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Revision 1.264 by root, Wed Jul 29 12:42:09 2009 UTC vs.
Revision 1.388 by root, Sun Oct 2 01:22:01 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - the DBI of event loop programming	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	and POE are various supported event loops/environments.	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
…		…
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.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Repository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
…		…
73	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
74	model you use.	79	model you use.
75		80
76	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
77	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
78	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
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	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
81	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.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	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
85	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
86	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
87	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
88	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
89	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,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	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
93	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
94	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
95	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
96	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
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	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
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	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
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	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>
117	module.	122	module.
118		123
119	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
120	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
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
122	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
123	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
124	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
125	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
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	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
140	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,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
144	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
145	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
146		150
147	=head1 WATCHERS	151	=head1 WATCHERS
148		152
149	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
150	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
…		…
155	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
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	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<<
160	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
161	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
162	widely between event loops.	166	widely between event loops.
163		167
164	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
165	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
166	to it).	170	to it).
167		171
168	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.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	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.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
180	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,
181	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
182	declared.	186	declared.
183		187
184	=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	);
185		195
186	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
187	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
188		198
189	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
…		…
204		214
205	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.
206	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
207	underlying file descriptor.	217	underlying file descriptor.
208		218
209	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
210	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
211	handles.	221	handles.
212		222
213	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
214	watcher.	224	watcher.
…		…
219	undef $w;	229	undef $w;
220	});	230	});
221		231
222	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
223		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
224	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 >>
225	method with the following mandatory arguments:	243	method with the following mandatory arguments:
226		244
227	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
228	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
…		…
230		248
231	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
234		252
235	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
236	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
238	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
239	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.
240		258
241	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
242	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
243	only approximate.	261	only approximate.
244		262
245	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
246		264
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		283
266	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
267	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
268	"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
269	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
270	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.
271		289
272	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
273	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
274	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)
275	timers.	293	timers.
276		294
277	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	296	AnyEvent API.
…		…
300	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
301	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
302		320
303	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		324
307	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
308	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
309		327
310	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>
311	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
312		330
313	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
314	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
315	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
316	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
317	after three seconds.	335	after three seconds.
318		336
…		…
338	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
339	account.	357	account.
340		358
341	=item AnyEvent->now_update	359	=item AnyEvent->now_update
342		360
343	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
344	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 >>,
345	AnyEvent->now >>, above).	363	above).
346		364
347	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
348	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
349	might affect timers and time-outs.	367	might affect timers and time-outs.
350		368
351	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
352	event loop's idea of "current time".	370	event loop's idea of "current time".
353		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
354	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.
355		380
356	=back	381	=back
357		382
358	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		386
360	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
361	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
362	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
363		390
…		…
380		407
381	Example: exit on SIGINT	408	Example: exit on SIGINT
382		409
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
385	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
386		430
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
388	callbacks to signals in a generic way, which is a pity, as you cannot do	432	attaching callbacks to signals in a generic way, which is a pity,
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	as you cannot do race-free signal handling in perl, requiring
		434	C libraries for this. AnyEvent will try to do its best, which
390	in some cases, signals will be delayed. The maximum time a signal might	435	means in some cases, signals will be delayed. The maximum time
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	a signal might be delayed is 10 seconds by default, but can
392	seconds). This variable can be changed only before the first signal	437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
393	watcher is created, and should be left alone otherwise. Higher values	438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the Ö<ENVIRONMENT VARIABLES>
394	will cause fewer spurious wake-ups, which is better for power and CPU	439	section for details.
		440
395	saving. All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
396	L<Async::Interrupt> module. This will not work with inherently broken	442	L<Async::Interrupt> module, which works with most event loops. It will not
397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
398	currently, as POE does it's own workaround with one-second latency). With	444	(and not with L<POE> currently). For those, you just have to suffer the
399	those, you just have to suffer the delays.	445	delays.
400		446
401	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
402		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
403	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.
404		452
405	The child process is specified by the C<pid> argument (one some backends,	453	The child process is specified by the C<pid> argument (on some backends,
406	using C<0> watches for any child process exit, on others this will	454	using C<0> watches for any child process exit, on others this will
407	croak). The watcher will be triggered only when the child process has	455	croak). The watcher will be triggered only when the child process has
408	finished and an exit status is available, not on any trace events	456	finished and an exit status is available, not on any trace events
409	(stopped/continued).	457	(stopped/continued).
410		458
…		…
432	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
433	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
434	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
435		483
436	As most event loops do not support waiting for child events, they will be	484	As most event loops do not support waiting for child events, they will be
437	emulated by AnyEvent in most cases, in which the latency and race problems	485	emulated by AnyEvent in most cases, in which case the latency and race
438	mentioned in the description of signal watchers apply.	486	problems mentioned in the description of signal watchers apply.
439		487
440	Example: fork a process and wait for it	488	Example: fork a process and wait for it
441		489
442	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
443		491
…		…
455	# do something else, then wait for process exit	503	# do something else, then wait for process exit
456	$done->recv;	504	$done->recv;
457		505
458	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
459		507
460	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
461	to do it instantly, but only when there is nothing better to do. This
462	"nothing better to do" is usually defined to be "no other events need
463	attention by the event loop".
464		509
465	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
466	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.
467	events. Instead of blocking, the idle watcher is invoked.
468		512
469	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
470	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
471	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
472		525
473	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
474	program is otherwise idle:	527	program is otherwise idle:
…		…
490	});	543	});
491	});	544	});
492		545
493	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
494		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
495	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
496	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
497	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
498		556
499	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
500	loop and 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).
501		559
502	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
503	because they represent a condition that must become true.	561	they represent a condition that must become true.
504		562
505	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
506		564
507	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
508	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
513	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
514	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
515	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<<
516	->send >> method).	574	->send >> method).
517		575
518	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
519	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:
520	in time where multiple outstanding events have been processed. And yet	578
521	another way to call them is transactions - each condition variable can be	579	=over 4
522	used to represent a transaction, which finishes at some point and delivers	580
523	a result. And yet some people know them as "futures" - a promise to	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
524	compute/deliver something that you can wait for.	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
525		599
526	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
527	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,
528	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
529	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
…		…
542		616
543	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
544	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
545	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
546	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
547	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
548		622
549	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
550	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
551	for the send to occur.	625	for the send to occur.
552		626
553	Example: wait for a timer.	627	Example: wait for a timer.
554		628
555	# wait till the result is ready	629	# condition: "wait till the timer is fired"
556	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
557		631
558	# do something such as adding a timer	632	# create the timer - we could wait for, say
559	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
560	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
561	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
562	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
563	after => 1,	637	after => 1,
564	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
565	);	639	);
566		640
567	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
568	# calls -<send	642	# calls ->send
569	$result_ready->recv;	643	$timer_fired->recv;
570		644
571	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
572	variables are also callable directly.	646	variables are also callable directly.
573		647
574	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
617	they were 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
618	C<send>.	692	C<send>.
619		693
620	=item $cv->croak ($error)	694	=item $cv->croak ($error)
621		695
622	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
623	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
624		698
625	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
626	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
627	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
628	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
629	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
630	the problem.	704	the problem.
631		705
632	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
633		707
634	=item $cv->end	708	=item $cv->end
…		…
637	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
638	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
639		713
640	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
641	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
642	>>, 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
643	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
644	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.
645		720
646	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
647	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
648	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).
649		724
…		…
671	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
672	sending.	747	sending.
673		748
674	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
675	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
676	begung can potentially be zero:	751	begun can potentially be zero:
677		752
678	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
679		754
680	my %result;	755	my %result;
681	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
682		757
683	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
684	$cv->begin;	759	$cv->begin;
685	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
686	$result{$host} = ...;	761	$result{$host} = ...;
…		…
702	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
703	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
704	doesn't execute once).	779	doesn't execute once).
705		780
706	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
707	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
708	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
709	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
710	call C<end>.	785	call C<end>.
711		786
712	=back	787	=back
…		…
719	=over 4	794	=over 4
720		795
721	=item $cv->recv	796	=item $cv->recv
722		797
723	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
724	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
725	normally.	800	normally.
726		801
727	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
728	will return immediately.	803	will return immediately.
729		804
…		…
746	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
747	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
748	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
749	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
750		825
751	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
752	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
753	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
754	waits otherwise.	829	waits otherwise.
755		830
756	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
762		837
763	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
764	replaces it before doing so.	839	replaces it before doing so.
765		840
766	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
767	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
768	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
769	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
770		846
771	=back	847	=back
772		848
773	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
774		850
…		…
777	=over 4	853	=over 4
778		854
779	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
780		856
781	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
782	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
783	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
784	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
785		861
786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
789		864
790	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
791		866
792	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
793	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
794	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
795	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
796	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
797		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
798	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
799	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
801	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
802	AnyEvent::Impl::Irssi used when running within irssi.	878	AnyEvent::Impl::Irssi used when running within irssi.
		879	AnyEvent::Impl::IOAsync based on IO::Async.
		880	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		881	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
803		882
804	=item Backends with special needs.	883	=item Backends with special needs.
805		884
806	Qt requires the Qt::Application to be instantiated first, but will	885	Qt requires the Qt::Application to be instantiated first, but will
807	otherwise be picked up automatically. As long as the main program	886	otherwise be picked up automatically. As long as the main program
808	instantiates the application before any AnyEvent watchers are created,	887	instantiates the application before any AnyEvent watchers are created,
809	everything should just work.	888	everything should just work.
810		889
811	AnyEvent::Impl::Qt based on Qt.	890	AnyEvent::Impl::Qt based on Qt.
812		891
813	Support for IO::Async can only be partial, as it is too broken and
814	architecturally limited to even support the AnyEvent API. It also
815	is the only event loop that needs the loop to be set explicitly, so
816	it can only be used by a main program knowing about AnyEvent. See
817	L<AnyEvent::Impl::Async> for the gory details.
818
819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
820
821	=item Event loops that are indirectly supported via other backends.	892	=item Event loops that are indirectly supported via other backends.
822		893
823	Some event loops can be supported via other modules:	894	Some event loops can be supported via other modules:
824		895
825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	896	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
850	Contains C<undef> until the first watcher is being created, before the	921	Contains C<undef> until the first watcher is being created, before the
851	backend has been autodetected.	922	backend has been autodetected.
