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Revision 1.297 by root, Thu Nov 19 01:55:57 2009 UTC vs.
Revision 1.358 by root, Sat Aug 13 02:35:32 2011 UTC

…		…
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 {
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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
…		…
403		407
404	Example: exit on SIGINT	408	Example: exit on SIGINT
405		409
406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
407		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
408	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
409		430
410	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
411	callbacks to signals in a generic way, which is a pity, as you cannot	432	callbacks to signals in a generic way, which is a pity, as you cannot
412	do race-free signal handling in perl, requiring C libraries for	433	do race-free signal handling in perl, requiring C libraries for
413	this. AnyEvent will try to do it's best, which means in some cases,	434	this. AnyEvent will try to do its best, which means in some cases,
414	signals will be delayed. The maximum time a signal might be delayed is	435	signals will be delayed. The maximum time a signal might be delayed is
415	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
416	variable can be changed only before the first signal watcher is created,	437	variable can be changed only before the first signal watcher is created,
417	and should be left alone otherwise. This variable determines how often	438	and should be left alone otherwise. This variable determines how often
418	AnyEvent polls for signals (in case a wake-up was missed). Higher values	439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
420	saving.	441	saving.
421		442
422	All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
423	L<Async::Interrupt> module, which works with most event loops. It will not	444	L<Async::Interrupt> module, which works with most event loops. It will not
424	work with inherently broken event loops such as L<Event> or L<Event::Lib>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
425	(and not with L<POE> currently, as POE does it's own workaround with	446	(and not with L<POE> currently, as POE does its own workaround with
426	one-second latency). For those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
427		448
428	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
429		450
430	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
431		452
432	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
433		454
434	The child process is specified by the C<pid> argument (one some backends,	455	The child process is specified by the C<pid> argument (on some backends,
435	using C<0> watches for any child process exit, on others this will	456	using C<0> watches for any child process exit, on others this will
436	croak). The watcher will be triggered only when the child process has	457	croak). The watcher will be triggered only when the child process has
437	finished and an exit status is available, not on any trace events	458	finished and an exit status is available, not on any trace events
438	(stopped/continued).	459	(stopped/continued).
439		460
…		…
461	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
462	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
463	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
464		485
465	As most event loops do not support waiting for child events, they will be	486	As most event loops do not support waiting for child events, they will be
466	emulated by AnyEvent in most cases, in which the latency and race problems	487	emulated by AnyEvent in most cases, in which case the latency and race
467	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
468		489
469	Example: fork a process and wait for it	490	Example: fork a process and wait for it
470		491
471	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
472		493
…		…
486		507
487	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
488		509
489	$w = AnyEvent->idle (cb => <callback>);	510	$w = AnyEvent->idle (cb => <callback>);
490		511
491	Sometimes there is a need to do something, but it is not so important	512	This will repeatedly invoke the callback after the process becomes idle,
492	to do it instantly, but only when there is nothing better to do. This	513	until either the watcher is destroyed or new events have been detected.
493	"nothing better to do" is usually defined to be "no other events need
494	attention by the event loop".
495		514
496	Idle watchers ideally get invoked when the event loop has nothing	515	Idle watchers are useful when there is a need to do something, but it
497	better to do, just before it would block the process to wait for new	516	is not so important (or wise) to do it instantly. The callback will be
498	events. Instead of blocking, the idle watcher is invoked.	517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
499		523
500	Most event loops unfortunately do not really support idle watchers (only	524	Unfortunately, most event loops do not really support idle watchers (only
501	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
502	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
503		527
504	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
505	program is otherwise idle:	529	program is otherwise idle:
…		…
533	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
534		558
535	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
536	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
537		561
538	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
539	because they represent a condition that must become true.	563	they represent a condition that must become true.
540		564
541	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
542		566
543	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
544	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
549	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
550	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
551	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
552	->send >> method).	576	->send >> method).
553		577
554	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
555	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
556	in time where multiple outstanding events have been processed. And yet	580
557	another way to call them is transactions - each condition variable can be	581	=over 4
558	used to represent a transaction, which finishes at some point and delivers	582
559	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
560	compute/deliver something that you can wait for.	584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
561		601
562	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
563	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
564	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
565	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
578		618
579	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
580	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
581	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
582	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
583	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
584		624
585	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
586	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
587	for the send to occur.	627	for the send to occur.
588		628
589	Example: wait for a timer.	629	Example: wait for a timer.
590		630
591	# wait till the result is ready	631	# condition: "wait till the timer is fired"
592	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
593		633
594	# do something such as adding a timer	634	# create the timer - we could wait for, say
595	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
596	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
597	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
598	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
599	after => 1,	639	after => 1,
600	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
601	);	641	);
602		642
603	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
604	# calls ->send	644	# calls ->send
605	$result_ready->recv;	645	$timer_fired->recv;
606		646
607	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
608	variables are also callable directly.	648	variables are also callable directly.
609		649
610	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
653	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
654	C<send>.	694	C<send>.
655		695
656	=item $cv->croak ($error)	696	=item $cv->croak ($error)
657		697
658	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
659	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
660		700
661	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
662	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
663	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
664	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
665	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
666	the problem.	706	the problem.
667		707
668	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
669		709
670	=item $cv->end	710	=item $cv->end
…		…
708	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
709	sending.	749	sending.
710		750
711	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
712	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
713	begung can potentially be zero:	753	begun can potentially be zero:
714		754
715	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
716		756
717	my %result;	757	my %result;
718	$cv->begin (sub { shift->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
…		…
739	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
740	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
741	doesn't execute once).	781	doesn't execute once).
742		782
743	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
744	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
745	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
746	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
747	call C<end>.	787	call C<end>.
748		788
749	=back	789	=back
…		…
756	=over 4	796	=over 4
757		797
758	=item $cv->recv	798	=item $cv->recv
759		799
760	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
761	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
762	normally.	802	normally.
763		803
764	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
765	will return immediately.	805	will return immediately.
766		806
…		…
783	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
784	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
785	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
786	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
787		827
788	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
789	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
790	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
791	waits otherwise.	831	waits otherwise.
792		832
793	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
798	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
799		839
800	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
801	replaces it before doing so.	841	replaces it before doing so.
