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Revision 1.277 by root, Sun Aug 9 13:27:23 2009 UTC vs.
Revision 1.414 by root, Wed Aug 21 08:40:28 2013 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	});
…		…
210		214
211	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.
212	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
213	underlying file descriptor.	217	underlying file descriptor.
214		218
215	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
216	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
217	handles.	221	handles.
218		222
219	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
220	watcher.	224	watcher.
…		…
244		248
245	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
246	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
247	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
248		252
249	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
250	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
251	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
252	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
253	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.
254		258
255	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
256	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
257	only approximate.	261	only approximate.
258		262
259	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
260		264
261	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
267		271
268	Example 2: fire an event after 0.5 seconds, then roughly every second.	272	Example 2: fire an event after 0.5 seconds, then roughly every second.
269		273
270	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {	274	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
271	warn "timeout\n";	275	warn "timeout\n";
272	};	276	});
273		277
274	=head3 TIMING ISSUES	278	=head3 TIMING ISSUES
275		279
276	There are two ways to handle timers: based on real time (relative, "fire	280	There are two ways to handle timers: based on real time (relative, "fire
277	in 10 seconds") and based on wallclock time (absolute, "fire at 12	281	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
279		283
280	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
281	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
282	"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
283	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
284	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.
285		289
286	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
287	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
288	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)
289	timers.	293	timers.
290		294
291	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
292	AnyEvent API.	296	AnyEvent API.
…		…
314	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
315	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
316		320
317	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
318	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
319	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
320		324
321	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
322	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
323		327
324	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>
325	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
326		330
327	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
328	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
329	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
330	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
331	after three seconds.	335	after three seconds.
332		336
…		…
352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
353	account.	357	account.
354		358
355	=item AnyEvent->now_update	359	=item AnyEvent->now_update
356		360
357	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
358	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 >>,
359	AnyEvent->now >>, above).	363	above).
360		364
361	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
362	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
363	might affect timers and time-outs.	367	might affect timers and time-outs.
364		368
365	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
366	event loop's idea of "current time".	370	event loop's idea of "current time".
		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).
367		378
368	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.
369		380
370	=back	381	=back
371		382
…		…
396		407
397	Example: exit on SIGINT	408	Example: exit on SIGINT
398		409
399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling)
		421	or "unsafe" (asynchronous) - the former might delay signal delivery
		422	indefinitely, the latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
401	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
402		430
403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support
404	callbacks to signals in a generic way, which is a pity, as you cannot	432	attaching callbacks to signals in a generic way, which is a pity,
405	do race-free signal handling in perl, requiring C libraries for	433	as you cannot do race-free signal handling in perl, requiring
406	this. AnyEvent will try to do it's best, which means in some cases,	434	C libraries for this. AnyEvent will try to do its best, which
407	signals will be delayed. The maximum time a signal might be delayed is	435	means in some cases, signals will be delayed. The maximum time
408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	a signal might be delayed is 10 seconds by default, but can
409	variable can be changed only before the first signal watcher is created,	437	be overriden via C<$ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY}> or
410	and should be left alone otherwise. This variable determines how often	438	C<$AnyEvent::MAX_SIGNAL_LATENCY> - see the L<ENVIRONMENT VARIABLES>
411	AnyEvent polls for signals (in case a wake-up was missed). Higher values	439	section for details.
412	will cause fewer spurious wake-ups, which is better for power and CPU
413	saving.
414		440
415	All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
416	L<Async::Interrupt> module, which works with most event loops. It will not	442	L<Async::Interrupt> module, which works with most event loops. It will not
417	work with inherently broken event loops such as L<Event> or L<Event::Lib>	443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
418	(and not with L<POE> currently, as POE does it's own workaround with	444	(and not with L<POE> currently). For those, you just have to suffer the
419	one-second latency). For those, you just have to suffer the delays.	445	delays.
420		446
421	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
422		448
423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
424		450
425	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.
426		452
427	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,
428	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
429	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
430	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
431	(stopped/continued).	457	(stopped/continued).
432		458
…		…
454	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
455	watcher before you C<fork> the child (alternatively, you can call	481	watcher before you C<fork> the child (alternatively, you can call
456	C<AnyEvent::detect>).	482	C<AnyEvent::detect>).
457		483
458	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
459	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
460	mentioned in the description of signal watchers apply.	486	problems mentioned in the description of signal watchers apply.
461		487
462	Example: fork a process and wait for it	488	Example: fork a process and wait for it
463		489
464	my $done = AnyEvent->condvar;	490	my $done = AnyEvent->condvar;
465		491
…		…
479		505
480	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
481		507
482	$w = AnyEvent->idle (cb => <callback>);	508	$w = AnyEvent->idle (cb => <callback>);
483		509
484	Sometimes there is a need to do something, but it is not so important	510	This will repeatedly invoke the callback after the process becomes idle,
485	to do it instantly, but only when there is nothing better to do. This	511	until either the watcher is destroyed or new events have been detected.
486	"nothing better to do" is usually defined to be "no other events need
487	attention by the event loop".
488		512
489	Idle watchers ideally get invoked when the event loop has nothing	513	Idle watchers are useful when there is a need to do something, but it
490	better to do, just before it would block the process to wait for new	514	is not so important (or wise) to do it instantly. The callback will be
491	events. Instead of blocking, the idle watcher is invoked.	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.
492		521
493	Most event loops unfortunately do not really support idle watchers (only	522	Unfortunately, most event loops do not really support idle watchers (only
494	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
495	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
496		525
497	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
498	program is otherwise idle:	527	program is otherwise idle:
…		…
526	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
527		556
528	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
529	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).
530		559
531	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
532	because they represent a condition that must become true.	561	they represent a condition that must become true.
533		562
534	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.
535		564
536	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
537	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
542	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
543	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
544	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<<
545	->send >> method).	574	->send >> method).
546		575
547	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
548	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:
549	in time where multiple outstanding events have been processed. And yet	578
550	another way to call them is transactions - each condition variable can be	579	=over 4
551	used to represent a transaction, which finishes at some point and delivers	580
552	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
553	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
554		599
555	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
556	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,
557	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
558	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
…		…
571		616
572	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
573	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
574	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
575	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
576	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
577		622
578	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
579	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
580	for the send to occur.	625	for the send to occur.
581		626
582	Example: wait for a timer.	627	Example: wait for a timer.
583		628
584	# wait till the result is ready	629	# condition: "wait till the timer is fired"
585	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
586		631
587	# do something such as adding a timer	632	# create the timer - we could wait for, say
588	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
589	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
590	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
591	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
592	after => 1,	637	after => 1,
593	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
594	);	639	);
595		640
596	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
597	# calls -<send	642	# calls ->send
598	$result_ready->recv;	643	$timer_fired->recv;
599		644
600	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
601	variables are also callable directly.	646	variables are also callable directly.
602		647
603	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
646	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
647	C<send>.	692	C<send>.
648		693
649	=item $cv->croak ($error)	694	=item $cv->croak ($error)
650		695
651	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
652	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
653		698
654	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
655	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
656	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
657	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
658	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
659	the problem.	704	the problem.
660		705
661	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
662		707
663	=item $cv->end	708	=item $cv->end
…		…
666	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
667	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
668		713
669	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
670	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
671	>>, 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
672	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
673	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.
674		720
675	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
676	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
677	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).
678		724
…		…
700	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
701	sending.	747	sending.
702		748
703	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
704	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
705	begung can potentially be zero:	751	begun can potentially be zero:
706		752
707	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
708		754
709	my %result;	755	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
711		757
712	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
713	$cv->begin;	759	$cv->begin;
714	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	761	$result{$host} = ...;
…		…
717	};	763	};
718	}	764	}
719		765
720	$cv->end;	766	$cv->end;
721		767
		768	...
		769
		770	my $results = $cv->recv;
		771
722	This code fragment supposedly pings a number of hosts and calls	772	This code fragment supposedly pings a number of hosts and calls
723	C<send> after results for all then have have been gathered - in any	773	C<send> after results for all then have have been gathered - in any
724	order. To achieve this, the code issues a call to C<begin> when it starts	774	order. To achieve this, the code issues a call to C<begin> when it starts
725	each ping request and calls C<end> when it has received some result for	775	each ping request and calls C<end> when it has received some result for
726	it. Since C<begin> and C<end> only maintain a counter, the order in which	776	it. Since C<begin> and C<end> only maintain a counter, the order in which
…		…
731	to be called once the counter reaches C<0>, and second, it ensures that	781	to be called once the counter reaches C<0>, and second, it ensures that
732	C<send> is called even when C<no> hosts are being pinged (the loop	782	C<send> is called even when C<no> hosts are being pinged (the loop
733	doesn't execute once).	783	doesn't execute once).
734		784
735	This is the general pattern when you "fan out" into multiple (but	785	This is the general pattern when you "fan out" into multiple (but
736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	786	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
737	the callback and ensure C<end> is called at least once, and then, for each	787	the callback and ensure C<end> is called at least once, and then, for each
738	subrequest you start, call C<begin> and for each subrequest you finish,	788	subrequest you start, call C<begin> and for each subrequest you finish,
739	call C<end>.	789	call C<end>.
740		790
741	=back	791	=back
…		…
748	=over 4	798	=over 4
749		799
750	=item $cv->recv	800	=item $cv->recv
751		801
752	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	802	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
753	>> methods have been called on c<$cv>, while servicing other watchers	803	>> methods have been called on C<$cv>, while servicing other watchers
754	normally.	804	normally.
755		805
756	You can only wait once on a condition - additional calls are valid but	806	You can only wait once on a condition - additional calls are valid but
757	will return immediately.	807	will return immediately.
758		808
…		…
761		811
762	In list context, all parameters passed to C<send> will be returned,	812	In list context, all parameters passed to C<send> will be returned,
763	in scalar context only the first one will be returned.	813	in scalar context only the first one will be returned.
764		814
765	Note that doing a blocking wait in a callback is not supported by any	815	Note that doing a blocking wait in a callback is not supported by any
766	event loop, that is, recursive invocation of a blocking C<< ->recv	816	event loop, that is, recursive invocation of a blocking C<< ->recv >> is
767	>> is not allowed, and the C<recv> call will C<croak> if such a	817	not allowed and the C<recv> call will C<croak> if such a condition is
768	condition is detected. This condition can be slightly loosened by using	818	detected. This requirement can be dropped by relying on L<Coro::AnyEvent>
769	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from	819	, which allows you to do a blocking C<< ->recv >> from any thread
770	any thread that doesn't run the event loop itself.	820	that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
		821	automatically when L<Coro> is used with L<AnyEvent>, so code does not need
		822	to do anything special to take advantage of that: any code that would
		823	normally block your program because it calls C<recv>, be executed in an
		824	C<async> thread instead without blocking other threads.
771		825
772	Not all event models support a blocking wait - some die in that case	826	Not all event models support a blocking wait - some die in that case
773	(programs might want to do that to stay interactive), so I<if you are	827	(programs might want to do that to stay interactive), so I<if you are
774	using this from a module, never require a blocking wait>. Instead, let the	828	using this from a module, never require a blocking wait>. Instead, let the
775	caller decide whether the call will block or not (for example, by coupling	829	caller decide whether the call will block or not (for example, by coupling
776	condition variables with some kind of request results and supporting	830	condition variables with some kind of request results and supporting
777	callbacks so the caller knows that getting the result will not block,	831	callbacks so the caller knows that getting the result will not block,
778	while still supporting blocking waits if the caller so desires).	832	while still supporting blocking waits if the caller so desires).