852		923
853	Afterwards it contains the event model that is being used, which is the	924	Afterwards it contains the event model that is being used, which is the
854	name of the Perl class implementing the model. This class is usually one	925	name of the Perl class implementing the model. This class is usually one
855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	926	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	927	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
857	will be C<urxvt::anyevent>).	928	will be C<urxvt::anyevent>).
858		929
859	=item AnyEvent::detect	930	=item AnyEvent::detect
860		931
861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	932	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
862	if necessary. You should only call this function right before you would	933	if necessary. You should only call this function right before you would
863	have created an AnyEvent watcher anyway, that is, as late as possible at	934	have created an AnyEvent watcher anyway, that is, as late as possible at
864	runtime, and not e.g. while initialising of your module.	935	runtime, and not e.g. during initialisation of your module.
		936
		937	The effect of calling this function is as if a watcher had been created
		938	(specifically, actions that happen "when the first watcher is created"
		939	happen when calling detetc as well).
865		940
866	If you need to do some initialisation before AnyEvent watchers are	941	If you need to do some initialisation before AnyEvent watchers are
867	created, use C<post_detect>.	942	created, use C<post_detect>.
868		943
869	=item $guard = AnyEvent::post_detect { BLOCK }	944	=item $guard = AnyEvent::post_detect { BLOCK }
870		945
871	Arranges for the code block to be executed as soon as the event model is	946	Arranges for the code block to be executed as soon as the event model is
872	autodetected (or immediately if this has already happened).	947	autodetected (or immediately if that has already happened).
873		948
874	The block will be executed I<after> the actual backend has been detected	949	The block will be executed I<after> the actual backend has been detected
875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	950	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	951	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
877	other initialisations - see the sources of L<AnyEvent::Strict> or	952	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
886	that automatically removes the callback again when it is destroyed (or	961	that automatically removes the callback again when it is destroyed (or
887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	962	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
888	a case where this is useful.	963	a case where this is useful.
889		964
890	Example: Create a watcher for the IO::AIO module and store it in	965	Example: Create a watcher for the IO::AIO module and store it in
891	C<$WATCHER>. Only do so after the event loop is initialised, though.	966	C<$WATCHER>, but do so only do so after the event loop is initialised.
892		967
893	our WATCHER;	968	our WATCHER;
894		969
895	my $guard = AnyEvent::post_detect {	970	my $guard = AnyEvent::post_detect {
896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	971	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
904	$WATCHER ||= $guard;	979	$WATCHER ||= $guard;
905		980
906	=item @AnyEvent::post_detect	981	=item @AnyEvent::post_detect
907		982
908	If there are any code references in this array (you can C<push> to it	983	If there are any code references in this array (you can C<push> to it
909	before or after loading AnyEvent), then they will called directly after	984	before or after loading AnyEvent), then they will be called directly
910	the event loop has been chosen.	985	after the event loop has been chosen.
911		986
912	You should check C<$AnyEvent::MODEL> before adding to this array, though:	987	You should check C<$AnyEvent::MODEL> before adding to this array, though:
913	if it is defined then the event loop has already been detected, and the	988	if it is defined then the event loop has already been detected, and the
914	array will be ignored.	989	array will be ignored.
915		990
916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	991	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
917	it,as it takes care of these details.	992	it, as it takes care of these details.
918		993
919	This variable is mainly useful for modules that can do something useful	994	This variable is mainly useful for modules that can do something useful
920	when AnyEvent is used and thus want to know when it is initialised, but do	995	when AnyEvent is used and thus want to know when it is initialised, but do
921	not need to even load it by default. This array provides the means to hook	996	not need to even load it by default. This array provides the means to hook
922	into AnyEvent passively, without loading it.	997	into AnyEvent passively, without loading it.
923		998
		999	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1000	together, you could put this into Coro (this is the actual code used by
		1001	Coro to accomplish this):
		1002
		1003	if (defined $AnyEvent::MODEL) {
		1004	# AnyEvent already initialised, so load Coro::AnyEvent
		1005	require Coro::AnyEvent;
		1006	} else {
		1007	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1008	# as soon as it is
		1009	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1010	}
		1011
		1012	=item AnyEvent::postpone { BLOCK }
		1013
		1014	Arranges for the block to be executed as soon as possible, but not before
		1015	the call itself returns. In practise, the block will be executed just
		1016	before the event loop polls for new events, or shortly afterwards.
		1017
		1018	This function never returns anything (to make the C<return postpone { ...
		1019	}> idiom more useful.
		1020
		1021	To understand the usefulness of this function, consider a function that
		1022	asynchronously does something for you and returns some transaction
		1023	object or guard to let you cancel the operation. For example,
		1024	C<AnyEvent::Socket::tcp_connect>:
		1025
		1026	# start a conenction attempt unless one is active
		1027	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1028	delete $self->{connect_guard};
		1029	...
		1030	};
		1031
		1032	Imagine that this function could instantly call the callback, for
		1033	example, because it detects an obvious error such as a negative port
		1034	number. Invoking the callback before the function returns causes problems
		1035	however: the callback will be called and will try to delete the guard
		1036	object. But since the function hasn't returned yet, there is nothing to
		1037	delete. When the function eventually returns it will assign the guard
		1038	object to C<< $self->{connect_guard} >>, where it will likely never be
		1039	deleted, so the program thinks it is still trying to connect.
		1040
		1041	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1042	callback directly on error:
		1043
		1044	$cb->(undef), return # signal error to callback, BAD!
		1045	if $some_error_condition;
		1046
		1047	It should use C<postpone>:
		1048
		1049	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1050	if $some_error_condition;
		1051
		1052	=item AnyEvent::log $level, $msg[, @args]
		1053
		1054	Log the given C<$msg> at the given C<$level>.
		1055
		1056	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1057	to see whether the message will be logged. If the test succeeds it will
		1058	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1059	the L<AnyEvent::Log> documentation for details.
		1060
		1061	If the test fails it will simply return. Right now this happens when a
		1062	numerical loglevel is used and it is larger than the level specified via
		1063	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1064
		1065	If you want to sprinkle loads of logging calls around your code, consider
		1066	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1067	which can reduce typing, codesize and can reduce the logging overhead
		1068	enourmously.
		1069
924	=back	1070	=back
925		1071
926	=head1 WHAT TO DO IN A MODULE	1072	=head1 WHAT TO DO IN A MODULE
927		1073
928	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1074	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
938	because it will stall the whole program, and the whole point of using	1084	because it will stall the whole program, and the whole point of using
939	events is to stay interactive.	1085	events is to stay interactive.
940		1086
941	It is fine, however, to call C<< ->recv >> when the user of your module	1087	It is fine, however, to call C<< ->recv >> when the user of your module
942	requests it (i.e. if you create a http request object ad have a method	1088	requests it (i.e. if you create a http request object ad have a method
943	called C<results> that returns the results, it should call C<< ->recv >>	1089	called C<results> that returns the results, it may call C<< ->recv >>
944	freely, as the user of your module knows what she is doing. always).	1090	freely, as the user of your module knows what she is doing. Always).
945		1091
946	=head1 WHAT TO DO IN THE MAIN PROGRAM	1092	=head1 WHAT TO DO IN THE MAIN PROGRAM
947		1093
948	There will always be a single main program - the only place that should	1094	There will always be a single main program - the only place that should
949	dictate which event model to use.	1095	dictate which event model to use.
950		1096
951	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1097	If the program is not event-based, it need not do anything special, even
952	do anything special (it does not need to be event-based) and let AnyEvent	1098	when it depends on a module that uses an AnyEvent. If the program itself
953	decide which implementation to chose if some module relies on it.	1099	uses AnyEvent, but does not care which event loop is used, all it needs
		1100	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1101	available loop implementation.
954		1102
955	If the main program relies on a specific event model - for example, in	1103	If the main program relies on a specific event model - for example, in
956	Gtk2 programs you have to rely on the Glib module - you should load the	1104	Gtk2 programs you have to rely on the Glib module - you should load the
957	event module before loading AnyEvent or any module that uses it: generally	1105	event module before loading AnyEvent or any module that uses it: generally
958	speaking, you should load it as early as possible. The reason is that	1106	speaking, you should load it as early as possible. The reason is that
959	modules might create watchers when they are loaded, and AnyEvent will	1107	modules might create watchers when they are loaded, and AnyEvent will
960	decide on the event model to use as soon as it creates watchers, and it	1108	decide on the event model to use as soon as it creates watchers, and it
961	might chose the wrong one unless you load the correct one yourself.	1109	might choose the wrong one unless you load the correct one yourself.
962		1110
963	You can chose to use a pure-perl implementation by loading the	1111	You can chose to use a pure-perl implementation by loading the
964	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1112	C<AnyEvent::Loop> module, which gives you similar behaviour
965	everywhere, but letting AnyEvent chose the model is generally better.	1113	everywhere, but letting AnyEvent chose the model is generally better.
966		1114
967	=head2 MAINLOOP EMULATION	1115	=head2 MAINLOOP EMULATION
968		1116
969	Sometimes (often for short test scripts, or even standalone programs who	1117	Sometimes (often for short test scripts, or even standalone programs who
…		…
982		1130
983		1131
984	=head1 OTHER MODULES	1132	=head1 OTHER MODULES
985		1133
986	The following is a non-exhaustive list of additional modules that use	1134	The following is a non-exhaustive list of additional modules that use
987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1135	AnyEvent as a client and can therefore be mixed easily with other
988	modules and other event loops in the same program. Some of the modules	1136	AnyEvent modules and other event loops in the same program. Some of the
989	come with AnyEvent, most are available via CPAN.	1137	modules come as part of AnyEvent, the others are available via CPAN (see
		1138	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1139	a longer non-exhaustive list), and the list is heavily biased towards
		1140	modules of the AnyEvent author himself :)
990		1141
991	=over 4	1142	=over 4
992		1143
993	=item L<AnyEvent::Util>	1144	=item L<AnyEvent::Util>
994		1145
995	Contains various utility functions that replace often-used but blocking	1146	Contains various utility functions that replace often-used blocking
996	functions such as C<inet_aton> by event-/callback-based versions.	1147	functions such as C<inet_aton> with event/callback-based versions.
