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Revision 1.279 by root, Sun Aug 9 16:05:11 2009 UTC vs.
Revision 1.419 by root, Thu Aug 28 15:26:20 2014 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, UV, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,
6	and POE are various supported event loops/environments.	6	Qt, 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
		492	# this forks and immediately calls exit in the child. this
		493	# normally has all sorts of bad consequences for your parent,
		494	# so take this as an example only. always fork and exec,
		495	# or call POSIX::_exit, in real code.
466	my $pid = fork or exit 5;	496	my $pid = fork or exit 5;
467		497
468	my $w = AnyEvent->child (	498	my $w = AnyEvent->child (
469	pid => $pid,	499	pid => $pid,
470	cb => sub {	500	cb => sub {
…		…
479		509
480	=head2 IDLE WATCHERS	510	=head2 IDLE WATCHERS
481		511
482	$w = AnyEvent->idle (cb => <callback>);	512	$w = AnyEvent->idle (cb => <callback>);
483		513
484	Sometimes there is a need to do something, but it is not so important	514	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	515	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		516
489	Idle watchers ideally get invoked when the event loop has nothing	517	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	518	is not so important (or wise) to do it instantly. The callback will be
491	events. Instead of blocking, the idle watcher is invoked.	519	invoked only when there is "nothing better to do", which is usually
		520	defined as "all outstanding events have been handled and no new events
		521	have been detected". That means that idle watchers ideally get invoked
		522	when the event loop has just polled for new events but none have been
		523	detected. Instead of blocking to wait for more events, the idle watchers
		524	will be invoked.
492		525
493	Most event loops unfortunately do not really support idle watchers (only	526	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	527	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
495	will simply call the callback "from time to time".	528	will simply call the callback "from time to time".
496		529
497	Example: read lines from STDIN, but only process them when the	530	Example: read lines from STDIN, but only process them when the
498	program is otherwise idle:	531	program is otherwise idle:
…		…
526	will actively watch for new events and call your callbacks.	559	will actively watch for new events and call your callbacks.
527		560
528	AnyEvent is slightly different: it expects somebody else to run the event	561	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).	562	loop and will only block when necessary (usually when told by the user).
530		563
531	The instrument to do that is called a "condition variable", so called	564	The tool to do that is called a "condition variable", so called because
532	because they represent a condition that must become true.	565	they represent a condition that must become true.
533		566
534	Now is probably a good time to look at the examples further below.	567	Now is probably a good time to look at the examples further below.
535		568
536	Condition variables can be created by calling the C<< AnyEvent->condvar	569	Condition variables can be created by calling the C<< AnyEvent->condvar
537	>> method, usually without arguments. The only argument pair allowed is	570	>> method, usually without arguments. The only argument pair allowed is
…		…
542	After creation, the condition variable is "false" until it becomes "true"	575	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	576	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<<	577	were a callback, read about the caveats in the description for the C<<
545	->send >> method).	578	->send >> method).
546		579
547	Condition variables are similar to callbacks, except that you can	580	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	581	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	582
550	another way to call them is transactions - each condition variable can be	583	=over 4
551	used to represent a transaction, which finishes at some point and delivers	584
552	a result. And yet some people know them as "futures" - a promise to	585	=item * Condition variables are like callbacks - you can call them (and pass them instead
553	compute/deliver something that you can wait for.	586	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		587
		588	=item * Condition variables are signals - one side can emit or send them,
		589	the other side can wait for them, or install a handler that is called when
		590	the signal fires.
		591
		592	=item * Condition variables are like "Merge Points" - points in your program
		593	where you merge multiple independent results/control flows into one.
		594
		595	=item * Condition variables represent a transaction - functions that start
		596	some kind of transaction can return them, leaving the caller the choice
		597	between waiting in a blocking fashion, or setting a callback.
		598
		599	=item * Condition variables represent future values, or promises to deliver
		600	some result, long before the result is available.
		601
		602	=back
554		603
555	Condition variables are very useful to signal that something has finished,	604	Condition variables are very useful to signal that something has finished,
556	for example, if you write a module that does asynchronous http requests,	605	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	606	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	607	availability of results. The user can either act when the callback is
…		…
571		620
572	Condition variables are represented by hash refs in perl, and the keys	621	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	622	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	623	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	624	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
576	it's C<new> method in your own C<new> method.	625	its C<new> method in your own C<new> method.
577		626
578	There are two "sides" to a condition variable - the "producer side" which	627	There are two "sides" to a condition variable - the "producer side" which
579	eventually calls C<< -> send >>, and the "consumer side", which waits	628	eventually calls C<< -> send >>, and the "consumer side", which waits
580	for the send to occur.	629	for the send to occur.
581		630
582	Example: wait for a timer.	631	Example: wait for a timer.
583		632
584	# wait till the result is ready	633	# condition: "wait till the timer is fired"
585	my $result_ready = AnyEvent->condvar;	634	my $timer_fired = AnyEvent->condvar;
586		635
587	# do something such as adding a timer	636	# create the timer - we could wait for, say
588	# or socket watcher the calls $result_ready->send	637	# a handle becomign ready, or even an
589	# when the "result" is ready.	638	# AnyEvent::HTTP request to finish, but
590	# in this case, we simply use a timer:	639	# in this case, we simply use a timer:
591	my $w = AnyEvent->timer (	640	my $w = AnyEvent->timer (
592	after => 1,	641	after => 1,
593	cb => sub { $result_ready->send },	642	cb => sub { $timer_fired->send },
594	);	643	);
595		644
596	# this "blocks" (while handling events) till the callback	645	# this "blocks" (while handling events) till the callback
597	# calls -<send	646	# calls ->send
598	$result_ready->recv;	647	$timer_fired->recv;
599		648
600	Example: wait for a timer, but take advantage of the fact that condition	649	Example: wait for a timer, but take advantage of the fact that condition
601	variables are also callable directly.	650	variables are also callable directly.
602		651
603	my $done = AnyEvent->condvar;	652	my $done = AnyEvent->condvar;
…		…
646	they were a code reference). Calling them directly is the same as calling	695	they were a code reference). Calling them directly is the same as calling
647	C<send>.	696	C<send>.
648		697
649	=item $cv->croak ($error)	698	=item $cv->croak ($error)
650		699
651	Similar to send, but causes all call's to C<< ->recv >> to invoke	700	Similar to send, but causes all calls to C<< ->recv >> to invoke
652	C<Carp::croak> with the given error message/object/scalar.	701	C<Carp::croak> with the given error message/object/scalar.
653		702
654	This can be used to signal any errors to the condition variable	703	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	704	user/consumer. Doing it this way instead of calling C<croak> directly
656	delays the error detetcion, but has the overwhelmign advantage that it	705	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	706	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	707	deep in some event callback with no connection to the actual code causing
659	the problem.	708	the problem.
660		709
661	=item $cv->begin ([group callback])	710	=item $cv->begin ([group callback])
662		711
663	=item $cv->end	712	=item $cv->end
…		…
666	one. For example, a function that pings many hosts in parallel might want	715	one. For example, a function that pings many hosts in parallel might want
667	to use a condition variable for the whole process.	716	to use a condition variable for the whole process.
668		717
669	Every call to C<< ->begin >> will increment a counter, and every call to	718	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	719	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	720	>>, 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	721	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.	722	>>, but that is not required. If no group callback was set, C<send> will
		723	be called without any arguments.
674		724
675	You can think of C<< $cv->send >> giving you an OR condition (one call	725	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	726	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).	727	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
678		728
…		…
699	This works because for every event source (EOF on file handle), there is	749	This works because for every event source (EOF on file handle), there is
700	one call to C<begin>, so the condvar waits for all calls to C<end> before	750	one call to C<begin>, so the condvar waits for all calls to C<end> before
701	sending.	751	sending.
702		752
703	The ping example mentioned above is slightly more complicated, as the	753	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	754	there are results to be passed back, and the number of tasks that are
705	begung can potentially be zero:	755	begun can potentially be zero:
706		756
707	my $cv = AnyEvent->condvar;	757	my $cv = AnyEvent->condvar;
708		758
709	my %result;	759	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	760	$cv->begin (sub { shift->send (\%result) });
711		761
712	for my $host (@list_of_hosts) {	762	for my $host (@list_of_hosts) {
713	$cv->begin;	763	$cv->begin;
714	ping_host_then_call_callback $host, sub {	764	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	765	$result{$host} = ...;
…		…
717	};	767	};
718	}	768	}
719		769
720	$cv->end;	770	$cv->end;
721		771
		772	...
		773
		774	my $results = $cv->recv;
		775
722	This code fragment supposedly pings a number of hosts and calls	776	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	777	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	778	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	779	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	780	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	785	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	786	C<send> is called even when C<no> hosts are being pinged (the loop
733	doesn't execute once).	787	doesn't execute once).
734		788
735	This is the general pattern when you "fan out" into multiple (but	789	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	790	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	791	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,	792	subrequest you start, call C<begin> and for each subrequest you finish,
739	call C<end>.	793	call C<end>.
740		794
741	=back	795	=back
…		…
748	=over 4	802	=over 4
749		803
750	=item $cv->recv	804	=item $cv->recv
751		805
752	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	806	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
753	>> methods have been called on c<$cv>, while servicing other watchers	807	>> methods have been called on C<$cv>, while servicing other watchers
754	normally.	808	normally.
755		809
756	You can only wait once on a condition - additional calls are valid but	810	You can only wait once on a condition - additional calls are valid but
757	will return immediately.	811	will return immediately.
758		812
…		…
761		815
762	In list context, all parameters passed to C<send> will be returned,	816	In list context, all parameters passed to C<send> will be returned,
763	in scalar context only the first one will be returned.	817	in scalar context only the first one will be returned.
764		818
765	Note that doing a blocking wait in a callback is not supported by any	819	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	820	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	821	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	822	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	823	, which allows you to do a blocking C<< ->recv >> from any thread
770	any thread that doesn't run the event loop itself.	824	that doesn't run the event loop itself. L<Coro::AnyEvent> is loaded
		825	automatically when L<Coro> is used with L<AnyEvent>, so code does not need
		826	to do anything special to take advantage of that: any code that would
		827	normally block your program because it calls C<recv>, be executed in an
		828	C<async> thread instead without blocking other threads.
771		829
772	Not all event models support a blocking wait - some die in that case	830	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	831	(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	832	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	833	caller decide whether the call will block or not (for example, by coupling
776	condition variables with some kind of request results and supporting	834	condition variables with some kind of request results and supporting
777	callbacks so the caller knows that getting the result will not block,	835	callbacks so the caller knows that getting the result will not block,
778	while still supporting blocking waits if the caller so desires).	836	while still supporting blocking waits if the caller so desires).