779		833
780	You can ensure that C<< -recv >> never blocks by setting a callback and	834	You can ensure that C<< ->recv >> never blocks by setting a callback and
781	only calling C<< ->recv >> from within that callback (or at a later	835	only calling C<< ->recv >> from within that callback (or at a later
782	time). This will work even when the event loop does not support blocking	836	time). This will work even when the event loop does not support blocking
783	waits otherwise.	837	waits otherwise.
784		838
785	=item $bool = $cv->ready	839	=item $bool = $cv->ready
…		…
790	=item $cb = $cv->cb ($cb->($cv))	844	=item $cb = $cv->cb ($cb->($cv))
791		845
792	This is a mutator function that returns the callback set and optionally	846	This is a mutator function that returns the callback set and optionally
793	replaces it before doing so.	847	replaces it before doing so.
794		848
795	The callback will be called when the condition becomes (or already was)	849	The callback will be called when the condition becomes "true", i.e. when
796	"true", i.e. when C<send> or C<croak> are called (or were called), with	850	C<send> or C<croak> are called, with the only argument being the
797	the only argument being the condition variable itself. Calling C<recv>	851	condition variable itself. If the condition is already true, the
		852	callback is called immediately when it is set. Calling C<recv> inside
798	inside the callback or at any later time is guaranteed not to block.	853	the callback or at any later time is guaranteed not to block.
799		854
800	=back	855	=back
801		856
802	=head1 SUPPORTED EVENT LOOPS/BACKENDS	857	=head1 SUPPORTED EVENT LOOPS/BACKENDS
803		858
…		…
811	use. If EV is not installed, then AnyEvent will fall back to its own	866	use. If EV is not installed, then AnyEvent will fall back to its own
812	pure-perl implementation, which is available everywhere as it comes with	867	pure-perl implementation, which is available everywhere as it comes with
813	AnyEvent itself.	868	AnyEvent itself.
814		869
815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	870	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	871	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
817		872
818	=item Backends that are transparently being picked up when they are used.	873	=item Backends that are transparently being picked up when they are used.
819		874
820	These will be used when they are currently loaded when the first watcher	875	These will be used if they are already loaded when the first watcher
821	is created, in which case it is assumed that the application is using	876	is created, in which case it is assumed that the application is using
822	them. This means that AnyEvent will automatically pick the right backend	877	them. This means that AnyEvent will automatically pick the right backend
823	when the main program loads an event module before anything starts to	878	when the main program loads an event module before anything starts to
824	create watchers. Nothing special needs to be done by the main program.	879	create watchers. Nothing special needs to be done by the main program.
825		880
…		…
827	AnyEvent::Impl::Glib based on Glib, slow but very stable.	882	AnyEvent::Impl::Glib based on Glib, slow but very stable.
828	AnyEvent::Impl::Tk based on Tk, very broken.	883	AnyEvent::Impl::Tk based on Tk, very broken.
829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	884	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830	AnyEvent::Impl::POE based on POE, very slow, some limitations.	885	AnyEvent::Impl::POE based on POE, very slow, some limitations.
831	AnyEvent::Impl::Irssi used when running within irssi.	886	AnyEvent::Impl::Irssi used when running within irssi.
		887	AnyEvent::Impl::IOAsync based on IO::Async.
		888	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		889	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
832		890
833	=item Backends with special needs.	891	=item Backends with special needs.
834		892
835	Qt requires the Qt::Application to be instantiated first, but will	893	Qt requires the Qt::Application to be instantiated first, but will
836	otherwise be picked up automatically. As long as the main program	894	otherwise be picked up automatically. As long as the main program
837	instantiates the application before any AnyEvent watchers are created,	895	instantiates the application before any AnyEvent watchers are created,
838	everything should just work.	896	everything should just work.
839		897
840	AnyEvent::Impl::Qt based on Qt.	898	AnyEvent::Impl::Qt based on Qt.
841		899
842	Support for IO::Async can only be partial, as it is too broken and
843	architecturally limited to even support the AnyEvent API. It also
844	is the only event loop that needs the loop to be set explicitly, so
845	it can only be used by a main program knowing about AnyEvent. See
846	L<AnyEvent::Impl::Async> for the gory details.
847
848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
849
850	=item Event loops that are indirectly supported via other backends.	900	=item Event loops that are indirectly supported via other backends.
851		901
852	Some event loops can be supported via other modules:	902	Some event loops can be supported via other modules:
853		903
854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	904	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
879	Contains C<undef> until the first watcher is being created, before the	929	Contains C<undef> until the first watcher is being created, before the
880	backend has been autodetected.	930	backend has been autodetected.
881		931
882	Afterwards it contains the event model that is being used, which is the	932	Afterwards it contains the event model that is being used, which is the
883	name of the Perl class implementing the model. This class is usually one	933	name of the Perl class implementing the model. This class is usually one
884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	934	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	935	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
886	will be C<urxvt::anyevent>).	936	will be C<urxvt::anyevent>).
887		937
888	=item AnyEvent::detect	938	=item AnyEvent::detect
889		939
890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	940	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
891	if necessary. You should only call this function right before you would	941	if necessary. You should only call this function right before you would
892	have created an AnyEvent watcher anyway, that is, as late as possible at	942	have created an AnyEvent watcher anyway, that is, as late as possible at
893	runtime, and not e.g. while initialising of your module.	943	runtime, and not e.g. during initialisation of your module.
		944
		945	The effect of calling this function is as if a watcher had been created
		946	(specifically, actions that happen "when the first watcher is created"
		947	happen when calling detetc as well).
894		948
895	If you need to do some initialisation before AnyEvent watchers are	949	If you need to do some initialisation before AnyEvent watchers are
896	created, use C<post_detect>.	950	created, use C<post_detect>.
897		951
898	=item $guard = AnyEvent::post_detect { BLOCK }	952	=item $guard = AnyEvent::post_detect { BLOCK }
899		953
900	Arranges for the code block to be executed as soon as the event model is	954	Arranges for the code block to be executed as soon as the event model is
901	autodetected (or immediately if this has already happened).	955	autodetected (or immediately if that has already happened).
902		956
903	The block will be executed I<after> the actual backend has been detected	957	The block will be executed I<after> the actual backend has been detected
904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	958	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	959	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906	other initialisations - see the sources of L<AnyEvent::Strict> or	960	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
915	that automatically removes the callback again when it is destroyed (or	969	that automatically removes the callback again when it is destroyed (or
916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	970	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
917	a case where this is useful.	971	a case where this is useful.
918		972
919	Example: Create a watcher for the IO::AIO module and store it in	973	Example: Create a watcher for the IO::AIO module and store it in
920	C<$WATCHER>. Only do so after the event loop is initialised, though.	974	C<$WATCHER>, but do so only do so after the event loop is initialised.
921		975
922	our WATCHER;	976	our WATCHER;
923		977
924	my $guard = AnyEvent::post_detect {	978	my $guard = AnyEvent::post_detect {
925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	979	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
933	$WATCHER ||= $guard;	987	$WATCHER ||= $guard;
934		988
935	=item @AnyEvent::post_detect	989	=item @AnyEvent::post_detect
936		990
937	If there are any code references in this array (you can C<push> to it	991	If there are any code references in this array (you can C<push> to it
938	before or after loading AnyEvent), then they will called directly after	992	before or after loading AnyEvent), then they will be called directly
939	the event loop has been chosen.	993	after the event loop has been chosen.
940		994
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	995	You should check C<$AnyEvent::MODEL> before adding to this array, though:
942	if it is defined then the event loop has already been detected, and the	996	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	997	array will be ignored.
944		998
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	999	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	1000	it, as it takes care of these details.
947		1001
948	This variable is mainly useful for modules that can do something useful	1002	This variable is mainly useful for modules that can do something useful
949	when AnyEvent is used and thus want to know when it is initialised, but do	1003	when AnyEvent is used and thus want to know when it is initialised, but do
950	not need to even load it by default. This array provides the means to hook	1004	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	1005	into AnyEvent passively, without loading it.
952		1006
		1007	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1008	together, you could put this into Coro (this is the actual code used by
		1009	Coro to accomplish this):
		1010
		1011	if (defined $AnyEvent::MODEL) {
		1012	# AnyEvent already initialised, so load Coro::AnyEvent
		1013	require Coro::AnyEvent;
		1014	} else {
		1015	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1016	# as soon as it is
		1017	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1018	}
		1019
		1020	=item AnyEvent::postpone { BLOCK }
		1021
		1022	Arranges for the block to be executed as soon as possible, but not before
		1023	the call itself returns. In practise, the block will be executed just
		1024	before the event loop polls for new events, or shortly afterwards.
		1025
		1026	This function never returns anything (to make the C<return postpone { ...
		1027	}> idiom more useful.
		1028
		1029	To understand the usefulness of this function, consider a function that
		1030	asynchronously does something for you and returns some transaction
		1031	object or guard to let you cancel the operation. For example,
		1032	C<AnyEvent::Socket::tcp_connect>:
		1033
		1034	# start a conenction attempt unless one is active
		1035	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1036	delete $self->{connect_guard};
		1037	...
		1038	};
		1039
		1040	Imagine that this function could instantly call the callback, for
		1041	example, because it detects an obvious error such as a negative port
		1042	number. Invoking the callback before the function returns causes problems
		1043	however: the callback will be called and will try to delete the guard
		1044	object. But since the function hasn't returned yet, there is nothing to
		1045	delete. When the function eventually returns it will assign the guard
		1046	object to C<< $self->{connect_guard} >>, where it will likely never be
		1047	deleted, so the program thinks it is still trying to connect.
		1048
		1049	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1050	callback directly on error:
		1051
		1052	$cb->(undef), return # signal error to callback, BAD!
		1053	if $some_error_condition;
		1054
		1055	It should use C<postpone>:
		1056
		1057	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1058	if $some_error_condition;
		1059
		1060	=item AnyEvent::log $level, $msg[, @args]
		1061
		1062	Log the given C<$msg> at the given C<$level>.
		1063
		1064	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1065	to see whether the message will be logged. If the test succeeds it will
		1066	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1067	the L<AnyEvent::Log> documentation for details.
		1068
		1069	If the test fails it will simply return. Right now this happens when a
		1070	numerical loglevel is used and it is larger than the level specified via
		1071	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1072
		1073	If you want to sprinkle loads of logging calls around your code, consider
		1074	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1075	which can reduce typing, codesize and can reduce the logging overhead
		1076	enourmously.