997		1148
998	=item L<AnyEvent::Socket>	1149	=item L<AnyEvent::Socket>
999		1150
1000	Provides various utility functions for (internet protocol) sockets,	1151	Provides various utility functions for (internet protocol) sockets,
1001	addresses and name resolution. Also functions to create non-blocking tcp	1152	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1003		1154
1004	=item L<AnyEvent::Handle>	1155	=item L<AnyEvent::Handle>
1005		1156
1006	Provide read and write buffers, manages watchers for reads and writes,	1157	Provide read and write buffers, manages watchers for reads and writes,
1007	supports raw and formatted I/O, I/O queued and fully transparent and	1158	supports raw and formatted I/O, I/O queued and fully transparent and
1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1159	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1009		1160
1010	=item L<AnyEvent::DNS>	1161	=item L<AnyEvent::DNS>
1011		1162
1012	Provides rich asynchronous DNS resolver capabilities.	1163	Provides rich asynchronous DNS resolver capabilities.
1013		1164
		1165	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1166
		1167	Implement event-based interfaces to the protocols of the same name (for
		1168	the curious, IGS is the International Go Server and FCP is the Freenet
		1169	Client Protocol).
		1170
1014	=item L<AnyEvent::HTTP>	1171	=item L<AnyEvent::AIO>
1015		1172
1016	A simple-to-use HTTP library that is capable of making a lot of concurrent	1173	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1017	HTTP requests.	1174	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1175	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1176	file I/O, and much more.
		1177
		1178	=item L<AnyEvent::Filesys::Notify>
		1179
		1180	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1181	path changes (e.g. "watch this directory for new files", "watch this
		1182	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1183	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1184	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1185	fall back to blocking scans at regular intervals transparently on other
		1186	platforms, so it's about as portable as it gets.
		1187
		1188	(I haven't used it myself, but I haven't heard anybody complaining about
		1189	it yet).
		1190
		1191	=item L<AnyEvent::DBI>
		1192
		1193	Executes L<DBI> requests asynchronously in a proxy process for you,
		1194	notifying you in an event-based way when the operation is finished.
1018		1195
1019	=item L<AnyEvent::HTTPD>	1196	=item L<AnyEvent::HTTPD>
1020		1197
1021	Provides a simple web application server framework.	1198	A simple embedded webserver.
1022		1199
1023	=item L<AnyEvent::FastPing>	1200	=item L<AnyEvent::FastPing>
1024		1201
1025	The fastest ping in the west.	1202	The fastest ping in the west.
1026		1203
1027	=item L<AnyEvent::DBI>
1028
1029	Executes L<DBI> requests asynchronously in a proxy process.
1030
1031	=item L<AnyEvent::AIO>
1032
1033	Truly asynchronous I/O, should be in the toolbox of every event
1034	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1035	together.
1036
1037	=item L<AnyEvent::BDB>
1038
1039	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1040	L<BDB> and AnyEvent together.
1041
1042	=item L<AnyEvent::GPSD>
1043
1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
1045
1046	=item L<AnyEvent::IRC>
1047
1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1049
1050	=item L<AnyEvent::XMPP>
1051
1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1053	Net::XMPP2>.
1054
1055	=item L<AnyEvent::IGS>
1056
1057	A non-blocking interface to the Internet Go Server protocol (used by
1058	L<App::IGS>).
1059
1060	=item L<Net::FCP>
1061
1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1063	of AnyEvent.
1064
1065	=item L<Event::ExecFlow>
1066
1067	High level API for event-based execution flow control.
1068
1069	=item L<Coro>	1204	=item L<Coro>
1070		1205
1071	Has special support for AnyEvent via L<Coro::AnyEvent>.	1206	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1207	to simply invert the flow control - don't call us, we will call you:
		1208
		1209	async {
		1210	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1211	print "5 seconds later!\n";
		1212
		1213	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1214	my $line = <STDIN>; # works for ttys
		1215
		1216	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1217	my ($body, $hdr) = Coro::rouse_wait;
		1218	};
1072		1219
1073	=back	1220	=back
1074		1221
1075	=cut	1222	=cut
1076		1223
1077	package AnyEvent;	1224	package AnyEvent;
1078		1225
1079	# basically a tuned-down version of common::sense	1226	# basically a tuned-down version of common::sense
1080	sub common_sense {	1227	sub common_sense {
1081	# no warnings	1228	# from common:.sense 3.4
1082	${^WARNING_BITS} ^= ${^WARNING_BITS};	1229	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1083	# use strict vars subs	1230	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1084	$^H |= 0x00000600;	1231	$^H |= 0x00000600;
1085	}	1232	}
1086		1233
1087	BEGIN { AnyEvent::common_sense }	1234	BEGIN { AnyEvent::common_sense }
1088		1235
1089	use Carp ();	1236	use Carp ();
1090		1237
1091	our $VERSION = 4.881;	1238	our $VERSION = '6.02';
1092	our $MODEL;	1239	our $MODEL;
1093
1094	our $AUTOLOAD;
1095	our @ISA;	1240	our @ISA;
1096
1097	our @REGISTRY;	1241	our @REGISTRY;
1098
1099	our $WIN32;
1100
1101	our $VERBOSE;	1242	our $VERBOSE;
		1243	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1244	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1102		1245
1103	BEGIN {	1246	BEGIN {
1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1247	require "AnyEvent/constants.pl";
		1248
1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1249	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1106		1250
1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1251	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1108	if ${^TAINT};	1252	if ${^TAINT};
1109		1253
1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1254	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1255	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1111		1256
1112	}	1257	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1258	if ${^TAINT};
1113		1259
1114	our $MAX_SIGNAL_LATENCY = 10;	1260	# $ENV{PERL_ANYEVENT_xxx} now valid
1115		1261
1116	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1262	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1117		1263
1118	{
1119	my $idx;	1264	my $idx;
1120	$PROTOCOL{$_} = ++$idx	1265	$PROTOCOL{$_} = ++$idx
1121	for reverse split /\s*,\s*/,	1266	for reverse split /\s*,\s*/,
1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1267	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1123	}	1268	}
1124		1269
		1270	our @post_detect;
		1271
		1272	sub post_detect(&) {
		1273	my ($cb) = @_;
		1274
		1275	push @post_detect, $cb;
		1276
		1277	defined wantarray
		1278	? bless \$cb, "AnyEvent::Util::postdetect"
		1279	: ()
		1280	}
		1281
		1282	sub AnyEvent::Util::postdetect::DESTROY {
		1283	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1284	}
		1285
		1286	our $POSTPONE_W;
		1287	our @POSTPONE;
		1288
		1289	sub _postpone_exec {
		1290	undef $POSTPONE_W;
		1291
		1292	&{ shift @POSTPONE }
		1293	while @POSTPONE;
		1294	}
		1295
		1296	sub postpone(&) {
		1297	push @POSTPONE, shift;
		1298
		1299	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1300
		1301	()
		1302	}
		1303
		1304	sub log($$;@) {
		1305	# only load the big bloated module when we actually are about to log something
		1306	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1307	local ($!, $@);
		1308	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1309	# AnyEvent::Log overwrites this function
		1310	goto &log;
		1311	}
		1312
		1313	0 # not logged
		1314	}
		1315
		1316	sub logger($;$) {
		1317	package AnyEvent::Log;
		1318
		1319	my ($level, $renabled) = @_;
		1320
		1321	$$renabled = $level <= $VERBOSE;
		1322
		1323	my $pkg = (caller)[0];
		1324
		1325	my $logger = [$pkg, $level, $renabled];
		1326
		1327	our %LOGGER;
		1328	$LOGGER{$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
1125	my @models = (	1352	our @models = (
1126	[EV:: => AnyEvent::Impl::EV:: , 1],	1353	[EV:: => AnyEvent::Impl::EV::],
1127	[Event:: => AnyEvent::Impl::Event::, 1],	1354	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1129	# everything below here will not (normally) be autoprobed	1355	# everything below here will not (normally) be autoprobed
1130	# as the pureperl backend should work everywhere	1356	# as the pure perl backend should work everywhere
1131	# 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
1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # 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
1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1362	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1363	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1364	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1365	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1138	[Wx:: => AnyEvent::Impl::POE::],	1366	[Wx:: => AnyEvent::Impl::POE::],
1139	[Prima:: => AnyEvent::Impl::POE::],	1367	[Prima:: => AnyEvent::Impl::POE::],
1140	# IO::Async is just too broken - we would need workarounds for its	1368	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1141	# byzantine signal and broken child handling, among others.	1369	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1142	# IO::Async is rather hard to detect, as it doesn't have any	1370	[FLTK:: => AnyEvent::Impl::FLTK::],
1143	# obvious default class.
1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1147	);	1371	);
1148		1372
1149	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, $reset_ae] : undef;
		1390
		1391	_isa_set;
		1392	}
		1393
		1394	# all autoloaded methods reserve the complete glob, not just the method slot.
		1395	# due to bugs in perls method cache implementation.
1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1396	our @methods = qw(io timer time now now_update signal child idle condvar);
1151		1397
1152	our @post_detect;
1153
1154	sub post_detect(&) {	1398	sub detect() {
1155	my ($cb) = @_;	1399	return $MODEL if $MODEL; # some programs keep references to detect
1156		1400
1157	if ($MODEL) {	1401	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1158	$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 => "AnyEvent: IO::Async::Loop::AnyEvent detected - this module is broken by design,\n"
		1406	. "abuses internals and breaks AnyEvent, will not continue."