779		837
780	You can ensure that C<< -recv >> never blocks by setting a callback and	838	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	839	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	840	time). This will work even when the event loop does not support blocking
783	waits otherwise.	841	waits otherwise.
784		842
785	=item $bool = $cv->ready	843	=item $bool = $cv->ready
…		…
790	=item $cb = $cv->cb ($cb->($cv))	848	=item $cb = $cv->cb ($cb->($cv))
791		849
792	This is a mutator function that returns the callback set and optionally	850	This is a mutator function that returns the callback set and optionally
793	replaces it before doing so.	851	replaces it before doing so.
794		852
795	The callback will be called when the condition becomes (or already was)	853	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	854	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>	855	condition variable itself. If the condition is already true, the
		856	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.	857	the callback or at any later time is guaranteed not to block.
799		858
800	=back	859	=back
801		860
802	=head1 SUPPORTED EVENT LOOPS/BACKENDS	861	=head1 SUPPORTED EVENT LOOPS/BACKENDS
803		862
…		…
811	use. If EV is not installed, then AnyEvent will fall back to its own	870	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	871	pure-perl implementation, which is available everywhere as it comes with
813	AnyEvent itself.	872	AnyEvent itself.
814		873
815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	874	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	875	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
817		876
818	=item Backends that are transparently being picked up when they are used.	877	=item Backends that are transparently being picked up when they are used.
819		878
820	These will be used when they are currently loaded when the first watcher	879	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	880	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	881	them. This means that AnyEvent will automatically pick the right backend
823	when the main program loads an event module before anything starts to	882	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.	883	create watchers. Nothing special needs to be done by the main program.
825		884
826	AnyEvent::Impl::Event based on Event, very stable, few glitches.	885	AnyEvent::Impl::Event based on Event, very stable, few glitches.
827	AnyEvent::Impl::Glib based on Glib, slow but very stable.	886	AnyEvent::Impl::Glib based on Glib, slow but very stable.
828	AnyEvent::Impl::Tk based on Tk, very broken.	887	AnyEvent::Impl::Tk based on Tk, very broken.
		888	AnyEvent::Impl::UV based on UV, innovated square wheels.
829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	889	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830	AnyEvent::Impl::POE based on POE, very slow, some limitations.	890	AnyEvent::Impl::POE based on POE, very slow, some limitations.
831	AnyEvent::Impl::Irssi used when running within irssi.	891	AnyEvent::Impl::Irssi used when running within irssi.
		892	AnyEvent::Impl::IOAsync based on IO::Async.
		893	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		894	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
832		895
833	=item Backends with special needs.	896	=item Backends with special needs.
834		897
835	Qt requires the Qt::Application to be instantiated first, but will	898	Qt requires the Qt::Application to be instantiated first, but will
836	otherwise be picked up automatically. As long as the main program	899	otherwise be picked up automatically. As long as the main program
837	instantiates the application before any AnyEvent watchers are created,	900	instantiates the application before any AnyEvent watchers are created,
838	everything should just work.	901	everything should just work.
839		902
840	AnyEvent::Impl::Qt based on Qt.	903	AnyEvent::Impl::Qt based on Qt.
841		904
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.	905	=item Event loops that are indirectly supported via other backends.
851		906
852	Some event loops can be supported via other modules:	907	Some event loops can be supported via other modules:
853		908
854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	909	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	934	Contains C<undef> until the first watcher is being created, before the
880	backend has been autodetected.	935	backend has been autodetected.
881		936
882	Afterwards it contains the event model that is being used, which is the	937	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	938	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	939	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	940	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
886	will be C<urxvt::anyevent>).	941	will be C<urxvt::anyevent>).
887		942
888	=item AnyEvent::detect	943	=item AnyEvent::detect
889		944
890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	945	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
891	if necessary. You should only call this function right before you would	946	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	947	have created an AnyEvent watcher anyway, that is, as late as possible at
893	runtime, and not e.g. while initialising of your module.	948	runtime, and not e.g. during initialisation of your module.
		949
		950	The effect of calling this function is as if a watcher had been created
		951	(specifically, actions that happen "when the first watcher is created"
		952	happen when calling detetc as well).
894		953
895	If you need to do some initialisation before AnyEvent watchers are	954	If you need to do some initialisation before AnyEvent watchers are
896	created, use C<post_detect>.	955	created, use C<post_detect>.
897		956
898	=item $guard = AnyEvent::post_detect { BLOCK }	957	=item $guard = AnyEvent::post_detect { BLOCK }
899		958
900	Arranges for the code block to be executed as soon as the event model is	959	Arranges for the code block to be executed as soon as the event model is
901	autodetected (or immediately if this has already happened).	960	autodetected (or immediately if that has already happened).
902		961
903	The block will be executed I<after> the actual backend has been detected	962	The block will be executed I<after> the actual backend has been detected
904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	963	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	964	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906	other initialisations - see the sources of L<AnyEvent::Strict> or	965	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
915	that automatically removes the callback again when it is destroyed (or	974	that automatically removes the callback again when it is destroyed (or
916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	975	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
917	a case where this is useful.	976	a case where this is useful.
918		977
919	Example: Create a watcher for the IO::AIO module and store it in	978	Example: Create a watcher for the IO::AIO module and store it in
920	C<$WATCHER>. Only do so after the event loop is initialised, though.	979	C<$WATCHER>, but do so only do so after the event loop is initialised.
921		980
922	our WATCHER;	981	our WATCHER;
923		982
924	my $guard = AnyEvent::post_detect {	983	my $guard = AnyEvent::post_detect {
925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	984	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
933	$WATCHER ||= $guard;	992	$WATCHER ||= $guard;
934		993
935	=item @AnyEvent::post_detect	994	=item @AnyEvent::post_detect
936		995
937	If there are any code references in this array (you can C<push> to it	996	If there are any code references in this array (you can C<push> to it
938	before or after loading AnyEvent), then they will called directly after	997	before or after loading AnyEvent), then they will be called directly
939	the event loop has been chosen.	998	after the event loop has been chosen.
940		999
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	1000	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	1001	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	1002	array will be ignored.
944		1003
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	1004	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	1005	it, as it takes care of these details.
947		1006
948	This variable is mainly useful for modules that can do something useful	1007	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	1008	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	1009	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	1010	into AnyEvent passively, without loading it.
952		1011
		1012	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1013	together, you could put this into Coro (this is the actual code used by
		1014	Coro to accomplish this):
		1015
		1016	if (defined $AnyEvent::MODEL) {
		1017	# AnyEvent already initialised, so load Coro::AnyEvent
		1018	require Coro::AnyEvent;
		1019	} else {
		1020	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1021	# as soon as it is
		1022	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1023	}
		1024
		1025	=item AnyEvent::postpone { BLOCK }
		1026
		1027	Arranges for the block to be executed as soon as possible, but not before
		1028	the call itself returns. In practise, the block will be executed just
		1029	before the event loop polls for new events, or shortly afterwards.
		1030
		1031	This function never returns anything (to make the C<return postpone { ...
		1032	}> idiom more useful.
		1033
		1034	To understand the usefulness of this function, consider a function that
		1035	asynchronously does something for you and returns some transaction
		1036	object or guard to let you cancel the operation. For example,
		1037	C<AnyEvent::Socket::tcp_connect>:
		1038
		1039	# start a connection attempt unless one is active
		1040	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1041	delete $self->{connect_guard};
		1042	...
		1043	};
		1044
		1045	Imagine that this function could instantly call the callback, for
		1046	example, because it detects an obvious error such as a negative port
		1047	number. Invoking the callback before the function returns causes problems
		1048	however: the callback will be called and will try to delete the guard
		1049	object. But since the function hasn't returned yet, there is nothing to
		1050	delete. When the function eventually returns it will assign the guard
		1051	object to C<< $self->{connect_guard} >>, where it will likely never be
		1052	deleted, so the program thinks it is still trying to connect.
		1053
		1054	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1055	callback directly on error:
		1056
		1057	$cb->(undef), return # signal error to callback, BAD!
		1058	if $some_error_condition;
		1059
		1060	It should use C<postpone>:
		1061
		1062	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1063	if $some_error_condition;
		1064
		1065	=item AnyEvent::log $level, $msg[, @args]
		1066
		1067	Log the given C<$msg> at the given C<$level>.
		1068
		1069	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1070	to see whether the message will be logged. If the test succeeds it will
		1071	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1072	the L<AnyEvent::Log> documentation for details.
		1073
		1074	If the test fails it will simply return. Right now this happens when a
		1075	numerical loglevel is used and it is larger than the level specified via
		1076	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1077
		1078	If you want to sprinkle loads of logging calls around your code, consider
		1079	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1080	which can reduce typing, codesize and can reduce the logging overhead
		1081	enourmously.
		1082
953	=back	1083	=back
954		1084
955	=head1 WHAT TO DO IN A MODULE	1085	=head1 WHAT TO DO IN A MODULE
956		1086
957	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1087	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	1097	because it will stall the whole program, and the whole point of using
968	events is to stay interactive.	1098	events is to stay interactive.
969		1099
970	It is fine, however, to call C<< ->recv >> when the user of your module	1100	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	1101	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 >>	1102	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).	1103	freely, as the user of your module knows what she is doing. Always).
974		1104
975	=head1 WHAT TO DO IN THE MAIN PROGRAM	1105	=head1 WHAT TO DO IN THE MAIN PROGRAM
976		1106
977	There will always be a single main program - the only place that should	1107	There will always be a single main program - the only place that should
978	dictate which event model to use.	1108	dictate which event model to use.
979		1109
980	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1110	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	1111	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.	1112	uses AnyEvent, but does not care which event loop is used, all it needs
		1113	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1114	available loop implementation.
983		1115
984	If the main program relies on a specific event model - for example, in	1116	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	1117	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	1118	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	1119	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	1120	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	1121	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.	1122	might choose the wrong one unless you load the correct one yourself.