		1077
953	=back	1078	=back
954		1079
955	=head1 WHAT TO DO IN A MODULE	1080	=head1 WHAT TO DO IN A MODULE
956		1081
957	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1082	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
967	because it will stall the whole program, and the whole point of using	1092	because it will stall the whole program, and the whole point of using
968	events is to stay interactive.	1093	events is to stay interactive.
969		1094
970	It is fine, however, to call C<< ->recv >> when the user of your module	1095	It is fine, however, to call C<< ->recv >> when the user of your module
971	requests it (i.e. if you create a http request object ad have a method	1096	requests it (i.e. if you create a http request object ad have a method
972	called C<results> that returns the results, it should call C<< ->recv >>	1097	called C<results> that returns the results, it may call C<< ->recv >>
973	freely, as the user of your module knows what she is doing. always).	1098	freely, as the user of your module knows what she is doing. Always).
974		1099
975	=head1 WHAT TO DO IN THE MAIN PROGRAM	1100	=head1 WHAT TO DO IN THE MAIN PROGRAM
976		1101
977	There will always be a single main program - the only place that should	1102	There will always be a single main program - the only place that should
978	dictate which event model to use.	1103	dictate which event model to use.
979		1104
980	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1105	If the program is not event-based, it need not do anything special, even
981	do anything special (it does not need to be event-based) and let AnyEvent	1106	when it depends on a module that uses an AnyEvent. If the program itself
982	decide which implementation to chose if some module relies on it.	1107	uses AnyEvent, but does not care which event loop is used, all it needs
		1108	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1109	available loop implementation.
983		1110
984	If the main program relies on a specific event model - for example, in	1111	If the main program relies on a specific event model - for example, in
985	Gtk2 programs you have to rely on the Glib module - you should load the	1112	Gtk2 programs you have to rely on the Glib module - you should load the
986	event module before loading AnyEvent or any module that uses it: generally	1113	event module before loading AnyEvent or any module that uses it: generally
987	speaking, you should load it as early as possible. The reason is that	1114	speaking, you should load it as early as possible. The reason is that
988	modules might create watchers when they are loaded, and AnyEvent will	1115	modules might create watchers when they are loaded, and AnyEvent will
989	decide on the event model to use as soon as it creates watchers, and it	1116	decide on the event model to use as soon as it creates watchers, and it
990	might chose the wrong one unless you load the correct one yourself.	1117	might choose the wrong one unless you load the correct one yourself.
991		1118
992	You can chose to use a pure-perl implementation by loading the	1119	You can chose to use a pure-perl implementation by loading the
993	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1120	C<AnyEvent::Loop> module, which gives you similar behaviour
994	everywhere, but letting AnyEvent chose the model is generally better.	1121	everywhere, but letting AnyEvent chose the model is generally better.
995		1122
996	=head2 MAINLOOP EMULATION	1123	=head2 MAINLOOP EMULATION
997		1124
998	Sometimes (often for short test scripts, or even standalone programs who	1125	Sometimes (often for short test scripts, or even standalone programs who
…		…
1011		1138
1012		1139
1013	=head1 OTHER MODULES	1140	=head1 OTHER MODULES
1014		1141
1015	The following is a non-exhaustive list of additional modules that use	1142	The following is a non-exhaustive list of additional modules that use
1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1143	AnyEvent as a client and can therefore be mixed easily with other
1017	modules and other event loops in the same program. Some of the modules	1144	AnyEvent modules and other event loops in the same program. Some of the
1018	come with AnyEvent, most are available via CPAN.	1145	modules come as part of AnyEvent, the others are available via CPAN (see
		1146	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1147	a longer non-exhaustive list), and the list is heavily biased towards
		1148	modules of the AnyEvent author himself :)
1019		1149
1020	=over 4	1150	=over 4
1021		1151
1022	=item L<AnyEvent::Util>	1152	=item L<AnyEvent::Util> (part of the AnyEvent distribution)
1023		1153
1024	Contains various utility functions that replace often-used but blocking	1154	Contains various utility functions that replace often-used blocking
1025	functions such as C<inet_aton> by event-/callback-based versions.	1155	functions such as C<inet_aton> with event/callback-based versions.
1026		1156
1027	=item L<AnyEvent::Socket>	1157	=item L<AnyEvent::Socket> (part of the AnyEvent distribution)
1028		1158
1029	Provides various utility functions for (internet protocol) sockets,	1159	Provides various utility functions for (internet protocol) sockets,
1030	addresses and name resolution. Also functions to create non-blocking tcp	1160	addresses and name resolution. Also functions to create non-blocking tcp
1031	connections or tcp servers, with IPv6 and SRV record support and more.	1161	connections or tcp servers, with IPv6 and SRV record support and more.
1032		1162
1033	=item L<AnyEvent::Handle>	1163	=item L<AnyEvent::Handle> (part of the AnyEvent distribution)
1034		1164
1035	Provide read and write buffers, manages watchers for reads and writes,	1165	Provide read and write buffers, manages watchers for reads and writes,
1036	supports raw and formatted I/O, I/O queued and fully transparent and	1166	supports raw and formatted I/O, I/O queued and fully transparent and
1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1167	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1038		1168
1039	=item L<AnyEvent::DNS>	1169	=item L<AnyEvent::DNS> (part of the AnyEvent distribution)
1040		1170
1041	Provides rich asynchronous DNS resolver capabilities.	1171	Provides rich asynchronous DNS resolver capabilities.
1042		1172
		1173	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1174
		1175	Implement event-based interfaces to the protocols of the same name (for
		1176	the curious, IGS is the International Go Server and FCP is the Freenet
		1177	Client Protocol).
		1178
		1179	=item L<AnyEvent::AIO> (part of the AnyEvent distribution)
		1180
		1181	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1182	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1183	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1184	file I/O, and much more.
		1185
		1186	=item L<AnyEvent::Filesys::Notify>
		1187
		1188	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1189	path changes (e.g. "watch this directory for new files", "watch this
		1190	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1191	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1192	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1193	fall back to blocking scans at regular intervals transparently on other
		1194	platforms, so it's about as portable as it gets.
		1195
		1196	(I haven't used it myself, but I haven't heard anybody complaining about
		1197	it yet).
		1198
1043	=item L<AnyEvent::HTTP>	1199	=item L<AnyEvent::DBI>
1044		1200
1045	A simple-to-use HTTP library that is capable of making a lot of concurrent	1201	Executes L<DBI> requests asynchronously in a proxy process for you,
1046	HTTP requests.	1202	notifying you in an event-based way when the operation is finished.
1047		1203
1048	=item L<AnyEvent::HTTPD>	1204	=item L<AnyEvent::HTTPD>
1049		1205
1050	Provides a simple web application server framework.	1206	A simple embedded webserver.
1051		1207
1052	=item L<AnyEvent::FastPing>	1208	=item L<AnyEvent::FastPing>
1053		1209
1054	The fastest ping in the west.	1210	The fastest ping in the west.
1055		1211
1056	=item L<AnyEvent::DBI>
1057
1058	Executes L<DBI> requests asynchronously in a proxy process.
1059
1060	=item L<AnyEvent::AIO>
1061
1062	Truly asynchronous I/O, should be in the toolbox of every event
1063	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1064	together.
1065
1066	=item L<AnyEvent::BDB>
1067
1068	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1069	L<BDB> and AnyEvent together.
1070
1071	=item L<AnyEvent::GPSD>
1072
1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
1074
1075	=item L<AnyEvent::IRC>
1076
1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1078
1079	=item L<AnyEvent::XMPP>
1080
1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1082	Net::XMPP2>.
1083
1084	=item L<AnyEvent::IGS>
1085
1086	A non-blocking interface to the Internet Go Server protocol (used by
1087	L<App::IGS>).
1088
1089	=item L<Net::FCP>
1090
1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1092	of AnyEvent.
1093
1094	=item L<Event::ExecFlow>
1095
1096	High level API for event-based execution flow control.
1097
1098	=item L<Coro>	1212	=item L<Coro>
1099		1213
1100	Has special support for AnyEvent via L<Coro::AnyEvent>.	1214	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1215	to simply invert the flow control - don't call us, we will call you:
		1216
		1217	async {
		1218	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1219	print "5 seconds later!\n";
		1220
		1221	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1222	my $line = <STDIN>; # works for ttys
		1223
		1224	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1225	my ($body, $hdr) = Coro::rouse_wait;
		1226	};
1101		1227
1102	=back	1228	=back
1103		1229
1104	=cut	1230	=cut
1105		1231
1106	package AnyEvent;	1232	package AnyEvent;
1107		1233
1108	# basically a tuned-down version of common::sense	1234	BEGIN {
1109	sub common_sense {	1235	require "AnyEvent/constants.pl";
1110	# no warnings	1236	&AnyEvent::common_sense;
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};
1112	# use strict vars subs
1113	$^H |= 0x00000600;
1114	}	1237	}
1115
1116	BEGIN { AnyEvent::common_sense }
1117		1238
1118	use Carp ();	1239	use Carp ();
1119		1240
1120	our $VERSION = 4.92;	1241	our $VERSION = '7.05';
1121	our $MODEL;	1242	our $MODEL;
1122
1123	our $AUTOLOAD;
1124	our @ISA;	1243	our @ISA;
1125
1126	our @REGISTRY;	1244	our @REGISTRY;
1127
1128	our $WIN32;
1129
1130	our $VERBOSE;	1245	our $VERBOSE;
		1246	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1247	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1131		1248
1132	BEGIN {	1249	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1250	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1135		1251
1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1252	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137	if ${^TAINT};	1253	if ${^TAINT};
1138		1254
1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1255	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1256	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1140		1257
1141	}	1258	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1259	if ${^TAINT};
1142		1260
1143	our $MAX_SIGNAL_LATENCY = 10;	1261	# $ENV{PERL_ANYEVENT_xxx} now valid
1144		1262
1145	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1263	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1146		1264
1147	{
1148	my $idx;	1265	my $idx;
1149	$PROTOCOL{$_} = ++$idx	1266	$PROTOCOL{$_} = ++$idx
1150	for reverse split /\s*,\s*/,	1267	for reverse split /\s*,\s*/,
1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1268	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152	}	1269	}
1153		1270
		1271	our @post_detect;
		1272
		1273	sub post_detect(&) {
		1274	my ($cb) = @_;
		1275
		1276	push @post_detect, $cb;
		1277
		1278	defined wantarray
		1279	? bless \$cb, "AnyEvent::Util::postdetect"
		1280	: ()
		1281	}
		1282
		1283	sub AnyEvent::Util::postdetect::DESTROY {
		1284	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1285	}
		1286
		1287	our $POSTPONE_W;
		1288	our @POSTPONE;
		1289
		1290	sub _postpone_exec {
		1291	undef $POSTPONE_W;
		1292
		1293	&{ shift @POSTPONE }
		1294	while @POSTPONE;
		1295	}
		1296
		1297	sub postpone(&) {
		1298	push @POSTPONE, shift;
		1299
		1300	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1301
		1302	()
		1303	}
		1304
		1305	sub log($$;@) {
		1306	# only load the big bloated module when we actually are about to log something
		1307	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1308	local ($!, $@);
		1309	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1310	# AnyEvent::Log overwrites this function
		1311	goto &log;
		1312	}
		1313
		1314	0 # not logged
		1315	}
		1316
		1317	sub _logger($;$) {
		1318	my ($level, $renabled) = @_;
		1319
		1320	$$renabled = $level <= $VERBOSE;
		1321
		1322	my $logger = [(caller)[0], $level, $renabled];
		1323
		1324	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1325
		1326	# return unless defined wantarray;
		1327	#
		1328	# require AnyEvent::Util;
		1329	# my $guard = AnyEvent::Util::guard (sub {
		1330	# # "clean up"
		1331	# delete $LOGGER{$logger+0};
		1332	# });
		1333	#
		1334	# sub {
		1335	# return 0 unless $$renabled;
		1336	#
		1337	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1338	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1339	# package AnyEvent::Log;
		1340	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1341	# }
		1342	}
		1343
		1344	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1345	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1346	}
		1347
1154	my @models = (	1348	our @models = (
1155	[EV:: => AnyEvent::Impl::EV:: , 1],	1349	[EV:: => AnyEvent::Impl::EV::],
1156	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1350	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1157	# everything below here will not (normally) be autoprobed	1351	# everything below here will not (normally) be autoprobed
1158	# as the pureperl backend should work everywhere	1352	# as the pure perl backend should work everywhere
1159	# and is usually faster	1353	# and is usually faster
		1354	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1160	[Event:: => AnyEvent::Impl::Event::, 1],	1355	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1356	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1357	# everything below here should not be autoloaded
1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1358	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1359	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1360	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1361	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1167	[Wx:: => AnyEvent::Impl::POE::],	1362	[Wx:: => AnyEvent::Impl::POE::],
1168	[Prima:: => AnyEvent::Impl::POE::],	1363	[Prima:: => AnyEvent::Impl::POE::],
1169	# IO::Async is just too broken - we would need workarounds for its	1364	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1170	# byzantine signal and broken child handling, among others.	1365	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1171	# IO::Async is rather hard to detect, as it doesn't have any	1366	[FLTK:: => AnyEvent::Impl::FLTK::],
1172	# obvious default class.