802		842
803	The callback will be called when the condition becomes (or already was)	843	The callback will be called when the condition becomes "true", i.e. when
804	"true", i.e. when C<send> or C<croak> are called (or were called), with	844	C<send> or C<croak> are called, with the only argument being the
805	the only argument being the condition variable itself. Calling C<recv>	845	condition variable itself. If the condition is already true, the
		846	callback is called immediately when it is set. Calling C<recv> inside
806	inside the callback or at any later time is guaranteed not to block.	847	the callback or at any later time is guaranteed not to block.
807		848
808	=back	849	=back
809		850
810	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
811		852
…		…
819	use. If EV is not installed, then AnyEvent will fall back to its own	860	use. If EV is not installed, then AnyEvent will fall back to its own
820	pure-perl implementation, which is available everywhere as it comes with	861	pure-perl implementation, which is available everywhere as it comes with
821	AnyEvent itself.	862	AnyEvent itself.
822		863
823	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
824	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
825		866
826	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
827		868
828	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
829	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
830	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
831	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
832	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
833		874
…		…
835	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
836	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
837	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
838	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
839	AnyEvent::Impl::Irssi used when running within irssi.	880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
840		884
841	=item Backends with special needs.	885	=item Backends with special needs.
842		886
843	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
844	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
845	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
846	everything should just work.	890	everything should just work.
847		891
848	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
849		893
850	Support for IO::Async can only be partial, as it is too broken and
851	architecturally limited to even support the AnyEvent API. It also
852	is the only event loop that needs the loop to be set explicitly, so
853	it can only be used by a main program knowing about AnyEvent. See
854	L<AnyEvent::Impl::Async> for the gory details.
855
856	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
857
858	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
859		895
860	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
861		897
862	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
887	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
888	backend has been autodetected.	924	backend has been autodetected.
889		925
890	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
891	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
892	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
893	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
894	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
895		931
896	=item AnyEvent::detect	932	=item AnyEvent::detect
897		933
898	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
899	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
900	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
901	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
902		938
903	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
904	created, use C<post_detect>.	940	created, use C<post_detect>.
905		941
906	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
907		943
908	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
909	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
910		946
911	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
914	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
923	that automatically removes the callback again when it is destroyed (or	959	that automatically removes the callback again when it is destroyed (or
924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
925	a case where this is useful.	961	a case where this is useful.
926		962
927	Example: Create a watcher for the IO::AIO module and store it in	963	Example: Create a watcher for the IO::AIO module and store it in
928	C<$WATCHER>. Only do so after the event loop is initialised, though.	964	C<$WATCHER>, but do so only do so after the event loop is initialised.
929		965
930	our WATCHER;	966	our WATCHER;
931		967
932	my $guard = AnyEvent::post_detect {	968	my $guard = AnyEvent::post_detect {
933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
941	$WATCHER ||= $guard;	977	$WATCHER ||= $guard;
942		978
943	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
944		980
945	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
946	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
947	the event loop has been chosen.	983	after the event loop has been chosen.
948		984
949	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
950	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
951	array will be ignored.	987	array will be ignored.
952		988
953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
954	it,as it takes care of these details.	990	it, as it takes care of these details.
955		991
956	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
957	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
958	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
959	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
960		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
		1049
961	=back	1050	=back
962		1051
963	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
964		1053
965	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1054	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
975	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
976	events is to stay interactive.	1065	events is to stay interactive.
977		1066
978	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
979	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
980	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
981	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
982		1071
983	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
984		1073
985	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
986	dictate which event model to use.	1075	dictate which event model to use.
987		1076
988	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
989	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
990	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
991		1082
992	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
993	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
994	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
995	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
996	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
997	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
998	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
999		1090
1000	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
1001	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
1002	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
1003		1094
1004	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
1005		1096
1006	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
1021	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
1022		1113
1023	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
1024	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
1025	modules and other event loops in the same program. Some of the modules	1116	modules and other event loops in the same program. Some of the modules
1026	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
1027		1118
1028	=over 4	1119	=over 4
1029		1120
1030	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
1031		1122
1032	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
1033	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
1034		1125
1035	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
1036		1127
1037	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
1038	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1040		1131
1041	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
1042		1133
1043	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
1044	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1046		1137
1047	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
1048		1139
1049	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
1050		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
1051	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
1052		1166
1053	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
1054	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
1055		1176
1056	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
1057		1178
1058	Provides a simple web application server framework.	1179	A simple embedded webserver.
1059		1180
1060	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
1061		1182
1062	The fastest ping in the west.	1183	The fastest ping in the west.
1063
1064	=item L<AnyEvent::DBI>
1065
1066	Executes L<DBI> requests asynchronously in a proxy process.
1067
1068	=item L<AnyEvent::AIO>
1069
1070	Truly asynchronous I/O, should be in the toolbox of every event
1071	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1072	together.
1073
1074	=item L<AnyEvent::BDB>
1075
1076	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1077	L<BDB> and AnyEvent together.
1078
1079	=item L<AnyEvent::GPSD>
1080
1081	A non-blocking interface to gpsd, a daemon delivering GPS information.
1082
1083	=item L<AnyEvent::IRC>
1084
1085	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1086
1087	=item L<AnyEvent::XMPP>
1088
1089	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1090	Net::XMPP2>.
1091
1092	=item L<AnyEvent::IGS>
1093
1094	A non-blocking interface to the Internet Go Server protocol (used by
1095	L<App::IGS>).
1096
1097	=item L<Net::FCP>
1098
1099	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1100	of AnyEvent.