991		1123
992	You can chose to use a pure-perl implementation by loading the	1124	You can chose to use a pure-perl implementation by loading the
993	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1125	C<AnyEvent::Loop> module, which gives you similar behaviour
994	everywhere, but letting AnyEvent chose the model is generally better.	1126	everywhere, but letting AnyEvent chose the model is generally better.
995		1127
996	=head2 MAINLOOP EMULATION	1128	=head2 MAINLOOP EMULATION
997		1129
998	Sometimes (often for short test scripts, or even standalone programs who	1130	Sometimes (often for short test scripts, or even standalone programs who
…		…
1011		1143
1012		1144
1013	=head1 OTHER MODULES	1145	=head1 OTHER MODULES
1014		1146
1015	The following is a non-exhaustive list of additional modules that use	1147	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	1148	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	1149	AnyEvent modules and other event loops in the same program. Some of the
1018	come with AnyEvent, most are available via CPAN.	1150	modules come as part of AnyEvent, the others are available via CPAN (see
		1151	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1152	a longer non-exhaustive list), and the list is heavily biased towards
		1153	modules of the AnyEvent author himself :)
1019		1154
1020	=over 4	1155	=over 4
1021		1156
1022	=item L<AnyEvent::Util>	1157	=item L<AnyEvent::Util> (part of the AnyEvent distribution)
1023		1158
1024	Contains various utility functions that replace often-used but blocking	1159	Contains various utility functions that replace often-used blocking
1025	functions such as C<inet_aton> by event-/callback-based versions.	1160	functions such as C<inet_aton> with event/callback-based versions.
1026		1161
1027	=item L<AnyEvent::Socket>	1162	=item L<AnyEvent::Socket> (part of the AnyEvent distribution)
1028		1163
1029	Provides various utility functions for (internet protocol) sockets,	1164	Provides various utility functions for (internet protocol) sockets,
1030	addresses and name resolution. Also functions to create non-blocking tcp	1165	addresses and name resolution. Also functions to create non-blocking tcp
1031	connections or tcp servers, with IPv6 and SRV record support and more.	1166	connections or tcp servers, with IPv6 and SRV record support and more.
1032		1167
1033	=item L<AnyEvent::Handle>	1168	=item L<AnyEvent::Handle> (part of the AnyEvent distribution)
1034		1169
1035	Provide read and write buffers, manages watchers for reads and writes,	1170	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	1171	supports raw and formatted I/O, I/O queued and fully transparent and
1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1172	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1038		1173
1039	=item L<AnyEvent::DNS>	1174	=item L<AnyEvent::DNS> (part of the AnyEvent distribution)
1040		1175
1041	Provides rich asynchronous DNS resolver capabilities.	1176	Provides rich asynchronous DNS resolver capabilities.
1042		1177
1043	=item L<AnyEvent::HTTP>	1178	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
1044		1179
1045	A simple-to-use HTTP library that is capable of making a lot of concurrent	1180	Implement event-based interfaces to the protocols of the same name (for
1046	HTTP requests.	1181	the curious, IGS is the International Go Server and FCP is the Freenet
		1182	Client Protocol).
1047		1183
		1184	=item L<AnyEvent::AIO> (part of the AnyEvent distribution)
		1185
		1186	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1187	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1188	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1189	file I/O, and much more.
		1190
		1191	=item L<AnyEvent::Fork>, L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool>, L<AnyEvent::Fork::Remote>
		1192
		1193	These let you safely fork new subprocesses, either locally or
		1194	remotely (e.g.v ia ssh), using some RPC protocol or not, without
		1195	the limitations normally imposed by fork (AnyEvent works fine for
		1196	example). Dynamically-resized worker pools are obviously included as well.
		1197
		1198	And they are quite tiny and fast as well - "abusing" L<AnyEvent::Fork>
		1199	just to exec external programs can easily beat using C<fork> and C<exec>
		1200	(or even C<system>) in most programs.
		1201
		1202	=item L<AnyEvent::Filesys::Notify>
		1203
		1204	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1205	path changes (e.g. "watch this directory for new files", "watch this
		1206	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1207	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1208	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1209	fall back to blocking scans at regular intervals transparently on other
		1210	platforms, so it's about as portable as it gets.
		1211
		1212	(I haven't used it myself, but it seems the biggest problem with it is
		1213	it quite bad performance).
		1214
1048	=item L<AnyEvent::HTTPD>	1215	=item L<AnyEvent::DBI>
1049		1216
1050	Provides a simple web application server framework.	1217	Executes L<DBI> requests asynchronously in a proxy process for you,
		1218	notifying you in an event-based way when the operation is finished.
1051		1219
1052	=item L<AnyEvent::FastPing>	1220	=item L<AnyEvent::FastPing>
1053		1221
1054	The fastest ping in the west.	1222	The fastest ping in the west.
1055		1223
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>	1224	=item L<Coro>
1099		1225
1100	Has special support for AnyEvent via L<Coro::AnyEvent>.	1226	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1227	to simply invert the flow control - don't call us, we will call you:
		1228
		1229	async {
		1230	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1231	print "5 seconds later!\n";
		1232
		1233	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1234	my $line = <STDIN>; # works for ttys
		1235
		1236	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1237	my ($body, $hdr) = Coro::rouse_wait;
		1238	};
1101		1239
1102	=back	1240	=back
1103		1241
1104	=cut	1242	=cut
1105		1243
1106	package AnyEvent;	1244	package AnyEvent;
1107		1245
1108	# basically a tuned-down version of common::sense	1246	BEGIN {
1109	sub common_sense {	1247	require "AnyEvent/constants.pl";
1110	# no warnings	1248	&AnyEvent::common_sense;
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};
1112	# use strict vars subs
1113	$^H |= 0x00000600;
1114	}	1249	}
1115
1116	BEGIN { AnyEvent::common_sense }
1117		1250
1118	use Carp ();	1251	use Carp ();
1119		1252
1120	our $VERSION = '5.0';	1253	our $VERSION = '7.07';
1121	our $MODEL;	1254	our $MODEL;
1122
1123	our $AUTOLOAD;
1124	our @ISA;	1255	our @ISA;
1125
1126	our @REGISTRY;	1256	our @REGISTRY;
1127
1128	our $WIN32;
1129
1130	our $VERBOSE;	1257	our $VERBOSE;
		1258	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		1259	our $MAX_SIGNAL_LATENCY = $ENV{PERL_ANYEVENT_MAX_SIGNAL_LATENCY} || 10; # executes after the BEGIN block below (tainting!)
1131		1260
1132	BEGIN {	1261	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1262	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1135		1263
1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1264	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137	if ${^TAINT};	1265	if ${^TAINT};
1138		1266
1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1267	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1268	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1140		1269
1141	}	1270	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1271	if ${^TAINT};
1142		1272
1143	our $MAX_SIGNAL_LATENCY = 10;	1273	# $ENV{PERL_ANYEVENT_xxx} now valid
1144		1274
1145	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1275	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
1146		1276
1147	{
1148	my $idx;	1277	my $idx;
1149	$PROTOCOL{$_} = ++$idx	1278	$PROTOCOL{$_} = ++$idx
1150	for reverse split /\s*,\s*/,	1279	for reverse split /\s*,\s*/,
1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1280	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152	}	1281	}
1153		1282
		1283	our @post_detect;
		1284
		1285	sub post_detect(&) {
		1286	my ($cb) = @_;
		1287
		1288	push @post_detect, $cb;
		1289
		1290	defined wantarray
		1291	? bless \$cb, "AnyEvent::Util::postdetect"
		1292	: ()
		1293	}
		1294
		1295	sub AnyEvent::Util::postdetect::DESTROY {
		1296	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1297	}
		1298
		1299	our $POSTPONE_W;
		1300	our @POSTPONE;
		1301
		1302	sub _postpone_exec {
		1303	undef $POSTPONE_W;
		1304
		1305	&{ shift @POSTPONE }
		1306	while @POSTPONE;
		1307	}
		1308
		1309	sub postpone(&) {
		1310	push @POSTPONE, shift;
		1311
		1312	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1313
		1314	()
		1315	}
		1316
		1317	sub log($$;@) {
		1318	# only load the big bloated module when we actually are about to log something
		1319	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1320	local ($!, $@);
		1321	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1322	# AnyEvent::Log overwrites this function
		1323	goto &log;
		1324	}
		1325
		1326	0 # not logged
		1327	}
		1328
		1329	sub _logger($;$) {
		1330	my ($level, $renabled) = @_;
		1331
		1332	$$renabled = $level <= $VERBOSE;
		1333
		1334	my $logger = [(caller)[0], $level, $renabled];
		1335
		1336	$AnyEvent::Log::LOGGER{$logger+0} = $logger;
		1337
		1338	# return unless defined wantarray;
		1339	#
		1340	# require AnyEvent::Util;
		1341	# my $guard = AnyEvent::Util::guard (sub {
		1342	# # "clean up"
		1343	# delete $LOGGER{$logger+0};
		1344	# });
		1345	#
		1346	# sub {
		1347	# return 0 unless $$renabled;
		1348	#
		1349	# $guard if 0; # keep guard alive, but don't cause runtime overhead
		1350	# require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1351	# package AnyEvent::Log;
		1352	# _log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1353	# }
		1354	}
		1355
		1356	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1357	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1358	}
		1359
1154	my @models = (	1360	our @models = (
1155	[EV:: => AnyEvent::Impl::EV:: , 1],	1361	[EV:: => AnyEvent::Impl::EV::],
1156	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1362	[AnyEvent::Loop:: => AnyEvent::Impl::Perl::],
1157	# everything below here will not (normally) be autoprobed	1363	# everything below here will not (normally) be autoprobed
1158	# as the pureperl backend should work everywhere	1364	# as the pure perl backend should work everywhere
1159	# and is usually faster	1365	# and is usually faster
		1366	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package, so msut be near the top
1160	[Event:: => AnyEvent::Impl::Event::, 1],	1367	[Event:: => AnyEvent::Impl::Event::], # slow, stable
1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1368	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
		1369	# everything below here should not be autoloaded
1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1370	[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	1371	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		1372	[UV:: => AnyEvent::Impl::UV::], # switched from libev, added back all bugs imaginable
1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1373	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1374	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1167	[Wx:: => AnyEvent::Impl::POE::],	1375	[Wx:: => AnyEvent::Impl::POE::],
1168	[Prima:: => AnyEvent::Impl::POE::],	1376	[Prima:: => AnyEvent::Impl::POE::],
1169	# IO::Async is just too broken - we would need workarounds for its	1377	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1170	# byzantine signal and broken child handling, among others.	1378	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1171	# IO::Async is rather hard to detect, as it doesn't have any	1379	[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	);	1380	);
1178		1381
1179	our %method = map +($_ => 1),	1382	our @isa_hook;
		1383
		1384	sub _isa_set {
		1385	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1386
		1387	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1388	for 1 .. $#pkg;
		1389
		1390	grep $_ && $_->[1], @isa_hook
		1391	and AE::_reset ();
		1392	}
		1393
		1394	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1395	sub _isa_hook($$;$) {
		1396	my ($i, $pkg, $reset_ae) = @_;
		1397
		1398	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1399
		1400	_isa_set;
		1401	}
		1402
		1403	# all autoloaded methods reserve the complete glob, not just the method slot.