1173	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1177	);	1367	);
1178		1368
1179	our %method = map +($_ => 1),	1369	our @isa_hook;
		1370
		1371	sub _isa_set {
		1372	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1373
		1374	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1375	for 1 .. $#pkg;
		1376
		1377	grep $_ && $_->[1], @isa_hook
		1378	and AE::_reset ();
		1379	}
		1380
		1381	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1382	sub _isa_hook($$;$) {
		1383	my ($i, $pkg, $reset_ae) = @_;
		1384
		1385	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1386
		1387	_isa_set;
		1388	}
		1389
		1390	# all autoloaded methods reserve the complete glob, not just the method slot.
		1391	# due to bugs in perls method cache implementation.
1180	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1392	our @methods = qw(io timer time now now_update signal child idle condvar);
1181		1393
1182	our @post_detect;
1183
1184	sub post_detect(&) {	1394	sub detect() {
1185	my ($cb) = @_;	1395	return $MODEL if $MODEL; # some programs keep references to detect
1186		1396
1187	if ($MODEL) {	1397	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1188	$cb->();	1398	# the author knows about the problems and what it does to AnyEvent as a whole
		1399	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1400	# anyway.
		1401	AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1402	. "design, abuses internals and breaks AnyEvent - will not continue."
		1403	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1189		1404
1190	undef	1405	local $!; # for good measure
		1406	local $SIG{__DIE__}; # we use eval
		1407
		1408	# free some memory
		1409	*detect = sub () { $MODEL };
		1410	# undef &func doesn't correctly update the method cache. grmbl.
		1411	# so we delete the whole glob. grmbl.
		1412	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1413	# a glob with an active sub. hrm. i hope it works, but perl is
		1414	# usually buggy in this department. sigh.
		1415	delete @{"AnyEvent::"}{@methods};
		1416	undef @methods;
		1417
		1418	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1419	my $model = $1;
		1420	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1421	if (eval "require $model") {
		1422	AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1423	$MODEL = $model;
1191	} else {	1424	} else {
1192	push @post_detect, $cb;	1425	AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1193		1426	}
1194	defined wantarray
1195	? bless \$cb, "AnyEvent::Util::postdetect"
1196	: ()
1197	}	1427	}
1198	}
1199		1428
1200	sub AnyEvent::Util::postdetect::DESTROY {	1429	# check for already loaded models
1201	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1202	}
1203
1204	sub detect() {
1205	unless ($MODEL) {	1430	unless ($MODEL) {
1206	local $SIG{__DIE__};	1431	for (@REGISTRY, @models) {
1207		1432	my ($package, $model) = @$_;
1208	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1433	if (${"$package\::VERSION"} > 0) {
1209	my $model = "AnyEvent::Impl::$1";
1210	if (eval "require $model") {	1434	if (eval "require $model") {
		1435	AnyEvent::log 7 => "Autodetected model '$model', using it.";
1211	$MODEL = $model;	1436	$MODEL = $model;
1212	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1437	last;
1213	} else {	1438	} else {
1214	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1439	AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
		1440	}
1215	}	1441	}
1216	}	1442	}
1217		1443
1218	# check for already loaded models
1219	unless ($MODEL) {	1444	unless ($MODEL) {
		1445	# try to autoload a model
1220	for (@REGISTRY, @models) {	1446	for (@REGISTRY, @models) {
1221	my ($package, $model) = @$_;	1447	my ($package, $model) = @$_;
		1448	if (
		1449	eval "require $package"
1222	if (${"$package\::VERSION"} > 0) {	1450	and ${"$package\::VERSION"} > 0
1223	if (eval "require $model") {	1451	and eval "require $model"
		1452	) {
		1453	AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1224	$MODEL = $model;	1454	$MODEL = $model;
1225	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1226	last;	1455	last;
1227	}
1228	}	1456	}
1229	}	1457	}
1230		1458
1231	unless ($MODEL) {
1232	# try to autoload a model
1233	for (@REGISTRY, @models) {
1234	my ($package, $model, $autoload) = @$_;
1235	if (
1236	$autoload
1237	and eval "require $package"
1238	and ${"$package\::VERSION"} > 0
1239	and eval "require $model"
1240	) {
1241	$MODEL = $model;
1242	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1243	last;
1244	}
1245	}
1246
1247	$MODEL	1459	$MODEL
1248	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1460	or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1249	}
1250	}	1461	}
1251
1252	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1253
1254	unshift @ISA, $MODEL;
1255
1256	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1257
1258	(shift @post_detect)->() while @post_detect;
1259	}	1462	}
1260		1463
		1464	# free memory only needed for probing
		1465	undef @models;
		1466	undef @REGISTRY;
		1467
		1468	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1469
		1470	# now nuke some methods that are overridden by the backend.
		1471	# SUPER usage is not allowed in these.
		1472	for (qw(time signal child idle)) {
		1473	undef &{"AnyEvent::Base::$_"}
		1474	if defined &{"$MODEL\::$_"};
		1475	}
		1476
		1477	_isa_set;
		1478
		1479	# we're officially open!
		1480
		1481	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1482	require AnyEvent::Strict;
		1483	}
		1484
		1485	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1486	require AnyEvent::Debug;
		1487	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1488	}
		1489
		1490	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1491	require AnyEvent::Socket;
		1492	require AnyEvent::Debug;
		1493
		1494	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1495	$shell =~ s/\$\$/$$/g;
		1496
		1497	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1498	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1499	}
		1500
		1501	# now the anyevent environment is set up as the user told us to, so
		1502	# call the actual user code - post detects
		1503
		1504	(shift @post_detect)->() while @post_detect;
		1505	undef @post_detect;
		1506
		1507	*post_detect = sub(&) {
		1508	shift->();
		1509
		1510	undef
		1511	};
		1512
1261	$MODEL	1513	$MODEL
1262	}	1514	}
1263		1515
1264	sub AUTOLOAD {	1516	for my $name (@methods) {
1265	(my $func = $AUTOLOAD) =~ s/.*://;	1517	*$name = sub {
1266		1518	detect;
1267	$method{$func}	1519	# we use goto because
1268	or Carp::croak "$func: not a valid method for AnyEvent objects";	1520	# a) it makes the thunk more transparent
1269		1521	# b) it allows us to delete the thunk later
1270	detect unless $MODEL;	1522	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1271		1523	};
1272	my $class = shift;
1273	$class->$func (@_);
1274	}	1524	}
1275		1525
1276	# utility function to dup a filehandle. this is used by many backends	1526	# utility function to dup a filehandle. this is used by many backends
1277	# to support binding more than one watcher per filehandle (they usually	1527	# to support binding more than one watcher per filehandle (they usually
1278	# allow only one watcher per fd, so we dup it to get a different one).	1528	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1288	# we assume CLOEXEC is already set by perl in all important cases	1538	# we assume CLOEXEC is already set by perl in all important cases
1289		1539
1290	($fh2, $rw)	1540	($fh2, $rw)
1291	}	1541	}
1292		1542
1293	#############################################################################	1543	=head1 SIMPLIFIED AE API
1294	# "new" API, currently only emulation of it	1544
1295	#############################################################################	1545	Starting with version 5.0, AnyEvent officially supports a second, much
		1546	simpler, API that is designed to reduce the calling, typing and memory
		1547	overhead by using function call syntax and a fixed number of parameters.
		1548
		1549	See the L<AE> manpage for details.
		1550
		1551	=cut
1296		1552
1297	package AE;	1553	package AE;
1298		1554
1299	our $VERSION = $AnyEvent::VERSION;	1555	our $VERSION = $AnyEvent::VERSION;
1300		1556
		1557	sub _reset() {
		1558	eval q{
		1559	# fall back to the main API by default - backends and AnyEvent::Base
		1560	# implementations can overwrite these.
		1561
1301	sub io($$$) {	1562	sub io($$$) {
1302	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1563	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1303	}	1564	}
1304		1565
1305	sub timer($$$) {	1566	sub timer($$$) {
1306	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1567	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1307	}	1568	}
1308		1569
1309	sub signal($$) {	1570	sub signal($$) {
1310	AnyEvent->signal (signal => $_[0], cb => $_[1])	1571	AnyEvent->signal (signal => $_[0], cb => $_[1])
1311	}	1572	}
1312		1573
1313	sub child($$) {	1574	sub child($$) {
1314	AnyEvent->child (pid => $_[0], cb => $_[1])	1575	AnyEvent->child (pid => $_[0], cb => $_[1])
1315	}	1576	}
1316		1577
1317	sub idle($) {	1578	sub idle($) {
1318	AnyEvent->idle (cb => $_[0])	1579	AnyEvent->idle (cb => $_[0]);
1319	}	1580	}
1320		1581
1321	sub cv(;&) {	1582	sub cv(;&) {
1322	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1583	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1323	}	1584	}
1324		1585
1325	sub now() {	1586	sub now() {
1326	AnyEvent->now	1587	AnyEvent->now
1327	}	1588	}
1328		1589
1329	sub now_update() {	1590	sub now_update() {
1330	AnyEvent->now_update	1591	AnyEvent->now_update
1331	}	1592	}
1332		1593
1333	sub time() {	1594	sub time() {
1334	AnyEvent->time	1595	AnyEvent->time
		1596	}
		1597
		1598	*postpone = \&AnyEvent::postpone;
		1599	*log = \&AnyEvent::log;
		1600	};
		1601	die if $@;
1335	}	1602	}
		1603
		1604	BEGIN { _reset }
1336		1605
1337	package AnyEvent::Base;	1606	package AnyEvent::Base;
1338		1607
1339	# default implementations for many methods	1608	# default implementations for many methods
1340		1609
1341	sub _time {	1610	sub time {
		1611	eval q{ # poor man's autoloading {}
1342	# probe for availability of Time::HiRes	1612	# probe for availability of Time::HiRes
1343	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1613	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1344	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1614	*time = sub { Time::HiRes::time () };
1345	*_time = \&Time::HiRes::time;	1615	*AE::time = \& Time::HiRes::time ;
		1616	*now = \&time;
		1617	AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1346	# if (eval "use POSIX (); (POSIX::times())...	1618	# if (eval "use POSIX (); (POSIX::times())...