		1407	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1159		1408
1160	undef	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;
1161	} else {	1428	} else {
1162	push @post_detect, $cb;	1429	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1163		1430	}
1164	defined wantarray
1165	? bless \$cb, "AnyEvent::Util::postdetect"
1166	: ()
1167	}	1431	}
1168	}
1169		1432
1170	sub AnyEvent::Util::postdetect::DESTROY {	1433	# check for already loaded models
1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1172	}
1173
1174	sub detect() {
1175	unless ($MODEL) {	1434	unless ($MODEL) {
1176	local $SIG{__DIE__};	1435	for (@REGISTRY, @models) {
1177		1436	my ($package, $model) = @$_;
1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1437	if (${"$package\::VERSION"} > 0) {
1179	my $model = "AnyEvent::Impl::$1";
1180	if (eval "require $model") {	1438	if (eval "require $model") {
		1439	AnyEvent::log 7 => "autodetected model '$model', using it.";
1181	$MODEL = $model;	1440	$MODEL = $model;
1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1441	last;
1183	} else {	1442	}
1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1185	}	1443	}
1186	}	1444	}
1187		1445
1188	# check for already loaded models
1189	unless ($MODEL) {	1446	unless ($MODEL) {
		1447	# try to autoload a model
1190	for (@REGISTRY, @models) {	1448	for (@REGISTRY, @models) {
1191	my ($package, $model) = @$_;	1449	my ($package, $model) = @$_;
		1450	if (
		1451	eval "require $package"
1192	if (${"$package\::VERSION"} > 0) {	1452	and ${"$package\::VERSION"} > 0
1193	if (eval "require $model") {	1453	and eval "require $model"
		1454	) {
		1455	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1194	$MODEL = $model;	1456	$MODEL = $model;
1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1196	last;	1457	last;
1197	}
1198	}	1458	}
1199	}	1459	}
1200		1460
1201	unless ($MODEL) {
1202	# try to autoload a model
1203	for (@REGISTRY, @models) {
1204	my ($package, $model, $autoload) = @$_;
1205	if (
1206	$autoload
1207	and eval "require $package"
1208	and ${"$package\::VERSION"} > 0
1209	and eval "require $model"
1210	) {
1211	$MODEL = $model;
1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1213	last;
1214	}
1215	}
1216
1217	$MODEL	1461	$MODEL
1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1462	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1219	}
1220	}	1463	}
1221
1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1223
1224	unshift @ISA, $MODEL;
1225
1226	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1227
1228	(shift @post_detect)->() while @post_detect;
1229	}	1464	}
1230		1465
		1466	# free memory only needed for probing
		1467	undef @models;
		1468	undef @REGISTRY;
		1469
		1470	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1471
		1472	# now nuke some methods that are overridden by the backend.
		1473	# SUPER usage is not allowed in these.
		1474	for (qw(time signal child idle)) {
		1475	undef &{"AnyEvent::Base::$_"}
		1476	if defined &{"$MODEL\::$_"};
		1477	}
		1478
		1479	_isa_set;
		1480
		1481	# we're officially open!
		1482
		1483	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1484	require AnyEvent::Strict;
		1485	}
		1486
		1487	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1488	require AnyEvent::Debug;
		1489	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1490	}
		1491
		1492	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1493	require AnyEvent::Socket;
		1494	require AnyEvent::Debug;
		1495
		1496	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1497	$shell =~ s/\$\$/$$/g;
		1498
		1499	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1500	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1501	}
		1502
		1503	# now the anyevent environment is set up as the user told us to, so
		1504	# call the actual user code - post detects
		1505
		1506	(shift @post_detect)->() while @post_detect;
		1507	undef @post_detect;
		1508
		1509	*post_detect = sub(&) {
		1510	shift->();
		1511
		1512	undef
		1513	};
		1514
1231	$MODEL	1515	$MODEL
1232	}	1516	}
1233		1517
1234	sub AUTOLOAD {	1518	for my $name (@methods) {
1235	(my $func = $AUTOLOAD) =~ s/.*://;	1519	*$name = sub {
1236		1520	detect;
1237	$method{$func}	1521	# we use goto because
1238	or Carp::croak "$func: not a valid method for AnyEvent objects";	1522	# a) it makes the thunk more transparent
1239		1523	# b) it allows us to delete the thunk later
1240	detect unless $MODEL;	1524	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1241		1525	};
1242	my $class = shift;
1243	$class->$func (@_);
1244	}	1526	}
1245		1527
1246	# utility function to dup a filehandle. this is used by many backends	1528	# utility function to dup a filehandle. this is used by many backends
1247	# to support binding more than one watcher per filehandle (they usually	1529	# to support binding more than one watcher per filehandle (they usually
1248	# allow only one watcher per fd, so we dup it to get a different one).	1530	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1258	# we assume CLOEXEC is already set by perl in all important cases	1540	# we assume CLOEXEC is already set by perl in all important cases
1259		1541
1260	($fh2, $rw)	1542	($fh2, $rw)
1261	}	1543	}
1262		1544
		1545	=head1 SIMPLIFIED AE API
		1546
		1547	Starting with version 5.0, AnyEvent officially supports a second, much
		1548	simpler, API that is designed to reduce the calling, typing and memory
		1549	overhead by using function call syntax and a fixed number of parameters.
		1550
		1551	See the L<AE> manpage for details.
		1552
		1553	=cut
		1554
		1555	package AE;
		1556
		1557	our $VERSION = $AnyEvent::VERSION;
		1558
		1559	sub _reset() {
		1560	eval q{
		1561	# fall back to the main API by default - backends and AnyEvent::Base
		1562	# implementations can overwrite these.
		1563
		1564	sub io($$$) {
		1565	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1566	}
		1567
		1568	sub timer($$$) {
		1569	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1570	}
		1571
		1572	sub signal($$) {
		1573	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1574	}
		1575
		1576	sub child($$) {
		1577	AnyEvent->child (pid => $_[0], cb => $_[1])
		1578	}
		1579
		1580	sub idle($) {
		1581	AnyEvent->idle (cb => $_[0]);
		1582	}
		1583
		1584	sub cv(;&) {
		1585	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1586	}
		1587
		1588	sub now() {
		1589	AnyEvent->now
		1590	}
		1591
		1592	sub now_update() {
		1593	AnyEvent->now_update
		1594	}
		1595
		1596	sub time() {
		1597	AnyEvent->time
		1598	}
		1599
		1600	*postpone = \&AnyEvent::postpone;
		1601	*log = \&AnyEvent::log;
		1602	};
		1603	die if $@;
		1604	}
		1605
		1606	BEGIN { _reset }
		1607
1263	package AnyEvent::Base;	1608	package AnyEvent::Base;
1264		1609
1265	# default implementations for many methods	1610	# default implementations for many methods
1266		1611
1267	sub _time {	1612	sub time {
		1613	eval q{ # poor man's autoloading {}
1268	# probe for availability of Time::HiRes	1614	# probe for availability of Time::HiRes
1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1615	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1616	*time = sub { Time::HiRes::time () };
1271	*_time = \&Time::HiRes::time;	1617	*AE::time = \& Time::HiRes::time ;
		1618	*now = \&time;
		1619	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1272	# if (eval "use POSIX (); (POSIX::times())...	1620	# if (eval "use POSIX (); (POSIX::times())...
1273	} else {	1621	} else {
		1622	*time = sub { CORE::time };
		1623	*AE::time = sub (){ CORE::time };
		1624	*now = \&time;
1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1625	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
1275	*_time = sub { time }; # epic fail	1626	}
1276	}	1627	};
		1628	die if $@;
1277		1629
1278	&_time	1630	&time
1279	}	1631	}
1280		1632
1281	sub time { _time }	1633	*now = \&time;
1282	sub now { _time }
1283	sub now_update { }	1634	sub now_update { }
1284		1635
		1636	sub _poll {
		1637	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1638	}
		1639
1285	# default implementation for ->condvar	1640	# default implementation for ->condvar
		1641	# in fact, the default should not be overwritten
1286		1642
1287	sub condvar {	1643	sub condvar {
		1644	eval q{ # poor man's autoloading {}
		1645	*condvar = sub {
1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1646	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1647	};
		1648
		1649	*AE::cv = sub (;&) {
		1650	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1651	};
		1652	};
		1653	die if $@;
		1654
		1655	&condvar
1289	}	1656	}
1290		1657
1291	# default implementation for ->signal	1658	# default implementation for ->signal
1292		1659
1293	our $HAVE_ASYNC_INTERRUPT;	1660	our $HAVE_ASYNC_INTERRUPT;
1294		1661
1295	sub _have_async_interrupt() {	1662	sub _have_async_interrupt() {
1296	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1663	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1297	&& eval "use Async::Interrupt 1.0 (); 1")	1664	&& eval "use Async::Interrupt 1.02 (); 1")
1298	unless defined $HAVE_ASYNC_INTERRUPT;	1665	unless defined $HAVE_ASYNC_INTERRUPT;
1299		1666
1300	$HAVE_ASYNC_INTERRUPT	1667	$HAVE_ASYNC_INTERRUPT
1301	}	1668	}
1302		1669
1303	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1670	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1304	our (%SIG_ASY, %SIG_ASY_W);	1671	our (%SIG_ASY, %SIG_ASY_W);
1305	our ($SIG_COUNT, $SIG_TW);	1672	our ($SIG_COUNT, $SIG_TW);
1306		1673
1307	sub _signal_exec {
1308	$HAVE_ASYNC_INTERRUPT
1309	? $SIGPIPE_R->drain
1310	: sysread $SIGPIPE_R, my $dummy, 9;
1311
1312	while (%SIG_EV) {
1313	for (keys %SIG_EV) {
1314	delete $SIG_EV{$_};
1315	$_->() for values %{ $SIG_CB{$_} || {} };
1316	}
1317	}
1318	}
1319
1320	# install a dummy wakeup watcher to reduce signal catching latency	1674	# install a dummy wakeup watcher to reduce signal catching latency
		1675	# used by Impls
1321	sub _sig_add() {	1676	sub _sig_add() {
1322	unless ($SIG_COUNT++) {	1677	unless ($SIG_COUNT++) {
1323	# try to align timer on a full-second boundary, if possible	1678	# try to align timer on a full-second boundary, if possible
1324	my $NOW = AnyEvent->now;	1679	my $NOW = AE::now;
1325		1680
1326	$SIG_TW = AnyEvent->timer (	1681	$SIG_TW = AE::timer
1327	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1682	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1328	interval => $MAX_SIGNAL_LATENCY,	1683	$MAX_SIGNAL_LATENCY,
1329	cb => sub { }, # just for the PERL_ASYNC_CHECK	1684	sub { } # just for the PERL_ASYNC_CHECK
1330	);	1685	;
1331	}	1686	}
1332	}	1687	}
1333		1688
1334	sub _sig_del {	1689	sub _sig_del {
1335	undef $SIG_TW	1690	undef $SIG_TW
1336	unless --$SIG_COUNT;	1691	unless --$SIG_COUNT;
1337	}	1692	}
1338		1693
1339	our $_sig_name_init; $_sig_name_init = sub {	1694	our $_sig_name_init; $_sig_name_init = sub {
		1695	eval q{ # poor man's autoloading {}
1340	undef $_sig_name_init;	1696	undef $_sig_name_init;
1341		1697
1342	if (_have_async_interrupt) {	1698	if (_have_async_interrupt) {
1343	*sig2num = \&Async::Interrupt::sig2num;	1699	*sig2num = \&Async::Interrupt::sig2num;
1344	*sig2name = \&Async::Interrupt::sig2name;	1700	*sig2name = \&Async::Interrupt::sig2name;
1345	} else {	1701	} else {
1346	require Config;	1702	require Config;
1347		1703
1348	my %signame2num;	1704	my %signame2num;
1349	@signame2num{ split ' ', $Config::Config{sig_name} }	1705	@signame2num{ split ' ', $Config::Config{sig_name} }
1350	= split ' ', $Config::Config{sig_num};	1706	= split ' ', $Config::Config{sig_num};
1351		1707
1352	my @signum2name;	1708	my @signum2name;
1353	@signum2name[values %signame2num] = keys %signame2num;	1709	@signum2name[values %signame2num] = keys %signame2num;
1354		1710
1355	*sig2num = sub($) {	1711	*sig2num = sub($) {
1356	$_[0] > 0 ? shift : $signame2num{+shift}	1712	$_[0] > 0 ? shift : $signame2num{+shift}
1357	};	1713	};
1358	*sig2name = sub ($) {	1714	*sig2name = sub ($) {
1359	$_[0] > 0 ? $signum2name[+shift] : shift	1715	$_[0] > 0 ? $signum2name[+shift] : shift
		1716	};
1360	};	1717	}
1361	}	1718	};
		1719	die if $@;
1362	};	1720	};
1363		1721
1364	sub sig2num ($) { &$_sig_name_init; &sig2num }	1722	sub sig2num ($) { &$_sig_name_init; &sig2num }
1365	sub sig2name($) { &$_sig_name_init; &sig2name }	1723	sub sig2name($) { &$_sig_name_init; &sig2name }
1366		1724
1367	sub _signal {	1725	sub signal {
		1726	eval q{ # poor man's autoloading {}
		1727	# probe for availability of Async::Interrupt
		1728	if (_have_async_interrupt) {
		1729	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
		1730
		1731	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1732	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1733
		1734	} else {
		1735	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1736
		1737	if (AnyEvent::WIN32) {
		1738	require AnyEvent::Util;
		1739
		1740	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1741	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1742	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1743	} else {
		1744	pipe $SIGPIPE_R, $SIGPIPE_W;
		1745	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1746	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1747
		1748	# not strictly required, as $^F is normally 2, but let's make sure...
