L<AnyEvent::DBI>
982
983	Executes L<DBI> requests asynchronously in a proxy process.
984
985	=item L<AnyEvent::AIO>
986
987	Truly asynchronous I/O, should be in the toolbox of every event
988	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
989	together.
990
991	=item L<AnyEvent::BDB>
992
993	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
994	L<BDB> and AnyEvent together.
995
996	=item L<AnyEvent::GPSD>
997
998	A non-blocking interface to gpsd, a daemon delivering GPS information.
999
1000	=item L<AnyEvent::IRC>
1001
1002	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1003
1004	=item L<AnyEvent::XMPP>
1005
1006	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1007	Net::XMPP2>.
1008
1009	=item L<AnyEvent::IGS>
1010
1011	A non-blocking interface to the Internet Go Server protocol (used by
1012	L<App::IGS>).
1013
1014	=item L<Net::FCP>
1015
1016	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1017	of AnyEvent.
1018
1019	=item L<Event::ExecFlow>
1020
1021	High level API for event-based execution flow control.
1022
1023	=item L<Coro>	1208	=item L<Coro>
1024		1209
1025	Has special support for AnyEvent via L<Coro::AnyEvent>.	1210	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1211	to simply invert the flow control - don't call us, we will call you:
		1212
		1213	async {
		1214	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1215	print "5 seconds later!\n";
		1216
		1217	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1218	my $line = <STDIN>; # works for ttys
		1219
		1220	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1221	my ($body, $hdr) = Coro::rouse_wait;
		1222	};
1026		1223
1027	=back	1224	=back
1028		1225
1029	=cut	1226	=cut
1030		1227
1031	package AnyEvent;	1228	package AnyEvent;
1032		1229
1033	no warnings;	1230	# basically a tuned-down version of common::sense
1034	use strict qw(vars subs);	1231	sub common_sense {
		1232	# from common:.sense 3.5
		1233	local $^W;
		1234	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1235	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1236	$^H |= 0x00000600;
		1237	}
1035		1238
		1239	BEGIN { AnyEvent::common_sense }
		1240
1036	use Carp;	1241	use Carp ();
1037		1242
1038	our $VERSION = 4.82;	1243	our $VERSION = '7.04';
1039	our $MODEL;	1244	our $MODEL;
1040
1041	our $AUTOLOAD;
1042	our @ISA;	1245	our @ISA;
1043
1044	our @REGISTRY;	1246	our @REGISTRY;
1045		1247	our $VERBOSE;
1046	our $WIN32;	1248	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1249	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1047		1250
1048	BEGIN {	1251	BEGIN {
1049	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1252	require "AnyEvent/constants.pl";
		1253
1050	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1254	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1051		1255
1052	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1256	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1053	if ${^TAINT};	1257	if ${^TAINT};
1054	}
1055		1258
1056	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1259	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1260	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1057		1261
1058	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1262	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1263	if ${^TAINT};
1059		1264
1060	{	1265	# $ENV{PERL_ANYEVENT_xxx} now valid
		1266
		1267	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1268
1061	my $idx;	1269	my $idx;
1062	$PROTOCOL{$_} = ++$idx	1270	$PROTOCOL{$_} = ++$idx
1063	for reverse split /\s*,\s*/,	1271	for reverse split /\s*,\s*/,
1064	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1272	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1065	}	1273	}
1066		1274
		1275	our @post_detect;
		1276
		1277	sub post_detect(&) {
		1278	my ($cb) = @_;
		1279
		1280	push @post_detect, $cb;
		1281
		1282	defined wantarray
		1283	? bless \$cb, "AnyEvent::Util::postdetect"
		1284	: ()
		1285	}
		1286
		1287	sub AnyEvent::Util::postdetect::DESTROY {
		1288	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1289	}
		1290
		1291	our $POSTPONE_W;
		1292	our @POSTPONE;
		1293
		1294	sub _postpone_exec {
		1295	undef $POSTPONE_W;
		1296
		1297	&{ shift @POSTPONE }
		1298	while @POSTPONE;
		1299	}
		1300
		1301	sub postpone(&) {
		1302	push @POSTPONE, shift;
		1303
		1304	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1305
		1306	()
		1307	}
		1308
		1309	sub log($$;@) {
		1310	# only load the big bloated module when we actually are about to log something
		1311	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1312	local ($!, $@);
		1313	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1314	# AnyEvent::Log overwrites this function
		1315	goto &log;
		1316	}
		1317
		1318	0 # not logged
		1319	}
		1320
		1321	sub _logger($;$) {
		1322	my ($level, $renabled) = @_;
		1323
		1324	$$renabled = $level <= $VERBOSE;
		1325
		1326	my $logger = [(caller)[0], $level, $renabled];
		1327
		1328	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1329
		1330	# return unless defined wantarray;
		1331	#
		1332	# require AnyEvent::Util;
		1333	# my $guard = AnyEvent::Util::guard (sub {
		1334	# # "clean up"
		1335	# delete $LOGGER{$logger+0};
		1336	# });
		1337	#
		1338	# sub {
		1339	# return 0 unless $$renabled;
		1340	#
		1341	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1342	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1343	# package AnyEvent::Log;
		1344	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1345	# }
		1346	}
		1347
		1348	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1349	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1350	}
		1351
1067	my @models = (	1352	our @models = (
1068	[EV:: => AnyEvent::Impl::EV::],	1353	[EV:: => AnyEvent::Impl::EV::],
1069	[Event:: => AnyEvent::Impl::Event::],
1070	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1354	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1071	# everything below here will not be autoprobed	1355	# everything below here will not (normally) be autoprobed
1072	# as the pureperl backend should work everywhere	1356	# as the pure perl backend should work everywhere
1073	# and is usually faster	1357	# and is usually faster
		1358	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
		1359	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1074	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1360	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1361	# everything below here should not be autoloaded
1075	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1362	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1076	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1363	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1077	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1364	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1078	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1365	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1079	[Wx:: => AnyEvent::Impl::POE::],	1366	[Wx:: => AnyEvent::Impl::POE::],
1080	[Prima:: => AnyEvent::Impl::POE::],	1367	[Prima:: => AnyEvent::Impl::POE::],
1081	# IO::Async is just too broken - we would need workarounds for its	1368	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1082	# byzantine signal and broken child handling, among others.	1369	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1083	# IO::Async is rather hard to detect, as it doesn't have any	1370	[FLTK:: => AnyEvent::Impl::FLTK::],
1084	# obvious default class.
1085	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1086	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1087	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1088	);	1371	);
1089		1372
1090	our %method = map +($_ => 1),	1373	our @isa_hook;
		1374
		1375	sub _isa_set {
		1376	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1377
		1378	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1379	for 1 .. $#pkg;
		1380
		1381	grep $_ && $_->[1], @isa_hook
		1382	and AE::_reset ();
		1383	}
		1384
		1385	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1386	sub _isa_hook($$;$) {
		1387	my ($i, $pkg, $reset_ae) = @_;
		1388
		1389	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1390
		1391	_isa_set;
		1392	}
		1393
		1394	# all autoloaded methods reserve the complete glob, not just the method slot.
		1395	# due to bugs in perls method cache implementation.
