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Revision 1.296 by root, Tue Nov 17 01:19:49 2009 UTC vs.
Revision 1.362 by root, Sun Aug 14 01:57:18 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.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
902		942
903	If you need to do some initialisation before AnyEvent watchers are	943	If you need to do some initialisation before AnyEvent watchers are
904	created, use C<post_detect>.	944	created, use C<post_detect>.
905		945
906	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
907		947
908	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
909	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
910		950
911	The block will be executed I<after> the actual backend has been detected	951	The block will be executed I<after> the actual backend has been detected
912	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
913	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
914	other initialisations - see the sources of L<AnyEvent::Strict> or	954	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
923	that automatically removes the callback again when it is destroyed (or	963	that automatically removes the callback again when it is destroyed (or
924	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
925	a case where this is useful.	965	a case where this is useful.
926		966
927	Example: Create a watcher for the IO::AIO module and store it in	967	Example: Create a watcher for the IO::AIO module and store it in
928	C<$WATCHER>. Only do so after the event loop is initialised, though.	968	C<$WATCHER>, but do so only do so after the event loop is initialised.
929		969
930	our WATCHER;	970	our WATCHER;
931		971
932	my $guard = AnyEvent::post_detect {	972	my $guard = AnyEvent::post_detect {
933	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
941	$WATCHER ||= $guard;	981	$WATCHER ||= $guard;
942		982
943	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
944		984
945	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
946	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
947	the event loop has been chosen.	987	after the event loop has been chosen.
948		988
949	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	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	990	if it is defined then the event loop has already been detected, and the
951	array will be ignored.	991	array will be ignored.
952		992
953	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
954	it,as it takes care of these details.	994	it, as it takes care of these details.
955		995
956	This variable is mainly useful for modules that can do something useful	996	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	997	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	998	not need to even load it by default. This array provides the means to hook
959	into AnyEvent passively, without loading it.	999	into AnyEvent passively, without loading it.
960		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
961	=back	1054	=back
962		1055
963	=head1 WHAT TO DO IN A MODULE	1056	=head1 WHAT TO DO IN A MODULE
964		1057
965	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1058	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	1068	because it will stall the whole program, and the whole point of using
976	events is to stay interactive.	1069	events is to stay interactive.
977		1070
978	It is fine, however, to call C<< ->recv >> when the user of your module	1071	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	1072	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 >>	1073	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).	1074	freely, as the user of your module knows what she is doing. Always).
982		1075
983	=head1 WHAT TO DO IN THE MAIN PROGRAM	1076	=head1 WHAT TO DO IN THE MAIN PROGRAM
984		1077
985	There will always be a single main program - the only place that should	1078	There will always be a single main program - the only place that should
986	dictate which event model to use.	1079	dictate which event model to use.
987		1080
988	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1081	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	1082	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.	1083	uses AnyEvent, but does not care which event loop is used, all it needs
		1084	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1085	available loop implementation.
991		1086
992	If the main program relies on a specific event model - for example, in	1087	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	1088	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	1089	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	1090	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	1091	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	1092	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.	1093	might choose the wrong one unless you load the correct one yourself.
999		1094
1000	You can chose to use a pure-perl implementation by loading the	1095	You can chose to use a pure-perl implementation by loading the
1001	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1096	C<AnyEvent::Loop> module, which gives you similar behaviour
1002	everywhere, but letting AnyEvent chose the model is generally better.	1097	everywhere, but letting AnyEvent chose the model is generally better.
1003		1098
1004	=head2 MAINLOOP EMULATION	1099	=head2 MAINLOOP EMULATION
1005		1100
1006	Sometimes (often for short test scripts, or even standalone programs who	1101	Sometimes (often for short test scripts, or even standalone programs who
…		…
1021	=head1 OTHER MODULES	1116	=head1 OTHER MODULES
1022		1117
1023	The following is a non-exhaustive list of additional modules that use	1118	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	1119	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	1120	modules and other event loops in the same program. Some of the modules
1026	come with AnyEvent, most are available via CPAN.	1121	come as part of AnyEvent, the others are available via CPAN.
1027		1122
1028	=over 4	1123	=over 4
1029		1124
1030	=item L<AnyEvent::Util>	1125	=item L<AnyEvent::Util>
1031		1126
1032	Contains various utility functions that replace often-used but blocking	1127	Contains various utility functions that replace often-used blocking
1033	functions such as C<inet_aton> by event-/callback-based versions.	1128	functions such as C<inet_aton> with event/callback-based versions.
1034		1129
1035	=item L<AnyEvent::Socket>	1130	=item L<AnyEvent::Socket>
1036		1131
1037	Provides various utility functions for (internet protocol) sockets,	1132	Provides various utility functions for (internet protocol) sockets,
1038	addresses and name resolution. Also functions to create non-blocking tcp	1133	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1040		1135
1041	=item L<AnyEvent::Handle>	1136	=item L<AnyEvent::Handle>
1042		1137
1043	Provide read and write buffers, manages watchers for reads and writes,	1138	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	1139	supports raw and formatted I/O, I/O queued and fully transparent and
1045	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1140	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1046		1141
1047	=item L<AnyEvent::DNS>	1142	=item L<AnyEvent::DNS>
1048		1143
1049	Provides rich asynchronous DNS resolver capabilities.	1144	Provides rich asynchronous DNS resolver capabilities.
1050		1145
		1146	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1147
		1148	Implement event-based interfaces to the protocols of the same name (for
		1149	the curious, IGS is the International Go Server and FCP is the Freenet
		1150	Client Protocol).
		1151
		1152	=item L<AnyEvent::Handle::UDP>
		1153
		1154	Here be danger!
		1155
		1156	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1157	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1158	its use of a stream-based API with a protocol that isn't streamable, that
		1159	the only way to improve it is to delete it.
		1160
		1161	It features data corruption (but typically only under load) and general
		1162	confusion. On top, the author is not only clueless about UDP but also
		1163	fact-resistant - some gems of his understanding: "connect doesn't work
		1164	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1165	packets", "I don't need to implement proper error checking as UDP doesn't
		1166	support error checking" and so on - he doesn't even understand what's
		1167	wrong with his module when it is explained to him.