1347	} else {	1619	} else {
1348	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1620	*time = sub { CORE::time };
1349	*_time = sub { time }; # epic fail	1621	*AE::time = sub (){ CORE::time };
		1622	*now = \&time;
		1623	AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
		1624	}
1350	}	1625	};
		1626	die if $@;
1351		1627
1352	&_time	1628	&time
1353	}	1629	}
1354		1630
1355	sub time { _time }	1631	*now = \&time;
1356	sub now { _time }
1357	sub now_update { }	1632	sub now_update { }
1358		1633
		1634	sub _poll {
		1635	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1636	}
		1637
1359	# default implementation for ->condvar	1638	# default implementation for ->condvar
		1639	# in fact, the default should not be overwritten
1360		1640
1361	sub condvar {	1641	sub condvar {
		1642	eval q{ # poor man's autoloading {}
		1643	*condvar = sub {
1362	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1644	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1645	};
		1646
		1647	*AE::cv = sub (;&) {
		1648	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1649	};
		1650	};
		1651	die if $@;
		1652
		1653	&condvar
1363	}	1654	}
1364		1655
1365	# default implementation for ->signal	1656	# default implementation for ->signal
1366		1657
1367	our $HAVE_ASYNC_INTERRUPT;	1658	our $HAVE_ASYNC_INTERRUPT;
1368		1659
1369	sub _have_async_interrupt() {	1660	sub _have_async_interrupt() {
1370	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1661	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1371	&& eval "use Async::Interrupt 1.0 (); 1")	1662	&& eval "use Async::Interrupt 1.02 (); 1")
1372	unless defined $HAVE_ASYNC_INTERRUPT;	1663	unless defined $HAVE_ASYNC_INTERRUPT;
1373		1664
1374	$HAVE_ASYNC_INTERRUPT	1665	$HAVE_ASYNC_INTERRUPT
1375	}	1666	}
1376		1667
1377	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1668	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1378	our (%SIG_ASY, %SIG_ASY_W);	1669	our (%SIG_ASY, %SIG_ASY_W);
1379	our ($SIG_COUNT, $SIG_TW);	1670	our ($SIG_COUNT, $SIG_TW);
1380		1671
1381	sub _signal_exec {
1382	$HAVE_ASYNC_INTERRUPT
1383	? $SIGPIPE_R->drain
1384	: sysread $SIGPIPE_R, my $dummy, 9;
1385
1386	while (%SIG_EV) {
1387	for (keys %SIG_EV) {
1388	delete $SIG_EV{$_};
1389	$_->() for values %{ $SIG_CB{$_} || {} };
1390	}
1391	}
1392	}
1393
1394	# install a dummy wakeup watcher to reduce signal catching latency	1672	# install a dummy wakeup watcher to reduce signal catching latency
		1673	# used by Impls
1395	sub _sig_add() {	1674	sub _sig_add() {
1396	unless ($SIG_COUNT++) {	1675	unless ($SIG_COUNT++) {
1397	# try to align timer on a full-second boundary, if possible	1676	# try to align timer on a full-second boundary, if possible
1398	my $NOW = AE::now;	1677	my $NOW = AE::now;
1399		1678
…		…
1409	undef $SIG_TW	1688	undef $SIG_TW
1410	unless --$SIG_COUNT;	1689	unless --$SIG_COUNT;
1411	}	1690	}
1412		1691
1413	our $_sig_name_init; $_sig_name_init = sub {	1692	our $_sig_name_init; $_sig_name_init = sub {
1414	eval q{ # poor man's autoloading	1693	eval q{ # poor man's autoloading {}
1415	undef $_sig_name_init;	1694	undef $_sig_name_init;
1416		1695
1417	if (_have_async_interrupt) {	1696	if (_have_async_interrupt) {
1418	*sig2num = \&Async::Interrupt::sig2num;	1697	*sig2num = \&Async::Interrupt::sig2num;
1419	*sig2name = \&Async::Interrupt::sig2name;	1698	*sig2name = \&Async::Interrupt::sig2name;
…		…
1443		1722
1444	sub signal {	1723	sub signal {
1445	eval q{ # poor man's autoloading {}	1724	eval q{ # poor man's autoloading {}
1446	# probe for availability of Async::Interrupt	1725	# probe for availability of Async::Interrupt
1447	if (_have_async_interrupt) {	1726	if (_have_async_interrupt) {
1448	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1727	AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1449		1728
1450	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1729	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1451	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1730	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1452		1731
1453	} else {	1732	} else {
1454	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1733	AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1455
1456	require Fcntl;
1457		1734
1458	if (AnyEvent::WIN32) {	1735	if (AnyEvent::WIN32) {
1459	require AnyEvent::Util;	1736	require AnyEvent::Util;
1460		1737
1461	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1738	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1462	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1739	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1463	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1740	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1464	} else {	1741	} else {
1465	pipe $SIGPIPE_R, $SIGPIPE_W;	1742	pipe $SIGPIPE_R, $SIGPIPE_W;
1466	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1743	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1467	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1744	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1468		1745
1469	# not strictly required, as $^F is normally 2, but let's make sure...	1746	# not strictly required, as $^F is normally 2, but let's make sure...
1470	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1747	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1471	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1748	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1472	}	1749	}
1473		1750
1474	$SIGPIPE_R	1751	$SIGPIPE_R
1475	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1752	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1476		1753
1477	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1754	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1478	}	1755	}
1479		1756
1480	*signal = sub {	1757	*signal = $HAVE_ASYNC_INTERRUPT
		1758	? sub {
1481	my (undef, %arg) = @_;	1759	my (undef, %arg) = @_;
1482		1760
1483	my $signal = uc $arg{signal}
1484	or Carp::croak "required option 'signal' is missing";
1485
1486	if ($HAVE_ASYNC_INTERRUPT) {
1487	# async::interrupt	1761	# async::interrupt
1488
1489	$signal = sig2num $signal;	1762	my $signal = sig2num $arg{signal};
1490	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1763	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1491		1764
1492	$SIG_ASY{$signal} ||= new Async::Interrupt	1765	$SIG_ASY{$signal} ||= new Async::Interrupt
1493	cb => sub { undef $SIG_EV{$signal} },	1766	cb => sub { undef $SIG_EV{$signal} },
1494	signal => $signal,	1767	signal => $signal,
1495	pipe => [$SIGPIPE_R->filenos],	1768	pipe => [$SIGPIPE_R->filenos],
1496	pipe_autodrain => 0,	1769	pipe_autodrain => 0,
1497	;	1770	;
1498		1771
1499	} else {	1772	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1773	}
		1774	: sub {
		1775	my (undef, %arg) = @_;
		1776
1500	# pure perl	1777	# pure perl
1501
1502	# AE::Util has been loaded in signal
1503	$signal = sig2name $signal;	1778	my $signal = sig2name $arg{signal};
1504	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1779	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1505		1780
1506	$SIG{$signal} ||= sub {	1781	$SIG{$signal} ||= sub {
1507	local $!;	1782	local $!;
1508	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1783	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1509	undef $SIG_EV{$signal};	1784	undef $SIG_EV{$signal};
1510	};	1785	};
1511		1786
1512	# can't do signal processing without introducing races in pure perl,	1787	# can't do signal processing without introducing races in pure perl,
1513	# so limit the signal latency.	1788	# so limit the signal latency.
1514	_sig_add;	1789	_sig_add;
1515	}
1516		1790
1517	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1791	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1792	}
1518	};	1793	;
1519		1794
1520	*AnyEvent::Base::signal::DESTROY = sub {	1795	*AnyEvent::Base::signal::DESTROY = sub {
1521	my ($signal, $cb) = @{$_[0]};	1796	my ($signal, $cb) = @{$_[0]};
1522		1797
1523	_sig_del;	1798	_sig_del;
…		…
1530	# print weird messages, or just unconditionally exit	1805	# print weird messages, or just unconditionally exit
1531	# instead of getting the default action.	1806	# instead of getting the default action.
1532	undef $SIG{$signal}	1807	undef $SIG{$signal}
1533	unless keys %{ $SIG_CB{$signal} };	1808	unless keys %{ $SIG_CB{$signal} };
1534	};	1809	};
		1810
		1811	*_signal_exec = sub {
		1812	$HAVE_ASYNC_INTERRUPT
		1813	? $SIGPIPE_R->drain
		1814	: sysread $SIGPIPE_R, (my $dummy), 9;
		1815
		1816	while (%SIG_EV) {
		1817	for (keys %SIG_EV) {
		1818	delete $SIG_EV{$_};
		1819	&$_ for values %{ $SIG_CB{$_} || {} };
		1820	}
		1821	}
		1822	};
1535	};	1823	};
1536	die if $@;	1824	die if $@;
		1825
1537	&signal	1826	&signal
1538	}	1827	}
1539		1828
1540	# default implementation for ->child	1829	# default implementation for ->child
1541		1830
1542	our %PID_CB;	1831	our %PID_CB;
1543	our $CHLD_W;	1832	our $CHLD_W;
1544	our $CHLD_DELAY_W;	1833	our $CHLD_DELAY_W;
1545	our $WNOHANG;
1546		1834
		1835	# used by many Impl's
1547	sub _emit_childstatus($$) {	1836	sub _emit_childstatus($$) {
1548	my (undef, $rpid, $rstatus) = @_;	1837	my (undef, $rpid, $rstatus) = @_;
1549		1838
1550	$_->($rpid, $rstatus)	1839	$_->($rpid, $rstatus)
1551	for values %{ $PID_CB{$rpid} || {} },	1840	for values %{ $PID_CB{$rpid} || {} },
1552	values %{ $PID_CB{0} || {} };	1841	values %{ $PID_CB{0} || {} };
1553	}	1842	}
1554		1843
1555	sub _sigchld {
1556	my $pid;