1091	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1396	our @methods = qw(io timer time now now_update signal child idle condvar);
1092		1397
1093	our @post_detect;
1094
1095	sub post_detect(&) {	1398	sub detect() {
1096	my ($cb) = @_;	1399	return $MODEL if $MODEL; # some programs keep references to detect
1097		1400
1098	if ($MODEL) {	1401	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1099	$cb->();	1402	# the author knows about the problems and what it does to AnyEvent as a whole
		1403	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1404	# anyway.
		1405	AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1406	. "design, abuses internals and breaks AnyEvent - will not continue."
		1407	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1100		1408
1101	1	1409	local $!; # for good measure
		1410	local $SIG{__DIE__}; # we use eval
		1411
		1412	# free some memory
		1413	*detect = sub () { $MODEL };
		1414	# undef &func doesn't correctly update the method cache. grmbl.
		1415	# so we delete the whole glob. grmbl.
		1416	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1417	# a glob with an active sub. hrm. i hope it works, but perl is
		1418	# usually buggy in this department. sigh.
		1419	delete @{"AnyEvent::"}{@methods};
		1420	undef @methods;
		1421
		1422	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1423	my $model = $1;
		1424	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1425	if (eval "require $model") {
		1426	AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1427	$MODEL = $model;
1102	} else {	1428	} else {
1103	push @post_detect, $cb;	1429	AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1104		1430	}
1105	defined wantarray
1106	? bless \$cb, "AnyEvent::Util::postdetect"
1107	: ()
1108	}	1431	}
1109	}
1110		1432
1111	sub AnyEvent::Util::postdetect::DESTROY {	1433	# check for already loaded models
1112	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1113	}
1114
1115	sub detect() {
1116	unless ($MODEL) {	1434	unless ($MODEL) {
1117	no strict 'refs';	1435	for (@REGISTRY, @models) {
1118	local $SIG{__DIE__};	1436	my ($package, $model) = @$_;
1119		1437	if (${"$package\::VERSION"} > 0) {
1120	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1121	my $model = "AnyEvent::Impl::$1";
1122	if (eval "require $model") {	1438	if (eval "require $model") {
		1439	AnyEvent::log 7 => "Autodetected model '$model', using it.";
1123	$MODEL = $model;	1440	$MODEL = $model;
1124	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;	1441	last;
1125	} else {	1442	} else {
1126	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;	1443	AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
		1444	}
1127	}	1445	}
1128	}	1446	}
1129		1447
1130	# check for already loaded models
1131	unless ($MODEL) {	1448	unless ($MODEL) {
		1449	# try to autoload a model
1132	for (@REGISTRY, @models) {	1450	for (@REGISTRY, @models) {
1133	my ($package, $model) = @$_;	1451	my ($package, $model) = @$_;
		1452	if (
		1453	eval "require $package"
1134	if (${"$package\::VERSION"} > 0) {	1454	and ${"$package\::VERSION"} > 0
1135	if (eval "require $model") {	1455	and eval "require $model"
		1456	) {
		1457	AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1136	$MODEL = $model;	1458	$MODEL = $model;
1137	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1138	last;	1459	last;
1139	}
1140	}	1460	}
1141	}	1461	}
1142		1462
1143	unless ($MODEL) {
1144	# try to load a model
1145
1146	for (@REGISTRY, @models) {
1147	my ($package, $model) = @$_;
1148	if (eval "require $package"
1149	and ${"$package\::VERSION"} > 0
1150	and eval "require $model") {
1151	$MODEL = $model;
1152	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1153	last;
1154	}
1155	}
1156
1157	$MODEL	1463	$MODEL
1158	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1464	or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1159	}
1160	}	1465	}
1161
1162	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1163
1164	unshift @ISA, $MODEL;
1165
1166	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1167
1168	(shift @post_detect)->() while @post_detect;
1169	}	1466	}
1170		1467
		1468	# free memory only needed for probing
		1469	undef @models;
		1470	undef @REGISTRY;
		1471
		1472	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1473
		1474	# now nuke some methods that are overridden by the backend.
		1475	# SUPER usage is not allowed in these.
		1476	for (qw(time signal child idle)) {
		1477	undef &{"AnyEvent::Base::$_"}
		1478	if defined &{"$MODEL\::$_"};
		1479	}
		1480
		1481	_isa_set;
		1482
		1483	# we're officially open!
		1484
		1485	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1486	require AnyEvent::Strict;
		1487	}
		1488
		1489	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1490	require AnyEvent::Debug;
		1491	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1492	}
		1493
		1494	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1495	require AnyEvent::Socket;
		1496	require AnyEvent::Debug;
		1497
		1498	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1499	$shell =~ s/\$\$/$$/g;
		1500
		1501	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1502	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1503	}
		1504
		1505	# now the anyevent environment is set up as the user told us to, so
		1506	# call the actual user code - post detects
		1507
		1508	(shift @post_detect)->() while @post_detect;
		1509	undef @post_detect;
		1510
		1511	*post_detect = sub(&) {
		1512	shift->();
		1513
		1514	undef
		1515	};
		1516
1171	$MODEL	1517	$MODEL
1172	}	1518	}
1173		1519
1174	sub AUTOLOAD {	1520	for my $name (@methods) {
1175	(my $func = $AUTOLOAD) =~ s/.*://;	1521	*$name = sub {
1176		1522	detect;
1177	$method{$func}	1523	# we use goto because
1178	or croak "$func: not a valid method for AnyEvent objects";	1524	# a) it makes the thunk more transparent
1179		1525	# b) it allows us to delete the thunk later
1180	detect unless $MODEL;	1526	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1181		1527	};
1182	my $class = shift;
1183	$class->$func (@_);
1184	}	1528	}
1185		1529
1186	# utility function to dup a filehandle. this is used by many backends	1530	# utility function to dup a filehandle. this is used by many backends
1187	# to support binding more than one watcher per filehandle (they usually	1531	# to support binding more than one watcher per filehandle (they usually
1188	# allow only one watcher per fd, so we dup it to get a different one).	1532	# allow only one watcher per fd, so we dup it to get a different one).
1189	sub _dupfh($$;$$) {	1533	sub _dupfh($$;$$) {
1190	my ($poll, $fh, $r, $w) = @_;	1534	my ($poll, $fh, $r, $w) = @_;
1191		1535
1192	# cygwin requires the fh mode to be matching, unix doesn't	1536	# cygwin requires the fh mode to be matching, unix doesn't
1193	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1537	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1194		1538
1195	open my $fh2, "$mode&", $fh	1539	open my $fh2, $mode, $fh
1196	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1540	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1197		1541
1198	# we assume CLOEXEC is already set by perl in all important cases	1542	# we assume CLOEXEC is already set by perl in all important cases
1199		1543
1200	($fh2, $rw)	1544	($fh2, $rw)
1201	}	1545	}
1202		1546
		1547	=head1 SIMPLIFIED AE API
		1548
		1549	Starting with version 5.0, AnyEvent officially supports a second, much
		1550	simpler, API that is designed to reduce the calling, typing and memory
		1551	overhead by using function call syntax and a fixed number of parameters.