1101
1102	=item L<Event::ExecFlow>
1103
1104	High level API for event-based execution flow control.
1105		1184
1106	=item L<Coro>	1185	=item L<Coro>
1107		1186
1108	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1109		1188
…		…
1113		1192
1114	package AnyEvent;	1193	package AnyEvent;
1115		1194
1116	# basically a tuned-down version of common::sense	1195	# basically a tuned-down version of common::sense
1117	sub common_sense {	1196	sub common_sense {
1118	# from common:.sense 1.0	1197	# from common:.sense 3.4
1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";	1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1120	# use strict vars subs	1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1121	$^H |= 0x00000600;	1200	$^H |= 0x00000600;
1122	}	1201	}
1123		1202
1124	BEGIN { AnyEvent::common_sense }	1203	BEGIN { AnyEvent::common_sense }
1125		1204
1126	use Carp ();	1205	use Carp ();
1127		1206
1128	our $VERSION = '5.21';	1207	our $VERSION = '5.34';
1129	our $MODEL;	1208	our $MODEL;
1130		1209
1131	our $AUTOLOAD;
1132	our @ISA;	1210	our @ISA;
1133		1211
1134	our @REGISTRY;	1212	our @REGISTRY;
1135		1213
1136	our $VERBOSE;	1214	our $VERBOSE;
1137		1215
1138	BEGIN {	1216	BEGIN {
1139	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1217	require "AnyEvent/constants.pl";
		1218
1140	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1219	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1141		1220
1142	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1221	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1143	if ${^TAINT};	1222	if ${^TAINT};
1144		1223
1145	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1224	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1155	$PROTOCOL{$_} = ++$idx	1234	$PROTOCOL{$_} = ++$idx
1156	for reverse split /\s*,\s*/,	1235	for reverse split /\s*,\s*/,
1157	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1236	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1158	}	1237	}
1159		1238
		1239	our @post_detect;
		1240
		1241	sub post_detect(&) {
		1242	my ($cb) = @_;
		1243
		1244	push @post_detect, $cb;
		1245
		1246	defined wantarray
		1247	? bless \$cb, "AnyEvent::Util::postdetect"
		1248	: ()
		1249	}
		1250
		1251	sub AnyEvent::Util::postdetect::DESTROY {
		1252	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1253	}
		1254
		1255	our $POSTPONE_W;
		1256	our @POSTPONE;
		1257
		1258	sub _postpone_exec {
		1259	undef $POSTPONE_W;
		1260
		1261	&{ shift @POSTPONE }
		1262	while @POSTPONE;
		1263	}
		1264
		1265	sub postpone(&) {
		1266	push @POSTPONE, shift;
		1267
		1268	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1269
		1270	()
		1271	}
		1272
1160	my @models = (	1273	our @models = (
1161	[EV:: => AnyEvent::Impl::EV:: , 1],	1274	[EV:: => AnyEvent::Impl::EV:: , 1],
1162	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1275	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1163	# everything below here will not (normally) be autoprobed	1276	# everything below here will not (normally) be autoprobed
1164	# as the pureperl backend should work everywhere	1277	# as the pure perl backend should work everywhere
1165	# and is usually faster	1278	# and is usually faster
1166	[Event:: => AnyEvent::Impl::Event::, 1],	1279	[Event:: => AnyEvent::Impl::Event::, 1],
1167	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1280	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1168	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1281	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1169	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1282	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1170	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1283	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1171	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1284	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1172	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1285	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1173	[Wx:: => AnyEvent::Impl::POE::],	1286	[Wx:: => AnyEvent::Impl::POE::],
1174	[Prima:: => AnyEvent::Impl::POE::],	1287	[Prima:: => AnyEvent::Impl::POE::],
1175	# IO::Async is just too broken - we would need workarounds for its	1288	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1176	# byzantine signal and broken child handling, among others.	1289	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1177	# IO::Async is rather hard to detect, as it doesn't have any	1290	[FLTK:: => AnyEvent::Impl::FLTK2::],
1178	# obvious default class.
1179	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1180	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1181	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1182	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1183	);	1291	);
1184		1292
1185	our %method = map +($_ => 1),	1293	# all autoloaded methods reserve the complete glob, not just the method slot.
		1294	# due to bugs in perls method cache implementation.
1186	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1295	our @methods = qw(io timer time now now_update signal child idle condvar);
1187		1296
1188	our @post_detect;
1189
1190	sub post_detect(&) {	1297	sub detect() {
1191	my ($cb) = @_;	1298	local $!; # for good measure
		1299	local $SIG{__DIE__}; # we use eval
1192		1300
1193	if ($MODEL) {	1301	# free some memory
1194	$cb->();	1302	*detect = sub () { $MODEL };
		1303	# undef &func doesn't correctly update the method cache. grmbl.
		1304	# so we delete the whole glob. grmbl.
		1305	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1306	# a glob with an active sub. hrm. i hope it works, but perl is
		1307	# usually buggy in this department. sigh.
		1308	delete @{"AnyEvent::"}{@methods};
		1309	undef @methods;
1195		1310
1196	undef	1311	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1312	my $model = $1;
		1313	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1314	if (eval "require $model") {
		1315	$MODEL = $model;
		1316	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1197	} else {	1317	} else {
1198	push @post_detect, $cb;	1318	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1199		1319	}
1200	defined wantarray
1201	? bless \$cb, "AnyEvent::Util::postdetect"
1202	: ()
1203	}	1320	}
1204	}
1205		1321
1206	sub AnyEvent::Util::postdetect::DESTROY {	1322	# check for already loaded models
1207	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1208	}
1209
1210	sub detect() {
1211	unless ($MODEL) {	1323	unless ($MODEL) {
1212	local $SIG{__DIE__};	1324	for (@REGISTRY, @models) {
1213		1325	my ($package, $model) = @$_;
1214	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1326	if (${"$package\::VERSION"} > 0) {
1215	my $model = "AnyEvent::Impl::$1";
1216	if (eval "require $model") {	1327	if (eval "require $model") {
1217	$MODEL = $model;	1328	$MODEL = $model;
1218	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1329	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1219	} else {	1330	last;
1220	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1331	}
1221	}	1332	}
1222	}	1333	}
1223		1334
1224	# check for already loaded models
1225	unless ($MODEL) {	1335	unless ($MODEL) {
		1336	# try to autoload a model
1226	for (@REGISTRY, @models) {	1337	for (@REGISTRY, @models) {
1227	my ($package, $model) = @$_;	1338	my ($package, $model, $autoload) = @$_;
		1339	if (
		1340	$autoload
		1341	and eval "require $package"
1228	if (${"$package\::VERSION"} > 0) {	1342	and ${"$package\::VERSION"} > 0
1229	if (eval "require $model") {	1343	and eval "require $model"
		1344	) {
1230	$MODEL = $model;	1345	$MODEL = $model;
1231	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1346	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1232	last;	1347	last;
1233	}
1234	}	1348	}
1235	}	1349	}
1236		1350
1237	unless ($MODEL) {
1238	# try to autoload a model
1239	for (@REGISTRY, @models) {
1240	my ($package, $model, $autoload) = @$_;
1241	if (
1242	$autoload
1243	and eval "require $package"
1244	and ${"$package\::VERSION"} > 0
1245	and eval "require $model"
1246	) {
1247	$MODEL = $model;
1248	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1249	last;
1250	}
1251	}
1252
1253	$MODEL	1351	$MODEL
1254	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1352	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1255	}
1256	}	1353	}
1257
1258	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1259
1260	unshift @ISA, $MODEL;
1261
1262	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1263
1264	(shift @post_detect)->() while @post_detect;
1265	}	1354	}
1266		1355
		1356	# free memory only needed for probing
		1357	undef @models;
		1358	undef @REGISTRY;
		1359
		1360	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1361	unshift @ISA, $MODEL;
		1362
		1363	# now nuke some methods that are overridden by the backend.
