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Revision 1.279 by root, Sun Aug 9 16:05:11 2009 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
27	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
28		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
		53
29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
30		55
31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
32	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
33		58
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	59	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	60	policy> and AnyEvent is I<small and efficient>.
36		61
37	First and foremost, I<AnyEvent is not an event model> itself, it only	62	First and foremost, I<AnyEvent is not an event model> itself, it only
38	interfaces to whatever event model the main program happens to use in a	63	interfaces to whatever event model the main program happens to use, in a
39	pragmatic way. For event models and certain classes of immortals alike,	64	pragmatic way. For event models and certain classes of immortals alike,
40	the statement "there can only be one" is a bitter reality: In general,	65	the statement "there can only be one" is a bitter reality: In general,
41	only one event loop can be active at the same time in a process. AnyEvent	66	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	67	cannot change this, but it can hide the differences between those event
		68	loops.
43		69
44	The goal of AnyEvent is to offer module authors the ability to do event	70	The goal of AnyEvent is to offer module authors the ability to do event
45	programming (waiting for I/O or timer events) without subscribing to a	71	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	72	religion, a way of living, and most importantly: without forcing your
47	module users into the same thing by forcing them to use the same event	73	module users into the same thing by forcing them to use the same event
48	model you use.	74	model you use.
49		75
50	For modules like POE or IO::Async (which is a total misnomer as it is	76	For modules like POE or IO::Async (which is a total misnomer as it is
51	actually doing all I/O I<synchronously>...), using them in your module is	77	actually doing all I/O I<synchronously>...), using them in your module is
52	like joining a cult: After you joined, you are dependent on them and you	78	like joining a cult: After you joined, you are dependent on them and you
53	cannot use anything else, as it is simply incompatible to everything that	79	cannot use anything else, as they are simply incompatible to everything
54	isn't itself. What's worse, all the potential users of your module are	80	that isn't them. What's worse, all the potential users of your
55	I<also> forced to use the same event loop you use.	81	module are I<also> forced to use the same event loop you use.
56		82
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	85	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60	your module uses one of those, every user of your module has to use it,	86	your module uses one of those, every user of your module has to use it,
61	too. But if your module uses AnyEvent, it works transparently with all	87	too. But if your module uses AnyEvent, it works transparently with all
62	event models it supports (including stuff like POE and IO::Async, as long	88	event models it supports (including stuff like IO::Async, as long as those
63	as those use one of the supported event loops. It is trivial to add new	89	use one of the supported event loops. It is trivial to add new event loops
64	event loops to AnyEvent, too, so it is future-proof).	90	to AnyEvent, too, so it is future-proof).
65		91
66	In addition to being free of having to use I<the one and only true event	92	In addition to being free of having to use I<the one and only true event
67	model>, AnyEvent also is free of bloat and policy: with POE or similar	93	model>, AnyEvent also is free of bloat and policy: with POE or similar
68	modules, you get an enormous amount of code and strict rules you have to	94	modules, you get an enormous amount of code and strict rules you have to
69	follow. AnyEvent, on the other hand, is lean and up to the point, by only	95	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
127	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
128	creating a watcher it will immediately "watch" for events and invoke the	154	creating a watcher it will immediately "watch" for events and invoke the
129	callback when the event occurs (of course, only when the event model	155	callback when the event occurs (of course, only when the event model
130	is in control).	156	is in control).
131		157
		158	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<<
		160	callbacks must not C<die> >>. The former is good programming practise in
		161	Perl and the latter stems from the fact that exception handling differs
		162	widely between event loops.
		163
132	To disable the watcher you have to destroy it (e.g. by setting the	164	To disable the watcher you have to destroy it (e.g. by setting the
133	variable you store it in to C<undef> or otherwise deleting all references	165	variable you store it in to C<undef> or otherwise deleting all references
134	to it).	166	to it).
135		167
136	All watchers are created by calling a method on the C<AnyEvent> class.	168	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
149	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
150	declared.	182	declared.
151		183
152	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
153		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
156		194
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
		196	for events (AnyEvent might or might not keep a reference to this file
		197	handle). Note that only file handles pointing to things for which
		198	non-blocking operation makes sense are allowed. This includes sockets,
		199	most character devices, pipes, fifos and so on, but not for example files
		200	or block devices.
		201
158	for events. C<poll> must be a string that is either C<r> or C<w>,	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	203	watcher waiting for "r"eadable or "w"ritable events, respectively.
		204
160	respectively. C<cb> is the callback to invoke each time the file handle	205	C<cb> is the callback to invoke each time the file handle becomes ready.
161	becomes ready.
162		206
163	Although the callback might get passed parameters, their value and	207	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	208	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	209	callbacks cannot use arguments passed to I/O watcher callbacks.