		1552
		1553	See the L<AE> manpage for details.
		1554
		1555	=cut
		1556
		1557	package AE;
		1558
		1559	our $VERSION = $AnyEvent::VERSION;
		1560
		1561	sub _reset() {
		1562	eval q{
		1563	# fall back to the main API by default - backends and AnyEvent::Base
		1564	# implementations can overwrite these.
		1565
		1566	sub io($$$) {
		1567	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1568	}
		1569
		1570	sub timer($$$) {
		1571	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1572	}
		1573
		1574	sub signal($$) {
		1575	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1576	}
		1577
		1578	sub child($$) {
		1579	AnyEvent->child (pid => $_[0], cb => $_[1])
		1580	}
		1581
		1582	sub idle($) {
		1583	AnyEvent->idle (cb => $_[0]);
		1584	}
		1585
		1586	sub cv(;&) {
		1587	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1588	}
		1589
		1590	sub now() {
		1591	AnyEvent->now
		1592	}
		1593
		1594	sub now_update() {
		1595	AnyEvent->now_update
		1596	}
		1597
		1598	sub time() {
		1599	AnyEvent->time
		1600	}
		1601
		1602	*postpone = \&AnyEvent::postpone;
		1603	*log = \&AnyEvent::log;
		1604	};
		1605	die if $@;
		1606	}
		1607
		1608	BEGIN { _reset }
		1609
1203	package AnyEvent::Base;	1610	package AnyEvent::Base;
1204		1611
1205	# default implementations for many methods	1612	# default implementations for many methods
1206		1613
1207	BEGIN {	1614	sub time {
		1615	eval q{ # poor man's autoloading {}
		1616	# probe for availability of Time::HiRes
1208	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1617	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1618	*time = sub { Time::HiRes::time () };
1209	*_time = \&Time::HiRes::time;	1619	*AE::time = \& Time::HiRes::time ;
		1620	*now = \&time;
		1621	AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1210	# if (eval "use POSIX (); (POSIX::times())...	1622	# if (eval "use POSIX (); (POSIX::times())...
1211	} else {	1623	} else {
1212	*_time = sub { time }; # epic fail	1624	*time = sub { CORE::time };
		1625	*AE::time = sub (){ CORE::time };
		1626	*now = \&time;
		1627	AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
		1628	}
		1629	};
		1630	die if $@;
		1631
		1632	&time
		1633	}
		1634
		1635	*now = \&time;
		1636	sub now_update { }
		1637
		1638	sub _poll {
		1639	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1640	}
		1641
		1642	# default implementation for ->condvar
		1643	# in fact, the default should not be overwritten
		1644
		1645	sub condvar {
		1646	eval q{ # poor man's autoloading {}
		1647	*condvar = sub {
		1648	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1649	};
		1650
		1651	*AE::cv = sub (;&) {
		1652	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1653	};
		1654	};
		1655	die if $@;
		1656
		1657	&condvar
		1658	}
		1659
		1660	# default implementation for ->signal
		1661
		1662	our $HAVE_ASYNC_INTERRUPT;
		1663
		1664	sub _have_async_interrupt() {
		1665	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1666	&& eval "use Async::Interrupt 1.02 (); 1")
		1667	unless defined $HAVE_ASYNC_INTERRUPT;
		1668
		1669	$HAVE_ASYNC_INTERRUPT
		1670	}
		1671
		1672	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1673	our (%SIG_ASY, %SIG_ASY_W);
		1674	our ($SIG_COUNT, $SIG_TW);
		1675
		1676	# install a dummy wakeup watcher to reduce signal catching latency
		1677	# used by Impls
		1678	sub _sig_add() {
		1679	unless ($SIG_COUNT++) {
		1680	# try to align timer on a full-second boundary, if possible
		1681	my $NOW = AE::now;
		1682
		1683	$SIG_TW = AE::timer
		1684	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1685	$MAX_SIGNAL_LATENCY,
		1686	sub { } # just for the PERL_ASYNC_CHECK
		1687	;
1213	}	1688	}
1214	}	1689	}
1215		1690
1216	sub time { _time }	1691	sub _sig_del {
1217	sub now { _time }	1692	undef $SIG_TW
1218	sub now_update { }	1693	unless --$SIG_COUNT;
1219
1220	# default implementation for ->condvar
1221
1222	sub condvar {
1223	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1224	}	1694	}
1225		1695
1226	# default implementation for ->signal	1696	our $_sig_name_init; $_sig_name_init = sub {
		1697	eval q{ # poor man's autoloading {}
		1698	undef $_sig_name_init;
1227		1699
1228	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1700	if (_have_async_interrupt) {
		1701	*sig2num = \&Async::Interrupt::sig2num;
		1702	*sig2name = \&Async::Interrupt::sig2name;
		1703	} else {
		1704	require Config;
1229		1705
1230	sub _signal_exec {	1706	my %signame2num;
1231	sysread $SIGPIPE_R, my $dummy, 4;	1707	@signame2num{ split ' ', $Config::Config{sig_name} }
		1708	= split ' ', $Config::Config{sig_num};
1232		1709
1233	while (%SIG_EV) {	1710	my @signum2name;
1234	for (keys %SIG_EV) {	1711	@signum2name[values %signame2num] = keys %signame2num;
1235	delete $SIG_EV{$_};	1712
1236	$_->() for values %{ $SIG_CB{$_} || {} };	1713	*sig2num = sub($) {
		1714	$_[0] > 0 ? shift : $signame2num{+shift}
		1715	};
		1716	*sig2name = sub ($) {
		1717	$_[0] > 0 ? $signum2name[+shift] : shift
		1718	};
1237	}	1719	}
1238	}	1720	};
1239	}	1721	die if $@;
		1722	};
		1723
		1724	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1725	sub sig2name($) { &$_sig_name_init; &sig2name }
1240		1726
1241	sub signal {	1727	sub signal {
1242	my (undef, %arg) = @_;	1728	eval q{ # poor man's autoloading {}
		1729	# probe for availability of Async::Interrupt
		1730	if (_have_async_interrupt) {
		1731	AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1243		1732
1244	unless ($SIGPIPE_R) {	1733	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1245	require Fcntl;	1734	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1246		1735
1247	if (AnyEvent::WIN32) {
1248	require AnyEvent::Util;
1249
1250	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1251	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1252	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1253	} else {	1736	} else {
		1737	AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
		1738
		1739	if (AnyEvent::WIN32) {
		1740	require AnyEvent::Util;
		1741
		1742	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1743	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1744	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1745	} else {
1254	pipe $SIGPIPE_R, $SIGPIPE_W;	1746	pipe $SIGPIPE_R, $SIGPIPE_W;
1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1747	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1748	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1257		1749
1258	# not strictly required, as $^F is normally 2, but let's make sure...	1750	# not strictly required, as $^F is normally 2, but let's make sure...