		1364	# SUPER usage is not allowed in these.
		1365	for (qw(time signal child idle)) {
		1366	undef &{"AnyEvent::Base::$_"}
		1367	if defined &{"$MODEL\::$_"};
		1368	}
		1369
		1370	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1371	require AnyEvent::Strict;
		1372	}
		1373
		1374	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1375	require AnyEvent::Debug;
		1376	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1377	}
		1378
		1379	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1380	require AnyEvent::Socket;
		1381	require AnyEvent::Debug;
		1382
		1383	my ($host, $service) = AnyEvent::Socket::parse_hostport ($ENV{PERL_ANYEVENT_DEBUG_SHELL});
		1384	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1385	}
		1386
		1387	(shift @post_detect)->() while @post_detect;
		1388	undef @post_detect;
		1389
		1390	*post_detect = sub(&) {
		1391	shift->();
		1392
		1393	undef
		1394	};
		1395
1267	$MODEL	1396	$MODEL
1268	}	1397	}
1269		1398
1270	sub AUTOLOAD {	1399	for my $name (@methods) {
1271	(my $func = $AUTOLOAD) =~ s/.*://;	1400	*$name = sub {
1272		1401	detect;
1273	$method{$func}	1402	# we use goto because
1274	or Carp::croak "$func: not a valid method for AnyEvent objects";	1403	# a) it makes the thunk more transparent
1275		1404	# b) it allows us to delete the thunk later
1276	detect unless $MODEL;	1405	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1277		1406	};
1278	my $class = shift;
1279	$class->$func (@_);
1280	}	1407	}
1281		1408
1282	# utility function to dup a filehandle. this is used by many backends	1409	# utility function to dup a filehandle. this is used by many backends
1283	# to support binding more than one watcher per filehandle (they usually	1410	# to support binding more than one watcher per filehandle (they usually
1284	# allow only one watcher per fd, so we dup it to get a different one).	1411	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1298		1425
1299	=head1 SIMPLIFIED AE API	1426	=head1 SIMPLIFIED AE API
1300		1427
1301	Starting with version 5.0, AnyEvent officially supports a second, much	1428	Starting with version 5.0, AnyEvent officially supports a second, much
1302	simpler, API that is designed to reduce the calling, typing and memory	1429	simpler, API that is designed to reduce the calling, typing and memory
1303	overhead.	1430	overhead by using function call syntax and a fixed number of parameters.
1304		1431
1305	See the L<AE> manpage for details.	1432	See the L<AE> manpage for details.
1306		1433
1307	=cut	1434	=cut
1308		1435
1309	package AE;	1436	package AE;
1310		1437
1311	our $VERSION = $AnyEvent::VERSION;	1438	our $VERSION = $AnyEvent::VERSION;
1312		1439
		1440	sub _reset() {
		1441	eval q{
		1442	# fall back to the main API by default - backends and AnyEvent::Base
		1443	# implementations can overwrite these.
		1444
1313	sub io($$$) {	1445	sub io($$$) {
1314	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1446	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1315	}	1447	}
1316		1448
1317	sub timer($$$) {	1449	sub timer($$$) {
1318	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1450	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1319	}	1451	}
1320		1452
1321	sub signal($$) {	1453	sub signal($$) {
1322	AnyEvent->signal (signal => $_[0], cb => $_[1])	1454	AnyEvent->signal (signal => $_[0], cb => $_[1])
1323	}	1455	}
1324		1456
1325	sub child($$) {	1457	sub child($$) {
1326	AnyEvent->child (pid => $_[0], cb => $_[1])	1458	AnyEvent->child (pid => $_[0], cb => $_[1])
1327	}	1459	}
1328		1460
1329	sub idle($) {	1461	sub idle($) {
1330	AnyEvent->idle (cb => $_[0])	1462	AnyEvent->idle (cb => $_[0]);
1331	}	1463	}
1332		1464
1333	sub cv(;&) {	1465	sub cv(;&) {
1334	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1466	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1335	}	1467	}
1336		1468
1337	sub now() {	1469	sub now() {
1338	AnyEvent->now	1470	AnyEvent->now
1339	}	1471	}
1340		1472
1341	sub now_update() {	1473	sub now_update() {
1342	AnyEvent->now_update	1474	AnyEvent->now_update
1343	}	1475	}
1344		1476
1345	sub time() {	1477	sub time() {
1346	AnyEvent->time	1478	AnyEvent->time
		1479	}
		1480
		1481	*postpone = \&AnyEvent::postpone;
		1482	};
		1483	die if $@;
1347	}	1484	}
		1485
		1486	BEGIN { _reset }
1348		1487
1349	package AnyEvent::Base;	1488	package AnyEvent::Base;
1350		1489
1351	# default implementations for many methods	1490	# default implementations for many methods
1352		1491
1353	sub _time() {	1492	sub time {
		1493	eval q{ # poor man's autoloading {}
1354	# probe for availability of Time::HiRes	1494	# probe for availability of Time::HiRes
1355	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1495	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1356	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1496	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1357	*_time = \&Time::HiRes::time;	1497	*AE::time = \&Time::HiRes::time;
1358	# if (eval "use POSIX (); (POSIX::times())...	1498	# if (eval "use POSIX (); (POSIX::times())...