		1404	# due to bugs in perls method cache implementation.
1180	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1405	our @methods = qw(io timer time now now_update signal child idle condvar);
1181		1406
1182	our @post_detect;
1183
1184	sub post_detect(&) {	1407	sub detect() {
1185	my ($cb) = @_;	1408	return $MODEL if $MODEL; # some programs keep references to detect
1186		1409
1187	if ($MODEL) {	1410	# IO::Async::Loop::AnyEvent is extremely evil, refuse to work with it
1188	$cb->();	1411	# the author knows about the problems and what it does to AnyEvent as a whole
		1412	# (and the ability of others to use AnyEvent), but simply wants to abuse AnyEvent
		1413	# anyway.
		1414	AnyEvent::log fatal => "IO::Async::Loop::AnyEvent detected - that module is broken by\n"
		1415	. "design, abuses internals and breaks AnyEvent - will not continue."
		1416	if exists $INC{"IO/Async/Loop/AnyEvent.pm"};
1189		1417
1190	undef	1418	local $!; # for good measure
		1419	local $SIG{__DIE__}; # we use eval
		1420
		1421	# free some memory
		1422	*detect = sub () { $MODEL };
		1423	# undef &func doesn't correctly update the method cache. grmbl.
		1424	# so we delete the whole glob. grmbl.
		1425	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1426	# a glob with an active sub. hrm. i hope it works, but perl is
		1427	# usually buggy in this department. sigh.
		1428	delete @{"AnyEvent::"}{@methods};
		1429	undef @methods;
		1430
		1431	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1432	my $model = $1;
		1433	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1434	if (eval "require $model") {
		1435	AnyEvent::log 7 => "Loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1436	$MODEL = $model;
1191	} else {	1437	} else {
1192	push @post_detect, $cb;	1438	AnyEvent::log 4 => "Unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1193		1439	}
1194	defined wantarray
1195	? bless \$cb, "AnyEvent::Util::postdetect"
1196	: ()
1197	}	1440	}
1198	}
1199		1441
1200	sub AnyEvent::Util::postdetect::DESTROY {	1442	# check for already loaded models
1201	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1202	}
1203
1204	sub detect() {
1205	unless ($MODEL) {	1443	unless ($MODEL) {
1206	local $SIG{__DIE__};	1444	for (@REGISTRY, @models) {
1207		1445	my ($package, $model) = @$_;
1208	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1446	if (${"$package\::VERSION"} > 0) {
1209	my $model = "AnyEvent::Impl::$1";
1210	if (eval "require $model") {	1447	if (eval "require $model") {
		1448	AnyEvent::log 7 => "Autodetected model '$model', using it.";
1211	$MODEL = $model;	1449	$MODEL = $model;
1212	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1450	last;
1213	} else {	1451	} else {
1214	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1452	AnyEvent::log 8 => "Detected event loop $package, but cannot load '$model', skipping: $@";
		1453	}
1215	}	1454	}
1216	}	1455	}
1217		1456
1218	# check for already loaded models
1219	unless ($MODEL) {	1457	unless ($MODEL) {
		1458	# try to autoload a model
1220	for (@REGISTRY, @models) {	1459	for (@REGISTRY, @models) {
1221	my ($package, $model) = @$_;	1460	my ($package, $model) = @$_;
		1461	if (
		1462	eval "require $package"
1222	if (${"$package\::VERSION"} > 0) {	1463	and ${"$package\::VERSION"} > 0
1223	if (eval "require $model") {	1464	and eval "require $model"
		1465	) {
		1466	AnyEvent::log 7 => "Autoloaded model '$model', using it.";
1224	$MODEL = $model;	1467	$MODEL = $model;
1225	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1226	last;	1468	last;
1227	}
1228	}	1469	}
1229	}	1470	}
1230		1471
1231	unless ($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	1472	$MODEL
1248	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1473	or AnyEvent::log fatal => "Backend autodetection failed - did you properly install AnyEvent?";
1249	}
1250	}	1474	}
1251
1252	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1253
1254	unshift @ISA, $MODEL;
1255
1256	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1257
1258	(shift @post_detect)->() while @post_detect;
1259	}	1475	}
1260		1476
		1477	# free memory only needed for probing
		1478	undef @models;
		1479	undef @REGISTRY;
		1480
		1481	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1482
		1483	# now nuke some methods that are overridden by the backend.
		1484	# SUPER usage is not allowed in these.
		1485	for (qw(time signal child idle)) {
		1486	undef &{"AnyEvent::Base::$_"}
		1487	if defined &{"$MODEL\::$_"};
		1488	}
		1489
		1490	_isa_set;
		1491
		1492	# we're officially open!
		1493
		1494	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1495	require AnyEvent::Strict;
		1496	}
		1497
		1498	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1499	require AnyEvent::Debug;
		1500	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1501	}
		1502
		1503	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1504	require AnyEvent::Socket;
		1505	require AnyEvent::Debug;
		1506
		1507	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1508	$shell =~ s/\$\$/$$/g;
		1509
		1510	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1511	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1512	}
		1513
		1514	# now the anyevent environment is set up as the user told us to, so
		1515	# call the actual user code - post detects
		1516
		1517	(shift @post_detect)->() while @post_detect;
		1518	undef @post_detect;
		1519
		1520	*post_detect = sub(&) {
		1521	shift->();
		1522
		1523	undef
		1524	};
		1525
1261	$MODEL	1526	$MODEL
1262	}	1527	}
1263		1528
1264	sub AUTOLOAD {	1529	for my $name (@methods) {
1265	(my $func = $AUTOLOAD) =~ s/.*://;	1530	*$name = sub {
1266		1531	detect;
1267	$method{$func}	1532	# we use goto because
1268	or Carp::croak "$func: not a valid method for AnyEvent objects";	1533	# a) it makes the thunk more transparent
1269		1534	# b) it allows us to delete the thunk later
1270	detect unless $MODEL;	1535	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1271		1536	};
1272	my $class = shift;
1273	$class->$func (@_);
1274	}	1537	}
1275		1538
1276	# utility function to dup a filehandle. this is used by many backends	1539	# utility function to dup a filehandle. this is used by many backends
1277	# to support binding more than one watcher per filehandle (they usually	1540	# 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).	1541	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1292		1555
1293	=head1 SIMPLIFIED AE API	1556	=head1 SIMPLIFIED AE API
1294		1557
1295	Starting with version 5.0, AnyEvent officially supports a second, much	1558	Starting with version 5.0, AnyEvent officially supports a second, much
1296	simpler, API that is designed to reduce the calling, typing and memory	1559	simpler, API that is designed to reduce the calling, typing and memory
1297	overhead.	1560	overhead by using function call syntax and a fixed number of parameters.
1298		1561
1299	See the L<AE> manpage for details.	1562	See the L<AE> manpage for details.
1300		1563
1301	=cut	1564	=cut
1302		1565
1303	package AE;	1566	package AE;
1304		1567
1305	our $VERSION = $AnyEvent::VERSION;	1568	our $VERSION = $AnyEvent::VERSION;
1306		1569
		1570	sub _reset() {
		1571	eval q{
		1572	# fall back to the main API by default - backends and AnyEvent::Base
		1573	# implementations can overwrite these.
		1574
1307	sub io($$$) {	1575	sub io($$$) {
1308	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1576	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1309	}	1577	}
1310		1578
1311	sub timer($$$) {	1579	sub timer($$$) {
1312	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1580	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1313	}	1581	}
1314		1582
1315	sub signal($$) {	1583	sub signal($$) {
1316	AnyEvent->signal (signal => $_[0], cb => $_[1])	1584	AnyEvent->signal (signal => $_[0], cb => $_[1])
1317	}	1585	}
1318		1586
1319	sub child($$) {	1587	sub child($$) {
1320	AnyEvent->child (pid => $_[0], cb => $_[1])	1588	AnyEvent->child (pid => $_[0], cb => $_[1])
1321	}	1589	}
1322		1590
1323	sub idle($) {	1591	sub idle($) {
1324	AnyEvent->idle (cb => $_[0])	1592	AnyEvent->idle (cb => $_[0]);
1325	}	1593	}
1326		1594
1327	sub cv(;&) {	1595	sub cv(;&) {
1328	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1596	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1329	}	1597	}
1330		1598
1331	sub now() {	1599	sub now() {
1332	AnyEvent->now	1600	AnyEvent->now
1333	}	1601	}
1334		1602
1335	sub now_update() {	1603	sub now_update() {
1336	AnyEvent->now_update	1604	AnyEvent->now_update
1337	}	1605	}
1338		1606
1339	sub time() {	1607	sub time() {
1340	AnyEvent->time	1608	AnyEvent->time
		1609	}
		1610
		1611	*postpone = \&AnyEvent::postpone;
		1612	*log = \&AnyEvent::log;
		1613	};
		1614	die if $@;
1341	}	1615	}
		1616
		1617	BEGIN { _reset }
1342		1618
1343	package AnyEvent::Base;	1619	package AnyEvent::Base;
1344		1620
1345	# default implementations for many methods	1621	# default implementations for many methods
1346		1622
1347	sub _time {	1623	sub time {
		1624	eval q{ # poor man's autoloading {}
1348	# probe for availability of Time::HiRes	1625	# probe for availability of Time::HiRes
1349	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1626	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1350	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1627	*time = sub { Time::HiRes::time () };
1351	*_time = \&Time::HiRes::time;	1628	*AE::time = \& Time::HiRes::time ;
		1629	*now = \&time;
		1630	AnyEvent::log 8 => "using Time::HiRes for sub-second timing accuracy.";
1352	# if (eval "use POSIX (); (POSIX::times())...	1631	# if (eval "use POSIX (); (POSIX::times())...