1259	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1751	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1260	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1752	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1753	}
		1754
		1755	$SIGPIPE_R
		1756	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1757
		1758	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1261	}	1759	}
1262		1760
1263	$SIGPIPE_R	1761	*signal = $HAVE_ASYNC_INTERRUPT
1264	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1762	? sub {
		1763	my (undef, %arg) = @_;
1265		1764
1266	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1765	# async::interrupt
1267	}
1268
1269	my $signal = uc $arg{signal}	1766	my $signal = sig2num $arg{signal};
1270	or Carp::croak "required option 'signal' is missing";
1271
1272	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1767	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1768
		1769	$SIG_ASY{$signal} ||= new Async::Interrupt
		1770	cb => sub { undef $SIG_EV{$signal} },
		1771	signal => $signal,
		1772	pipe => [$SIGPIPE_R->filenos],
		1773	pipe_autodrain => 0,
		1774	;
		1775
		1776	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1777	}
		1778	: sub {
		1779	my (undef, %arg) = @_;
		1780
		1781	# pure perl
		1782	my $signal = sig2name $arg{signal};
		1783	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1784
1273	$SIG{$signal} ||= sub {	1785	$SIG{$signal} ||= sub {
1274	local $!;	1786	local $!;
1275	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1787	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1276	undef $SIG_EV{$signal};	1788	undef $SIG_EV{$signal};
		1789	};
		1790
		1791	# can't do signal processing without introducing races in pure perl,
		1792	# so limit the signal latency.
		1793	_sig_add;
		1794
		1795	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1796	}
		1797	;
		1798
		1799	*AnyEvent::Base::signal::DESTROY = sub {
		1800	my ($signal, $cb) = @{$_[0]};
		1801
		1802	_sig_del;
		1803
		1804	delete $SIG_CB{$signal}{$cb};
		1805
		1806	$HAVE_ASYNC_INTERRUPT
		1807	? delete $SIG_ASY{$signal}
		1808	: # delete doesn't work with older perls - they then
		1809	# print weird messages, or just unconditionally exit
		1810	# instead of getting the default action.
		1811	undef $SIG{$signal}
		1812	unless keys %{ $SIG_CB{$signal} };
		1813	};
		1814
		1815	*_signal_exec = sub {
		1816	$HAVE_ASYNC_INTERRUPT
		1817	? $SIGPIPE_R->drain
		1818	: sysread $SIGPIPE_R, (my $dummy), 9;
		1819
		1820	while (%SIG_EV) {
		1821	for (keys %SIG_EV) {
		1822	delete $SIG_EV{$_};
		1823	&$_ for values %{ $SIG_CB{$_} || {} };
		1824	}
		1825	}
		1826	};
1277	};	1827	};
		1828	die if $@;
1278		1829
1279	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1830	&signal
1280	}
1281
1282	sub AnyEvent::Base::signal::DESTROY {
1283	my ($signal, $cb) = @{$_[0]};
1284
1285	delete $SIG_CB{$signal}{$cb};
1286
1287	# delete doesn't work with older perls - they then
1288	# print weird messages, or just unconditionally exit
1289	# instead of getting the default action.
1290	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1291	}	1831	}
1292		1832
1293	# default implementation for ->child	1833	# default implementation for ->child
1294		1834
1295	our %PID_CB;	1835	our %PID_CB;
1296	our $CHLD_W;	1836	our $CHLD_W;
1297	our $CHLD_DELAY_W;	1837	our $CHLD_DELAY_W;
1298	our $WNOHANG;
1299		1838
1300	sub _sigchld {	1839	# used by many Impl's
1301	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1840	sub _emit_childstatus($$) {
		1841	my (undef, $rpid, $rstatus) = @_;
		1842
		1843	$_->($rpid, $rstatus)
1302	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1844	for values %{ $PID_CB{$rpid} || {} },
1303	(values %{ $PID_CB{0} || {} });	1845	values %{ $PID_CB{0} || {} };
1304	}
1305	}	1846	}
1306		1847
1307	sub child {	1848	sub child {
		1849	eval q{ # poor man's autoloading {}
		1850	*_sigchld = sub {
		1851	my $pid;
		1852
		1853	AnyEvent->_emit_childstatus ($pid, $?)
		1854	while ($pid = waitpid -1, WNOHANG) > 0;
		1855	};
		1856
		1857	*child = sub {
1308	my (undef, %arg) = @_;	1858	my (undef, %arg) = @_;
1309		1859
1310	defined (my $pid = $arg{pid} + 0)	1860	my $pid = $arg{pid};
1311	or Carp::croak "required option 'pid' is missing";	1861	my $cb = $arg{cb};
1312		1862
1313	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1863	$PID_CB{$pid}{$cb+0} = $cb;
1314		1864
1315	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1316
1317	unless ($CHLD_W) {	1865	unless ($CHLD_W) {
1318	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1866	$CHLD_W = AE::signal CHLD => \&_sigchld;
1319	# child could be a zombie already, so make at least one round	1867	# child could be a zombie already, so make at least one round
1320	&_sigchld;	1868	&_sigchld;
1321	}	1869	}
1322		1870
1323	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1871	bless [$pid, $cb+0], "AnyEvent::Base::child"
1324	}	1872	};
1325		1873
1326	sub AnyEvent::Base::child::DESTROY {	1874	*AnyEvent::Base::child::DESTROY = sub {
1327	my ($pid, $cb) = @{$_[0]};	1875	my ($pid, $icb) = @{$_[0]};
1328		1876
1329	delete $PID_CB{$pid}{$cb};	1877	delete $PID_CB{$pid}{$icb};
1330	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1878	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1331		1879
1332	undef $CHLD_W unless keys %PID_CB;	1880	undef $CHLD_W unless keys %PID_CB;
		1881	};
		1882	};
		1883	die if $@;
		1884
		1885	&child
1333	}	1886	}
1334		1887
1335	# idle emulation is done by simply using a timer, regardless	1888	# idle emulation is done by simply using a timer, regardless
1336	# of whether the process is idle or not, and not letting	1889	# of whether the process is idle or not, and not letting
1337	# the callback use more than 50% of the time.	1890	# the callback use more than 50% of the time.
1338	sub idle {	1891	sub idle {
		1892	eval q{ # poor man's autoloading {}
		1893	*idle = sub {
1339	my (undef, %arg) = @_;	1894	my (undef, %arg) = @_;
1340		1895
1341	my ($cb, $w, $rcb) = $arg{cb};	1896	my ($cb, $w, $rcb) = $arg{cb};
1342		1897
1343	$rcb = sub {	1898	$rcb = sub {
1344	if ($cb) {	1899	if ($cb) {
1345	$w = _time;	1900	$w = AE::time;
1346	&$cb;	1901	&$cb;
1347	$w = _time - $w;	1902	$w = AE::time - $w;
1348		1903
1349	# never use more then 50% of the time for the idle watcher,	1904	# never use more then 50% of the time for the idle watcher,
1350	# within some limits	1905	# within some limits
1351	$w = 0.0001 if $w < 0.0001;	1906	$w = 0.0001 if $w < 0.0001;
1352	$w = 5 if $w > 5;	1907	$w = 5 if $w > 5;
1353		1908
1354	$w = AnyEvent->timer (after => $w, cb => $rcb);	1909	$w = AE::timer $w, 0, $rcb;
1355	} else {	1910	} else {
1356	# clean up...	1911	# clean up...