		1749	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1750	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1751	}
		1752
		1753	$SIGPIPE_R
		1754	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1755
		1756	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1757	}
		1758
		1759	*signal = $HAVE_ASYNC_INTERRUPT
		1760	? sub {
1368	my (undef, %arg) = @_;	1761	my (undef, %arg) = @_;
1369		1762
1370	my $signal = uc $arg{signal}
1371	or Carp::croak "required option 'signal' is missing";
1372
1373	if ($HAVE_ASYNC_INTERRUPT) {
1374	# async::interrupt	1763	# async::interrupt
1375
1376	$signal = sig2num $signal;	1764	my $signal = sig2num $arg{signal};
1377	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1765	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1378		1766
1379	$SIG_ASY{$signal} ||= new Async::Interrupt	1767	$SIG_ASY{$signal} ||= new Async::Interrupt
1380	cb => sub { undef $SIG_EV{$signal} },	1768	cb => sub { undef $SIG_EV{$signal} },
1381	signal => $signal,	1769	signal => $signal,
1382	pipe => [$SIGPIPE_R->filenos],	1770	pipe => [$SIGPIPE_R->filenos],
1383	pipe_autodrain => 0,	1771	pipe_autodrain => 0,
		1772	;
		1773
		1774	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1775	}
		1776	: sub {
		1777	my (undef, %arg) = @_;
		1778
		1779	# pure perl
		1780	my $signal = sig2name $arg{signal};
		1781	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1782
		1783	$SIG{$signal} ||= sub {
		1784	local $!;
		1785	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1786	undef $SIG_EV{$signal};
		1787	};
		1788
		1789	# can't do signal processing without introducing races in pure perl,
		1790	# so limit the signal latency.
		1791	_sig_add;
		1792
		1793	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1794	}
1384	;	1795	;
1385		1796
1386	} else {	1797	*AnyEvent::Base::signal::DESTROY = sub {
1387	# pure perl	1798	my ($signal, $cb) = @{$_[0]};
1388		1799
1389	# AE::Util has been loaded in signal	1800	_sig_del;
1390	$signal = sig2name $signal;
1391	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1392		1801
1393	$SIG{$signal} ||= sub {	1802	delete $SIG_CB{$signal}{$cb};
1394	local $!;	1803
1395	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1804	$HAVE_ASYNC_INTERRUPT
		1805	? delete $SIG_ASY{$signal}
		1806	: # delete doesn't work with older perls - they then
		1807	# print weird messages, or just unconditionally exit
		1808	# instead of getting the default action.
1396	undef $SIG_EV{$signal};	1809	undef $SIG{$signal}
		1810	unless keys %{ $SIG_CB{$signal} };
1397	};	1811	};
1398		1812
1399	# can't do signal processing without introducing races in pure perl,	1813	*_signal_exec = sub {
1400	# so limit the signal latency.	1814	$HAVE_ASYNC_INTERRUPT
1401	_sig_add;	1815	? $SIGPIPE_R->drain
1402	}	1816	: sysread $SIGPIPE_R, (my $dummy), 9;
1403		1817
1404	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1818	while (%SIG_EV) {
1405	}	1819	for (keys %SIG_EV) {
1406		1820	delete $SIG_EV{$_};
1407	sub signal {	1821	&$_ for values %{ $SIG_CB{$_} || {} };
1408	# probe for availability of Async::Interrupt	1822	}
1409	if (_have_async_interrupt) {	1823	}
1410	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1411
1412	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1413	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1414
1415	} else {
1416	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1417
1418	require Fcntl;
1419
1420	if (AnyEvent::WIN32) {
1421	require AnyEvent::Util;
1422
1423	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1424	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1425	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1426	} else {
1427	pipe $SIGPIPE_R, $SIGPIPE_W;
1428	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1429	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1430
1431	# not strictly required, as $^F is normally 2, but let's make sure...
1432	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1433	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1434	}	1824	};
1435
1436	$SIGPIPE_R
1437	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1438
1439	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1440	}	1825	};
		1826	die if $@;
1441		1827
1442	*signal = \&_signal;
1443	&signal	1828	&signal
1444	}
1445
1446	sub AnyEvent::Base::signal::DESTROY {
1447	my ($signal, $cb) = @{$_[0]};
1448
1449	_sig_del;
1450
1451	delete $SIG_CB{$signal}{$cb};
1452
1453	$HAVE_ASYNC_INTERRUPT
1454	? delete $SIG_ASY{$signal}
1455	: # delete doesn't work with older perls - they then
1456	# print weird messages, or just unconditionally exit
1457	# instead of getting the default action.
1458	undef $SIG{$signal}
1459	unless keys %{ $SIG_CB{$signal} };
1460	}	1829	}
1461		1830
1462	# default implementation for ->child	1831	# default implementation for ->child
1463		1832
1464	our %PID_CB;	1833	our %PID_CB;
1465	our $CHLD_W;	1834	our $CHLD_W;
1466	our $CHLD_DELAY_W;	1835	our $CHLD_DELAY_W;
1467	our $WNOHANG;
1468		1836
		1837	# used by many Impl's
1469	sub _emit_childstatus($$) {	1838	sub _emit_childstatus($$) {
1470	my (undef, $rpid, $rstatus) = @_;	1839	my (undef, $rpid, $rstatus) = @_;
1471		1840
1472	$_->($rpid, $rstatus)	1841	$_->($rpid, $rstatus)
1473	for values %{ $PID_CB{$rpid} || {} },	1842	for values %{ $PID_CB{$rpid} || {} },
1474	values %{ $PID_CB{0} || {} };	1843	values %{ $PID_CB{0} || {} };
1475	}	1844	}
1476		1845
1477	sub _sigchld {
1478	my $pid;
1479
1480	AnyEvent->_emit_childstatus ($pid, $?)
1481	while ($pid = waitpid -1, $WNOHANG) > 0;
1482	}
1483
1484	sub child {	1846	sub child {
		1847	eval q{ # poor man's autoloading {}
		1848	*_sigchld = sub {
		1849	my $pid;
		1850
		1851	AnyEvent->_emit_childstatus ($pid, $?)
		1852	while ($pid = waitpid -1, WNOHANG) > 0;
		1853	};
		1854
		1855	*child = sub {
1485	my (undef, %arg) = @_;	1856	my (undef, %arg) = @_;
1486		1857
1487	defined (my $pid = $arg{pid} + 0)	1858	my $pid = $arg{pid};
1488	or Carp::croak "required option 'pid' is missing";	1859	my $cb = $arg{cb};
1489		1860
1490	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1861	$PID_CB{$pid}{$cb+0} = $cb;
1491		1862
1492	# WNOHANG is almost cetrainly 1 everywhere
1493	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1494	? 1
1495	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1496
1497	unless ($CHLD_W) {	1863	unless ($CHLD_W) {
1498	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1864	$CHLD_W = AE::signal CHLD => \&_sigchld;
1499	# child could be a zombie already, so make at least one round	1865	# child could be a zombie already, so make at least one round
1500	&_sigchld;	1866	&_sigchld;
1501	}	1867	}
1502		1868
1503	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1869	bless [$pid, $cb+0], "AnyEvent::Base::child"
1504	}	1870	};
1505		1871
1506	sub AnyEvent::Base::child::DESTROY {	1872	*AnyEvent::Base::child::DESTROY = sub {
1507	my ($pid, $cb) = @{$_[0]};	1873	my ($pid, $icb) = @{$_[0]};
1508		1874
1509	delete $PID_CB{$pid}{$cb};	1875	delete $PID_CB{$pid}{$icb};
1510	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1876	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1511		1877
1512	undef $CHLD_W unless keys %PID_CB;	1878	undef $CHLD_W unless keys %PID_CB;
		1879	};
		1880	};
		1881	die if $@;
		1882
		1883	&child
1513	}	1884	}
1514		1885
1515	# idle emulation is done by simply using a timer, regardless	1886	# idle emulation is done by simply using a timer, regardless
1516	# of whether the process is idle or not, and not letting	1887	# of whether the process is idle or not, and not letting
1517	# the callback use more than 50% of the time.	1888	# the callback use more than 50% of the time.