1353	} else {	1632	} else {
1354	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1633	*time = sub { CORE::time };
1355	*_time = sub { time }; # epic fail	1634	*AE::time = sub (){ CORE::time };
		1635	*now = \&time;
		1636	AnyEvent::log 3 => "Using built-in time(), no sub-second resolution!";
		1637	}
1356	}	1638	};
		1639	die if $@;
1357		1640
1358	&_time	1641	&time
1359	}	1642	}
1360		1643
1361	sub time { _time }	1644	*now = \&time;
1362	sub now { _time }
1363	sub now_update { }	1645	sub now_update { }
1364		1646
		1647	sub _poll {
		1648	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1649	}
		1650
1365	# default implementation for ->condvar	1651	# default implementation for ->condvar
		1652	# in fact, the default should not be overwritten
1366		1653
1367	sub condvar {	1654	sub condvar {
		1655	eval q{ # poor man's autoloading {}
		1656	*condvar = sub {
1368	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1657	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1658	};
		1659
		1660	*AE::cv = sub (;&) {
		1661	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1662	};
		1663	};
		1664	die if $@;
		1665
		1666	&condvar
1369	}	1667	}
1370		1668
1371	# default implementation for ->signal	1669	# default implementation for ->signal
1372		1670
1373	our $HAVE_ASYNC_INTERRUPT;	1671	our $HAVE_ASYNC_INTERRUPT;
1374		1672
1375	sub _have_async_interrupt() {	1673	sub _have_async_interrupt() {
1376	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1674	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1377	&& eval "use Async::Interrupt 1.0 (); 1")	1675	&& eval "use Async::Interrupt 1.02 (); 1")
1378	unless defined $HAVE_ASYNC_INTERRUPT;	1676	unless defined $HAVE_ASYNC_INTERRUPT;
1379		1677
1380	$HAVE_ASYNC_INTERRUPT	1678	$HAVE_ASYNC_INTERRUPT
1381	}	1679	}
1382		1680
1383	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1681	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1384	our (%SIG_ASY, %SIG_ASY_W);	1682	our (%SIG_ASY, %SIG_ASY_W);
1385	our ($SIG_COUNT, $SIG_TW);	1683	our ($SIG_COUNT, $SIG_TW);
1386		1684
1387	sub _signal_exec {
1388	$HAVE_ASYNC_INTERRUPT
1389	? $SIGPIPE_R->drain
1390	: sysread $SIGPIPE_R, my $dummy, 9;
1391
1392	while (%SIG_EV) {
1393	for (keys %SIG_EV) {
1394	delete $SIG_EV{$_};
1395	$_->() for values %{ $SIG_CB{$_} || {} };
1396	}
1397	}
1398	}
1399
1400	# install a dummy wakeup watcher to reduce signal catching latency	1685	# install a dummy wakeup watcher to reduce signal catching latency
		1686	# used by Impls
1401	sub _sig_add() {	1687	sub _sig_add() {
1402	unless ($SIG_COUNT++) {	1688	unless ($SIG_COUNT++) {
1403	# try to align timer on a full-second boundary, if possible	1689	# try to align timer on a full-second boundary, if possible
1404	my $NOW = AE::now;	1690	my $NOW = AE::now;
1405		1691
…		…
1415	undef $SIG_TW	1701	undef $SIG_TW
1416	unless --$SIG_COUNT;	1702	unless --$SIG_COUNT;
1417	}	1703	}
1418		1704
1419	our $_sig_name_init; $_sig_name_init = sub {	1705	our $_sig_name_init; $_sig_name_init = sub {
1420	eval q{ # poor man's autoloading	1706	eval q{ # poor man's autoloading {}
1421	undef $_sig_name_init;	1707	undef $_sig_name_init;
1422		1708
1423	if (_have_async_interrupt) {	1709	if (_have_async_interrupt) {
1424	*sig2num = \&Async::Interrupt::sig2num;	1710	*sig2num = \&Async::Interrupt::sig2num;
1425	*sig2name = \&Async::Interrupt::sig2name;	1711	*sig2name = \&Async::Interrupt::sig2name;
…		…
1449		1735
1450	sub signal {	1736	sub signal {
1451	eval q{ # poor man's autoloading {}	1737	eval q{ # poor man's autoloading {}
1452	# probe for availability of Async::Interrupt	1738	# probe for availability of Async::Interrupt
1453	if (_have_async_interrupt) {	1739	if (_have_async_interrupt) {
1454	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1740	AnyEvent::log 8 => "Using Async::Interrupt for race-free signal handling.";
1455		1741
1456	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1742	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1457	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1743	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1458		1744
1459	} else {	1745	} else {
1460	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1746	AnyEvent::log 8 => "Using emulated perl signal handling with latency timer.";
1461
1462	require Fcntl;
1463		1747
1464	if (AnyEvent::WIN32) {	1748	if (AnyEvent::WIN32) {
1465	require AnyEvent::Util;	1749	require AnyEvent::Util;
1466		1750
1467	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1751	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1468	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1752	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1469	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1753	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1470	} else {	1754	} else {
1471	pipe $SIGPIPE_R, $SIGPIPE_W;	1755	pipe $SIGPIPE_R, $SIGPIPE_W;
1472	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1756	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1473	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1757	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1474		1758
1475	# not strictly required, as $^F is normally 2, but let's make sure...	1759	# not strictly required, as $^F is normally 2, but let's make sure...
1476	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1760	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1477	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1761	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1478	}	1762	}
1479		1763
1480	$SIGPIPE_R	1764	$SIGPIPE_R
1481	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1765	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1482		1766
1483	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1767	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1484	}	1768	}
1485		1769
1486	*signal = sub {	1770	*signal = $HAVE_ASYNC_INTERRUPT
		1771	? sub {
1487	my (undef, %arg) = @_;	1772	my (undef, %arg) = @_;
1488		1773
1489	my $signal = uc $arg{signal}
1490	or Carp::croak "required option 'signal' is missing";
1491
1492	if ($HAVE_ASYNC_INTERRUPT) {
1493	# async::interrupt	1774	# async::interrupt
1494
1495	$signal = sig2num $signal;	1775	my $signal = sig2num $arg{signal};
1496	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1776	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1497		1777
1498	$SIG_ASY{$signal} ||= new Async::Interrupt	1778	$SIG_ASY{$signal} ||= new Async::Interrupt
1499	cb => sub { undef $SIG_EV{$signal} },	1779	cb => sub { undef $SIG_EV{$signal} },
1500	signal => $signal,	1780	signal => $signal,
1501	pipe => [$SIGPIPE_R->filenos],	1781	pipe => [$SIGPIPE_R->filenos],
1502	pipe_autodrain => 0,	1782	pipe_autodrain => 0,
1503	;	1783	;
1504		1784
1505	} else {	1785	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1786	}
		1787	: sub {
		1788	my (undef, %arg) = @_;
		1789
1506	# pure perl	1790	# pure perl
1507
1508	# AE::Util has been loaded in signal
1509	$signal = sig2name $signal;	1791	my $signal = sig2name $arg{signal};
1510	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1792	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1511		1793
1512	$SIG{$signal} ||= sub {	1794	$SIG{$signal} ||= sub {
1513	local $!;	1795	local $!;
1514	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1796	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1515	undef $SIG_EV{$signal};	1797	undef $SIG_EV{$signal};
1516	};	1798	};
1517		1799
1518	# can't do signal processing without introducing races in pure perl,	1800	# can't do signal processing without introducing races in pure perl,
1519	# so limit the signal latency.	1801	# so limit the signal latency.
1520	_sig_add;	1802	_sig_add;
1521	}
1522		1803
1523	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1804	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1805	}
1524	};	1806	;
1525		1807
1526	*AnyEvent::Base::signal::DESTROY = sub {	1808	*AnyEvent::Base::signal::DESTROY = sub {
1527	my ($signal, $cb) = @{$_[0]};	1809	my ($signal, $cb) = @{$_[0]};
1528		1810
1529	_sig_del;	1811	_sig_del;
…		…
1536	# print weird messages, or just unconditionally exit	1818	# print weird messages, or just unconditionally exit
1537	# instead of getting the default action.	1819	# instead of getting the default action.
1538	undef $SIG{$signal}	1820	undef $SIG{$signal}
1539	unless keys %{ $SIG_CB{$signal} };	1821	unless keys %{ $SIG_CB{$signal} };
1540	};	1822	};
		1823
		1824	*_signal_exec = sub {
		1825	$HAVE_ASYNC_INTERRUPT
		1826	? $SIGPIPE_R->drain
		1827	: sysread $SIGPIPE_R, (my $dummy), 9;
		1828
		1829	while (%SIG_EV) {
		1830	for (keys %SIG_EV) {
		1831	delete $SIG_EV{$_};
		1832	&$_ for values %{ $SIG_CB{$_} || {} };
		1833	}
		1834	}
		1835	};
1541	};	1836	};
1542	die if $@;	1837	die if $@;
		1838
1543	&signal	1839	&signal
1544	}	1840	}
1545		1841
1546	# default implementation for ->child	1842	# default implementation for ->child
1547		1843
1548	our %PID_CB;	1844	our %PID_CB;
1549	our $CHLD_W;	1845	our $CHLD_W;
1550	our $CHLD_DELAY_W;	1846	our $CHLD_DELAY_W;
1551	our $WNOHANG;
1552		1847
		1848	# used by many Impl's
1553	sub _emit_childstatus($$) {	1849	sub _emit_childstatus($$) {
1554	my (undef, $rpid, $rstatus) = @_;	1850	my (undef, $rpid, $rstatus) = @_;
1555		1851
1556	$_->($rpid, $rstatus)	1852	$_->($rpid, $rstatus)
1557	for values %{ $PID_CB{$rpid} || {} },	1853	for values %{ $PID_CB{$rpid} || {} },
1558	values %{ $PID_CB{0} || {} };	1854	values %{ $PID_CB{0} || {} };
1559	}	1855	}
1560		1856
1561	sub _sigchld {
1562	my $pid;