1357	undef $w;	1912	undef $w;
1358	undef $rcb;	1913	undef $rcb;
		1914	}
		1915	};
		1916
		1917	$w = AE::timer 0.05, 0, $rcb;
		1918
		1919	bless \\$cb, "AnyEvent::Base::idle"
1359	}	1920	};
		1921
		1922	*AnyEvent::Base::idle::DESTROY = sub {
		1923	undef $${$_[0]};
		1924	};
1360	};	1925	};
		1926	die if $@;
1361		1927
1362	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1928	&idle
1363
1364	bless \\$cb, "AnyEvent::Base::idle"
1365	}
1366
1367	sub AnyEvent::Base::idle::DESTROY {
1368	undef $${$_[0]};
1369	}	1929	}
1370		1930
1371	package AnyEvent::CondVar;	1931	package AnyEvent::CondVar;
1372		1932
1373	our @ISA = AnyEvent::CondVar::Base::;	1933	our @ISA = AnyEvent::CondVar::Base::;
1374		1934
		1935	# only to be used for subclassing
		1936	sub new {
		1937	my $class = shift;
		1938	bless AnyEvent->condvar (@_), $class
		1939	}
		1940
1375	package AnyEvent::CondVar::Base;	1941	package AnyEvent::CondVar::Base;
1376		1942
1377	use overload	1943	#use overload
1378	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1944	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1379	fallback => 1;	1945	# fallback => 1;
		1946
		1947	# save 300+ kilobytes by dirtily hardcoding overloading
		1948	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1949	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1950	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1951	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1952
		1953	our $WAITING;
1380		1954
1381	sub _send {	1955	sub _send {
1382	# nop	1956	# nop
		1957	}
		1958
		1959	sub _wait {
		1960	AnyEvent->_poll until $_[0]{_ae_sent};
1383	}	1961	}
1384		1962
1385	sub send {	1963	sub send {
1386	my $cv = shift;	1964	my $cv = shift;
1387	$cv->{_ae_sent} = [@_];	1965	$cv->{_ae_sent} = [@_];
…		…
1396		1974
1397	sub ready {	1975	sub ready {
1398	$_[0]{_ae_sent}	1976	$_[0]{_ae_sent}
1399	}	1977	}
1400		1978
1401	sub _wait {
1402	AnyEvent->one_event while !$_[0]{_ae_sent};
1403	}
1404
1405	sub recv {	1979	sub recv {
		1980	unless ($_[0]{_ae_sent}) {
		1981	$WAITING
		1982	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1983
		1984	local $WAITING = 1;
1406	$_[0]->_wait;	1985	$_[0]->_wait;
		1986	}
1407		1987
1408	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1988	$_[0]{_ae_croak}
1409	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1989	and Carp::croak $_[0]{_ae_croak};
		1990
		1991	wantarray
		1992	? @{ $_[0]{_ae_sent} }
		1993	: $_[0]{_ae_sent}[0]
1410	}	1994	}
1411		1995
1412	sub cb {	1996	sub cb {
1413	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1997	my $cv = shift;
		1998
		1999	@_
		2000	and $cv->{_ae_cb} = shift
		2001	and $cv->{_ae_sent}
		2002	and (delete $cv->{_ae_cb})->($cv);
		2003
1414	$_[0]{_ae_cb}	2004	$cv->{_ae_cb}
1415	}	2005	}
1416		2006
1417	sub begin {	2007	sub begin {
1418	++$_[0]{_ae_counter};	2008	++$_[0]{_ae_counter};
1419	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2009	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1424	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2014	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1425	}	2015	}
1426		2016
1427	# undocumented/compatibility with pre-3.4	2017	# undocumented/compatibility with pre-3.4
1428	*broadcast = \&send;	2018	*broadcast = \&send;
1429	*wait = \&_wait;	2019	*wait = \&recv;
1430		2020
1431	=head1 ERROR AND EXCEPTION HANDLING	2021	=head1 ERROR AND EXCEPTION HANDLING
1432		2022
1433	In general, AnyEvent does not do any error handling - it relies on the	2023	In general, AnyEvent does not do any error handling - it relies on the
1434	caller to do that if required. The L<AnyEvent::Strict> module (see also	2024	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1446	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2036	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1447	so on.	2037	so on.
1448		2038
1449	=head1 ENVIRONMENT VARIABLES	2039	=head1 ENVIRONMENT VARIABLES
1450		2040
1451	The following environment variables are used by this module or its	2041	AnyEvent supports a number of environment variables that tune the
1452	submodules.	2042	runtime behaviour. They are usually evaluated when AnyEvent is
		2043	loaded, initialised, or a submodule that uses them is loaded. Many of
		2044	them also cause AnyEvent to load additional modules - for example,
		2045	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2046	loaded.
1453		2047
1454	Note that AnyEvent will remove I<all> environment variables starting with	2048	All the environment variables documented here start with
1455	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2049	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1456	enabled.	2050	namespace. Other modules are encouraged (but by no means required) to use
		2051	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2052	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2053	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2054	variables starting with C<AE_>, see below).
		2055
		2056	All variables can also be set via the C<AE_> prefix, that is, instead
		2057	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2058	case there is a clash btween anyevent and another program that uses
		2059	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2060	variable to the empty string, as those variables take precedence.
		2061
		2062	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2063	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2064	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2065	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2066	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2067	is set).
		2068
		2069	The exact algorithm is currently:
		2070
		2071	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2072	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2073	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2074
		2075	This ensures that child processes will not see the C<AE_> variables.
		2076
		2077	The following environment variables are currently known to AnyEvent:
1457		2078
1458	=over 4	2079	=over 4
1459		2080
1460	=item C<PERL_ANYEVENT_VERBOSE>	2081	=item C<PERL_ANYEVENT_VERBOSE>
1461		2082
1462	By default, AnyEvent will be completely silent except in fatal	2083	By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1463	conditions. You can set this environment variable to make AnyEvent more	2084	higher (see L<AnyEvent::Log>). You can set this environment variable to a
1464	talkative.	2085	numerical loglevel to make AnyEvent more (or less) talkative.
1465		2086
		2087	If you want to do more than just set the global logging level
		2088	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2089	complex specifications.
		2090
		2091	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2092	everything else at defaults.
		2093
1466	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2094	When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1467	conditions, such as not being able to load the event model specified by	2095	conditions, such as not being able to load the event model specified by
1468	C<PERL_ANYEVENT_MODEL>.	2096	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2097	is the minimum recommended level for use during development.
1469		2098
1470	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2099	When set to C<7> or higher (info), AnyEvent reports which event model it
1471	model it chooses.	2100	chooses.
		2101
		2102	When set to C<8> or higher (debug), then AnyEvent will report extra
		2103	information on which optional modules it loads and how it implements
		2104	certain features.
		2105
		2106	=item C<PERL_ANYEVENT_LOG>
		2107
		2108	Accepts rather complex logging specifications. For example, you could log
		2109	all C<debug> messages of some module to stderr, warnings and above to
		2110	stderr, and errors and above to syslog, with:
		2111
		2112	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2113
		2114	For the rather extensive details, see L<AnyEvent::Log>.
		2115
		2116	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2117	so will take effect even before AnyEvent has initialised itself.