1557
1558	AnyEvent->_emit_childstatus ($pid, $?)
1559	while ($pid = waitpid -1, $WNOHANG) > 0;
1560	}
1561
1562	sub child {	1844	sub child {
		1845	eval q{ # poor man's autoloading {}
		1846	*_sigchld = sub {
		1847	my $pid;
		1848
		1849	AnyEvent->_emit_childstatus ($pid, $?)
		1850	while ($pid = waitpid -1, WNOHANG) > 0;
		1851	};
		1852
		1853	*child = sub {
1563	my (undef, %arg) = @_;	1854	my (undef, %arg) = @_;
1564		1855
1565	defined (my $pid = $arg{pid} + 0)	1856	my $pid = $arg{pid};
1566	or Carp::croak "required option 'pid' is missing";	1857	my $cb = $arg{cb};
1567		1858
1568	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1859	$PID_CB{$pid}{$cb+0} = $cb;
1569		1860
1570	# WNOHANG is almost cetrainly 1 everywhere
1571	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1572	? 1
1573	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1574
1575	unless ($CHLD_W) {	1861	unless ($CHLD_W) {
1576	$CHLD_W = AE::signal CHLD => \&_sigchld;	1862	$CHLD_W = AE::signal CHLD => \&_sigchld;
1577	# child could be a zombie already, so make at least one round	1863	# child could be a zombie already, so make at least one round
1578	&_sigchld;	1864	&_sigchld;
1579	}	1865	}
1580		1866
1581	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1867	bless [$pid, $cb+0], "AnyEvent::Base::child"
1582	}	1868	};
1583		1869
1584	sub AnyEvent::Base::child::DESTROY {	1870	*AnyEvent::Base::child::DESTROY = sub {
1585	my ($pid, $cb) = @{$_[0]};	1871	my ($pid, $icb) = @{$_[0]};
1586		1872
1587	delete $PID_CB{$pid}{$cb};	1873	delete $PID_CB{$pid}{$icb};
1588	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1874	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1589		1875
1590	undef $CHLD_W unless keys %PID_CB;	1876	undef $CHLD_W unless keys %PID_CB;
		1877	};
		1878	};
		1879	die if $@;
		1880
		1881	&child
1591	}	1882	}
1592		1883
1593	# idle emulation is done by simply using a timer, regardless	1884	# idle emulation is done by simply using a timer, regardless
1594	# of whether the process is idle or not, and not letting	1885	# of whether the process is idle or not, and not letting
1595	# the callback use more than 50% of the time.	1886	# the callback use more than 50% of the time.
1596	sub idle {	1887	sub idle {
		1888	eval q{ # poor man's autoloading {}
		1889	*idle = sub {
1597	my (undef, %arg) = @_;	1890	my (undef, %arg) = @_;
1598		1891
1599	my ($cb, $w, $rcb) = $arg{cb};	1892	my ($cb, $w, $rcb) = $arg{cb};
1600		1893
1601	$rcb = sub {	1894	$rcb = sub {
1602	if ($cb) {	1895	if ($cb) {
1603	$w = _time;	1896	$w = AE::time;
1604	&$cb;	1897	&$cb;
1605	$w = _time - $w;	1898	$w = AE::time - $w;
1606		1899
1607	# never use more then 50% of the time for the idle watcher,	1900	# never use more then 50% of the time for the idle watcher,
1608	# within some limits	1901	# within some limits
1609	$w = 0.0001 if $w < 0.0001;	1902	$w = 0.0001 if $w < 0.0001;
1610	$w = 5 if $w > 5;	1903	$w = 5 if $w > 5;
1611		1904
1612	$w = AE::timer $w, 0, $rcb;	1905	$w = AE::timer $w, 0, $rcb;
1613	} else {	1906	} else {
1614	# clean up...	1907	# clean up...
1615	undef $w;	1908	undef $w;
1616	undef $rcb;	1909	undef $rcb;
		1910	}
		1911	};
		1912
		1913	$w = AE::timer 0.05, 0, $rcb;
		1914
		1915	bless \\$cb, "AnyEvent::Base::idle"
1617	}	1916	};
		1917
		1918	*AnyEvent::Base::idle::DESTROY = sub {
		1919	undef $${$_[0]};
		1920	};
1618	};	1921	};
		1922	die if $@;
1619		1923
1620	$w = AE::timer 0.05, 0, $rcb;	1924	&idle
1621
1622	bless \\$cb, "AnyEvent::Base::idle"
1623	}
1624
1625	sub AnyEvent::Base::idle::DESTROY {
1626	undef $${$_[0]};
1627	}	1925	}
1628		1926
1629	package AnyEvent::CondVar;	1927	package AnyEvent::CondVar;
1630		1928
1631	our @ISA = AnyEvent::CondVar::Base::;	1929	our @ISA = AnyEvent::CondVar::Base::;
		1930
		1931	# only to be used for subclassing
		1932	sub new {
		1933	my $class = shift;
		1934	bless AnyEvent->condvar (@_), $class
		1935	}
1632		1936
1633	package AnyEvent::CondVar::Base;	1937	package AnyEvent::CondVar::Base;
1634		1938
1635	#use overload	1939	#use overload
1636	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1940	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1646		1950
1647	sub _send {	1951	sub _send {
1648	# nop	1952	# nop
1649	}	1953	}
1650		1954
		1955	sub _wait {
		1956	AnyEvent->_poll until $_[0]{_ae_sent};
		1957	}
		1958
1651	sub send {	1959	sub send {
1652	my $cv = shift;	1960	my $cv = shift;
1653	$cv->{_ae_sent} = [@_];	1961	$cv->{_ae_sent} = [@_];
1654	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1962	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1655	$cv->_send;	1963	$cv->_send;
…		…
1662		1970
1663	sub ready {	1971	sub ready {
1664	$_[0]{_ae_sent}	1972	$_[0]{_ae_sent}
1665	}	1973	}
1666		1974
1667	sub _wait {
1668	$WAITING
1669	and !$_[0]{_ae_sent}
1670	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1671
1672	local $WAITING = 1;
1673	AnyEvent->one_event while !$_[0]{_ae_sent};
1674	}
1675
1676	sub recv {	1975	sub recv {
		1976	unless ($_[0]{_ae_sent}) {
		1977	$WAITING
		1978	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1979
		1980	local $WAITING = 1;
1677	$_[0]->_wait;	1981	$_[0]->_wait;
		1982	}
1678		1983
1679	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1984	$_[0]{_ae_croak}
1680	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1985	and Carp::croak $_[0]{_ae_croak};
		1986
		1987	wantarray
		1988	? @{ $_[0]{_ae_sent} }
		1989	: $_[0]{_ae_sent}[0]
1681	}	1990	}
1682		1991
1683	sub cb {	1992	sub cb {
1684	my $cv = shift;	1993	my $cv = shift;
1685		1994
…		…
1701	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2010	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1702	}	2011	}
1703		2012
1704	# undocumented/compatibility with pre-3.4	2013	# undocumented/compatibility with pre-3.4
1705	*broadcast = \&send;	2014	*broadcast = \&send;
1706	*wait = \&_wait;	2015	*wait = \&recv;
1707		2016
1708	=head1 ERROR AND EXCEPTION HANDLING	2017	=head1 ERROR AND EXCEPTION HANDLING
1709		2018
1710	In general, AnyEvent does not do any error handling - it relies on the	2019	In general, AnyEvent does not do any error handling - it relies on the
1711	caller to do that if required. The L<AnyEvent::Strict> module (see also	2020	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1723	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2032	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1724	so on.	2033	so on.
1725		2034
1726	=head1 ENVIRONMENT VARIABLES	2035	=head1 ENVIRONMENT VARIABLES
1727		2036
1728	The following environment variables are used by this module or its	2037	AnyEvent supports a number of environment variables that tune the
1729	submodules.	2038	runtime behaviour. They are usually evaluated when AnyEvent is
		2039	loaded, initialised, or a submodule that uses them is loaded. Many of
		2040	them also cause AnyEvent to load additional modules - for example,
		2041	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2042	loaded.
1730		2043
1731	Note that AnyEvent will remove I<all> environment variables starting with	2044	All the environment variables documented here start with
1732	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2045	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1733	enabled.	2046	namespace. Other modules are encouraged (but by no means required) to use
		2047	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2048	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2049	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2050	variables starting with C<AE_>, see below).
		2051
		2052	All variables can also be set via the C<AE_> prefix, that is, instead
		2053	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2054	case there is a clash btween anyevent and another program that uses
		2055	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2056	variable to the empty string, as those variables take precedence.
		2057
		2058	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2059	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2060	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2061	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2062	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2063	is set).
		2064
		2065	The exact algorithm is currently:
		2066
		2067	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2068	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2069	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2070
		2071	This ensures that child processes will not see the C<AE_> variables.
		2072
		2073	The following environment variables are currently known to AnyEvent:
1734		2074
1735	=over 4	2075	=over 4
1736		2076
1737	=item C<PERL_ANYEVENT_VERBOSE>	2077	=item C<PERL_ANYEVENT_VERBOSE>
1738		2078
1739	By default, AnyEvent will be completely silent except in fatal	2079	By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1740	conditions. You can set this environment variable to make AnyEvent more	2080	higher (see L<AnyEvent::Log>). You can set this environment variable to a
1741	talkative.	2081	numerical loglevel to make AnyEvent more (or less) talkative.
1742		2082
		2083	If you want to do more than just set the global logging level
		2084	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2085	complex specifications.
		2086
		2087	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2088	everything else at defaults.
		2089
1743	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2090	When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1744	conditions, such as not being able to load the event model specified by	2091	conditions, such as not being able to load the event model specified by
1745	C<PERL_ANYEVENT_MODEL>.	2092	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2093	is the minimum recommended level for use during development.
1746		2094
1747	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2095	When set to C<7> or higher (info), AnyEvent reports which event model it
1748	model it chooses.	2096	chooses.
1749		2097
1750	When set to C<8> or higher, then AnyEvent will report extra information on	2098	When set to C<8> or higher (debug), then AnyEvent will report extra
1751	which optional modules it loads and how it implements certain features.	2099	information on which optional modules it loads and how it implements
		2100	certain features.
		2101
		2102	=item C<PERL_ANYEVENT_LOG>
		2103
		2104	Accepts rather complex logging specifications. For example, you could log
		2105	all C<debug> messages of some module to stderr, warnings and above to
		2106	stderr, and errors and above to syslog, with:
		2107
		2108	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2109
		2110	For the rather extensive details, see L<AnyEvent::Log>.
		2111
		2112	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2113	so will take effect even before AnyEvent has initialised itself.
		2114
		2115	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2116	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2117	using the latter saves a few hundred kB of memory unless a module
		2118	explicitly needs the extra features of AnyEvent::Log.
1752		2119
1753	=item C<PERL_ANYEVENT_STRICT>	2120	=item C<PERL_ANYEVENT_STRICT>
1754		2121
1755	AnyEvent does not do much argument checking by default, as thorough	2122	AnyEvent does not do much argument checking by default, as thorough
1756	argument checking is very costly. Setting this variable to a true value	2123	argument checking is very costly. Setting this variable to a true value
…		…
1758	check the arguments passed to most method calls. If it finds any problems,	2125	check the arguments passed to most method calls. If it finds any problems,
1759	it will croak.	2126	it will croak.