		1168
1051	=item L<AnyEvent::HTTP>	1169	=item L<AnyEvent::DBI>
1052		1170
1053	A simple-to-use HTTP library that is capable of making a lot of concurrent	1171	Executes L<DBI> requests asynchronously in a proxy process for you,
1054	HTTP requests.	1172	notifying you in an event-based way when the operation is finished.
		1173
		1174	=item L<AnyEvent::AIO>
		1175
		1176	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1177	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1178	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1179	file I/O, and much more.
1055		1180
1056	=item L<AnyEvent::HTTPD>	1181	=item L<AnyEvent::HTTPD>
1057		1182
1058	Provides a simple web application server framework.	1183	A simple embedded webserver.
1059		1184
1060	=item L<AnyEvent::FastPing>	1185	=item L<AnyEvent::FastPing>
1061		1186
1062	The fastest ping in the west.	1187	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		1188
1106	=item L<Coro>	1189	=item L<Coro>
1107		1190
1108	Has special support for AnyEvent via L<Coro::AnyEvent>.	1191	Has special support for AnyEvent via L<Coro::AnyEvent>.
1109		1192
…		…
1113		1196
1114	package AnyEvent;	1197	package AnyEvent;
1115		1198
1116	# basically a tuned-down version of common::sense	1199	# basically a tuned-down version of common::sense
1117	sub common_sense {	1200	sub common_sense {
1118	# from common:.sense 1.0	1201	# from common:.sense 3.4
1119	${^WARNING_BITS} = "\xfc\x3f\xf3\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x03";	1202	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1120	# use strict vars subs	1203	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1121	$^H |= 0x00000600;	1204	$^H |= 0x00000600;
1122	}	1205	}
1123		1206
1124	BEGIN { AnyEvent::common_sense }	1207	BEGIN { AnyEvent::common_sense }
1125		1208
1126	use Carp ();	1209	use Carp ();
1127		1210
1128	our $VERSION = '5.202';	1211	our $VERSION = '6.01';
1129	our $MODEL;	1212	our $MODEL;
1130		1213
1131	our $AUTOLOAD;
1132	our @ISA;	1214	our @ISA;
1133		1215
1134	our @REGISTRY;	1216	our @REGISTRY;
1135		1217
1136	our $WIN32;
1137
1138	our $VERBOSE;	1218	our $VERBOSE;
1139		1219
1140	BEGIN {	1220	BEGIN {
1141	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1221	require "AnyEvent/constants.pl";
		1222
1142	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1223	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1143		1224
1144	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1225	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1145	if ${^TAINT};	1226	if ${^TAINT};
1146		1227
1147	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1228	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1157	$PROTOCOL{$_} = ++$idx	1238	$PROTOCOL{$_} = ++$idx
1158	for reverse split /\s*,\s*/,	1239	for reverse split /\s*,\s*/,
1159	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1240	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1160	}	1241	}
1161		1242
		1243	our @post_detect;
		1244
		1245	sub post_detect(&) {
		1246	my ($cb) = @_;
		1247
		1248	push @post_detect, $cb;
		1249
		1250	defined wantarray
		1251	? bless \$cb, "AnyEvent::Util::postdetect"
		1252	: ()
		1253	}
		1254
		1255	sub AnyEvent::Util::postdetect::DESTROY {
		1256	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1257	}
		1258
		1259	our $POSTPONE_W;
		1260	our @POSTPONE;
		1261
		1262	sub _postpone_exec {
		1263	undef $POSTPONE_W;
		1264
		1265	&{ shift @POSTPONE }
		1266	while @POSTPONE;
		1267	}
		1268
		1269	sub postpone(&) {
		1270	push @POSTPONE, shift;
		1271
		1272	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1273
		1274	()
		1275	}
		1276
1162	my @models = (	1277	our @models = (
1163	[EV:: => AnyEvent::Impl::EV:: , 1],	1278	[EV:: => AnyEvent::Impl::EV:: , 1],
1164	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1279	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1165	# everything below here will not (normally) be autoprobed	1280	# everything below here will not (normally) be autoprobed
1166	# as the pureperl backend should work everywhere	1281	# as the pure perl backend should work everywhere
1167	# and is usually faster	1282	# and is usually faster
1168	[Event:: => AnyEvent::Impl::Event::, 1],	1283	[Event:: => AnyEvent::Impl::Event::, 1],
1169	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1284	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1170	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1285	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1171	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1286	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1172	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1287	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1173	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1288	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1174	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1289	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1175	[Wx:: => AnyEvent::Impl::POE::],	1290	[Wx:: => AnyEvent::Impl::POE::],
1176	[Prima:: => AnyEvent::Impl::POE::],	1291	[Prima:: => AnyEvent::Impl::POE::],
1177	# IO::Async is just too broken - we would need workarounds for its	1292	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1178	# byzantine signal and broken child handling, among others.	1293	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1179	# IO::Async is rather hard to detect, as it doesn't have any	1294	[FLTK:: => AnyEvent::Impl::FLTK2::],
1180	# obvious default class.
1181	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1182	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1183	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1184	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1185	);	1295	);
1186		1296
1187	our %method = map +($_ => 1),	1297	our @isa_hook;
		1298
		1299	sub _isa_set {
		1300	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1301
		1302	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1303	for 1 .. $#pkg;
		1304
		1305	grep $_ && $_->[1], @isa_hook
		1306	and AE::_reset ();
		1307	}
		1308
		1309	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1310	sub _isa_hook($$;$) {
		1311	my ($i, $pkg, $reset_ae) = @_;
		1312
		1313	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1314
		1315	_isa_set;
		1316	}
		1317
		1318	# all autoloaded methods reserve the complete glob, not just the method slot.
		1319	# due to bugs in perls method cache implementation.