		2118
		2119	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2120	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2121	using the latter saves a few hundred kB of memory unless a module
		2122	explicitly needs the extra features of AnyEvent::Log.
1472		2123
1473	=item C<PERL_ANYEVENT_STRICT>	2124	=item C<PERL_ANYEVENT_STRICT>
1474		2125
1475	AnyEvent does not do much argument checking by default, as thorough	2126	AnyEvent does not do much argument checking by default, as thorough
1476	argument checking is very costly. Setting this variable to a true value	2127	argument checking is very costly. Setting this variable to a true value
…		…
1478	check the arguments passed to most method calls. If it finds any problems,	2129	check the arguments passed to most method calls. If it finds any problems,
1479	it will croak.	2130	it will croak.
1480		2131
1481	In other words, enables "strict" mode.	2132	In other words, enables "strict" mode.
1482		2133
1483	Unlike C<use strict>, it is definitely recommended to keep it off in	2134	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1484	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2135	>>, it is definitely recommended to keep it off in production. Keeping
1485	developing programs can be very useful, however.	2136	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2137	can be very useful, however.
		2138
		2139	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2140
		2141	If this env variable is nonempty, then its contents will be interpreted by
		2142	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2143	replacing every occurance of C<$$> by the process pid). The shell object
		2144	is saved in C<$AnyEvent::Debug::SHELL>.
		2145
		2146	This happens when the first watcher is created.
		2147
		2148	For example, to bind a debug shell on a unix domain socket in
		2149	F<< /tmp/debug<pid>.sock >>, you could use this:
		2150
		2151	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2152	# connect with e.g.: socat readline /tmp/debug123.sock
		2153
		2154	Or to bind to tcp port 4545 on localhost:
		2155
		2156	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2157	# connect with e.g.: telnet localhost 4545
		2158
		2159	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2160	multiuser systems.
		2161
		2162	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2163
		2164	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2165	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1486		2166
1487	=item C<PERL_ANYEVENT_MODEL>	2167	=item C<PERL_ANYEVENT_MODEL>
1488		2168
1489	This can be used to specify the event model to be used by AnyEvent, before	2169	This can be used to specify the event model to be used by AnyEvent, before
1490	auto detection and -probing kicks in. It must be a string consisting	2170	auto detection and -probing kicks in.
1491	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2171
		2172	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2173	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1492	and the resulting module name is loaded and if the load was successful,	2174	resulting module name is loaded and - if the load was successful - used as
1493	used as event model. If it fails to load AnyEvent will proceed with	2175	event model backend. If it fails to load then AnyEvent will proceed with
1494	auto detection and -probing.	2176	auto detection and -probing.
1495		2177
1496	This functionality might change in future versions.	2178	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2179	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2180	the end of a string designates a module name and quotes it appropriately).
1497		2181
1498	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2182	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1499	could start your program like this:	2183	could start your program like this:
1500		2184
1501	PERL_ANYEVENT_MODEL=Perl perl ...	2185	PERL_ANYEVENT_MODEL=Perl perl ...
		2186
		2187	=item C<PERL_ANYEVENT_IO_MODEL>
		2188
		2189	The current file I/O model - see L<AnyEvent::IO> for more info.
		2190
		2191	At the moment, only C<Perl> (small, pure-perl, synchronous) and
		2192	C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
		2193	L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1502		2194
1503	=item C<PERL_ANYEVENT_PROTOCOLS>	2195	=item C<PERL_ANYEVENT_PROTOCOLS>
1504		2196
1505	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	2197	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1506	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	2198	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
…		…
1519	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2211	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1520	- only support IPv4, never try to resolve or contact IPv6	2212	- only support IPv4, never try to resolve or contact IPv6
1521	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2213	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1522	IPv6, but prefer IPv6 over IPv4.	2214	IPv6, but prefer IPv6 over IPv4.
1523		2215
		2216	=item C<PERL_ANYEVENT_HOSTS>
		2217
		2218	This variable, if specified, overrides the F</etc/hosts> file used by
		2219	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2220	from that file instead.
		2221
1524	=item C<PERL_ANYEVENT_EDNS0>	2222	=item C<PERL_ANYEVENT_EDNS0>
1525		2223
1526	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2224	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1527	for DNS. This extension is generally useful to reduce DNS traffic, but	2225	DNS. This extension is generally useful to reduce DNS traffic, especially
1528	some (broken) firewalls drop such DNS packets, which is why it is off by	2226	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1529	default.	2227	packets, which is why it is off by default.
1530		2228
1531	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2229	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1532	EDNS0 in its DNS requests.	2230	EDNS0 in its DNS requests.
1533		2231
1534	=item C<PERL_ANYEVENT_MAX_FORKS>	2232	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1540		2238
1541	The default value for the C<max_outstanding> parameter for the default DNS	2239	The default value for the C<max_outstanding> parameter for the default DNS
1542	resolver - this is the maximum number of parallel DNS requests that are	2240	resolver - this is the maximum number of parallel DNS requests that are
1543	sent to the DNS server.	2241	sent to the DNS server.
1544		2242
		2243	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2244
		2245	Perl has inherently racy signal handling (you can basically choose between
		2246	losing signals and memory corruption) - pure perl event loops (including
		2247	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2248	have to poll regularly to avoid losing signals.
		2249
		2250	Some event loops are racy, but don't poll regularly, and some event loops
		2251	are written in C but are still racy. For those event loops, AnyEvent
		2252	installs a timer that regularly wakes up the event loop.
		2253
		2254	By default, the interval for this timer is C<10> seconds, but you can
		2255	override this delay with this environment variable (or by setting
		2256	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2257	watchers).
		2258
		2259	Lower values increase CPU (and energy) usage, higher values can introduce
		2260	long delays when reaping children or waiting for signals.
		2261
		2262	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2263	polling (with most event loops).
		2264
1545	=item C<PERL_ANYEVENT_RESOLV_CONF>	2265	=item C<PERL_ANYEVENT_RESOLV_CONF>
1546		2266
1547	The file to use instead of F</etc/resolv.conf> (or OS-specific	2267	The absolute path to a F<resolv.conf>-style file to use instead of
1548	configuration) in the default resolver. When set to the empty string, no	2268	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1549	default config will be used.	2269	resolver, or the empty string to select the default configuration.
1550		2270
1551	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2271	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1552		2272
1553	When neither C<ca_file> nor C<ca_path> was specified during	2273	When neither C<ca_file> nor C<ca_path> was specified during
1554	L<AnyEvent::TLS> context creation, and either of these environment	2274	L<AnyEvent::TLS> context creation, and either of these environment
1555	variables exist, they will be used to specify CA certificate locations	2275	variables are nonempty, they will be used to specify CA certificate
1556	instead of a system-dependent default.	2276	locations instead of a system-dependent default.
		2277
		2278	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2279
		2280	When these are set to C<1>, then the respective modules are not
		2281	loaded. Mostly good for testing AnyEvent itself.