1563
1564	AnyEvent->_emit_childstatus ($pid, $?)
1565	while ($pid = waitpid -1, $WNOHANG) > 0;
1566	}
1567
1568	sub child {	1857	sub child {
		1858	eval q{ # poor man's autoloading {}
		1859	*_sigchld = sub {
		1860	my $pid;
		1861
		1862	AnyEvent->_emit_childstatus ($pid, $?)
		1863	while ($pid = waitpid -1, WNOHANG) > 0;
		1864	};
		1865
		1866	*child = sub {
1569	my (undef, %arg) = @_;	1867	my (undef, %arg) = @_;
1570		1868
1571	defined (my $pid = $arg{pid} + 0)	1869	my $pid = $arg{pid};
1572	or Carp::croak "required option 'pid' is missing";	1870	my $cb = $arg{cb};
1573		1871
1574	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1872	$PID_CB{$pid}{$cb+0} = $cb;
1575		1873
1576	# WNOHANG is almost cetrainly 1 everywhere
1577	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1578	? 1
1579	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1580
1581	unless ($CHLD_W) {	1874	unless ($CHLD_W) {
1582	$CHLD_W = AE::signal CHLD => \&_sigchld;	1875	$CHLD_W = AE::signal CHLD => \&_sigchld;
1583	# child could be a zombie already, so make at least one round	1876	# child could be a zombie already, so make at least one round
1584	&_sigchld;	1877	&_sigchld;
1585	}	1878	}
1586		1879
1587	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1880	bless [$pid, $cb+0], "AnyEvent::Base::child"
1588	}	1881	};
1589		1882
1590	sub AnyEvent::Base::child::DESTROY {	1883	*AnyEvent::Base::child::DESTROY = sub {
1591	my ($pid, $cb) = @{$_[0]};	1884	my ($pid, $icb) = @{$_[0]};
1592		1885
1593	delete $PID_CB{$pid}{$cb};	1886	delete $PID_CB{$pid}{$icb};
1594	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1887	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1595		1888
1596	undef $CHLD_W unless keys %PID_CB;	1889	undef $CHLD_W unless keys %PID_CB;
		1890	};
		1891	};
		1892	die if $@;
		1893
		1894	&child
1597	}	1895	}
1598		1896
1599	# idle emulation is done by simply using a timer, regardless	1897	# idle emulation is done by simply using a timer, regardless
1600	# of whether the process is idle or not, and not letting	1898	# of whether the process is idle or not, and not letting
1601	# the callback use more than 50% of the time.	1899	# the callback use more than 50% of the time.
1602	sub idle {	1900	sub idle {
		1901	eval q{ # poor man's autoloading {}
		1902	*idle = sub {
1603	my (undef, %arg) = @_;	1903	my (undef, %arg) = @_;
1604		1904
1605	my ($cb, $w, $rcb) = $arg{cb};	1905	my ($cb, $w, $rcb) = $arg{cb};
1606		1906
1607	$rcb = sub {	1907	$rcb = sub {
1608	if ($cb) {	1908	if ($cb) {
1609	$w = _time;	1909	$w = AE::time;
1610	&$cb;	1910	&$cb;
1611	$w = _time - $w;	1911	$w = AE::time - $w;
1612		1912
1613	# never use more then 50% of the time for the idle watcher,	1913	# never use more then 50% of the time for the idle watcher,
1614	# within some limits	1914	# within some limits
1615	$w = 0.0001 if $w < 0.0001;	1915	$w = 0.0001 if $w < 0.0001;
1616	$w = 5 if $w > 5;	1916	$w = 5 if $w > 5;
1617		1917
1618	$w = AE::timer $w, 0, $rcb;	1918	$w = AE::timer $w, 0, $rcb;
1619	} else {	1919	} else {
1620	# clean up...	1920	# clean up...
1621	undef $w;	1921	undef $w;
1622	undef $rcb;	1922	undef $rcb;
		1923	}
		1924	};
		1925
		1926	$w = AE::timer 0.05, 0, $rcb;
		1927
		1928	bless \\$cb, "AnyEvent::Base::idle"
1623	}	1929	};
		1930
		1931	*AnyEvent::Base::idle::DESTROY = sub {
		1932	undef $${$_[0]};
		1933	};
1624	};	1934	};
		1935	die if $@;
1625		1936
1626	$w = AE::timer 0.05, 0, $rcb;	1937	&idle
1627
1628	bless \\$cb, "AnyEvent::Base::idle"
1629	}
1630
1631	sub AnyEvent::Base::idle::DESTROY {
1632	undef $${$_[0]};
1633	}	1938	}
1634		1939
1635	package AnyEvent::CondVar;	1940	package AnyEvent::CondVar;
1636		1941
1637	our @ISA = AnyEvent::CondVar::Base::;	1942	our @ISA = AnyEvent::CondVar::Base::;
		1943
		1944	# only to be used for subclassing
		1945	sub new {
		1946	my $class = shift;
		1947	bless AnyEvent->condvar (@_), $class
		1948	}
1638		1949
1639	package AnyEvent::CondVar::Base;	1950	package AnyEvent::CondVar::Base;
1640		1951
1641	#use overload	1952	#use overload
1642	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1953	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1652		1963
1653	sub _send {	1964	sub _send {
1654	# nop	1965	# nop
1655	}	1966	}
1656		1967
		1968	sub _wait {
		1969	AnyEvent->_poll until $_[0]{_ae_sent};
		1970	}
		1971
1657	sub send {	1972	sub send {
1658	my $cv = shift;	1973	my $cv = shift;
1659	$cv->{_ae_sent} = [@_];	1974	$cv->{_ae_sent} = [@_];
1660	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1975	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1661	$cv->_send;	1976	$cv->_send;
…		…
1668		1983
1669	sub ready {	1984	sub ready {
1670	$_[0]{_ae_sent}	1985	$_[0]{_ae_sent}
1671	}	1986	}
1672		1987
1673	sub _wait {
1674	$WAITING
1675	and !$_[0]{_ae_sent}
1676	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1677
1678	local $WAITING = 1;
1679	AnyEvent->one_event while !$_[0]{_ae_sent};
1680	}
1681
1682	sub recv {	1988	sub recv {
		1989	unless ($_[0]{_ae_sent}) {
		1990	$WAITING
		1991	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1992
		1993	local $WAITING = 1;
1683	$_[0]->_wait;	1994	$_[0]->_wait;
		1995	}
1684		1996
1685	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1997	$_[0]{_ae_croak}
1686	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1998	and Carp::croak $_[0]{_ae_croak};
		1999
		2000	wantarray
		2001	? @{ $_[0]{_ae_sent} }
		2002	: $_[0]{_ae_sent}[0]
1687	}	2003	}
1688		2004
1689	sub cb {	2005	sub cb {
1690	my $cv = shift;	2006	my $cv = shift;
1691		2007
…		…
1707	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2023	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1708	}	2024	}
1709		2025
1710	# undocumented/compatibility with pre-3.4	2026	# undocumented/compatibility with pre-3.4
1711	*broadcast = \&send;	2027	*broadcast = \&send;
1712	*wait = \&_wait;	2028	*wait = \&recv;
1713		2029
1714	=head1 ERROR AND EXCEPTION HANDLING	2030	=head1 ERROR AND EXCEPTION HANDLING
1715		2031
1716	In general, AnyEvent does not do any error handling - it relies on the	2032	In general, AnyEvent does not do any error handling - it relies on the
1717	caller to do that if required. The L<AnyEvent::Strict> module (see also	2033	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1729	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2045	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1730	so on.	2046	so on.
1731		2047
1732	=head1 ENVIRONMENT VARIABLES	2048	=head1 ENVIRONMENT VARIABLES
1733		2049
1734	The following environment variables are used by this module or its	2050	AnyEvent supports a number of environment variables that tune the
1735	submodules.	2051	runtime behaviour. They are usually evaluated when AnyEvent is
		2052	loaded, initialised, or a submodule that uses them is loaded. Many of
		2053	them also cause AnyEvent to load additional modules - for example,
		2054	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2055	loaded.
1736		2056
1737	Note that AnyEvent will remove I<all> environment variables starting with	2057	All the environment variables documented here start with
1738	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2058	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1739	enabled.	2059	namespace. Other modules are encouraged (but by no means required) to use
		2060	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2061	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2062	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2063	variables starting with C<AE_>, see below).
		2064
		2065	All variables can also be set via the C<AE_> prefix, that is, instead
		2066	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2067	case there is a clash btween anyevent and another program that uses
		2068	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2069	variable to the empty string, as those variables take precedence.
		2070
		2071	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2072	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2073	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2074	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2075	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2076	is set).
		2077
		2078	The exact algorithm is currently:
		2079
		2080	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2081	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2082	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2083
		2084	This ensures that child processes will not see the C<AE_> variables.
		2085
		2086	The following environment variables are currently known to AnyEvent:
1740		2087
1741	=over 4	2088	=over 4
1742		2089
1743	=item C<PERL_ANYEVENT_VERBOSE>	2090	=item C<PERL_ANYEVENT_VERBOSE>
1744		2091
1745	By default, AnyEvent will be completely silent except in fatal	2092	By default, AnyEvent will log messages with loglevel C<4> (C<error>) or
1746	conditions. You can set this environment variable to make AnyEvent more	2093	higher (see L<AnyEvent::Log>). You can set this environment variable to a
1747	talkative.	2094	numerical loglevel to make AnyEvent more (or less) talkative.
1748		2095
		2096	If you want to do more than just set the global logging level
		2097	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2098	complex specifications.
		2099
		2100	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2101	everything else at defaults.
		2102
1749	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2103	When set to C<5> or higher (C<warn>), AnyEvent warns about unexpected
1750	conditions, such as not being able to load the event model specified by	2104	conditions, such as not being able to load the event model specified by
1751	C<PERL_ANYEVENT_MODEL>.	2105	C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an exception - this
		2106	is the minimum recommended level for use during development.
1752		2107
1753	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2108	When set to C<7> or higher (info), AnyEvent reports which event model it
1754	model it chooses.	2109	chooses.
1755		2110
1756	When set to C<8> or higher, then AnyEvent will report extra information on	2111	When set to C<8> or higher (debug), then AnyEvent will report extra
1757	which optional modules it loads and how it implements certain features.	2112	information on which optional modules it loads and how it implements
		2113	certain features.