1188	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1320	our @methods = qw(io timer time now now_update signal child idle condvar);
1189		1321
1190	our @post_detect;
1191
1192	sub post_detect(&) {	1322	sub detect() {
1193	my ($cb) = @_;	1323	local $!; # for good measure
		1324	local $SIG{__DIE__}; # we use eval
1194		1325
1195	if ($MODEL) {	1326	# free some memory
1196	$cb->();	1327	*detect = sub () { $MODEL };
		1328	# undef &func doesn't correctly update the method cache. grmbl.
		1329	# so we delete the whole glob. grmbl.
		1330	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1331	# a glob with an active sub. hrm. i hope it works, but perl is
		1332	# usually buggy in this department. sigh.
		1333	delete @{"AnyEvent::"}{@methods};
		1334	undef @methods;
1197		1335
1198	undef	1336	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1337	my $model = $1;
		1338	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1339	if (eval "require $model") {
		1340	$MODEL = $model;
		1341	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1199	} else {	1342	} else {
1200	push @post_detect, $cb;	1343	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1201		1344	}
1202	defined wantarray
1203	? bless \$cb, "AnyEvent::Util::postdetect"
1204	: ()
1205	}	1345	}
1206	}
1207		1346
1208	sub AnyEvent::Util::postdetect::DESTROY {	1347	# check for already loaded models
1209	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1210	}
1211
1212	sub detect() {
1213	unless ($MODEL) {	1348	unless ($MODEL) {
1214	local $SIG{__DIE__};	1349	for (@REGISTRY, @models) {
1215		1350	my ($package, $model) = @$_;
1216	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1351	if (${"$package\::VERSION"} > 0) {
1217	my $model = "AnyEvent::Impl::$1";
1218	if (eval "require $model") {	1352	if (eval "require $model") {
1219	$MODEL = $model;	1353	$MODEL = $model;
1220	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1354	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1221	} else {	1355	last;
1222	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1356	}
1223	}	1357	}
1224	}	1358	}
1225		1359
1226	# check for already loaded models
1227	unless ($MODEL) {	1360	unless ($MODEL) {
		1361	# try to autoload a model
1228	for (@REGISTRY, @models) {	1362	for (@REGISTRY, @models) {
1229	my ($package, $model) = @$_;	1363	my ($package, $model, $autoload) = @$_;
		1364	if (
		1365	$autoload
		1366	and eval "require $package"
1230	if (${"$package\::VERSION"} > 0) {	1367	and ${"$package\::VERSION"} > 0
1231	if (eval "require $model") {	1368	and eval "require $model"
		1369	) {
1232	$MODEL = $model;	1370	$MODEL = $model;
1233	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1371	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1234	last;	1372	last;
1235	}
1236	}	1373	}
1237	}	1374	}
1238		1375
1239	unless ($MODEL) {
1240	# try to autoload a model
1241	for (@REGISTRY, @models) {
1242	my ($package, $model, $autoload) = @$_;
1243	if (
1244	$autoload
1245	and eval "require $package"
1246	and ${"$package\::VERSION"} > 0
1247	and eval "require $model"
1248	) {
1249	$MODEL = $model;
1250	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1251	last;
1252	}
1253	}
1254
1255	$MODEL	1376	$MODEL
1256	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1377	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1257	}
1258	}	1378	}
1259
1260	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1261
1262	unshift @ISA, $MODEL;
1263
1264	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1265
1266	(shift @post_detect)->() while @post_detect;
1267	}	1379	}
1268		1380
		1381	# free memory only needed for probing
		1382	undef @models;
		1383	undef @REGISTRY;
		1384
		1385	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1386
		1387	# now nuke some methods that are overridden by the backend.
		1388	# SUPER usage is not allowed in these.
		1389	for (qw(time signal child idle)) {
		1390	undef &{"AnyEvent::Base::$_"}
		1391	if defined &{"$MODEL\::$_"};
		1392	}
		1393
		1394	_isa_set;
		1395
		1396	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1397	require AnyEvent::Strict;
		1398	}
		1399
		1400	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1401	require AnyEvent::Debug;
		1402	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1403	}
		1404
		1405	if (exists $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1406	require AnyEvent::Socket;
		1407	require AnyEvent::Debug;
		1408
		1409	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1410	$shell =~ s/\$\$/$$/g;
		1411
		1412	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1413	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1414	}
		1415
		1416	(shift @post_detect)->() while @post_detect;
		1417	undef @post_detect;
		1418
		1419	*post_detect = sub(&) {
		1420	shift->();
		1421
		1422	undef
		1423	};
		1424
1269	$MODEL	1425	$MODEL
1270	}	1426	}
1271		1427
1272	sub AUTOLOAD {	1428	for my $name (@methods) {
1273	(my $func = $AUTOLOAD) =~ s/.*://;	1429	*$name = sub {
1274		1430	detect;
1275	$method{$func}	1431	# we use goto because
1276	or Carp::croak "$func: not a valid method for AnyEvent objects";	1432	# a) it makes the thunk more transparent
1277		1433	# b) it allows us to delete the thunk later
1278	detect unless $MODEL;	1434	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1279		1435	};
1280	my $class = shift;
1281	$class->$func (@_);
1282	}	1436	}
1283		1437
1284	# utility function to dup a filehandle. this is used by many backends	1438	# utility function to dup a filehandle. this is used by many backends
1285	# to support binding more than one watcher per filehandle (they usually	1439	# to support binding more than one watcher per filehandle (they usually
1286	# allow only one watcher per fd, so we dup it to get a different one).	1440	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1300		1454
1301	=head1 SIMPLIFIED AE API	1455	=head1 SIMPLIFIED AE API
1302		1456
1303	Starting with version 5.0, AnyEvent officially supports a second, much	1457	Starting with version 5.0, AnyEvent officially supports a second, much
1304	simpler, API that is designed to reduce the calling, typing and memory	1458	simpler, API that is designed to reduce the calling, typing and memory
1305	overhead.	1459	overhead by using function call syntax and a fixed number of parameters.