1557		2282
1558	=back	2283	=back
1559		2284
1560	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2285	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1561		2286
…		…
1619	warn "read: $input\n"; # output what has been read	2344	warn "read: $input\n"; # output what has been read
1620	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2345	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1621	},	2346	},
1622	);	2347	);
1623		2348
1624	my $time_watcher; # can only be used once
1625
1626	sub new_timer {
1627	$timer = AnyEvent->timer (after => 1, cb => sub {	2349	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1628	warn "timeout\n"; # print 'timeout' about every second	2350	warn "timeout\n"; # print 'timeout' at most every second
1629	&new_timer; # and restart the time
1630	});	2351	});
1631	}
1632
1633	new_timer; # create first timer
1634		2352
1635	$cv->recv; # wait until user enters /^q/i	2353	$cv->recv; # wait until user enters /^q/i
1636		2354
1637	=head1 REAL-WORLD EXAMPLE	2355	=head1 REAL-WORLD EXAMPLE
1638		2356
…		…
1711		2429
1712	The actual code goes further and collects all errors (C<die>s, exceptions)	2430	The actual code goes further and collects all errors (C<die>s, exceptions)
1713	that occurred during request processing. The C<result> method detects	2431	that occurred during request processing. The C<result> method detects
1714	whether an exception as thrown (it is stored inside the $txn object)	2432	whether an exception as thrown (it is stored inside the $txn object)
1715	and just throws the exception, which means connection errors and other	2433	and just throws the exception, which means connection errors and other
1716	problems get reported tot he code that tries to use the result, not in a	2434	problems get reported to the code that tries to use the result, not in a
1717	random callback.	2435	random callback.
1718		2436
1719	All of this enables the following usage styles:	2437	All of this enables the following usage styles:
1720		2438
1721	1. Blocking:	2439	1. Blocking:
…		…
1769	through AnyEvent. The benchmark creates a lot of timers (with a zero	2487	through AnyEvent. The benchmark creates a lot of timers (with a zero
1770	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2488	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1771	which it is), lets them fire exactly once and destroys them again.	2489	which it is), lets them fire exactly once and destroys them again.
1772		2490
1773	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2491	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1774	distribution.	2492	distribution. It uses the L<AE> interface, which makes a real difference
		2493	for the EV and Perl backends only.
1775		2494
1776	=head3 Explanation of the columns	2495	=head3 Explanation of the columns
1777		2496
1778	I<watcher> is the number of event watchers created/destroyed. Since	2497	I<watcher> is the number of event watchers created/destroyed. Since
1779	different event models feature vastly different performances, each event	2498	different event models feature vastly different performances, each event
…		…
1800	watcher.	2519	watcher.
1801		2520
1802	=head3 Results	2521	=head3 Results
1803		2522
1804	name watchers bytes create invoke destroy comment	2523	name watchers bytes create invoke destroy comment
1805	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2524	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1806	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2525	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1807	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2526	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1808	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2527	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1809	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2528	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1810	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2529	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1811	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2530	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1812	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2531	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1813	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2532	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1814	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2533	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1815	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2534	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1816	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2535	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1817		2536
1818	=head3 Discussion	2537	=head3 Discussion
1819		2538
1820	The benchmark does I<not> measure scalability of the event loop very	2539	The benchmark does I<not> measure scalability of the event loop very
1821	well. For example, a select-based event loop (such as the pure perl one)	2540	well. For example, a select-based event loop (such as the pure perl one)
…		…
1833	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2552	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1834	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2553	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1835	cycles with POE.	2554	cycles with POE.
1836		2555
1837	C<EV> is the sole leader regarding speed and memory use, which are both	2556	C<EV> is the sole leader regarding speed and memory use, which are both
1838	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2557	maximal/minimal, respectively. When using the L<AE> API there is zero
		2558	overhead (when going through the AnyEvent API create is about 5-6 times
		2559	slower, with other times being equal, so still uses far less memory than
1839	far less memory than any other event loop and is still faster than Event	2560	any other event loop and is still faster than Event natively).
1840	natively.
1841		2561
1842	The pure perl implementation is hit in a few sweet spots (both the	2562	The pure perl implementation is hit in a few sweet spots (both the
1843	constant timeout and the use of a single fd hit optimisations in the perl	2563	constant timeout and the use of a single fd hit optimisations in the perl
1844	interpreter and the backend itself). Nevertheless this shows that it	2564	interpreter and the backend itself). Nevertheless this shows that it
1845	adds very little overhead in itself. Like any select-based backend its	2565	adds very little overhead in itself. Like any select-based backend its
…		…
1893	(even when used without AnyEvent), but most event loops have acceptable	2613	(even when used without AnyEvent), but most event loops have acceptable
1894	performance with or without AnyEvent.	2614	performance with or without AnyEvent.
1895		2615
1896	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2616	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1897	the actual event loop, only with extremely fast event loops such as EV	2617	the actual event loop, only with extremely fast event loops such as EV
1898	adds AnyEvent significant overhead.	2618	does AnyEvent add significant overhead.
1899		2619
1900	=item * You should avoid POE like the plague if you want performance or	2620	=item * You should avoid POE like the plague if you want performance or
1901	reasonable memory usage.	2621	reasonable memory usage.
1902		2622
1903	=back	2623	=back
…		…
1919	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2639	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1920	(1%) are active. This mirrors the activity of large servers with many	2640	(1%) are active. This mirrors the activity of large servers with many
1921	connections, most of which are idle at any one point in time.	2641	connections, most of which are idle at any one point in time.
1922		2642
1923	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2643	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1924	distribution.	2644	distribution. It uses the L<AE> interface, which makes a real difference
		2645	for the EV and Perl backends only.
1925		2646
1926	=head3 Explanation of the columns	2647	=head3 Explanation of the columns
1927		2648
1928	I<sockets> is the number of sockets, and twice the number of "servers" (as	2649	I<sockets> is the number of sockets, and twice the number of "servers" (as
1929	each server has a read and write socket end).	2650	each server has a read and write socket end).
…		…
1937	a new one that moves the timeout into the future.	2658	a new one that moves the timeout into the future.
1938		2659
1939	=head3 Results	2660	=head3 Results
1940		2661
1941	name sockets create request	2662	name sockets create request
1942	EV 20000 69.01 11.16	2663	EV 20000 62.66 7.99
1943	Perl 20000 73.32 35.87	2664	Perl 20000 68.32 32.64
1944	IOAsync 20000 157.00 98.14 epoll	2665	IOAsync 20000 174.06 101.15 epoll
1945	IOAsync 20000 159.31 616.06 poll	2666	IOAsync 20000 174.67 610.84 poll
1946	Event 20000 212.62 257.32	2667	Event 20000 202.69 242.91
1947	Glib 20000 651.16 1896.30	2668	Glib 20000 557.01 1689.52
1948	POE 20000 349.67 12317.24 uses POE::Loop::Event	2669	POE 20000 341.54 12086.32 uses POE::Loop::Event
1949		2670
1950	=head3 Discussion	2671	=head3 Discussion
1951		2672
1952	This benchmark I<does> measure scalability and overall performance of the	2673	This benchmark I<does> measure scalability and overall performance of the
1953	particular event loop.	2674	particular event loop.
…		…
2079	As you can see, the AnyEvent + EV combination even beats the	2800	As you can see, the AnyEvent + EV combination even beats the
2080	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2801	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2081	backend easily beats IO::Lambda and POE.	2802	backend easily beats IO::Lambda and POE.