		2114
		2115	=item C<PERL_ANYEVENT_LOG>
		2116
		2117	Accepts rather complex logging specifications. For example, you could log
		2118	all C<debug> messages of some module to stderr, warnings and above to
		2119	stderr, and errors and above to syslog, with:
		2120
		2121	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2122
		2123	For the rather extensive details, see L<AnyEvent::Log>.
		2124
		2125	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2126	so will take effect even before AnyEvent has initialised itself.
		2127
		2128	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2129	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2130	using the latter saves a few hundred kB of memory unless a module
		2131	explicitly needs the extra features of AnyEvent::Log.
1758		2132
1759	=item C<PERL_ANYEVENT_STRICT>	2133	=item C<PERL_ANYEVENT_STRICT>
1760		2134
1761	AnyEvent does not do much argument checking by default, as thorough	2135	AnyEvent does not do much argument checking by default, as thorough
1762	argument checking is very costly. Setting this variable to a true value	2136	argument checking is very costly. Setting this variable to a true value
…		…
1764	check the arguments passed to most method calls. If it finds any problems,	2138	check the arguments passed to most method calls. If it finds any problems,
1765	it will croak.	2139	it will croak.
1766		2140
1767	In other words, enables "strict" mode.	2141	In other words, enables "strict" mode.
1768		2142
1769	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2143	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1770	>>, it is definitely recommended to keep it off in production. Keeping	2144	>>, it is definitely recommended to keep it off in production. Keeping
1771	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2145	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1772	can be very useful, however.	2146	can be very useful, however.
1773		2147
		2148	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2149
		2150	If this env variable is nonempty, then its contents will be interpreted by
		2151	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2152	replacing every occurance of C<$$> by the process pid). The shell object
		2153	is saved in C<$AnyEvent::Debug::SHELL>.
		2154
		2155	This happens when the first watcher is created.
		2156
		2157	For example, to bind a debug shell on a unix domain socket in
		2158	F<< /tmp/debug<pid>.sock >>, you could use this:
		2159
		2160	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2161	# connect with e.g.: socat readline /tmp/debug123.sock
		2162
		2163	Or to bind to tcp port 4545 on localhost:
		2164
		2165	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2166	# connect with e.g.: telnet localhost 4545
		2167
		2168	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2169	multiuser systems.
		2170
		2171	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2172
		2173	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2174	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2175
1774	=item C<PERL_ANYEVENT_MODEL>	2176	=item C<PERL_ANYEVENT_MODEL>
1775		2177
1776	This can be used to specify the event model to be used by AnyEvent, before	2178	This can be used to specify the event model to be used by AnyEvent, before
1777	auto detection and -probing kicks in. It must be a string consisting	2179	auto detection and -probing kicks in.
1778	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2180
		2181	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2182	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1779	and the resulting module name is loaded and if the load was successful,	2183	resulting module name is loaded and - if the load was successful - used as
1780	used as event model. If it fails to load AnyEvent will proceed with	2184	event model backend. If it fails to load then AnyEvent will proceed with
1781	auto detection and -probing.	2185	auto detection and -probing.
1782		2186
1783	This functionality might change in future versions.	2187	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2188	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2189	the end of a string designates a module name and quotes it appropriately).
1784		2190
1785	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2191	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1786	could start your program like this:	2192	could start your program like this:
1787		2193
1788	PERL_ANYEVENT_MODEL=Perl perl ...	2194	PERL_ANYEVENT_MODEL=Perl perl ...
		2195
		2196	=item C<PERL_ANYEVENT_IO_MODEL>
		2197
		2198	The current file I/O model - see L<AnyEvent::IO> for more info.
		2199
		2200	At the moment, only C<Perl> (small, pure-perl, synchronous) and
		2201	C<IOAIO> (truly asynchronous) are supported. The default is C<IOAIO> if
		2202	L<AnyEvent::AIO> can be loaded, otherwise it is C<Perl>.
1789		2203
1790	=item C<PERL_ANYEVENT_PROTOCOLS>	2204	=item C<PERL_ANYEVENT_PROTOCOLS>
1791		2205
1792	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences	2206	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1793	for IPv4 or IPv6. The default is unspecified (and might change, or be the result	2207	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
…		…
1798	used, and preference will be given to protocols mentioned earlier in the	2212	used, and preference will be given to protocols mentioned earlier in the
1799	list.	2213	list.
1800		2214
1801	This variable can effectively be used for denial-of-service attacks	2215	This variable can effectively be used for denial-of-service attacks
1802	against local programs (e.g. when setuid), although the impact is likely	2216	against local programs (e.g. when setuid), although the impact is likely
1803	small, as the program has to handle conenction and other failures anyways.	2217	small, as the program has to handle connection and other failures anyways.
1804		2218
1805	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,	2219	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1806	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2220	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1807	- only support IPv4, never try to resolve or contact IPv6	2221	- only support IPv4, never try to resolve or contact IPv6
1808	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2222	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1809	IPv6, but prefer IPv6 over IPv4.	2223	IPv6, but prefer IPv6 over IPv4.
1810		2224
		2225	=item C<PERL_ANYEVENT_HOSTS>
		2226
		2227	This variable, if specified, overrides the F</etc/hosts> file used by
		2228	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2229	from that file instead.
		2230
1811	=item C<PERL_ANYEVENT_EDNS0>	2231	=item C<PERL_ANYEVENT_EDNS0>
1812		2232
1813	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2233	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1814	for DNS. This extension is generally useful to reduce DNS traffic, but	2234	DNS. This extension is generally useful to reduce DNS traffic, especially
1815	some (broken) firewalls drop such DNS packets, which is why it is off by	2235	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1816	default.	2236	packets, which is why it is off by default.
1817		2237
1818	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2238	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1819	EDNS0 in its DNS requests.	2239	EDNS0 in its DNS requests.
1820		2240
1821	=item C<PERL_ANYEVENT_MAX_FORKS>	2241	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1827		2247
1828	The default value for the C<max_outstanding> parameter for the default DNS	2248	The default value for the C<max_outstanding> parameter for the default DNS
1829	resolver - this is the maximum number of parallel DNS requests that are	2249	resolver - this is the maximum number of parallel DNS requests that are
1830	sent to the DNS server.	2250	sent to the DNS server.
1831		2251
		2252	=item C<PERL_ANYEVENT_MAX_SIGNAL_LATENCY>
		2253
		2254	Perl has inherently racy signal handling (you can basically choose between
		2255	losing signals and memory corruption) - pure perl event loops (including
		2256	C<AnyEvent::Loop>, when C<Async::Interrupt> isn't available) therefore
		2257	have to poll regularly to avoid losing signals.
		2258
		2259	Some event loops are racy, but don't poll regularly, and some event loops
		2260	are written in C but are still racy. For those event loops, AnyEvent
		2261	installs a timer that regularly wakes up the event loop.
		2262
		2263	By default, the interval for this timer is C<10> seconds, but you can
		2264	override this delay with this environment variable (or by setting
		2265	the C<$AnyEvent::MAX_SIGNAL_LATENCY> variable before creating signal
		2266	watchers).
		2267
		2268	Lower values increase CPU (and energy) usage, higher values can introduce
		2269	long delays when reaping children or waiting for signals.
		2270
		2271	The L<AnyEvent::Async> module, if available, will be used to avoid this
		2272	polling (with most event loops).
		2273
1832	=item C<PERL_ANYEVENT_RESOLV_CONF>	2274	=item C<PERL_ANYEVENT_RESOLV_CONF>
1833		2275
1834	The file to use instead of F</etc/resolv.conf> (or OS-specific	2276	The absolute path to a F<resolv.conf>-style file to use instead of
1835	configuration) in the default resolver. When set to the empty string, no	2277	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1836	default config will be used.	2278	resolver, or the empty string to select the default configuration.
1837		2279
1838	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2280	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1839		2281
1840	When neither C<ca_file> nor C<ca_path> was specified during	2282	When neither C<ca_file> nor C<ca_path> was specified during
1841	L<AnyEvent::TLS> context creation, and either of these environment	2283	L<AnyEvent::TLS> context creation, and either of these environment
1842	variables exist, they will be used to specify CA certificate locations	2284	variables are nonempty, they will be used to specify CA certificate
1843	instead of a system-dependent default.	2285	locations instead of a system-dependent default.
1844		2286
1845	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2287	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1846		2288
1847	When these are set to C<1>, then the respective modules are not	2289	When these are set to C<1>, then the respective modules are not
1848	loaded. Mostly good for testing AnyEvent itself.	2290	loaded. Mostly good for testing AnyEvent itself.
…		…
1911	warn "read: $input\n"; # output what has been read	2353	warn "read: $input\n"; # output what has been read
1912	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2354	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1913	},	2355	},
1914	);	2356	);
1915		2357
1916	my $time_watcher; # can only be used once
1917
1918	sub new_timer {
1919	$timer = AnyEvent->timer (after => 1, cb => sub {	2358	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1920	warn "timeout\n"; # print 'timeout' about every second	2359	warn "timeout\n"; # print 'timeout' at most every second
1921	&new_timer; # and restart the time
1922	});	2360	});
1923	}
1924
1925	new_timer; # create first timer
1926		2361
1927	$cv->recv; # wait until user enters /^q/i	2362	$cv->recv; # wait until user enters /^q/i
1928		2363
1929	=head1 REAL-WORLD EXAMPLE	2364	=head1 REAL-WORLD EXAMPLE
1930		2365
…		…
2003		2438
2004	The actual code goes further and collects all errors (C<die>s, exceptions)	2439	The actual code goes further and collects all errors (C<die>s, exceptions)
2005	that occurred during request processing. The C<result> method detects	2440	that occurred during request processing. The C<result> method detects
2006	whether an exception as thrown (it is stored inside the $txn object)	2441	whether an exception as thrown (it is stored inside the $txn object)
2007	and just throws the exception, which means connection errors and other	2442	and just throws the exception, which means connection errors and other
2008	problems get reported tot he code that tries to use the result, not in a	2443	problems get reported to the code that tries to use the result, not in a
2009	random callback.	2444	random callback.
2010		2445
2011	All of this enables the following usage styles:	2446	All of this enables the following usage styles:
2012		2447
2013	1. Blocking:	2448	1. Blocking:
…		…
2187	(even when used without AnyEvent), but most event loops have acceptable	2622	(even when used without AnyEvent), but most event loops have acceptable
2188	performance with or without AnyEvent.	2623	performance with or without AnyEvent.