1760		2127
1761	In other words, enables "strict" mode.	2128	In other words, enables "strict" mode.
1762		2129
1763	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2130	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1764	>>, it is definitely recommended to keep it off in production. Keeping	2131	>>, it is definitely recommended to keep it off in production. Keeping
1765	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2132	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1766	can be very useful, however.	2133	can be very useful, however.
1767		2134
		2135	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2136
		2137	If this env variable is nonempty, then its contents will be interpreted by
		2138	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2139	replacing every occurance of C<$$> by the process pid). The shell object
		2140	is saved in C<$AnyEvent::Debug::SHELL>.
		2141
		2142	This happens when the first watcher is created.
		2143
		2144	For example, to bind a debug shell on a unix domain socket in
		2145	F<< /tmp/debug<pid>.sock >>, you could use this:
		2146
		2147	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2148	# connect with e.g.: socat readline /tmp/debug123.sock
		2149
		2150	Or to bind to tcp port 4545 on localhost:
		2151
		2152	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2153	# connect with e.g.: telnet localhost 4545
		2154
		2155	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2156	multiuser systems.
		2157
		2158	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2159
		2160	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2161	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2162
1768	=item C<PERL_ANYEVENT_MODEL>	2163	=item C<PERL_ANYEVENT_MODEL>
1769		2164
1770	This can be used to specify the event model to be used by AnyEvent, before	2165	This can be used to specify the event model to be used by AnyEvent, before
1771	auto detection and -probing kicks in. It must be a string consisting	2166	auto detection and -probing kicks in.
1772	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2167
		2168	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2169	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1773	and the resulting module name is loaded and if the load was successful,	2170	resulting module name is loaded and - if the load was successful - used as
1774	used as event model. If it fails to load AnyEvent will proceed with	2171	event model backend. If it fails to load then AnyEvent will proceed with
1775	auto detection and -probing.	2172	auto detection and -probing.
1776		2173
1777	This functionality might change in future versions.	2174	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2175	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2176	the end of a string designates a module name and quotes it appropriately).
1778		2177
1779	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2178	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1780	could start your program like this:	2179	could start your program like this:
1781		2180
1782	PERL_ANYEVENT_MODEL=Perl perl ...	2181	PERL_ANYEVENT_MODEL=Perl perl ...
		2182
		2183	=item C<PERL_ANYEVENT_IO_MODEL>
		2184
		2185	The current file I/O model - see L<AnyEvent::IO> for more info.
		2186
		2187	At the moment, only C<Perl> (small, pure-perl, synchronous) and
		2188	C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
		2189	L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1783		2190
1784	=item C<PERL_ANYEVENT_PROTOCOLS>	2191	=item C<PERL_ANYEVENT_PROTOCOLS>
1785		2192
1786	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	2193	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1787	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	2194	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
…		…
1800	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2207	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1801	- only support IPv4, never try to resolve or contact IPv6	2208	- only support IPv4, never try to resolve or contact IPv6
1802	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2209	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1803	IPv6, but prefer IPv6 over IPv4.	2210	IPv6, but prefer IPv6 over IPv4.
1804		2211
		2212	=item C<PERL_ANYEVENT_HOSTS>
		2213
		2214	This variable, if specified, overrides the F</etc/hosts> file used by
		2215	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2216	from that file instead.
		2217
1805	=item C<PERL_ANYEVENT_EDNS0>	2218	=item C<PERL_ANYEVENT_EDNS0>
1806		2219
1807	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2220	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1808	for DNS. This extension is generally useful to reduce DNS traffic, but	2221	DNS. This extension is generally useful to reduce DNS traffic, especially
1809	some (broken) firewalls drop such DNS packets, which is why it is off by	2222	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1810	default.	2223	packets, which is why it is off by default.
1811		2224
1812	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2225	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1813	EDNS0 in its DNS requests.	2226	EDNS0 in its DNS requests.
1814		2227
1815	=item C<PERL_ANYEVENT_MAX_FORKS>	2228	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1821		2234
1822	The default value for the C<max_outstanding> parameter for the default DNS	2235	The default value for the C<max_outstanding> parameter for the default DNS
1823	resolver - this is the maximum number of parallel DNS requests that are	2236	resolver - this is the maximum number of parallel DNS requests that are
1824	sent to the DNS server.	2237	sent to the DNS server.
1825		2238
		2239	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2240
		2241	Perl has inherently racy signal handling (you can basically choose between
		2242	losing signals and memory corruption) - pure perl event loops (including
		2243	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2244	have to poll regularly to avoid losing signals.
		2245
		2246	Some event loops are racy, but don't poll regularly, and some event loops
		2247	are written in C but are still racy. For those event loops, AnyEvent
		2248	installs a timer that regularly wakes up the event loop.
		2249
		2250	By default, the interval for this timer is C<10> seconds, but you can
		2251	override this delay with this environment variable (or by setting
		2252	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2253	watchers).
		2254
		2255	Lower values increase CPU (and energy) usage, higher values can introduce
		2256	long delays when reaping children or waiting for signals.
		2257
		2258	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2259	polling (with most event loops).
		2260
1826	=item C<PERL_ANYEVENT_RESOLV_CONF>	2261	=item C<PERL_ANYEVENT_RESOLV_CONF>
1827		2262
1828	The file to use instead of F</etc/resolv.conf> (or OS-specific	2263	The absolute path to a F<resolv.conf>-style file to use instead of
1829	configuration) in the default resolver. When set to the empty string, no	2264	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1830	default config will be used.	2265	resolver, or the empty string to select the default configuration.
1831		2266
1832	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2267	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1833		2268
1834	When neither C<ca_file> nor C<ca_path> was specified during	2269	When neither C<ca_file> nor C<ca_path> was specified during
1835	L<AnyEvent::TLS> context creation, and either of these environment	2270	L<AnyEvent::TLS> context creation, and either of these environment
1836	variables exist, they will be used to specify CA certificate locations	2271	variables are nonempty, they will be used to specify CA certificate
1837	instead of a system-dependent default.	2272	locations instead of a system-dependent default.
1838		2273
1839	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2274	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1840		2275
1841	When these are set to C<1>, then the respective modules are not	2276	When these are set to C<1>, then the respective modules are not
1842	loaded. Mostly good for testing AnyEvent itself.	2277	loaded. Mostly good for testing AnyEvent itself.
…		…
1905	warn "read: $input\n"; # output what has been read	2340	warn "read: $input\n"; # output what has been read
1906	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2341	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1907	},	2342	},
1908	);	2343	);
1909		2344
1910	my $time_watcher; # can only be used once
1911
1912	sub new_timer {
1913	$timer = AnyEvent->timer (after => 1, cb => sub {	2345	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1914	warn "timeout\n"; # print 'timeout' about every second	2346	warn "timeout\n"; # print 'timeout' at most every second
1915	&new_timer; # and restart the time
1916	});	2347	});
1917	}
1918
1919	new_timer; # create first timer
1920		2348
1921	$cv->recv; # wait until user enters /^q/i	2349	$cv->recv; # wait until user enters /^q/i
1922		2350
1923	=head1 REAL-WORLD EXAMPLE	2351	=head1 REAL-WORLD EXAMPLE
1924		2352
…		…
1997		2425
1998	The actual code goes further and collects all errors (C<die>s, exceptions)	2426	The actual code goes further and collects all errors (C<die>s, exceptions)
1999	that occurred during request processing. The C<result> method detects	2427	that occurred during request processing. The C<result> method detects
2000	whether an exception as thrown (it is stored inside the $txn object)	2428	whether an exception as thrown (it is stored inside the $txn object)
2001	and just throws the exception, which means connection errors and other	2429	and just throws the exception, which means connection errors and other
2002	problems get reported tot he code that tries to use the result, not in a	2430	problems get reported to the code that tries to use the result, not in a
2003	random callback.	2431	random callback.
2004		2432
2005	All of this enables the following usage styles:	2433	All of this enables the following usage styles:
2006		2434
2007	1. Blocking:	2435	1. Blocking:
…		…
2055	through AnyEvent. The benchmark creates a lot of timers (with a zero	2483	through AnyEvent. The benchmark creates a lot of timers (with a zero
2056	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2484	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
2057	which it is), lets them fire exactly once and destroys them again.	2485	which it is), lets them fire exactly once and destroys them again.
2058		2486
2059	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2487	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2060	distribution.	2488	distribution. It uses the L<AE> interface, which makes a real difference
		2489	for the EV and Perl backends only.
2061		2490
2062	=head3 Explanation of the columns	2491	=head3 Explanation of the columns
2063		2492
2064	I<watcher> is the number of event watchers created/destroyed. Since	2493	I<watcher> is the number of event watchers created/destroyed. Since
2065	different event models feature vastly different performances, each event	2494	different event models feature vastly different performances, each event
…		…
2086	watcher.	2515	watcher.
2087		2516
2088	=head3 Results	2517	=head3 Results
2089		2518
2090	name watchers bytes create invoke destroy comment	2519	name watchers bytes create invoke destroy comment
2091	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2520	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2092	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2521	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2093	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2522	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2094	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2523	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2095	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2524	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2096	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2525	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2097	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2526	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2098	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2527	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2099	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2528	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2100	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2529	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2101	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2530	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2102	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2531	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2103		2532
2104	=head3 Discussion	2533	=head3 Discussion
2105		2534
2106	The benchmark does I<not> measure scalability of the event loop very	2535	The benchmark does I<not> measure scalability of the event loop very
2107	well. For example, a select-based event loop (such as the pure perl one)	2536	well. For example, a select-based event loop (such as the pure perl one)
…		…
2119	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2548	benchmark machine, handling an event takes roughly 1600 CPU cycles with
2120	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2549	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2121	cycles with POE.	2550	cycles with POE.
2122		2551
2123	C<EV> is the sole leader regarding speed and memory use, which are both	2552	C<EV> is the sole leader regarding speed and memory use, which are both
2124	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2553	maximal/minimal, respectively. When using the L<AE> API there is zero
		2554	overhead (when going through the AnyEvent API create is about 5-6 times
		2555	slower, with other times being equal, so still uses far less memory than
2125	far less memory than any other event loop and is still faster than Event	2556	any other event loop and is still faster than Event natively).
2126	natively.
2127		2557
2128	The pure perl implementation is hit in a few sweet spots (both the	2558	The pure perl implementation is hit in a few sweet spots (both the
2129	constant timeout and the use of a single fd hit optimisations in the perl	2559	constant timeout and the use of a single fd hit optimisations in the perl
2130	interpreter and the backend itself). Nevertheless this shows that it	2560	interpreter and the backend itself). Nevertheless this shows that it
2131	adds very little overhead in itself. Like any select-based backend its	2561	adds very little overhead in itself. Like any select-based backend its
…		…
2179	(even when used without AnyEvent), but most event loops have acceptable	2609	(even when used without AnyEvent), but most event loops have acceptable
2180	performance with or without AnyEvent.	2610	performance with or without AnyEvent.