1306		1460
1307	See the L<AE> manpage for details.	1461	See the L<AE> manpage for details.
1308		1462
1309	=cut	1463	=cut
1310		1464
1311	package AE;	1465	package AE;
1312		1466
1313	our $VERSION = $AnyEvent::VERSION;	1467	our $VERSION = $AnyEvent::VERSION;
1314		1468
		1469	sub _reset() {
		1470	eval q{
		1471	# fall back to the main API by default - backends and AnyEvent::Base
		1472	# implementations can overwrite these.
		1473
1315	sub io($$$) {	1474	sub io($$$) {
1316	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1475	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1317	}	1476	}
1318		1477
1319	sub timer($$$) {	1478	sub timer($$$) {
1320	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1479	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1321	}	1480	}
1322		1481
1323	sub signal($$) {	1482	sub signal($$) {
1324	AnyEvent->signal (signal => $_[0], cb => $_[1])	1483	AnyEvent->signal (signal => $_[0], cb => $_[1])
1325	}	1484	}
1326		1485
1327	sub child($$) {	1486	sub child($$) {
1328	AnyEvent->child (pid => $_[0], cb => $_[1])	1487	AnyEvent->child (pid => $_[0], cb => $_[1])
1329	}	1488	}
1330		1489
1331	sub idle($) {	1490	sub idle($) {
1332	AnyEvent->idle (cb => $_[0])	1491	AnyEvent->idle (cb => $_[0]);
1333	}	1492	}
1334		1493
1335	sub cv(;&) {	1494	sub cv(;&) {
1336	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1495	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1337	}	1496	}
1338		1497
1339	sub now() {	1498	sub now() {
1340	AnyEvent->now	1499	AnyEvent->now
1341	}	1500	}
1342		1501
1343	sub now_update() {	1502	sub now_update() {
1344	AnyEvent->now_update	1503	AnyEvent->now_update
1345	}	1504	}
1346		1505
1347	sub time() {	1506	sub time() {
1348	AnyEvent->time	1507	AnyEvent->time
		1508	}
		1509
		1510	*postpone = \&AnyEvent::postpone;
		1511	};
		1512	die if $@;
1349	}	1513	}
		1514
		1515	BEGIN { _reset }
1350		1516
1351	package AnyEvent::Base;	1517	package AnyEvent::Base;
1352		1518
1353	# default implementations for many methods	1519	# default implementations for many methods
1354		1520
1355	sub _time() {	1521	sub time {
		1522	eval q{ # poor man's autoloading {}
1356	# probe for availability of Time::HiRes	1523	# probe for availability of Time::HiRes
1357	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1524	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1358	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1525	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1526	*time = sub { Time::HiRes::time () };
1359	*_time = \&Time::HiRes::time;	1527	*AE::time = \& Time::HiRes::time ;
1360	# if (eval "use POSIX (); (POSIX::times())...	1528	# if (eval "use POSIX (); (POSIX::times())...
1361	} else {	1529	} else {
1362	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1530	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1363	*_time = sub { time }; # epic fail	1531	*time = sub { CORE::time };
		1532	*AE::time = sub (){ CORE::time };
		1533	}
		1534
		1535	*now = \&time;
1364	}	1536	};
		1537	die if $@;
1365		1538
1366	&_time	1539	&time
1367	}	1540	}
1368		1541
1369	sub time { _time }	1542	*now = \&time;
1370	sub now { _time }
1371	sub now_update { }	1543	sub now_update { }
1372		1544
		1545	sub _poll {
		1546	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1547	}
		1548
1373	# default implementation for ->condvar	1549	# default implementation for ->condvar
		1550	# in fact, the default should not be overwritten
1374		1551
1375	sub condvar {	1552	sub condvar {
		1553	eval q{ # poor man's autoloading {}
		1554	*condvar = sub {
1376	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1555	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1556	};
		1557
		1558	*AE::cv = sub (;&) {
		1559	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1560	};
		1561	};
		1562	die if $@;
		1563
		1564	&condvar
1377	}	1565	}
1378		1566
1379	# default implementation for ->signal	1567	# default implementation for ->signal
1380		1568
1381	our $HAVE_ASYNC_INTERRUPT;	1569	our $HAVE_ASYNC_INTERRUPT;
…		…
1390		1578
1391	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1579	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1392	our (%SIG_ASY, %SIG_ASY_W);	1580	our (%SIG_ASY, %SIG_ASY_W);
1393	our ($SIG_COUNT, $SIG_TW);	1581	our ($SIG_COUNT, $SIG_TW);
1394		1582
1395	sub _signal_exec {
1396	$HAVE_ASYNC_INTERRUPT
1397	? $SIGPIPE_R->drain
1398	: sysread $SIGPIPE_R, (my $dummy), 9;
1399
1400	while (%SIG_EV) {
1401	for (keys %SIG_EV) {
1402	delete $SIG_EV{$_};
1403	$_->() for values %{ $SIG_CB{$_} || {} };
1404	}
1405	}
1406	}
1407
1408	# install a dummy wakeup watcher to reduce signal catching latency	1583	# install a dummy wakeup watcher to reduce signal catching latency
		1584	# used by Impls
1409	sub _sig_add() {	1585	sub _sig_add() {
1410	unless ($SIG_COUNT++) {	1586	unless ($SIG_COUNT++) {
1411	# try to align timer on a full-second boundary, if possible	1587	# try to align timer on a full-second boundary, if possible
1412	my $NOW = AE::now;	1588	my $NOW = AE::now;
1413		1589
…		…
1423	undef $SIG_TW	1599	undef $SIG_TW
1424	unless --$SIG_COUNT;	1600	unless --$SIG_COUNT;
1425	}	1601	}
1426		1602
1427	our $_sig_name_init; $_sig_name_init = sub {	1603	our $_sig_name_init; $_sig_name_init = sub {
1428	eval q{ # poor man's autoloading	1604	eval q{ # poor man's autoloading {}
1429	undef $_sig_name_init;	1605	undef $_sig_name_init;
1430		1606
1431	if (_have_async_interrupt) {	1607	if (_have_async_interrupt) {
1432	*sig2num = \&Async::Interrupt::sig2num;	1608	*sig2num = \&Async::Interrupt::sig2num;
1433	*sig2name = \&Async::Interrupt::sig2name;	1609	*sig2name = \&Async::Interrupt::sig2name;
…		…
1465	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1641	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1466		1642
1467	} else {	1643	} else {
1468	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1644	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1469		1645
1470	require Fcntl;
1471
1472	if (AnyEvent::WIN32) {	1646	if (AnyEvent::WIN32) {
1473	require AnyEvent::Util;	1647	require AnyEvent::Util;
1474		1648
1475	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1649	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1476	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1650	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1477	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1651	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1478	} else {	1652	} else {
1479	pipe $SIGPIPE_R, $SIGPIPE_W;	1653	pipe $SIGPIPE_R, $SIGPIPE_W;
1480	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1654	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1481	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1655	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1482		1656
1483	# not strictly required, as $^F is normally 2, but let's make sure...	1657	# not strictly required, as $^F is normally 2, but let's make sure...