2189		2624
2190	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2625	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2191	the actual event loop, only with extremely fast event loops such as EV	2626	the actual event loop, only with extremely fast event loops such as EV
2192	adds AnyEvent significant overhead.	2627	does AnyEvent add significant overhead.
2193		2628
2194	=item * You should avoid POE like the plague if you want performance or	2629	=item * You should avoid POE like the plague if you want performance or
2195	reasonable memory usage.	2630	reasonable memory usage.
2196		2631
2197	=back	2632	=back
…		…
2374	As you can see, the AnyEvent + EV combination even beats the	2809	As you can see, the AnyEvent + EV combination even beats the
2375	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2810	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2376	backend easily beats IO::Lambda and POE.	2811	backend easily beats IO::Lambda and POE.
2377		2812
2378	And even the 100% non-blocking version written using the high-level (and	2813	And even the 100% non-blocking version written using the high-level (and
2379	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2814	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2380	large margin, even though it does all of DNS, tcp-connect and socket I/O	2815	higher level ("unoptimised") abstractions by a large margin, even though
2381	in a non-blocking way.	2816	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2382		2817
2383	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2818	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2384	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2819	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2385	part of the IO::lambda distribution and were used without any changes.	2820	part of the IO::Lambda distribution and were used without any changes.
2386		2821
2387		2822
2388	=head1 SIGNALS	2823	=head1 SIGNALS
2389		2824
2390	AnyEvent currently installs handlers for these signals:	2825	AnyEvent currently installs handlers for these signals:
…		…
2427	unless defined $SIG{PIPE};	2862	unless defined $SIG{PIPE};
2428		2863
2429	=head1 RECOMMENDED/OPTIONAL MODULES	2864	=head1 RECOMMENDED/OPTIONAL MODULES
2430		2865
2431	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2866	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2432	it's built-in modules) are required to use it.	2867	its built-in modules) are required to use it.
2433		2868
2434	That does not mean that AnyEvent won't take advantage of some additional	2869	That does not mean that AnyEvent won't take advantage of some additional
2435	modules if they are installed.	2870	modules if they are installed.
2436		2871
2437	This section epxlains which additional modules will be used, and how they	2872	This section explains which additional modules will be used, and how they
2438	affect AnyEvent's operetion.	2873	affect AnyEvent's operation.
2439		2874
2440	=over 4	2875	=over 4
2441		2876
2442	=item L<Async::Interrupt>	2877	=item L<Async::Interrupt>
2443		2878
…		…
2448	catch the signals) with some delay (default is 10 seconds, look for	2883	catch the signals) with some delay (default is 10 seconds, look for
2449	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2884	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2450		2885
2451	If this module is available, then it will be used to implement signal	2886	If this module is available, then it will be used to implement signal
2452	catching, which means that signals will not be delayed, and the event loop	2887	catching, which means that signals will not be delayed, and the event loop
2453	will not be interrupted regularly, which is more efficient (And good for	2888	will not be interrupted regularly, which is more efficient (and good for
2454	battery life on laptops).	2889	battery life on laptops).
2455		2890
2456	This affects not just the pure-perl event loop, but also other event loops	2891	This affects not just the pure-perl event loop, but also other event loops
2457	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2892	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2458		2893
…		…
2470	automatic timer adjustments even when no monotonic clock is available,	2905	automatic timer adjustments even when no monotonic clock is available,
2471	can take avdantage of advanced kernel interfaces such as C<epoll> and	2906	can take avdantage of advanced kernel interfaces such as C<epoll> and
2472	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2907	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2473	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2908	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2474		2909
		2910	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2911	then this module will do nothing for you.
		2912
2475	=item L<Guard>	2913	=item L<Guard>
2476		2914
2477	The guard module, when used, will be used to implement	2915	The guard module, when used, will be used to implement
2478	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2916	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2479	lot less memory), but otherwise doesn't affect guard operation much. It is	2917	lot less memory), but otherwise doesn't affect guard operation much. It is
2480	purely used for performance.	2918	purely used for performance.
2481		2919
2482	=item L<JSON> and L<JSON::XS>	2920	=item L<JSON> and L<JSON::XS>
2483		2921
2484	This module is required when you want to read or write JSON data via	2922	One of these modules is required when you want to read or write JSON data
2485	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2923	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2486	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2924	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2487
2488	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2489	installed.
2490		2925
2491	=item L<Net::SSLeay>	2926	=item L<Net::SSLeay>
2492		2927
2493	Implementing TLS/SSL in Perl is certainly interesting, but not very	2928	Implementing TLS/SSL in Perl is certainly interesting, but not very
2494	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2929	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2495	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2930	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2496		2931
2497	=item L<Time::HiRes>	2932	=item L<Time::HiRes>
2498		2933
2499	This module is part of perl since release 5.008. It will be used when the	2934	This module is part of perl since release 5.008. It will be used when the
2500	chosen event library does not come with a timing source on it's own. The	2935	chosen event library does not come with a timing source of its own. The
2501	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2936	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2502	try to use a monotonic clock for timing stability.	2937	try to use a monotonic clock for timing stability.
2503		2938
		2939	=item L<AnyEvent::AIO> (and L<IO::AIO>)
		2940
		2941	The default implementation of L<AnyEvent::IO> is to do I/O synchronously,
		2942	stopping programs while they access the disk, which is fine for a lot of
		2943	programs.
		2944
		2945	Installing AnyEvent::AIO (and its IO::AIO dependency) makes it switch to
		2946	a true asynchronous implementation, so event processing can continue even
		2947	while waiting for disk I/O.
		2948
2504	=back	2949	=back
2505		2950
2506		2951
2507	=head1 FORK	2952	=head1 FORK
2508		2953
2509	Most event libraries are not fork-safe. The ones who are usually are	2954	Most event libraries are not fork-safe. The ones who are usually are
2510	because they rely on inefficient but fork-safe C<select> or C<poll>	2955	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2511	calls. Only L<EV> is fully fork-aware.	2956	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2957	are usually badly thought-out hacks that are incompatible with fork in
		2958	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2959	continue event-processing in both parent and child (or both, if you know
		2960	what you are doing).
		2961
		2962	This means that, in general, you cannot fork and do event processing in
		2963	the child if the event library was initialised before the fork (which
		2964	usually happens when the first AnyEvent watcher is created, or the library
		2965	is loaded).
2512		2966
2513	If you have to fork, you must either do so I<before> creating your first	2967	If you have to fork, you must either do so I<before> creating your first
2514	watcher OR you must not use AnyEvent at all in the child OR you must do	2968	watcher OR you must not use AnyEvent at all in the child OR you must do
2515	something completely out of the scope of AnyEvent.	2969	something completely out of the scope of AnyEvent (see below).
		2970
		2971	The problem of doing event processing in the parent I<and> the child
		2972	is much more complicated: even for backends that I<are> fork-aware or
		2973	fork-safe, their behaviour is not usually what you want: fork clones all
		2974	watchers, that means all timers, I/O watchers etc. are active in both
		2975	parent and child, which is almost never what you want. Using C<exec>
		2976	to start worker children from some kind of manage prrocess is usually
		2977	preferred, because it is much easier and cleaner, at the expense of having
		2978	to have another binary.
		2979
		2980	In addition to logical problems with fork, there are also implementation
		2981	problems. For example, on POSIX systems, you cannot fork at all in Perl
		2982	code if a thread (I am talking of pthreads here) was ever created in the
		2983	process, and this is just the tip of the iceberg. In general, using fork
		2984	from Perl is difficult, and attempting to use fork without an exec to
		2985	implement some kind of parallel processing is almost certainly doomed.
		2986
		2987	To safely fork and exec, you should use a module such as
		2988	L<Proc::FastSpawn> that let's you safely fork and exec new processes.
		2989
		2990	If you want to do multiprocessing using processes, you can
		2991	look at the L<AnyEvent::Fork> module (and some related modules
		2992	such as L<AnyEvent::Fork::RPC>, L<AnyEvent::Fork::Pool> and
		2993	L<AnyEvent::Fork::Remote>). This module allows you to safely create
		2994	subprocesses without any limitations - you can use X11 toolkits or
		2995	AnyEvent in the children created by L<AnyEvent::Fork> safely and without
		2996	any special precautions.
2516		2997
2517		2998
2518	=head1 SECURITY CONSIDERATIONS	2999	=head1 SECURITY CONSIDERATIONS
2519		3000
2520	AnyEvent can be forced to load any event model via	3001	AnyEvent can be forced to load any event model via
…		…
2550	pronounced).	3031	pronounced).
2551		3032
2552		3033
2553	=head1 SEE ALSO	3034	=head1 SEE ALSO
2554		3035
2555	Utility functions: L<AnyEvent::Util>.	3036	Tutorial/Introduction: L<AnyEvent::Intro>.
2556		3037
2557	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	3038	FAQ: L<AnyEvent::FAQ>.
2558	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	3039
		3040	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		3041	(simply logging).
		3042
		3043	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		3044	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		3045
		3046	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		3047	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		3048	L<Qt>, L<POE>, L<FLTK>.
2559		3049
2560	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	3050	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2561	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	3051	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2562	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	3052	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2563	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	3053	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		3054	L<AnyEvent::Impl::FLTK>.
2564		3055
2565	Non-blocking file handles, sockets, TCP clients and	3056	Non-blocking handles, pipes, stream sockets, TCP clients and
2566	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	3057	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2567		3058
		3059	Asynchronous File I/O: L<AnyEvent::IO>.
		3060
2568	Asynchronous DNS: L<AnyEvent::DNS>.	3061	Asynchronous DNS: L<AnyEvent::DNS>.
2569		3062
2570	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	3063	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2571	L<Coro::Event>,
2572		3064
2573	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	3065	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2574	L<AnyEvent::HTTP>.	3066	L<AnyEvent::HTTP>.
2575		3067
2576		3068
2577	=head1 AUTHOR	3069	=head1 AUTHOR
2578		3070
2579	Marc Lehmann <schmorp@schmorp.de>	3071	Marc Lehmann <schmorp@schmorp.de>
2580	http://home.schmorp.de/	3072	http://anyevent.schmorp.de
2581		3073
2582	=cut	3074	=cut
2583		3075
2584	1	3076	1
2585		3077

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