166		210
…		…
181	undef $w;	225	undef $w;
182	});	226	});
183		227
184	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
185		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
186	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
187	method with the following mandatory arguments:	239	method with the following mandatory arguments:
188		240
189	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
190	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
193	Although the callback might get passed parameters, their value and	245	Although the callback might get passed parameters, their value and
194	presence is undefined and you cannot rely on them. Portable AnyEvent	246	presence is undefined and you cannot rely on them. Portable AnyEvent
195	callbacks cannot use arguments passed to time watcher callbacks.	247	callbacks cannot use arguments passed to time watcher callbacks.
196		248
197	The callback will normally be invoked once only. If you specify another	249	The callback will normally be invoked once only. If you specify another
198	parameter, C<interval>, as a positive number, then the callback will be	250	parameter, C<interval>, as a strictly positive number (> 0), then the
199	invoked regularly at that interval (in fractional seconds) after the first	251	callback will be invoked regularly at that interval (in fractional
200	invocation.	252	seconds) after the first invocation. If C<interval> is specified with a
		253	false value, then it is treated as if it were missing.
201		254
202	The callback will be rescheduled before invoking the callback, but no	255	The callback will be rescheduled before invoking the callback, but no
203	attempt is done to avoid timer drift in most backends, so the interval is	256	attempt is done to avoid timer drift in most backends, so the interval is
204	only approximate.	257	only approximate.
205		258
…		…
297	In either case, if you care (and in most cases, you don't), then you	350	In either case, if you care (and in most cases, you don't), then you
298	can get whatever behaviour you want with any event loop, by taking the	351	can get whatever behaviour you want with any event loop, by taking the
299	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
300	account.	353	account.
301		354
		355	=item AnyEvent->now_update
		356
		357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		358	the current time for each loop iteration (see the discussion of L<<
		359	AnyEvent->now >>, above).
		360
		361	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
		363	might affect timers and time-outs.
		364
		365	When this is the case, you can call this method, which will update the
		366	event loop's idea of "current time".
		367
		368	Note that updating the time I<might> cause some events to be handled.
		369
302	=back	370	=back
303		371
304	=head2 SIGNAL WATCHERS	372	=head2 SIGNAL WATCHERS
305		373
		374	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
		375
306	You can watch for signals using a signal watcher, C<signal> is the signal	376	You can watch for signals using a signal watcher, C<signal> is the signal
307	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	377	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
308	be invoked whenever a signal occurs.	378	callback to be invoked whenever a signal occurs.
309		379
310	Although the callback might get passed parameters, their value and	380	Although the callback might get passed parameters, their value and
311	presence is undefined and you cannot rely on them. Portable AnyEvent	381	presence is undefined and you cannot rely on them. Portable AnyEvent
312	callbacks cannot use arguments passed to signal watcher callbacks.	382	callbacks cannot use arguments passed to signal watcher callbacks.
313		383
…		…
315	invocation, and callback invocation will be synchronous. Synchronous means	385	invocation, and callback invocation will be synchronous. Synchronous means
316	that it might take a while until the signal gets handled by the process,	386	that it might take a while until the signal gets handled by the process,
317	but it is guaranteed not to interrupt any other callbacks.	387	but it is guaranteed not to interrupt any other callbacks.
318		388
319	The main advantage of using these watchers is that you can share a signal	389	The main advantage of using these watchers is that you can share a signal
320	between multiple watchers.	390	between multiple watchers, and AnyEvent will ensure that signals will not
		391	interrupt your program at bad times.
321		392
322	This watcher might use C<%SIG>, so programs overwriting those signals	393	This watcher might use C<%SIG> (depending on the event loop used),
323	directly will likely not work correctly.	394	so programs overwriting those signals directly will likely not work
		395	correctly.
324		396
325	Example: exit on SIGINT	397	Example: exit on SIGINT
326		398
327	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
328		400
		401	=head3 Signal Races, Delays and Workarounds
		402
		403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		404	callbacks to signals in a generic way, which is a pity, as you cannot
		405	do race-free signal handling in perl, requiring C libraries for
		406	this. AnyEvent will try to do it's best, which means in some cases,
		407	signals will be delayed. The maximum time a signal might be delayed is
		408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		409	variable can be changed only before the first signal watcher is created,
		410	and should be left alone otherwise. This variable determines how often
		411	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		412	will cause fewer spurious wake-ups, which is better for power and CPU
		413	saving.
		414
		415	All these problems can be avoided by installing the optional
		416	L<Async::Interrupt> module, which works with most event loops. It will not
		417	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		418	(and not with L<POE> currently, as POE does it's own workaround with
		419	one-second latency). For those, you just have to suffer the delays.
		420
329	=head2 CHILD PROCESS WATCHERS	421	=head2 CHILD PROCESS WATCHERS
330		422
		423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		424
331	You can also watch on a child process exit and catch its exit status.	425	You can also watch on a child process exit and catch its exit status.
332		426
333	The child process is specified by the C<pid> argument (if set to C<0>, it	427	The child process is specified by the C<pid> argument (one some backends,
334	watches for any child process exit). The watcher will trigger as often	428	using C<0> watches for any child process exit, on others this will
335	as status change for the child are received. This works by installing a	429	croak). The watcher will be triggered only when the child process has
336	signal handler for C<SIGCHLD>. The callback will be called with the pid	430	finished and an exit status is available, not on any trace events
337	and exit status (as returned by waitpid), so unlike other watcher types,	431	(stopped/continued).