1484	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1658	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1485	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1659	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1486	}	1660	}
1487		1661
1488	$SIGPIPE_R	1662	$SIGPIPE_R
1489	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1663	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1490		1664
1491	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1665	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1492	}	1666	}
1493		1667
1494	*signal = sub {	1668	*signal = $HAVE_ASYNC_INTERRUPT
		1669	? sub {
1495	my (undef, %arg) = @_;	1670	my (undef, %arg) = @_;
1496		1671
1497	my $signal = uc $arg{signal}
1498	or Carp::croak "required option 'signal' is missing";
1499
1500	if ($HAVE_ASYNC_INTERRUPT) {
1501	# async::interrupt	1672	# async::interrupt
1502
1503	$signal = sig2num $signal;	1673	my $signal = sig2num $arg{signal};
1504	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1674	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1505		1675
1506	$SIG_ASY{$signal} ||= new Async::Interrupt	1676	$SIG_ASY{$signal} ||= new Async::Interrupt
1507	cb => sub { undef $SIG_EV{$signal} },	1677	cb => sub { undef $SIG_EV{$signal} },
1508	signal => $signal,	1678	signal => $signal,
1509	pipe => [$SIGPIPE_R->filenos],	1679	pipe => [$SIGPIPE_R->filenos],
1510	pipe_autodrain => 0,	1680	pipe_autodrain => 0,
1511	;	1681	;
1512		1682
1513	} else {	1683	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1684	}
		1685	: sub {
		1686	my (undef, %arg) = @_;
		1687
1514	# pure perl	1688	# pure perl
1515
1516	# AE::Util has been loaded in signal
1517	$signal = sig2name $signal;	1689	my $signal = sig2name $arg{signal};
1518	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1690	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1519		1691
1520	$SIG{$signal} ||= sub {	1692	$SIG{$signal} ||= sub {
1521	local $!;	1693	local $!;
1522	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1694	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1523	undef $SIG_EV{$signal};	1695	undef $SIG_EV{$signal};
1524	};	1696	};
1525		1697
1526	# can't do signal processing without introducing races in pure perl,	1698	# can't do signal processing without introducing races in pure perl,
1527	# so limit the signal latency.	1699	# so limit the signal latency.
1528	_sig_add;	1700	_sig_add;
1529	}
1530		1701
1531	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1702	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1703	}
1532	};	1704	;
1533		1705
1534	*AnyEvent::Base::signal::DESTROY = sub {	1706	*AnyEvent::Base::signal::DESTROY = sub {
1535	my ($signal, $cb) = @{$_[0]};	1707	my ($signal, $cb) = @{$_[0]};
1536		1708
1537	_sig_del;	1709	_sig_del;
…		…
1544	# print weird messages, or just unconditionally exit	1716	# print weird messages, or just unconditionally exit
1545	# instead of getting the default action.	1717	# instead of getting the default action.
1546	undef $SIG{$signal}	1718	undef $SIG{$signal}
1547	unless keys %{ $SIG_CB{$signal} };	1719	unless keys %{ $SIG_CB{$signal} };
1548	};	1720	};
		1721
		1722	*_signal_exec = sub {
		1723	$HAVE_ASYNC_INTERRUPT
		1724	? $SIGPIPE_R->drain
		1725	: sysread $SIGPIPE_R, (my $dummy), 9;
		1726
		1727	while (%SIG_EV) {
		1728	for (keys %SIG_EV) {
		1729	delete $SIG_EV{$_};
		1730	&$_ for values %{ $SIG_CB{$_} || {} };
		1731	}
		1732	}
		1733	};
1549	};	1734	};
1550	die if $@;	1735	die if $@;
		1736
1551	&signal	1737	&signal
1552	}	1738	}
1553		1739
1554	# default implementation for ->child	1740	# default implementation for ->child
1555		1741
1556	our %PID_CB;	1742	our %PID_CB;
1557	our $CHLD_W;	1743	our $CHLD_W;
1558	our $CHLD_DELAY_W;	1744	our $CHLD_DELAY_W;
1559	our $WNOHANG;
1560		1745
		1746	# used by many Impl's
1561	sub _emit_childstatus($$) {	1747	sub _emit_childstatus($$) {
1562	my (undef, $rpid, $rstatus) = @_;	1748	my (undef, $rpid, $rstatus) = @_;
1563		1749
1564	$_->($rpid, $rstatus)	1750	$_->($rpid, $rstatus)
1565	for values %{ $PID_CB{$rpid} || {} },	1751	for values %{ $PID_CB{$rpid} || {} },
1566	values %{ $PID_CB{0} || {} };	1752	values %{ $PID_CB{0} || {} };
1567	}	1753	}
1568		1754
1569	sub _sigchld {
1570	my $pid;