2181		2611
2182	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2612	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2183	the actual event loop, only with extremely fast event loops such as EV	2613	the actual event loop, only with extremely fast event loops such as EV
2184	adds AnyEvent significant overhead.	2614	does AnyEvent add significant overhead.
2185		2615
2186	=item * You should avoid POE like the plague if you want performance or	2616	=item * You should avoid POE like the plague if you want performance or
2187	reasonable memory usage.	2617	reasonable memory usage.
2188		2618
2189	=back	2619	=back
…		…
2205	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2635	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2206	(1%) are active. This mirrors the activity of large servers with many	2636	(1%) are active. This mirrors the activity of large servers with many
2207	connections, most of which are idle at any one point in time.	2637	connections, most of which are idle at any one point in time.
2208		2638
2209	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2639	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2210	distribution.	2640	distribution. It uses the L<AE> interface, which makes a real difference
		2641	for the EV and Perl backends only.
2211		2642
2212	=head3 Explanation of the columns	2643	=head3 Explanation of the columns
2213		2644
2214	I<sockets> is the number of sockets, and twice the number of "servers" (as	2645	I<sockets> is the number of sockets, and twice the number of "servers" (as
2215	each server has a read and write socket end).	2646	each server has a read and write socket end).
…		…
2223	a new one that moves the timeout into the future.	2654	a new one that moves the timeout into the future.
2224		2655
2225	=head3 Results	2656	=head3 Results
2226		2657
2227	name sockets create request	2658	name sockets create request
2228	EV 20000 69.01 11.16	2659	EV 20000 62.66 7.99
2229	Perl 20000 73.32 35.87	2660	Perl 20000 68.32 32.64
2230	IOAsync 20000 157.00 98.14 epoll	2661	IOAsync 20000 174.06 101.15 epoll
2231	IOAsync 20000 159.31 616.06 poll	2662	IOAsync 20000 174.67 610.84 poll
2232	Event 20000 212.62 257.32	2663	Event 20000 202.69 242.91
2233	Glib 20000 651.16 1896.30	2664	Glib 20000 557.01 1689.52
2234	POE 20000 349.67 12317.24 uses POE::Loop::Event	2665	POE 20000 341.54 12086.32 uses POE::Loop::Event
2235		2666
2236	=head3 Discussion	2667	=head3 Discussion
2237		2668
2238	This benchmark I<does> measure scalability and overall performance of the	2669	This benchmark I<does> measure scalability and overall performance of the
2239	particular event loop.	2670	particular event loop.
…		…
2365	As you can see, the AnyEvent + EV combination even beats the	2796	As you can see, the AnyEvent + EV combination even beats the
2366	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2797	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2367	backend easily beats IO::Lambda and POE.	2798	backend easily beats IO::Lambda and POE.
2368		2799
2369	And even the 100% non-blocking version written using the high-level (and	2800	And even the 100% non-blocking version written using the high-level (and
2370	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2801	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2371	large margin, even though it does all of DNS, tcp-connect and socket I/O	2802	higher level ("unoptimised") abstractions by a large margin, even though
2372	in a non-blocking way.	2803	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2373		2804
2374	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2805	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2375	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2806	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2376	part of the IO::lambda distribution and were used without any changes.	2807	part of the IO::Lambda distribution and were used without any changes.
2377		2808
2378		2809
2379	=head1 SIGNALS	2810	=head1 SIGNALS
2380		2811
2381	AnyEvent currently installs handlers for these signals:	2812	AnyEvent currently installs handlers for these signals:
…		…
2418	unless defined $SIG{PIPE};	2849	unless defined $SIG{PIPE};
2419		2850
2420	=head1 RECOMMENDED/OPTIONAL MODULES	2851	=head1 RECOMMENDED/OPTIONAL MODULES
2421		2852
2422	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2853	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2423	it's built-in modules) are required to use it.	2854	its built-in modules) are required to use it.
2424		2855
2425	That does not mean that AnyEvent won't take advantage of some additional	2856	That does not mean that AnyEvent won't take advantage of some additional
2426	modules if they are installed.	2857	modules if they are installed.
2427		2858
2428	This section epxlains which additional modules will be used, and how they	2859	This section explains which additional modules will be used, and how they
2429	affect AnyEvent's operetion.	2860	affect AnyEvent's operation.
2430		2861
2431	=over 4	2862	=over 4
2432		2863
2433	=item L<Async::Interrupt>	2864	=item L<Async::Interrupt>
2434		2865
…		…
2439	catch the signals) with some delay (default is 10 seconds, look for	2870	catch the signals) with some delay (default is 10 seconds, look for
2440	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2871	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2441		2872
2442	If this module is available, then it will be used to implement signal	2873	If this module is available, then it will be used to implement signal
2443	catching, which means that signals will not be delayed, and the event loop	2874	catching, which means that signals will not be delayed, and the event loop
2444	will not be interrupted regularly, which is more efficient (And good for	2875	will not be interrupted regularly, which is more efficient (and good for
2445	battery life on laptops).	2876	battery life on laptops).
2446		2877
2447	This affects not just the pure-perl event loop, but also other event loops	2878	This affects not just the pure-perl event loop, but also other event loops
2448	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2879	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2449		2880
…		…
2461	automatic timer adjustments even when no monotonic clock is available,	2892	automatic timer adjustments even when no monotonic clock is available,
2462	can take avdantage of advanced kernel interfaces such as C<epoll> and	2893	can take avdantage of advanced kernel interfaces such as C<epoll> and
2463	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2894	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2464	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2895	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2465		2896
		2897	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2898	then this module will do nothing for you.
		2899
2466	=item L<Guard>	2900	=item L<Guard>
2467		2901
2468	The guard module, when used, will be used to implement	2902	The guard module, when used, will be used to implement
2469	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2903	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2470	lot less memory), but otherwise doesn't affect guard operation much. It is	2904	lot less memory), but otherwise doesn't affect guard operation much. It is
2471	purely used for performance.	2905	purely used for performance.
2472		2906
2473	=item L<JSON> and L<JSON::XS>	2907	=item L<JSON> and L<JSON::XS>
2474		2908
2475	This module is required when you want to read or write JSON data via	2909	One of these modules is required when you want to read or write JSON data
2476	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2910	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2477	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2911	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2478
2479	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2480	installed.
2481		2912
2482	=item L<Net::SSLeay>	2913	=item L<Net::SSLeay>
2483		2914
2484	Implementing TLS/SSL in Perl is certainly interesting, but not very	2915	Implementing TLS/SSL in Perl is certainly interesting, but not very
2485	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2916	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2486	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2917	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2487		2918
2488	=item L<Time::HiRes>	2919	=item L<Time::HiRes>
2489		2920
2490	This module is part of perl since release 5.008. It will be used when the	2921	This module is part of perl since release 5.008. It will be used when the
2491	chosen event library does not come with a timing source on it's own. The	2922	chosen event library does not come with a timing source of its own. The
2492	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2923	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2493	try to use a monotonic clock for timing stability.	2924	try to use a monotonic clock for timing stability.
2494		2925
		2926	=item L<AnyEvent::AIO> (and L<IO::AIO>)
		2927
		2928	The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
		2929	stopping programs while they access the disk, which is fine for a lot of
		2930	programs.
		2931
		2932	Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
		2933	a true asynchronous implementation, so event processing can continue even
		2934	while waiting for disk I/O.
		2935
2495	=back	2936	=back
2496		2937
2497		2938
2498	=head1 FORK	2939	=head1 FORK
2499		2940
2500	Most event libraries are not fork-safe. The ones who are usually are	2941	Most event libraries are not fork-safe. The ones who are usually are
2501	because they rely on inefficient but fork-safe C<select> or C<poll>	2942	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2502	calls. Only L<EV> is fully fork-aware.	2943	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2944	are usually badly thought-out hacks that are incompatible with fork in
		2945	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2946	continue event-processing in both parent and child (or both, if you know
		2947	what you are doing).
		2948
		2949	This means that, in general, you cannot fork and do event processing in
		2950	the child if the event library was initialised before the fork (which
		2951	usually happens when the first AnyEvent watcher is created, or the library
		2952	is loaded).
2503		2953
2504	If you have to fork, you must either do so I<before> creating your first	2954	If you have to fork, you must either do so I<before> creating your first
2505	watcher OR you must not use AnyEvent at all in the child OR you must do	2955	watcher OR you must not use AnyEvent at all in the child OR you must do
2506	something completely out of the scope of AnyEvent.	2956	something completely out of the scope of AnyEvent.
		2957
		2958	The problem of doing event processing in the parent I<and> the child
		2959	is much more complicated: even for backends that I<are> fork-aware or
		2960	fork-safe, their behaviour is not usually what you want: fork clones all
		2961	watchers, that means all timers, I/O watchers etc. are active in both
		2962	parent and child, which is almost never what you want. USing C<exec>
		2963	to start worker children from some kind of manage rprocess is usually
		2964	preferred, because it is much easier and cleaner, at the expense of having
		2965	to have another binary.
2507		2966
2508		2967
2509	=head1 SECURITY CONSIDERATIONS	2968	=head1 SECURITY CONSIDERATIONS
2510		2969
2511	AnyEvent can be forced to load any event model via	2970	AnyEvent can be forced to load any event model via
…		…
2541	pronounced).	3000	pronounced).
2542		3001
2543		3002
2544	=head1 SEE ALSO	3003	=head1 SEE ALSO
2545		3004
2546	Utility functions: L<AnyEvent::Util>.	3005	Tutorial/Introduction: L<AnyEvent::Intro>.
2547		3006
2548	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	3007	FAQ: L<AnyEvent::FAQ>.
2549	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	3008
		3009	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		3010	(simply logging).
		3011
		3012	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		3013	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		3014
		3015	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3016	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3017	L<Qt>, L<POE>, L<FLTK>.
2550		3018
2551	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3019	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2552	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3020	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2553	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3021	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2554	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	3022	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3023	L<AnyEvent::Impl::FLTK>.
2555		3024
2556	Non-blocking file handles, sockets, TCP clients and	3025	Non-blocking handles, pipes, stream sockets, TCP clients and
2557	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3026	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2558		3027
		3028	Asynchronous File I/O: L<AnyEvent::IO>.
		3029
2559	Asynchronous DNS: L<AnyEvent::DNS>.	3030	Asynchronous DNS: L<AnyEvent::DNS>.
2560		3031
2561	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3032	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2562	L<Coro::Event>,
2563		3033
2564	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3034	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2565	L<AnyEvent::HTTP>.	3035	L<AnyEvent::HTTP>.
2566		3036
2567		3037
2568	=head1 AUTHOR	3038	=head1 AUTHOR
2569		3039
2570	Marc Lehmann <schmorp@schmorp.de>	3040	Marc Lehmann <schmorp@schmorp.de>
2571	http://home.schmorp.de/	3041	http://anyevent.schmorp.de
2572		3042
2573	=cut	3043	=cut
2574		3044
2575	1	3045	1
2576		3046

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