1359	} else {	1499	} else {
1360	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1500	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1361	*_time = sub { time }; # epic fail	1501	*AE::time = sub (){ time }; # epic fail
		1502	}
		1503
		1504	*time = sub { AE::time }; # different prototypes
1362	}	1505	};
		1506	die if $@;
1363		1507
1364	&_time	1508	&time
1365	}	1509	}
1366		1510
1367	sub time { _time }	1511	*now = \&time;
1368	sub now { _time }	1512
1369	sub now_update { }	1513	sub now_update { }
1370		1514
		1515	sub _poll {
		1516	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1517	}
		1518
1371	# default implementation for ->condvar	1519	# default implementation for ->condvar
		1520	# in fact, the default should not be overwritten
1372		1521
1373	sub condvar {	1522	sub condvar {
		1523	eval q{ # poor man's autoloading {}
		1524	*condvar = sub {
1374	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1525	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1526	};
		1527
		1528	*AE::cv = sub (;&) {
		1529	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1530	};
		1531	};
		1532	die if $@;
		1533
		1534	&condvar
1375	}	1535	}
1376		1536
1377	# default implementation for ->signal	1537	# default implementation for ->signal
1378		1538
1379	our $HAVE_ASYNC_INTERRUPT;	1539	our $HAVE_ASYNC_INTERRUPT;
…		…
1388		1548
1389	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1549	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1390	our (%SIG_ASY, %SIG_ASY_W);	1550	our (%SIG_ASY, %SIG_ASY_W);
1391	our ($SIG_COUNT, $SIG_TW);	1551	our ($SIG_COUNT, $SIG_TW);
1392		1552
1393	sub _signal_exec {
1394	$HAVE_ASYNC_INTERRUPT
1395	? $SIGPIPE_R->drain
1396	: sysread $SIGPIPE_R, (my $dummy), 9;
1397
1398	while (%SIG_EV) {
1399	for (keys %SIG_EV) {
1400	delete $SIG_EV{$_};
1401	$_->() for values %{ $SIG_CB{$_} || {} };
1402	}
1403	}
1404	}
1405
1406	# install a dummy wakeup watcher to reduce signal catching latency	1553	# install a dummy wakeup watcher to reduce signal catching latency
		1554	# used by Impls
1407	sub _sig_add() {	1555	sub _sig_add() {
1408	unless ($SIG_COUNT++) {	1556	unless ($SIG_COUNT++) {
1409	# try to align timer on a full-second boundary, if possible	1557	# try to align timer on a full-second boundary, if possible
1410	my $NOW = AE::now;	1558	my $NOW = AE::now;
1411		1559
…		…
1421	undef $SIG_TW	1569	undef $SIG_TW
1422	unless --$SIG_COUNT;	1570	unless --$SIG_COUNT;
1423	}	1571	}
1424		1572
1425	our $_sig_name_init; $_sig_name_init = sub {	1573	our $_sig_name_init; $_sig_name_init = sub {
1426	eval q{ # poor man's autoloading	1574	eval q{ # poor man's autoloading {}
1427	undef $_sig_name_init;	1575	undef $_sig_name_init;
1428		1576
1429	if (_have_async_interrupt) {	1577	if (_have_async_interrupt) {
1430	*sig2num = \&Async::Interrupt::sig2num;	1578	*sig2num = \&Async::Interrupt::sig2num;
1431	*sig2name = \&Async::Interrupt::sig2name;	1579	*sig2name = \&Async::Interrupt::sig2name;
…		…
1463	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1611	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1464		1612
1465	} else {	1613	} else {
1466	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1614	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1467		1615
1468	require Fcntl;
1469
1470	if (AnyEvent::WIN32) {	1616	if (AnyEvent::WIN32) {
1471	require AnyEvent::Util;	1617	require AnyEvent::Util;
1472		1618
1473	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1619	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1474	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1620	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1475	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1621	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1476	} else {	1622	} else {
1477	pipe $SIGPIPE_R, $SIGPIPE_W;	1623	pipe $SIGPIPE_R, $SIGPIPE_W;
1478	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1624	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1479	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1625	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1480		1626
1481	# not strictly required, as $^F is normally 2, but let's make sure...	1627	# not strictly required, as $^F is normally 2, but let's make sure...
1482	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1628	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1483	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1629	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1484	}	1630	}
1485		1631
1486	$SIGPIPE_R	1632	$SIGPIPE_R
1487	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1633	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1488		1634
1489	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1635	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1490	}	1636	}
1491		1637
1492	*signal = sub {	1638	*signal = $HAVE_ASYNC_INTERRUPT
		1639	? sub {
1493	my (undef, %arg) = @_;	1640	my (undef, %arg) = @_;
1494		1641
1495	my $signal = uc $arg{signal}
1496	or Carp::croak "required option 'signal' is missing";
1497
1498	if ($HAVE_ASYNC_INTERRUPT) {
1499	# async::interrupt	1642	# async::interrupt
1500
1501	$signal = sig2num $signal;	1643	my $signal = sig2num $arg{signal};
1502	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1644	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1503		1645
1504	$SIG_ASY{$signal} ||= new Async::Interrupt	1646	$SIG_ASY{$signal} ||= new Async::Interrupt
1505	cb => sub { undef $SIG_EV{$signal} },	1647	cb => sub { undef $SIG_EV{$signal} },
1506	signal => $signal,	1648	signal => $signal,
1507	pipe => [$SIGPIPE_R->filenos],	1649	pipe => [$SIGPIPE_R->filenos],
1508	pipe_autodrain => 0,	1650	pipe_autodrain => 0,
1509	;	1651	;
1510		1652
1511	} else {	1653	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1654	}
		1655	: sub {
		1656	my (undef, %arg) = @_;
		1657
1512	# pure perl	1658	# pure perl
1513
1514	# AE::Util has been loaded in signal
1515	$signal = sig2name $signal;	1659	my $signal = sig2name $arg{signal};
1516	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1660	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1517		1661
1518	$SIG{$signal} ||= sub {	1662	$SIG{$signal} ||= sub {
1519	local $!;	1663	local $!;
1520	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1664	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1521	undef $SIG_EV{$signal};	1665	undef $SIG_EV{$signal};
1522	};	1666	};
1523		1667
1524	# can't do signal processing without introducing races in pure perl,	1668	# can't do signal processing without introducing races in pure perl,
1525	# so limit the signal latency.	1669	# so limit the signal latency.
1526	_sig_add;	1670	_sig_add;
1527	}
1528		1671
1529	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1672	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1673	}
1530	};	1674	;
1531		1675
1532	*AnyEvent::Base::signal::DESTROY = sub {	1676	*AnyEvent::Base::signal::DESTROY = sub {
1533	my ($signal, $cb) = @{$_[0]};	1677	my ($signal, $cb) = @{$_[0]};
1534		1678
1535	_sig_del;	1679	_sig_del;
…		…
1542	# print weird messages, or just unconditionally exit	1686	# print weird messages, or just unconditionally exit
1543	# instead of getting the default action.	1687	# instead of getting the default action.