1571
1572	AnyEvent->_emit_childstatus ($pid, $?)
1573	while ($pid = waitpid -1, $WNOHANG) > 0;
1574	}
1575
1576	sub child {	1755	sub child {
		1756	eval q{ # poor man's autoloading {}
		1757	*_sigchld = sub {
		1758	my $pid;
		1759
		1760	AnyEvent->_emit_childstatus ($pid, $?)
		1761	while ($pid = waitpid -1, WNOHANG) > 0;
		1762	};
		1763
		1764	*child = sub {
1577	my (undef, %arg) = @_;	1765	my (undef, %arg) = @_;
1578		1766
1579	defined (my $pid = $arg{pid} + 0)	1767	my $pid = $arg{pid};
1580	or Carp::croak "required option 'pid' is missing";	1768	my $cb = $arg{cb};
1581		1769
1582	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1770	$PID_CB{$pid}{$cb+0} = $cb;
1583		1771
1584	# WNOHANG is almost cetrainly 1 everywhere
1585	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1586	? 1
1587	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1588
1589	unless ($CHLD_W) {	1772	unless ($CHLD_W) {
1590	$CHLD_W = AE::signal CHLD => \&_sigchld;	1773	$CHLD_W = AE::signal CHLD => \&_sigchld;
1591	# child could be a zombie already, so make at least one round	1774	# child could be a zombie already, so make at least one round
1592	&_sigchld;	1775	&_sigchld;
1593	}	1776	}
1594		1777
1595	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1778	bless [$pid, $cb+0], "AnyEvent::Base::child"
1596	}	1779	};
1597		1780
1598	sub AnyEvent::Base::child::DESTROY {	1781	*AnyEvent::Base::child::DESTROY = sub {
1599	my ($pid, $cb) = @{$_[0]};	1782	my ($pid, $icb) = @{$_[0]};
1600		1783
1601	delete $PID_CB{$pid}{$cb};	1784	delete $PID_CB{$pid}{$icb};
1602	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1785	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1603		1786
1604	undef $CHLD_W unless keys %PID_CB;	1787	undef $CHLD_W unless keys %PID_CB;
		1788	};
		1789	};
		1790	die if $@;
		1791
		1792	&child
1605	}	1793	}
1606		1794
1607	# idle emulation is done by simply using a timer, regardless	1795	# idle emulation is done by simply using a timer, regardless
1608	# of whether the process is idle or not, and not letting	1796	# of whether the process is idle or not, and not letting
1609	# the callback use more than 50% of the time.	1797	# the callback use more than 50% of the time.
1610	sub idle {	1798	sub idle {
		1799	eval q{ # poor man's autoloading {}
		1800	*idle = sub {
1611	my (undef, %arg) = @_;	1801	my (undef, %arg) = @_;
1612		1802
1613	my ($cb, $w, $rcb) = $arg{cb};	1803	my ($cb, $w, $rcb) = $arg{cb};
1614		1804
1615	$rcb = sub {	1805	$rcb = sub {
1616	if ($cb) {	1806	if ($cb) {
1617	$w = _time;	1807	$w = AE::time;
1618	&$cb;	1808	&$cb;
1619	$w = _time - $w;	1809	$w = AE::time - $w;
1620		1810
1621	# never use more then 50% of the time for the idle watcher,	1811	# never use more then 50% of the time for the idle watcher,
1622	# within some limits	1812	# within some limits
1623	$w = 0.0001 if $w < 0.0001;	1813	$w = 0.0001 if $w < 0.0001;
1624	$w = 5 if $w > 5;	1814	$w = 5 if $w > 5;
1625		1815
1626	$w = AE::timer $w, 0, $rcb;	1816	$w = AE::timer $w, 0, $rcb;
1627	} else {	1817	} else {
1628	# clean up...	1818	# clean up...
1629	undef $w;	1819	undef $w;
1630	undef $rcb;	1820	undef $rcb;
		1821	}
		1822	};
		1823
		1824	$w = AE::timer 0.05, 0, $rcb;
		1825
		1826	bless \\$cb, "AnyEvent::Base::idle"
1631	}	1827	};
		1828
		1829	*AnyEvent::Base::idle::DESTROY = sub {
		1830	undef $${$_[0]};
		1831	};
1632	};	1832	};
		1833	die if $@;
1633		1834
1634	$w = AE::timer 0.05, 0, $rcb;	1835	&idle
1635
1636	bless \\$cb, "AnyEvent::Base::idle"
1637	}
1638
1639	sub AnyEvent::Base::idle::DESTROY {
1640	undef $${$_[0]};
1641	}	1836	}
1642		1837
1643	package AnyEvent::CondVar;	1838	package AnyEvent::CondVar;
1644		1839
1645	our @ISA = AnyEvent::CondVar::Base::;	1840	our @ISA = AnyEvent::CondVar::Base::;
		1841
		1842	# only to be used for subclassing
		1843	sub new {
		1844	my $class = shift;
		1845	bless AnyEvent->condvar (@_), $class
		1846	}
1646		1847
1647	package AnyEvent::CondVar::Base;	1848	package AnyEvent::CondVar::Base;
1648		1849
1649	#use overload	1850	#use overload
1650	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1851	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1660		1861
1661	sub _send {	1862	sub _send {
1662	# nop	1863	# nop
1663	}	1864	}
1664		1865
		1866	sub _wait {
		1867	AnyEvent->_poll until $_[0]{_ae_sent};
		1868	}
		1869
1665	sub send {	1870	sub send {
1666	my $cv = shift;	1871	my $cv = shift;
1667	$cv->{_ae_sent} = [@_];	1872	$cv->{_ae_sent} = [@_];
1668	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1873	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1669	$cv->_send;	1874	$cv->_send;
…		…
1676		1881
1677	sub ready {	1882	sub ready {
1678	$_[0]{_ae_sent}	1883	$_[0]{_ae_sent}
1679	}	1884	}
1680		1885
1681	sub _wait {
1682	$WAITING
1683	and !$_[0]{_ae_sent}
1684	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1685
1686	local $WAITING = 1;
1687	AnyEvent->one_event while !$_[0]{_ae_sent};
1688	}
1689
1690	sub recv {	1886	sub recv {
		1887	unless ($_[0]{_ae_sent}) {
		1888	$WAITING
		1889	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1890
		1891	local $WAITING = 1;
1691	$_[0]->_wait;	1892	$_[0]->_wait;
		1893	}
1692		1894
1693	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1895	$_[0]{_ae_croak}
1694	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1896	and Carp::croak $_[0]{_ae_croak};
		1897
		1898	wantarray
		1899	? @{ $_[0]{_ae_sent} }
		1900	: $_[0]{_ae_sent}[0]
1695	}	1901	}
1696		1902
1697	sub cb {	1903	sub cb {
1698	my $cv = shift;	1904	my $cv = shift;
1699		1905
…		…
1715	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1921	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1716	}	1922	}
1717		1923
1718	# undocumented/compatibility with pre-3.4	1924	# undocumented/compatibility with pre-3.4
1719	*broadcast = \&send;	1925	*broadcast = \&send;
1720	*wait = \&_wait;	1926	*wait = \&recv;
1721		1927
1722	=head1 ERROR AND EXCEPTION HANDLING	1928	=head1 ERROR AND EXCEPTION HANDLING
1723		1929
1724	In general, AnyEvent does not do any error handling - it relies on the	1930	In general, AnyEvent does not do any error handling - it relies on the
1725	caller to do that if required. The L<AnyEvent::Strict> module (see also	1931	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1772	check the arguments passed to most method calls. If it finds any problems,	1978	check the arguments passed to most method calls. If it finds any problems,
1773	it will croak.	1979	it will croak.