1518	sub idle {	1889	sub idle {
		1890	eval q{ # poor man's autoloading {}
		1891	*idle = sub {
1519	my (undef, %arg) = @_;	1892	my (undef, %arg) = @_;
1520		1893
1521	my ($cb, $w, $rcb) = $arg{cb};	1894	my ($cb, $w, $rcb) = $arg{cb};
1522		1895
1523	$rcb = sub {	1896	$rcb = sub {
1524	if ($cb) {	1897	if ($cb) {
1525	$w = _time;	1898	$w = AE::time;
1526	&$cb;	1899	&$cb;
1527	$w = _time - $w;	1900	$w = AE::time - $w;
1528		1901
1529	# never use more then 50% of the time for the idle watcher,	1902	# never use more then 50% of the time for the idle watcher,
1530	# within some limits	1903	# within some limits
1531	$w = 0.0001 if $w < 0.0001;	1904	$w = 0.0001 if $w < 0.0001;
1532	$w = 5 if $w > 5;	1905	$w = 5 if $w > 5;
1533		1906
1534	$w = AnyEvent->timer (after => $w, cb => $rcb);	1907	$w = AE::timer $w, 0, $rcb;
1535	} else {	1908	} else {
1536	# clean up...	1909	# clean up...
1537	undef $w;	1910	undef $w;
1538	undef $rcb;	1911	undef $rcb;
		1912	}
		1913	};
		1914
		1915	$w = AE::timer 0.05, 0, $rcb;
		1916
		1917	bless \\$cb, "AnyEvent::Base::idle"
1539	}	1918	};
		1919
		1920	*AnyEvent::Base::idle::DESTROY = sub {
		1921	undef $${$_[0]};
		1922	};
1540	};	1923	};
		1924	die if $@;
1541		1925
1542	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1926	&idle
1543
1544	bless \\$cb, "AnyEvent::Base::idle"
1545	}
1546
1547	sub AnyEvent::Base::idle::DESTROY {
1548	undef $${$_[0]};
1549	}	1927	}
1550		1928
1551	package AnyEvent::CondVar;	1929	package AnyEvent::CondVar;
1552		1930
1553	our @ISA = AnyEvent::CondVar::Base::;	1931	our @ISA = AnyEvent::CondVar::Base::;
		1932
		1933	# only to be used for subclassing
		1934	sub new {
		1935	my $class = shift;
		1936	bless AnyEvent->condvar (@_), $class
		1937	}
1554		1938
1555	package AnyEvent::CondVar::Base;	1939	package AnyEvent::CondVar::Base;
1556		1940
1557	#use overload	1941	#use overload
1558	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1942	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1568		1952
1569	sub _send {	1953	sub _send {
1570	# nop	1954	# nop
1571	}	1955	}
1572		1956
		1957	sub _wait {
		1958	AnyEvent->_poll until $_[0]{_ae_sent};
		1959	}
		1960
1573	sub send {	1961	sub send {
1574	my $cv = shift;	1962	my $cv = shift;
1575	$cv->{_ae_sent} = [@_];	1963	$cv->{_ae_sent} = [@_];
1576	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1964	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1577	$cv->_send;	1965	$cv->_send;
…		…
1584		1972
1585	sub ready {	1973	sub ready {
1586	$_[0]{_ae_sent}	1974	$_[0]{_ae_sent}
1587	}	1975	}
1588		1976
1589	sub _wait {
1590	$WAITING
1591	and !$_[0]{_ae_sent}
1592	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1593
1594	local $WAITING = 1;
1595	AnyEvent->one_event while !$_[0]{_ae_sent};
1596	}
1597
1598	sub recv {	1977	sub recv {
		1978	unless ($_[0]{_ae_sent}) {
		1979	$WAITING
		1980	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1981
		1982	local $WAITING = 1;
1599	$_[0]->_wait;	1983	$_[0]->_wait;
		1984	}
1600		1985
1601	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1986	$_[0]{_ae_croak}
1602	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1987	and Carp::croak $_[0]{_ae_croak};
		1988
		1989	wantarray
		1990	? @{ $_[0]{_ae_sent} }
		1991	: $_[0]{_ae_sent}[0]
1603	}	1992	}
1604		1993
1605	sub cb {	1994	sub cb {
1606	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1995	my $cv = shift;
		1996
		1997	@_
		1998	and $cv->{_ae_cb} = shift
		1999	and $cv->{_ae_sent}
		2000	and (delete $cv->{_ae_cb})->($cv);
		2001
1607	$_[0]{_ae_cb}	2002	$cv->{_ae_cb}
1608	}	2003	}
1609		2004
1610	sub begin {	2005	sub begin {
1611	++$_[0]{_ae_counter};	2006	++$_[0]{_ae_counter};
1612	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	2007	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1617	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2012	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1618	}	2013	}
1619		2014
1620	# undocumented/compatibility with pre-3.4	2015	# undocumented/compatibility with pre-3.4
1621	*broadcast = \&send;	2016	*broadcast = \&send;
1622	*wait = \&_wait;	2017	*wait = \&recv;
1623		2018
1624	=head1 ERROR AND EXCEPTION HANDLING	2019	=head1 ERROR AND EXCEPTION HANDLING
1625		2020
1626	In general, AnyEvent does not do any error handling - it relies on the	2021	In general, AnyEvent does not do any error handling - it relies on the
1627	caller to do that if required. The L<AnyEvent::Strict> module (see also	2022	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1639	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2034	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1640	so on.	2035	so on.
1641		2036
1642	=head1 ENVIRONMENT VARIABLES	2037	=head1 ENVIRONMENT VARIABLES
1643		2038
1644	The following environment variables are used by this module or its	2039	AnyEvent supports a number of environment variables that tune the
1645	submodules.	2040	runtime behaviour. They are usually evaluated when AnyEvent is
		2041	loaded, initialised, or a submodule that uses them is loaded. Many of
		2042	them also cause AnyEvent to load additional modules - for example,
		2043	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2044	loaded.
1646		2045
1647	Note that AnyEvent will remove I<all> environment variables starting with	2046	All the environment variables documented here start with
1648	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2047	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1649	enabled.	2048	namespace. Other modules are encouraged (but by no means required) to use
		2049	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2050	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2051	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2052	variables starting with C<AE_>, see below).
		2053
		2054	All variables can also be set via the C<AE_> prefix, that is, instead
		2055	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2056	case there is a clash btween anyevent and another program that uses
		2057	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2058	variable to the empty string, as those variables take precedence.
		2059
		2060	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2061	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2062	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2063	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2064	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2065	is set).
		2066
		2067	The exact algorithm is currently:
		2068
		2069	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2070	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2071	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2072
		2073	This ensures that child processes will not see the C<AE_> variables.
		2074
		2075	The following environment variables are currently known to AnyEvent:
1650		2076
1651	=over 4	2077	=over 4
1652		2078
1653	=item C<PERL_ANYEVENT_VERBOSE>	2079	=item C<PERL_ANYEVENT_VERBOSE>
1654		2080
1655	By default, AnyEvent will be completely silent except in fatal	2081	By default, AnyEvent will only log messages with loglevel C<3>
1656	conditions. You can set this environment variable to make AnyEvent more	2082	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2083	environment variable to a numerical loglevel to make AnyEvent more (or
1657	talkative.	2084	less) talkative.
1658		2085
		2086	If you want to do more than just set the global logging level
		2087	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2088	complex specifications.
		2089
		2090	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2091	the default logging settings.
		2092
1659	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2093	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1660	conditions, such as not being able to load the event model specified by	2094	unexpected conditions, such as not being able to load the event model
1661	C<PERL_ANYEVENT_MODEL>.	2095	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2096	exception - this is the minimum recommended level.
1662		2097
1663	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2098	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1664	model it chooses.	2099	chooses.
1665		2100
1666	When set to C<8> or higher, then AnyEvent will report extra information on	2101	When set to C<8> or higher (debug), then AnyEvent will report extra information on
1667	which optional modules it loads and how it implements certain features.	2102	which optional modules it loads and how it implements certain features.
		2103
		2104	=item C<PERL_ANYEVENT_LOG>
		2105
		2106	Accepts rather complex logging specifications. For example, you could log
		2107	all C<debug> messages of some module to stderr, warnings and above to
		2108	stderr, and errors and above to syslog, with:
		2109
		2110	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2111
		2112	For the rather extensive details, see L<AnyEvent::Log>.
		2113
		2114	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2115	so will take effect even before AnyEvent has initialised itself.
		2116
		2117	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2118	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2119	using the latter saves a few hundred kB of memory until the first message
		2120	is being logged.
1668		2121
1669	=item C<PERL_ANYEVENT_STRICT>	2122	=item C<PERL_ANYEVENT_STRICT>
1670		2123
1671	AnyEvent does not do much argument checking by default, as thorough	2124	AnyEvent does not do much argument checking by default, as thorough
1672	argument checking is very costly. Setting this variable to a true value	2125	argument checking is very costly. Setting this variable to a true value
…		…
1674	check the arguments passed to most method calls. If it finds any problems,	2127	check the arguments passed to most method calls. If it finds any problems,
1675	it will croak.	2128	it will croak.
1676		2129
1677	In other words, enables "strict" mode.	2130	In other words, enables "strict" mode.
1678		2131
1679	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2132	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1680	>>, it is definitely recommended to keep it off in production. Keeping	2133	>>, it is definitely recommended to keep it off in production. Keeping
1681	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2134	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1682	can be very useful, however.	2135	can be very useful, however.