1544	undef $SIG{$signal}	1688	undef $SIG{$signal}
1545	unless keys %{ $SIG_CB{$signal} };	1689	unless keys %{ $SIG_CB{$signal} };
1546	};	1690	};
		1691
		1692	*_signal_exec = sub {
		1693	$HAVE_ASYNC_INTERRUPT
		1694	? $SIGPIPE_R->drain
		1695	: sysread $SIGPIPE_R, (my $dummy), 9;
		1696
		1697	while (%SIG_EV) {
		1698	for (keys %SIG_EV) {
		1699	delete $SIG_EV{$_};
		1700	&$_ for values %{ $SIG_CB{$_} || {} };
		1701	}
		1702	}
		1703	};
1547	};	1704	};
1548	die if $@;	1705	die if $@;
		1706
1549	&signal	1707	&signal
1550	}	1708	}
1551		1709
1552	# default implementation for ->child	1710	# default implementation for ->child
1553		1711
1554	our %PID_CB;	1712	our %PID_CB;
1555	our $CHLD_W;	1713	our $CHLD_W;
1556	our $CHLD_DELAY_W;	1714	our $CHLD_DELAY_W;
1557	our $WNOHANG;
1558		1715
		1716	# used by many Impl's
1559	sub _emit_childstatus($$) {	1717	sub _emit_childstatus($$) {
1560	my (undef, $rpid, $rstatus) = @_;	1718	my (undef, $rpid, $rstatus) = @_;
1561		1719
1562	$_->($rpid, $rstatus)	1720	$_->($rpid, $rstatus)
1563	for values %{ $PID_CB{$rpid} || {} },	1721	for values %{ $PID_CB{$rpid} || {} },
1564	values %{ $PID_CB{0} || {} };	1722	values %{ $PID_CB{0} || {} };
1565	}	1723	}
1566		1724
1567	sub _sigchld {
1568	my $pid;
1569
1570	AnyEvent->_emit_childstatus ($pid, $?)
1571	while ($pid = waitpid -1, $WNOHANG) > 0;
1572	}
1573
1574	sub child {	1725	sub child {
		1726	eval q{ # poor man's autoloading {}
		1727	*_sigchld = sub {
		1728	my $pid;
		1729
		1730	AnyEvent->_emit_childstatus ($pid, $?)
		1731	while ($pid = waitpid -1, WNOHANG) > 0;
		1732	};
		1733
		1734	*child = sub {
1575	my (undef, %arg) = @_;	1735	my (undef, %arg) = @_;
1576		1736
1577	defined (my $pid = $arg{pid} + 0)	1737	my $pid = $arg{pid};
1578	or Carp::croak "required option 'pid' is missing";	1738	my $cb = $arg{cb};
1579		1739
1580	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1740	$PID_CB{$pid}{$cb+0} = $cb;
1581		1741
1582	# WNOHANG is almost cetrainly 1 everywhere
1583	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1584	? 1
1585	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1586
1587	unless ($CHLD_W) {	1742	unless ($CHLD_W) {
1588	$CHLD_W = AE::signal CHLD => \&_sigchld;	1743	$CHLD_W = AE::signal CHLD => \&_sigchld;
1589	# child could be a zombie already, so make at least one round	1744	# child could be a zombie already, so make at least one round
1590	&_sigchld;	1745	&_sigchld;
1591	}	1746	}
1592		1747
1593	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1748	bless [$pid, $cb+0], "AnyEvent::Base::child"
1594	}	1749	};
1595		1750
1596	sub AnyEvent::Base::child::DESTROY {	1751	*AnyEvent::Base::child::DESTROY = sub {
1597	my ($pid, $cb) = @{$_[0]};	1752	my ($pid, $icb) = @{$_[0]};
1598		1753
1599	delete $PID_CB{$pid}{$cb};	1754	delete $PID_CB{$pid}{$icb};
1600	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1755	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1601		1756
1602	undef $CHLD_W unless keys %PID_CB;	1757	undef $CHLD_W unless keys %PID_CB;
		1758	};
		1759	};
		1760	die if $@;
		1761
		1762	&child
1603	}	1763	}
1604		1764
1605	# idle emulation is done by simply using a timer, regardless	1765	# idle emulation is done by simply using a timer, regardless
1606	# of whether the process is idle or not, and not letting	1766	# of whether the process is idle or not, and not letting
1607	# the callback use more than 50% of the time.	1767	# the callback use more than 50% of the time.
1608	sub idle {	1768	sub idle {
		1769	eval q{ # poor man's autoloading {}
		1770	*idle = sub {
1609	my (undef, %arg) = @_;	1771	my (undef, %arg) = @_;
1610		1772
1611	my ($cb, $w, $rcb) = $arg{cb};	1773	my ($cb, $w, $rcb) = $arg{cb};
1612		1774
1613	$rcb = sub {	1775	$rcb = sub {
1614	if ($cb) {	1776	if ($cb) {
1615	$w = _time;	1777	$w = AE::time;
1616	&$cb;	1778	&$cb;
1617	$w = _time - $w;	1779	$w = AE::time - $w;
1618		1780
1619	# never use more then 50% of the time for the idle watcher,	1781	# never use more then 50% of the time for the idle watcher,
1620	# within some limits	1782	# within some limits
1621	$w = 0.0001 if $w < 0.0001;	1783	$w = 0.0001 if $w < 0.0001;
1622	$w = 5 if $w > 5;	1784	$w = 5 if $w > 5;
1623		1785
1624	$w = AE::timer $w, 0, $rcb;	1786	$w = AE::timer $w, 0, $rcb;
1625	} else {	1787	} else {
1626	# clean up...	1788	# clean up...