1774		1980
1775	In other words, enables "strict" mode.	1981	In other words, enables "strict" mode.
1776		1982
1777	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1983	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1778	>>, it is definitely recommended to keep it off in production. Keeping	1984	>>, it is definitely recommended to keep it off in production. Keeping
1779	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1985	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1780	can be very useful, however.	1986	can be very useful, however.
1781		1987
		1988	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		1989
		1990	If this env variable is set, then its contents will be interpreted by
		1991	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		1992	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		1993	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		1994
		1995	This takes place when the first watcher is created.
		1996
		1997	For example, to bind a debug shell on a unix domain socket in
		1998	F<< /tmp/debug<pid>.sock >>, you could use this:
		1999
		2000	PERL_ANYEVENT_DEBUG_SHELL=unix/:/tmp/debug\$\$.sock perlprog
		2001
		2002	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2003	systems.
		2004
		2005	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2006
		2007	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2008	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2009
1782	=item C<PERL_ANYEVENT_MODEL>	2010	=item C<PERL_ANYEVENT_MODEL>
1783		2011
1784	This can be used to specify the event model to be used by AnyEvent, before	2012	This can be used to specify the event model to be used by AnyEvent, before
1785	auto detection and -probing kicks in. It must be a string consisting	2013	auto detection and -probing kicks in.
1786	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2014
		2015	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2016	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1787	and the resulting module name is loaded and if the load was successful,	2017	resulting module name is loaded and - if the load was successful - used as
1788	used as event model. If it fails to load AnyEvent will proceed with	2018	event model backend. If it fails to load then AnyEvent will proceed with
1789	auto detection and -probing.	2019	auto detection and -probing.
1790		2020
1791	This functionality might change in future versions.	2021	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2022	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2023	the end of a string designates a module name and quotes it appropriately).
1792		2024
1793	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2025	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1794	could start your program like this:	2026	could start your program like this:
1795		2027
1796	PERL_ANYEVENT_MODEL=Perl perl ...	2028	PERL_ANYEVENT_MODEL=Perl perl ...
1797		2029
1798	=item C<PERL_ANYEVENT_PROTOCOLS>	2030	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
2004		2236
2005	The actual code goes further and collects all errors (C<die>s, exceptions)	2237	The actual code goes further and collects all errors (C<die>s, exceptions)
2006	that occurred during request processing. The C<result> method detects	2238	that occurred during request processing. The C<result> method detects
2007	whether an exception as thrown (it is stored inside the $txn object)	2239	whether an exception as thrown (it is stored inside the $txn object)
2008	and just throws the exception, which means connection errors and other	2240	and just throws the exception, which means connection errors and other
2009	problems get reported tot he code that tries to use the result, not in a	2241	problems get reported to the code that tries to use the result, not in a
2010	random callback.	2242	random callback.
2011		2243
2012	All of this enables the following usage styles:	2244	All of this enables the following usage styles:
2013		2245
2014	1. Blocking:	2246	1. Blocking:
…		…
2188	(even when used without AnyEvent), but most event loops have acceptable	2420	(even when used without AnyEvent), but most event loops have acceptable
2189	performance with or without AnyEvent.	2421	performance with or without AnyEvent.
2190		2422
2191	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2423	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2192	the actual event loop, only with extremely fast event loops such as EV	2424	the actual event loop, only with extremely fast event loops such as EV
2193	adds AnyEvent significant overhead.	2425	does AnyEvent add significant overhead.
2194		2426
2195	=item * You should avoid POE like the plague if you want performance or	2427	=item * You should avoid POE like the plague if you want performance or
2196	reasonable memory usage.	2428	reasonable memory usage.
2197		2429
2198	=back	2430	=back
…		…
2428	unless defined $SIG{PIPE};	2660	unless defined $SIG{PIPE};
2429		2661
2430	=head1 RECOMMENDED/OPTIONAL MODULES	2662	=head1 RECOMMENDED/OPTIONAL MODULES
2431		2663
2432	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2664	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2433	it's built-in modules) are required to use it.	2665	its built-in modules) are required to use it.
2434		2666
2435	That does not mean that AnyEvent won't take advantage of some additional	2667	That does not mean that AnyEvent won't take advantage of some additional
2436	modules if they are installed.	2668	modules if they are installed.
2437		2669
2438	This section epxlains which additional modules will be used, and how they	2670	This section explains which additional modules will be used, and how they
2439	affect AnyEvent's operetion.	2671	affect AnyEvent's operation.