1683		2136
		2137	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2138
		2139	If this env variable is nonempty, then its contents will be interpreted by
		2140	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2141	replacing every occurance of C<$$> by the process pid). The shell object
		2142	is saved in C<$AnyEvent::Debug::SHELL>.
		2143
		2144	This happens when the first watcher is created.
		2145
		2146	For example, to bind a debug shell on a unix domain socket in
		2147	F<< /tmp/debug<pid>.sock >>, you could use this:
		2148
		2149	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2150	# connect with e.g.: socat readline /tmp/debug123.sock
		2151
		2152	Or to bind to tcp port 4545 on localhost:
		2153
		2154	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2155	# connect with e.g.: telnet localhost 4545
		2156
		2157	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2158	multiuser systems.
		2159
		2160	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2161
		2162	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2163	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2164
1684	=item C<PERL_ANYEVENT_MODEL>	2165	=item C<PERL_ANYEVENT_MODEL>
1685		2166
1686	This can be used to specify the event model to be used by AnyEvent, before	2167	This can be used to specify the event model to be used by AnyEvent, before
1687	auto detection and -probing kicks in. It must be a string consisting	2168	auto detection and -probing kicks in.
1688	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2169
		2170	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2171	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1689	and the resulting module name is loaded and if the load was successful,	2172	resulting module name is loaded and - if the load was successful - used as
1690	used as event model. If it fails to load AnyEvent will proceed with	2173	event model backend. If it fails to load then AnyEvent will proceed with
1691	auto detection and -probing.	2174	auto detection and -probing.
1692		2175
1693	This functionality might change in future versions.	2176	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2177	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2178	the end of a string designates a module name and quotes it appropriately).
1694		2179
1695	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2180	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1696	could start your program like this:	2181	could start your program like this:
1697		2182
1698	PERL_ANYEVENT_MODEL=Perl perl ...	2183	PERL_ANYEVENT_MODEL=Perl perl ...
1699		2184
1700	=item C<PERL_ANYEVENT_PROTOCOLS>	2185	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1716	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2201	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1717	- only support IPv4, never try to resolve or contact IPv6	2202	- only support IPv4, never try to resolve or contact IPv6
1718	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2203	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1719	IPv6, but prefer IPv6 over IPv4.	2204	IPv6, but prefer IPv6 over IPv4.
1720		2205
		2206	=item C<PERL_ANYEVENT_HOSTS>
		2207
		2208	This variable, if specified, overrides the F</etc/hosts> file used by
		2209	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2210	from that file instead.
		2211
1721	=item C<PERL_ANYEVENT_EDNS0>	2212	=item C<PERL_ANYEVENT_EDNS0>
1722		2213
1723	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2214	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1724	for DNS. This extension is generally useful to reduce DNS traffic, but	2215	DNS. This extension is generally useful to reduce DNS traffic, especially
1725	some (broken) firewalls drop such DNS packets, which is why it is off by	2216	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1726	default.	2217	packets, which is why it is off by default.
1727		2218
1728	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2219	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1729	EDNS0 in its DNS requests.	2220	EDNS0 in its DNS requests.
1730		2221
1731	=item C<PERL_ANYEVENT_MAX_FORKS>	2222	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1737		2228
1738	The default value for the C<max_outstanding> parameter for the default DNS	2229	The default value for the C<max_outstanding> parameter for the default DNS
1739	resolver - this is the maximum number of parallel DNS requests that are	2230	resolver - this is the maximum number of parallel DNS requests that are
1740	sent to the DNS server.	2231	sent to the DNS server.
1741		2232
		2233	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2234
		2235	Perl has inherently racy signal handling (you can basically choose between
		2236	losing signals and memory corruption) - pure perl event loops (including
		2237	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2238	have to poll regularly to avoid losing signals.
		2239
		2240	Some event loops are racy, but don't poll regularly, and some event loops
		2241	are written in C but are still racy. For those event loops, AnyEvent
		2242	installs a timer that regularly wakes up the event loop.
		2243
		2244	By default, the interval for this timer is C<10> seconds, but you can
		2245	override this delay with this environment variable (or by setting
		2246	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2247	watchers).
		2248
		2249	Lower values increase CPU (and energy) usage, higher values can introduce
		2250	long delays when reaping children or waiting for signals.
		2251
		2252	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2253	polling (with most event loops).
		2254
1742	=item C<PERL_ANYEVENT_RESOLV_CONF>	2255	=item C<PERL_ANYEVENT_RESOLV_CONF>
1743		2256
1744	The file to use instead of F</etc/resolv.conf> (or OS-specific	2257	The absolute path to a F<resolv.conf>-style file to use instead of
1745	configuration) in the default resolver. When set to the empty string, no	2258	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1746	default config will be used.	2259	resolver, or the empty string to select the default configuration.
1747		2260
1748	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2261	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1749		2262
1750	When neither C<ca_file> nor C<ca_path> was specified during	2263	When neither C<ca_file> nor C<ca_path> was specified during
1751	L<AnyEvent::TLS> context creation, and either of these environment	2264	L<AnyEvent::TLS> context creation, and either of these environment
1752	variables exist, they will be used to specify CA certificate locations	2265	variables are nonempty, they will be used to specify CA certificate
1753	instead of a system-dependent default.	2266	locations instead of a system-dependent default.
1754		2267
1755	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2268	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1756		2269
1757	When these are set to C<1>, then the respective modules are not	2270	When these are set to C<1>, then the respective modules are not
1758	loaded. Mostly good for testing AnyEvent itself.	2271	loaded. Mostly good for testing AnyEvent itself.
…		…
1821	warn "read: $input\n"; # output what has been read	2334	warn "read: $input\n"; # output what has been read
1822	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2335	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1823	},	2336	},
1824	);	2337	);
1825		2338
1826	my $time_watcher; # can only be used once
1827
1828	sub new_timer {
1829	$timer = AnyEvent->timer (after => 1, cb => sub {	2339	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1830	warn "timeout\n"; # print 'timeout' about every second	2340	warn "timeout\n"; # print 'timeout' at most every second
1831	&new_timer; # and restart the time
1832	});	2341	});
1833	}
1834
1835	new_timer; # create first timer
1836		2342
1837	$cv->recv; # wait until user enters /^q/i	2343	$cv->recv; # wait until user enters /^q/i
1838		2344
1839	=head1 REAL-WORLD EXAMPLE	2345	=head1 REAL-WORLD EXAMPLE
1840		2346
…		…
1913		2419
1914	The actual code goes further and collects all errors (C<die>s, exceptions)	2420	The actual code goes further and collects all errors (C<die>s, exceptions)
1915	that occurred during request processing. The C<result> method detects	2421	that occurred during request processing. The C<result> method detects
1916	whether an exception as thrown (it is stored inside the $txn object)	2422	whether an exception as thrown (it is stored inside the $txn object)
1917	and just throws the exception, which means connection errors and other	2423	and just throws the exception, which means connection errors and other
1918	problems get reported tot he code that tries to use the result, not in a	2424	problems get reported to the code that tries to use the result, not in a
1919	random callback.	2425	random callback.
1920		2426
1921	All of this enables the following usage styles:	2427	All of this enables the following usage styles:
1922		2428
1923	1. Blocking:	2429	1. Blocking:
…		…
1971	through AnyEvent. The benchmark creates a lot of timers (with a zero	2477	through AnyEvent. The benchmark creates a lot of timers (with a zero
1972	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2478	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1973	which it is), lets them fire exactly once and destroys them again.	2479	which it is), lets them fire exactly once and destroys them again.
1974		2480
1975	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2481	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1976	distribution.	2482	distribution. It uses the L<AE> interface, which makes a real difference
		2483	for the EV and Perl backends only.
1977		2484
1978	=head3 Explanation of the columns	2485	=head3 Explanation of the columns
1979		2486
1980	I<watcher> is the number of event watchers created/destroyed. Since	2487	I<watcher> is the number of event watchers created/destroyed. Since
1981	different event models feature vastly different performances, each event	2488	different event models feature vastly different performances, each event
…		…
2002	watcher.	2509	watcher.
2003		2510
2004	=head3 Results	2511	=head3 Results
2005		2512
2006	name watchers bytes create invoke destroy comment	2513	name watchers bytes create invoke destroy comment
2007	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2514	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2008	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2515	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2009	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2516	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2010	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2517	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2011	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2518	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2012	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2519	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2013	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2520	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2014	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2521	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2015	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2522	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2016	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2523	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2017	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2524	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2018	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2525	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2019		2526
2020	=head3 Discussion	2527	=head3 Discussion
2021		2528
2022	The benchmark does I<not> measure scalability of the event loop very	2529	The benchmark does I<not> measure scalability of the event loop very
2023	well. For example, a select-based event loop (such as the pure perl one)	2530	well. For example, a select-based event loop (such as the pure perl one)
…		…
2035	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2542	benchmark machine, handling an event takes roughly 1600 CPU cycles with
2036	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2543	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2037	cycles with POE.	2544	cycles with POE.
2038		2545
2039	C<EV> is the sole leader regarding speed and memory use, which are both	2546	C<EV> is the sole leader regarding speed and memory use, which are both
2040	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2547	maximal/minimal, respectively. When using the L<AE> API there is zero
		2548	overhead (when going through the AnyEvent API create is about 5-6 times
		2549	slower, with other times being equal, so still uses far less memory than
2041	far less memory than any other event loop and is still faster than Event	2550	any other event loop and is still faster than Event natively).
2042	natively.
2043		2551
2044	The pure perl implementation is hit in a few sweet spots (both the	2552	The pure perl implementation is hit in a few sweet spots (both the
2045	constant timeout and the use of a single fd hit optimisations in the perl	2553	constant timeout and the use of a single fd hit optimisations in the perl
2046	interpreter and the backend itself). Nevertheless this shows that it	2554	interpreter and the backend itself). Nevertheless this shows that it
2047	adds very little overhead in itself. Like any select-based backend its	2555	adds very little overhead in itself. Like any select-based backend its
…		…
2095	(even when used without AnyEvent), but most event loops have acceptable	2603	(even when used without AnyEvent), but most event loops have acceptable
2096	performance with or without AnyEvent.	2604	performance with or without AnyEvent.