1627	undef $w;	1789	undef $w;
1628	undef $rcb;	1790	undef $rcb;
		1791	}
		1792	};
		1793
		1794	$w = AE::timer 0.05, 0, $rcb;
		1795
		1796	bless \\$cb, "AnyEvent::Base::idle"
1629	}	1797	};
		1798
		1799	*AnyEvent::Base::idle::DESTROY = sub {
		1800	undef $${$_[0]};
		1801	};
1630	};	1802	};
		1803	die if $@;
1631		1804
1632	$w = AE::timer 0.05, 0, $rcb;	1805	&idle
1633
1634	bless \\$cb, "AnyEvent::Base::idle"
1635	}
1636
1637	sub AnyEvent::Base::idle::DESTROY {
1638	undef $${$_[0]};
1639	}	1806	}
1640		1807
1641	package AnyEvent::CondVar;	1808	package AnyEvent::CondVar;
1642		1809
1643	our @ISA = AnyEvent::CondVar::Base::;	1810	our @ISA = AnyEvent::CondVar::Base::;
		1811
		1812	# only to be used for subclassing
		1813	sub new {
		1814	my $class = shift;
		1815	bless AnyEvent->condvar (@_), $class
		1816	}
1644		1817
1645	package AnyEvent::CondVar::Base;	1818	package AnyEvent::CondVar::Base;
1646		1819
1647	#use overload	1820	#use overload
1648	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1821	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1658		1831
1659	sub _send {	1832	sub _send {
1660	# nop	1833	# nop
1661	}	1834	}
1662		1835
		1836	sub _wait {
		1837	AnyEvent->_poll until $_[0]{_ae_sent};
		1838	}
		1839
1663	sub send {	1840	sub send {
1664	my $cv = shift;	1841	my $cv = shift;
1665	$cv->{_ae_sent} = [@_];	1842	$cv->{_ae_sent} = [@_];
1666	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1843	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1667	$cv->_send;	1844	$cv->_send;
…		…
1674		1851
1675	sub ready {	1852	sub ready {
1676	$_[0]{_ae_sent}	1853	$_[0]{_ae_sent}
1677	}	1854	}
1678		1855
1679	sub _wait {
1680	$WAITING
1681	and !$_[0]{_ae_sent}
1682	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1683
1684	local $WAITING = 1;
1685	AnyEvent->one_event while !$_[0]{_ae_sent};
1686	}
1687
1688	sub recv {	1856	sub recv {
		1857	unless ($_[0]{_ae_sent}) {
		1858	$WAITING
		1859	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1860
		1861	local $WAITING = 1;
1689	$_[0]->_wait;	1862	$_[0]->_wait;
		1863	}
1690		1864
1691	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1865	$_[0]{_ae_croak}
1692	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1866	and Carp::croak $_[0]{_ae_croak};
		1867
		1868	wantarray
		1869	? @{ $_[0]{_ae_sent} }
		1870	: $_[0]{_ae_sent}[0]
1693	}	1871	}
1694		1872
1695	sub cb {	1873	sub cb {
1696	my $cv = shift;	1874	my $cv = shift;
1697		1875
…		…
1713	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1891	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1714	}	1892	}
1715		1893
1716	# undocumented/compatibility with pre-3.4	1894	# undocumented/compatibility with pre-3.4
1717	*broadcast = \&send;	1895	*broadcast = \&send;
1718	*wait = \&_wait;	1896	*wait = \&recv;
1719		1897
1720	=head1 ERROR AND EXCEPTION HANDLING	1898	=head1 ERROR AND EXCEPTION HANDLING
1721		1899
1722	In general, AnyEvent does not do any error handling - it relies on the	1900	In general, AnyEvent does not do any error handling - it relies on the
1723	caller to do that if required. The L<AnyEvent::Strict> module (see also	1901	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1770	check the arguments passed to most method calls. If it finds any problems,	1948	check the arguments passed to most method calls. If it finds any problems,
1771	it will croak.	1949	it will croak.
1772		1950
1773	In other words, enables "strict" mode.	1951	In other words, enables "strict" mode.
1774		1952
1775	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1953	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1776	>>, it is definitely recommended to keep it off in production. Keeping	1954	>>, it is definitely recommended to keep it off in production. Keeping
1777	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1955	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1778	can be very useful, however.	1956	can be very useful, however.
1779		1957
		1958	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1959
		1960	If this env variable is set, then its contents will be
		1961	interpreted by C<AnyEvent::Socket::parse_hostport> and an
		1962	C<AnyEvent::Debug::shell> is bound on that port. The shell object is saved
		1963	in C<$AnyEvent::Debug::SHELL>.
		1964
		1965	For example, to bind a debug shell on a unix domain socket in
		1966	F</tmp/debug.sock>, you could use this:
		1967
		1968	PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug.sock perlprog
		1969
		1970	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		1971
		1972	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		1973	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		1974
1780	=item C<PERL_ANYEVENT_MODEL>	1975	=item C<PERL_ANYEVENT_MODEL>
1781		1976
1782	This can be used to specify the event model to be used by AnyEvent, before	1977	This can be used to specify the event model to be used by AnyEvent, before
1783	auto detection and -probing kicks in. It must be a string consisting	1978	auto detection and -probing kicks in.
1784	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1979
		1980	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		1981	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1785	and the resulting module name is loaded and if the load was successful,	1982	resulting module name is loaded and - if the load was successful - used as
1786	used as event model. If it fails to load AnyEvent will proceed with	1983	event model backend. If it fails to load then AnyEvent will proceed with
1787	auto detection and -probing.	1984	auto detection and -probing.
1788		1985
1789	This functionality might change in future versions.	1986	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		1987	nothing gets prepended and the module name is used as-is (hint: C<::> at
		1988	the end of a string designates a module name and quotes it appropriately).
1790		1989
1791	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1990	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1792	could start your program like this:	1991	could start your program like this:
1793		1992
1794	PERL_ANYEVENT_MODEL=Perl perl ...	1993	PERL_ANYEVENT_MODEL=Perl perl ...
1795		1994
1796	=item C<PERL_ANYEVENT_PROTOCOLS>	1995	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
2002		2201
2003	The actual code goes further and collects all errors (C<die>s, exceptions)	2202	The actual code goes further and collects all errors (C<die>s, exceptions)
2004	that occurred during request processing. The C<result> method detects	2203	that occurred during request processing. The C<result> method detects
2005	whether an exception as thrown (it is stored inside the $txn object)	2204	whether an exception as thrown (it is stored inside the $txn object)
2006	and just throws the exception, which means connection errors and other	2205	and just throws the exception, which means connection errors and other
2007	problems get reported tot he code that tries to use the result, not in a	2206	problems get reported to the code that tries to use the result, not in a
2008	random callback.	2207	random callback.
2009		2208
2010	All of this enables the following usage styles:	2209	All of this enables the following usage styles:
2011		2210
2012	1. Blocking:	2211	1. Blocking:
…		…
2426	unless defined $SIG{PIPE};	2625	unless defined $SIG{PIPE};
2427		2626
2428	=head1 RECOMMENDED/OPTIONAL MODULES	2627	=head1 RECOMMENDED/OPTIONAL MODULES
2429		2628
2430	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2629	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2431	it's built-in modules) are required to use it.	2630	its built-in modules) are required to use it.