2082		2803
2083	And even the 100% non-blocking version written using the high-level (and	2804	And even the 100% non-blocking version written using the high-level (and
2084	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2805	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2085	large margin, even though it does all of DNS, tcp-connect and socket I/O	2806	higher level ("unoptimised") abstractions by a large margin, even though
2086	in a non-blocking way.	2807	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2087		2808
2088	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2809	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2089	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2810	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2090	part of the IO::lambda distribution and were used without any changes.	2811	part of the IO::Lambda distribution and were used without any changes.
2091		2812
2092		2813
2093	=head1 SIGNALS	2814	=head1 SIGNALS
2094		2815
2095	AnyEvent currently installs handlers for these signals:	2816	AnyEvent currently installs handlers for these signals:
…		…
2129	if $SIG{CHLD} eq 'IGNORE';	2850	if $SIG{CHLD} eq 'IGNORE';
2130		2851
2131	$SIG{PIPE} = sub { }	2852	$SIG{PIPE} = sub { }
2132	unless defined $SIG{PIPE};	2853	unless defined $SIG{PIPE};
2133		2854
		2855	=head1 RECOMMENDED/OPTIONAL MODULES
		2856
		2857	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2858	its built-in modules) are required to use it.
		2859
		2860	That does not mean that AnyEvent won't take advantage of some additional
		2861	modules if they are installed.
		2862
		2863	This section explains which additional modules will be used, and how they
		2864	affect AnyEvent's operation.
		2865
		2866	=over 4
		2867
		2868	=item L<Async::Interrupt>
		2869
		2870	This slightly arcane module is used to implement fast signal handling: To
		2871	my knowledge, there is no way to do completely race-free and quick
		2872	signal handling in pure perl. To ensure that signals still get
		2873	delivered, AnyEvent will start an interval timer to wake up perl (and
		2874	catch the signals) with some delay (default is 10 seconds, look for
		2875	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2876
		2877	If this module is available, then it will be used to implement signal
		2878	catching, which means that signals will not be delayed, and the event loop
		2879	will not be interrupted regularly, which is more efficient (and good for
		2880	battery life on laptops).
		2881
		2882	This affects not just the pure-perl event loop, but also other event loops
		2883	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2884
		2885	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2886	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2887	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2888	does nothing for those backends.
		2889
		2890	=item L<EV>
		2891
		2892	This module isn't really "optional", as it is simply one of the backend
		2893	event loops that AnyEvent can use. However, it is simply the best event
		2894	loop available in terms of features, speed and stability: It supports
		2895	the AnyEvent API optimally, implements all the watcher types in XS, does
		2896	automatic timer adjustments even when no monotonic clock is available,
		2897	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2898	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2899	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2900
		2901	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2902	then this module will do nothing for you.
		2903
		2904	=item L<Guard>
		2905
		2906	The guard module, when used, will be used to implement
		2907	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2908	lot less memory), but otherwise doesn't affect guard operation much. It is
		2909	purely used for performance.
		2910
		2911	=item L<JSON> and L<JSON::XS>
		2912
		2913	One of these modules is required when you want to read or write JSON data
		2914	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2915	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2916
		2917	=item L<Net::SSLeay>
		2918
		2919	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2920	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2921	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2922
		2923	=item L<Time::HiRes>
		2924
		2925	This module is part of perl since release 5.008. It will be used when the
		2926	chosen event library does not come with a timing source of its own. The
		2927	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2928	try to use a monotonic clock for timing stability.
		2929
		2930	=back
		2931
		2932
2134	=head1 FORK	2933	=head1 FORK
2135		2934
2136	Most event libraries are not fork-safe. The ones who are usually are	2935	Most event libraries are not fork-safe. The ones who are usually are
2137	because they rely on inefficient but fork-safe C<select> or C<poll>	2936	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2138	calls. Only L<EV> is fully fork-aware.	2937	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2938	are usually badly thought-out hacks that are incompatible with fork in
		2939	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2940	continue event-processing in both parent and child (or both, if you know
		2941	what you are doing).
		2942
		2943	This means that, in general, you cannot fork and do event processing in
		2944	the child if the event library was initialised before the fork (which
		2945	usually happens when the first AnyEvent watcher is created, or the library
		2946	is loaded).
2139		2947
2140	If you have to fork, you must either do so I<before> creating your first	2948	If you have to fork, you must either do so I<before> creating your first
2141	watcher OR you must not use AnyEvent at all in the child.	2949	watcher OR you must not use AnyEvent at all in the child OR you must do
		2950	something completely out of the scope of AnyEvent.
		2951
		2952	The problem of doing event processing in the parent I<and> the child
		2953	is much more complicated: even for backends that I<are> fork-aware or
		2954	fork-safe, their behaviour is not usually what you want: fork clones all
		2955	watchers, that means all timers, I/O watchers etc. are active in both
		2956	parent and child, which is almost never what you want. USing C<exec>
		2957	to start worker children from some kind of manage rprocess is usually
		2958	preferred, because it is much easier and cleaner, at the expense of having
		2959	to have another binary.
2142		2960
2143		2961
2144	=head1 SECURITY CONSIDERATIONS	2962	=head1 SECURITY CONSIDERATIONS
2145		2963
2146	AnyEvent can be forced to load any event model via	2964	AnyEvent can be forced to load any event model via
…		…
2176	pronounced).	2994	pronounced).
2177		2995
2178		2996
2179	=head1 SEE ALSO	2997	=head1 SEE ALSO
2180		2998
2181	Utility functions: L<AnyEvent::Util>.	2999	Tutorial/Introduction: L<AnyEvent::Intro>.
2182		3000
2183	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	3001	FAQ: L<AnyEvent::FAQ>.
2184	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	3002
		3003	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		3004	(simply logging).
		3005
		3006	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		3007	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		3008
		3009	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3010	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3011	L<Qt>, L<POE>, L<FLTK>.
2185		3012
2186	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3013	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2187	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3014	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2188	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3015	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2189	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	3016	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3017	L<AnyEvent::Impl::FLTK>.
2190		3018
2191	Non-blocking file handles, sockets, TCP clients and	3019	Non-blocking handles, pipes, stream sockets, TCP clients and
2192	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3020	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2193		3021
		3022	Asynchronous File I/O: L<AnyEvent::IO>.
		3023
2194	Asynchronous DNS: L<AnyEvent::DNS>.	3024	Asynchronous DNS: L<AnyEvent::DNS>.
2195		3025
2196	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3026	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2197	L<Coro::Event>,
2198		3027
2199	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3028	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2200	L<AnyEvent::HTTP>.	3029	L<AnyEvent::HTTP>.
2201		3030
2202		3031
2203	=head1 AUTHOR	3032	=head1 AUTHOR
2204		3033
2205	Marc Lehmann <schmorp@schmorp.de>	3034	Marc Lehmann <schmorp@schmorp.de>
2206	http://home.schmorp.de/	3035	http://anyevent.schmorp.de
2207		3036
2208	=cut	3037	=cut
2209		3038
2210	1	3039	1
2211		3040

Diff Legend

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