2440		2672
2441	=over 4	2673	=over 4
2442		2674
2443	=item L<Async::Interrupt>	2675	=item L<Async::Interrupt>
2444		2676
…		…
2449	catch the signals) with some delay (default is 10 seconds, look for	2681	catch the signals) with some delay (default is 10 seconds, look for
2450	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2682	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2451		2683
2452	If this module is available, then it will be used to implement signal	2684	If this module is available, then it will be used to implement signal
2453	catching, which means that signals will not be delayed, and the event loop	2685	catching, which means that signals will not be delayed, and the event loop
2454	will not be interrupted regularly, which is more efficient (And good for	2686	will not be interrupted regularly, which is more efficient (and good for
2455	battery life on laptops).	2687	battery life on laptops).
2456		2688
2457	This affects not just the pure-perl event loop, but also other event loops	2689	This affects not just the pure-perl event loop, but also other event loops
2458	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2690	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2459		2691
…		…
2471	automatic timer adjustments even when no monotonic clock is available,	2703	automatic timer adjustments even when no monotonic clock is available,
2472	can take avdantage of advanced kernel interfaces such as C<epoll> and	2704	can take avdantage of advanced kernel interfaces such as C<epoll> and
2473	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2705	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2474	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2706	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2475		2707
		2708	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2709	then this module will do nothing for you.
		2710
2476	=item L<Guard>	2711	=item L<Guard>
2477		2712
2478	The guard module, when used, will be used to implement	2713	The guard module, when used, will be used to implement
2479	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2714	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2480	lot less memory), but otherwise doesn't affect guard operation much. It is	2715	lot less memory), but otherwise doesn't affect guard operation much. It is
2481	purely used for performance.	2716	purely used for performance.
2482		2717
2483	=item L<JSON> and L<JSON::XS>	2718	=item L<JSON> and L<JSON::XS>
2484		2719
2485	One of these modules is required when you want to read or write JSON data	2720	One of these modules is required when you want to read or write JSON data
2486	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2721	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2487	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2722	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2488
2489	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2490	installed.
2491		2723
2492	=item L<Net::SSLeay>	2724	=item L<Net::SSLeay>
2493		2725
2494	Implementing TLS/SSL in Perl is certainly interesting, but not very	2726	Implementing TLS/SSL in Perl is certainly interesting, but not very
2495	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2727	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2496	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2728	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2497		2729
2498	=item L<Time::HiRes>	2730	=item L<Time::HiRes>
2499		2731
2500	This module is part of perl since release 5.008. It will be used when the	2732	This module is part of perl since release 5.008. It will be used when the
2501	chosen event library does not come with a timing source on it's own. The	2733	chosen event library does not come with a timing source of its own. The
2502	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2734	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2503	try to use a monotonic clock for timing stability.	2735	try to use a monotonic clock for timing stability.
2504		2736
2505	=back	2737	=back
2506		2738
2507		2739
2508	=head1 FORK	2740	=head1 FORK
2509		2741
2510	Most event libraries are not fork-safe. The ones who are usually are	2742	Most event libraries are not fork-safe. The ones who are usually are
2511	because they rely on inefficient but fork-safe C<select> or C<poll>	2743	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2512	calls. Only L<EV> is fully fork-aware.	2744	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2745	are usually badly thought-out hacks that are incompatible with fork in
		2746	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2747	continue event-processing in both parent and child (or both, if you know
		2748	what you are doing).
		2749
		2750	This means that, in general, you cannot fork and do event processing in
		2751	the child if the event library was initialised before the fork (which
		2752	usually happens when the first AnyEvent watcher is created, or the library
		2753	is loaded).
2513		2754
2514	If you have to fork, you must either do so I<before> creating your first	2755	If you have to fork, you must either do so I<before> creating your first
2515	watcher OR you must not use AnyEvent at all in the child OR you must do	2756	watcher OR you must not use AnyEvent at all in the child OR you must do
2516	something completely out of the scope of AnyEvent.	2757	something completely out of the scope of AnyEvent.
		2758
		2759	The problem of doing event processing in the parent I<and> the child
		2760	is much more complicated: even for backends that I<are> fork-aware or
		2761	fork-safe, their behaviour is not usually what you want: fork clones all
		2762	watchers, that means all timers, I/O watchers etc. are active in both
		2763	parent and child, which is almost never what you want. USing C<exec>
		2764	to start worker children from some kind of manage rprocess is usually
		2765	preferred, because it is much easier and cleaner, at the expense of having
		2766	to have another binary.
2517		2767
2518		2768
2519	=head1 SECURITY CONSIDERATIONS	2769	=head1 SECURITY CONSIDERATIONS
2520		2770
2521	AnyEvent can be forced to load any event model via	2771	AnyEvent can be forced to load any event model via
…		…
2551	pronounced).	2801	pronounced).
2552		2802
2553		2803
2554	=head1 SEE ALSO	2804	=head1 SEE ALSO
2555		2805
		2806	Tutorial/Introduction: L<AnyEvent::Intro>.
		2807
		2808	FAQ: L<AnyEvent::FAQ>.
		2809
2556	Utility functions: L<AnyEvent::Util>.	2810	Utility functions: L<AnyEvent::Util>.
2557		2811
2558	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2812	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2559	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2813	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2560		2814
2561	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2815	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2562	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2816	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2563	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2817	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2564	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2818	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2566	Non-blocking file handles, sockets, TCP clients and	2820	Non-blocking file handles, sockets, TCP clients and
2567	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2821	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2568		2822
2569	Asynchronous DNS: L<AnyEvent::DNS>.	2823	Asynchronous DNS: L<AnyEvent::DNS>.
2570		2824
2571	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2825	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2572	L<Coro::Event>,
2573		2826
2574	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2827	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2575	L<AnyEvent::HTTP>.	2828	L<AnyEvent::HTTP>.
2576		2829
2577		2830
2578	=head1 AUTHOR	2831	=head1 AUTHOR
2579		2832

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