2432		2631
2433	That does not mean that AnyEvent won't take advantage of some additional	2632	That does not mean that AnyEvent won't take advantage of some additional
2434	modules if they are installed.	2633	modules if they are installed.
2435		2634
2436	This section epxlains which additional modules will be used, and how they	2635	This section explains which additional modules will be used, and how they
2437	affect AnyEvent's operetion.	2636	affect AnyEvent's operation.
2438		2637
2439	=over 4	2638	=over 4
2440		2639
2441	=item L<Async::Interrupt>	2640	=item L<Async::Interrupt>
2442		2641
…		…
2447	catch the signals) with some delay (default is 10 seconds, look for	2646	catch the signals) with some delay (default is 10 seconds, look for
2448	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2647	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2449		2648
2450	If this module is available, then it will be used to implement signal	2649	If this module is available, then it will be used to implement signal
2451	catching, which means that signals will not be delayed, and the event loop	2650	catching, which means that signals will not be delayed, and the event loop
2452	will not be interrupted regularly, which is more efficient (And good for	2651	will not be interrupted regularly, which is more efficient (and good for
2453	battery life on laptops).	2652	battery life on laptops).
2454		2653
2455	This affects not just the pure-perl event loop, but also other event loops	2654	This affects not just the pure-perl event loop, but also other event loops
2456	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2655	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2457		2656
…		…
2469	automatic timer adjustments even when no monotonic clock is available,	2668	automatic timer adjustments even when no monotonic clock is available,
2470	can take avdantage of advanced kernel interfaces such as C<epoll> and	2669	can take avdantage of advanced kernel interfaces such as C<epoll> and
2471	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2670	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2472	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2671	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2473		2672
		2673	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2674	then this module will do nothing for you.
		2675
2474	=item L<Guard>	2676	=item L<Guard>
2475		2677
2476	The guard module, when used, will be used to implement	2678	The guard module, when used, will be used to implement
2477	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2679	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2478	lot less memory), but otherwise doesn't affect guard operation much. It is	2680	lot less memory), but otherwise doesn't affect guard operation much. It is
2479	purely used for performance.	2681	purely used for performance.
2480		2682
2481	=item L<JSON> and L<JSON::XS>	2683	=item L<JSON> and L<JSON::XS>
2482		2684
2483	One of these modules is required when you want to read or write JSON data	2685	One of these modules is required when you want to read or write JSON data
2484	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2686	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2485	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2687	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2486
2487	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2488	installed.
2489		2688
2490	=item L<Net::SSLeay>	2689	=item L<Net::SSLeay>
2491		2690
2492	Implementing TLS/SSL in Perl is certainly interesting, but not very	2691	Implementing TLS/SSL in Perl is certainly interesting, but not very
2493	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2692	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2494	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2693	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2495		2694
2496	=item L<Time::HiRes>	2695	=item L<Time::HiRes>
2497		2696
2498	This module is part of perl since release 5.008. It will be used when the	2697	This module is part of perl since release 5.008. It will be used when the
2499	chosen event library does not come with a timing source on it's own. The	2698	chosen event library does not come with a timing source of its own. The
2500	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2699	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2501	try to use a monotonic clock for timing stability.	2700	try to use a monotonic clock for timing stability.
2502		2701
2503	=back	2702	=back
2504		2703
2505		2704
2506	=head1 FORK	2705	=head1 FORK
2507		2706
2508	Most event libraries are not fork-safe. The ones who are usually are	2707	Most event libraries are not fork-safe. The ones who are usually are
2509	because they rely on inefficient but fork-safe C<select> or C<poll>	2708	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2510	calls. Only L<EV> is fully fork-aware.	2709	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2710	are usually badly thought-out hacks that are incompatible with fork in
		2711	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2712	continue event-processing in both parent and child (or both, if you know
		2713	what you are doing).
		2714
		2715	This means that, in general, you cannot fork and do event processing in
		2716	the child if the event library was initialised before the fork (which
		2717	usually happens when the first AnyEvent watcher is created, or the library
		2718	is loaded).
2511		2719
2512	If you have to fork, you must either do so I<before> creating your first	2720	If you have to fork, you must either do so I<before> creating your first
2513	watcher OR you must not use AnyEvent at all in the child OR you must do	2721	watcher OR you must not use AnyEvent at all in the child OR you must do
2514	something completely out of the scope of AnyEvent.	2722	something completely out of the scope of AnyEvent.
		2723
		2724	The problem of doing event processing in the parent I<and> the child
		2725	is much more complicated: even for backends that I<are> fork-aware or
		2726	fork-safe, their behaviour is not usually what you want: fork clones all
		2727	watchers, that means all timers, I/O watchers etc. are active in both
		2728	parent and child, which is almost never what you want. USing C<exec>
		2729	to start worker children from some kind of manage rprocess is usually
		2730	preferred, because it is much easier and cleaner, at the expense of having
		2731	to have another binary.
2515		2732
2516		2733
2517	=head1 SECURITY CONSIDERATIONS	2734	=head1 SECURITY CONSIDERATIONS
2518		2735
2519	AnyEvent can be forced to load any event model via	2736	AnyEvent can be forced to load any event model via
…		…
2549	pronounced).	2766	pronounced).
2550		2767
2551		2768
2552	=head1 SEE ALSO	2769	=head1 SEE ALSO
2553		2770
		2771	Tutorial/Introduction: L<AnyEvent::Intro>.
		2772
		2773	FAQ: L<AnyEvent::FAQ>.
		2774
2554	Utility functions: L<AnyEvent::Util>.	2775	Utility functions: L<AnyEvent::Util>.
2555		2776
2556	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2777	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2557	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2778	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2558		2779
2559	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2780	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2560	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2781	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2561	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2782	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2562	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2783	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2564	Non-blocking file handles, sockets, TCP clients and	2785	Non-blocking file handles, sockets, TCP clients and
2565	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2786	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2566		2787
2567	Asynchronous DNS: L<AnyEvent::DNS>.	2788	Asynchronous DNS: L<AnyEvent::DNS>.
2568		2789
2569	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2790	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2570	L<Coro::Event>,
2571		2791
2572	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2792	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2573	L<AnyEvent::HTTP>.	2793	L<AnyEvent::HTTP>.
2574		2794
2575		2795
2576	=head1 AUTHOR	2796	=head1 AUTHOR
2577		2797

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