2097		2605
2098	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2606	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2099	the actual event loop, only with extremely fast event loops such as EV	2607	the actual event loop, only with extremely fast event loops such as EV
2100	adds AnyEvent significant overhead.	2608	does AnyEvent add significant overhead.
2101		2609
2102	=item * You should avoid POE like the plague if you want performance or	2610	=item * You should avoid POE like the plague if you want performance or
2103	reasonable memory usage.	2611	reasonable memory usage.
2104		2612
2105	=back	2613	=back
…		…
2121	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2629	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2122	(1%) are active. This mirrors the activity of large servers with many	2630	(1%) are active. This mirrors the activity of large servers with many
2123	connections, most of which are idle at any one point in time.	2631	connections, most of which are idle at any one point in time.
2124		2632
2125	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2633	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2126	distribution.	2634	distribution. It uses the L<AE> interface, which makes a real difference
		2635	for the EV and Perl backends only.
2127		2636
2128	=head3 Explanation of the columns	2637	=head3 Explanation of the columns
2129		2638
2130	I<sockets> is the number of sockets, and twice the number of "servers" (as	2639	I<sockets> is the number of sockets, and twice the number of "servers" (as
2131	each server has a read and write socket end).	2640	each server has a read and write socket end).
…		…
2139	a new one that moves the timeout into the future.	2648	a new one that moves the timeout into the future.
2140		2649
2141	=head3 Results	2650	=head3 Results
2142		2651
2143	name sockets create request	2652	name sockets create request
2144	EV 20000 69.01 11.16	2653	EV 20000 62.66 7.99
2145	Perl 20000 73.32 35.87	2654	Perl 20000 68.32 32.64
2146	IOAsync 20000 157.00 98.14 epoll	2655	IOAsync 20000 174.06 101.15 epoll
2147	IOAsync 20000 159.31 616.06 poll	2656	IOAsync 20000 174.67 610.84 poll
2148	Event 20000 212.62 257.32	2657	Event 20000 202.69 242.91
2149	Glib 20000 651.16 1896.30	2658	Glib 20000 557.01 1689.52
2150	POE 20000 349.67 12317.24 uses POE::Loop::Event	2659	POE 20000 341.54 12086.32 uses POE::Loop::Event
2151		2660
2152	=head3 Discussion	2661	=head3 Discussion
2153		2662
2154	This benchmark I<does> measure scalability and overall performance of the	2663	This benchmark I<does> measure scalability and overall performance of the
2155	particular event loop.	2664	particular event loop.
…		…
2281	As you can see, the AnyEvent + EV combination even beats the	2790	As you can see, the AnyEvent + EV combination even beats the
2282	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2791	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2283	backend easily beats IO::Lambda and POE.	2792	backend easily beats IO::Lambda and POE.
2284		2793
2285	And even the 100% non-blocking version written using the high-level (and	2794	And even the 100% non-blocking version written using the high-level (and
2286	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2795	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2287	large margin, even though it does all of DNS, tcp-connect and socket I/O	2796	higher level ("unoptimised") abstractions by a large margin, even though
2288	in a non-blocking way.	2797	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2289		2798
2290	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2799	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2291	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2800	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2292	part of the IO::lambda distribution and were used without any changes.	2801	part of the IO::Lambda distribution and were used without any changes.
2293		2802
2294		2803
2295	=head1 SIGNALS	2804	=head1 SIGNALS
2296		2805
2297	AnyEvent currently installs handlers for these signals:	2806	AnyEvent currently installs handlers for these signals:
…		…
2334	unless defined $SIG{PIPE};	2843	unless defined $SIG{PIPE};
2335		2844
2336	=head1 RECOMMENDED/OPTIONAL MODULES	2845	=head1 RECOMMENDED/OPTIONAL MODULES
2337		2846
2338	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2847	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2339	it's built-in modules) are required to use it.	2848	its built-in modules) are required to use it.
2340		2849
2341	That does not mean that AnyEvent won't take advantage of some additional	2850	That does not mean that AnyEvent won't take advantage of some additional
2342	modules if they are installed.	2851	modules if they are installed.
2343		2852
2344	This section epxlains which additional modules will be used, and how they	2853	This section explains which additional modules will be used, and how they
2345	affect AnyEvent's operetion.	2854	affect AnyEvent's operation.
2346		2855
2347	=over 4	2856	=over 4
2348		2857
2349	=item L<Async::Interrupt>	2858	=item L<Async::Interrupt>
2350		2859
…		…
2355	catch the signals) with some delay (default is 10 seconds, look for	2864	catch the signals) with some delay (default is 10 seconds, look for
2356	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2865	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2357		2866
2358	If this module is available, then it will be used to implement signal	2867	If this module is available, then it will be used to implement signal
2359	catching, which means that signals will not be delayed, and the event loop	2868	catching, which means that signals will not be delayed, and the event loop
2360	will not be interrupted regularly, which is more efficient (And good for	2869	will not be interrupted regularly, which is more efficient (and good for
2361	battery life on laptops).	2870	battery life on laptops).
2362		2871
2363	This affects not just the pure-perl event loop, but also other event loops	2872	This affects not just the pure-perl event loop, but also other event loops
2364	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2873	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2365		2874
…		…
2377	automatic timer adjustments even when no monotonic clock is available,	2886	automatic timer adjustments even when no monotonic clock is available,
2378	can take avdantage of advanced kernel interfaces such as C<epoll> and	2887	can take avdantage of advanced kernel interfaces such as C<epoll> and
2379	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2888	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2380	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2889	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2381		2890
		2891	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2892	then this module will do nothing for you.
		2893
2382	=item L<Guard>	2894	=item L<Guard>
2383		2895
2384	The guard module, when used, will be used to implement	2896	The guard module, when used, will be used to implement
2385	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2897	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2386	lot less memory), but otherwise doesn't affect guard operation much. It is	2898	lot less memory), but otherwise doesn't affect guard operation much. It is
2387	purely used for performance.	2899	purely used for performance.
2388		2900
2389	=item L<JSON> and L<JSON::XS>	2901	=item L<JSON> and L<JSON::XS>
2390		2902
2391	This module is required when you want to read or write JSON data via	2903	One of these modules is required when you want to read or write JSON data
2392	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2904	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2393	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2905	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2394
2395	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2396	installed.
2397		2906
2398	=item L<Net::SSLeay>	2907	=item L<Net::SSLeay>
2399		2908
2400	Implementing TLS/SSL in Perl is certainly interesting, but not very	2909	Implementing TLS/SSL in Perl is certainly interesting, but not very
2401	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2910	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2402	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2911	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2403		2912
2404	=item L<Time::HiRes>	2913	=item L<Time::HiRes>
2405		2914
2406	This module is part of perl since release 5.008. It will be used when the	2915	This module is part of perl since release 5.008. It will be used when the
2407	chosen event library does not come with a timing source on it's own. The	2916	chosen event library does not come with a timing source of its own. The
2408	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2917	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2409	try to use a monotonic clock for timing stability.	2918	try to use a monotonic clock for timing stability.
2410		2919
2411	=back	2920	=back
2412		2921
2413		2922
2414	=head1 FORK	2923	=head1 FORK
2415		2924
2416	Most event libraries are not fork-safe. The ones who are usually are	2925	Most event libraries are not fork-safe. The ones who are usually are
2417	because they rely on inefficient but fork-safe C<select> or C<poll>	2926	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2418	calls. Only L<EV> is fully fork-aware.	2927	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2928	are usually badly thought-out hacks that are incompatible with fork in
		2929	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2930	continue event-processing in both parent and child (or both, if you know
		2931	what you are doing).
		2932
		2933	This means that, in general, you cannot fork and do event processing in
		2934	the child if the event library was initialised before the fork (which
		2935	usually happens when the first AnyEvent watcher is created, or the library
		2936	is loaded).
2419		2937
2420	If you have to fork, you must either do so I<before> creating your first	2938	If you have to fork, you must either do so I<before> creating your first
2421	watcher OR you must not use AnyEvent at all in the child OR you must do	2939	watcher OR you must not use AnyEvent at all in the child OR you must do
2422	something completely out of the scope of AnyEvent.	2940	something completely out of the scope of AnyEvent.
		2941
		2942	The problem of doing event processing in the parent I<and> the child
		2943	is much more complicated: even for backends that I<are> fork-aware or
		2944	fork-safe, their behaviour is not usually what you want: fork clones all
		2945	watchers, that means all timers, I/O watchers etc. are active in both
		2946	parent and child, which is almost never what you want. USing C<exec>
		2947	to start worker children from some kind of manage rprocess is usually
		2948	preferred, because it is much easier and cleaner, at the expense of having
		2949	to have another binary.
2423		2950
2424		2951
2425	=head1 SECURITY CONSIDERATIONS	2952	=head1 SECURITY CONSIDERATIONS
2426		2953
2427	AnyEvent can be forced to load any event model via	2954	AnyEvent can be forced to load any event model via
…		…
2457	pronounced).	2984	pronounced).
2458		2985
2459		2986
2460	=head1 SEE ALSO	2987	=head1 SEE ALSO
2461		2988
2462	Utility functions: L<AnyEvent::Util>.	2989	Tutorial/Introduction: L<AnyEvent::Intro>.
2463		2990
2464	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2991	FAQ: L<AnyEvent::FAQ>.
2465	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2992
		2993	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2994	(simply logging).
		2995
		2996	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2997	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2998
		2999	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3000	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3001	L<Qt>, L<POE>, L<FLTK>.
2466		3002
2467	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3003	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2468	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3004	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2469	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3005	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2470	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	3006	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3007	L<AnyEvent::Impl::FLTK>.
2471		3008
2472	Non-blocking file handles, sockets, TCP clients and	3009	Non-blocking handles, pipes, stream sockets, TCP clients and
2473	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3010	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2474		3011
2475	Asynchronous DNS: L<AnyEvent::DNS>.	3012	Asynchronous DNS: L<AnyEvent::DNS>.
2476		3013
2477	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3014	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2478	L<Coro::Event>,
2479		3015
2480	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3016	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2481	L<AnyEvent::HTTP>.	3017	L<AnyEvent::HTTP>.
2482		3018
2483		3019
2484	=head1 AUTHOR	3020	=head1 AUTHOR
2485		3021

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