338	you I<can> rely on child watcher callback arguments.	432
		433	The callback will be called with the pid and exit status (as returned by
		434	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		435	callback arguments.
		436
		437	This watcher type works by installing a signal handler for C<SIGCHLD>,
		438	and since it cannot be shared, nothing else should use SIGCHLD or reap
		439	random child processes (waiting for specific child processes, e.g. inside
		440	C<system>, is just fine).
339		441
340	There is a slight catch to child watchers, however: you usually start them	442	There is a slight catch to child watchers, however: you usually start them
341	I<after> the child process was created, and this means the process could	443	I<after> the child process was created, and this means the process could
342	have exited already (and no SIGCHLD will be sent anymore).	444	have exited already (and no SIGCHLD will be sent anymore).
343		445
344	Not all event models handle this correctly (POE doesn't), but even for	446	Not all event models handle this correctly (neither POE nor IO::Async do,
		447	see their AnyEvent::Impl manpages for details), but even for event models
345	event models that I<do> handle this correctly, they usually need to be	448	that I<do> handle this correctly, they usually need to be loaded before
346	loaded before the process exits (i.e. before you fork in the first place).	449	the process exits (i.e. before you fork in the first place). AnyEvent's
		450	pure perl event loop handles all cases correctly regardless of when you
		451	start the watcher.
347		452
348	This means you cannot create a child watcher as the very first thing in an	453	This means you cannot create a child watcher as the very first
349	AnyEvent program, you I<have> to create at least one watcher before you	454	thing in an AnyEvent program, you I<have> to create at least one
350	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	455	watcher before you C<fork> the child (alternatively, you can call
		456	C<AnyEvent::detect>).
		457
		458	As most event loops do not support waiting for child events, they will be
		459	emulated by AnyEvent in most cases, in which the latency and race problems
		460	mentioned in the description of signal watchers apply.
351		461
352	Example: fork a process and wait for it	462	Example: fork a process and wait for it
353		463
354	my $done = AnyEvent->condvar;	464	my $done = AnyEvent->condvar;
355		465
…		…
365	);	475	);
366		476
367	# do something else, then wait for process exit	477	# do something else, then wait for process exit
368	$done->recv;	478	$done->recv;
369		479
		480	=head2 IDLE WATCHERS
		481
		482	$w = AnyEvent->idle (cb => <callback>);
		483
		484	Sometimes there is a need to do something, but it is not so important
		485	to do it instantly, but only when there is nothing better to do. This
		486	"nothing better to do" is usually defined to be "no other events need
		487	attention by the event loop".
		488
		489	Idle watchers ideally get invoked when the event loop has nothing
		490	better to do, just before it would block the process to wait for new
		491	events. Instead of blocking, the idle watcher is invoked.
		492
		493	Most event loops unfortunately do not really support idle watchers (only
		494	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		495	will simply call the callback "from time to time".
		496
		497	Example: read lines from STDIN, but only process them when the
		498	program is otherwise idle:
		499
		500	my @lines; # read data
		501	my $idle_w;
		502	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		503	push @lines, scalar <STDIN>;
		504
		505	# start an idle watcher, if not already done
		506	$idle_w ||= AnyEvent->idle (cb => sub {
		507	# handle only one line, when there are lines left
		508	if (my $line = shift @lines) {
		509	print "handled when idle: $line";
		510	} else {
		511	# otherwise disable the idle watcher again
		512	undef $idle_w;
		513	}
		514	});
		515	});
		516
370	=head2 CONDITION VARIABLES	517	=head2 CONDITION VARIABLES
		518
		519	$cv = AnyEvent->condvar;
		520
		521	$cv->send (<list>);
		522	my @res = $cv->recv;
371		523
372	If you are familiar with some event loops you will know that all of them	524	If you are familiar with some event loops you will know that all of them
373	require you to run some blocking "loop", "run" or similar function that	525	require you to run some blocking "loop", "run" or similar function that
374	will actively watch for new events and call your callbacks.	526	will actively watch for new events and call your callbacks.
375		527
376	AnyEvent is different, it expects somebody else to run the event loop and	528	AnyEvent is slightly different: it expects somebody else to run the event
377	will only block when necessary (usually when told by the user).	529	loop and will only block when necessary (usually when told by the user).
378		530
379	The instrument to do that is called a "condition variable", so called	531	The instrument to do that is called a "condition variable", so called
380	because they represent a condition that must become true.	532	because they represent a condition that must become true.
		533
		534	Now is probably a good time to look at the examples further below.
381		535
382	Condition variables can be created by calling the C<< AnyEvent->condvar	536	Condition variables can be created by calling the C<< AnyEvent->condvar
383	>> method, usually without arguments. The only argument pair allowed is	537	>> method, usually without arguments. The only argument pair allowed is
384	C<cb>, which specifies a callback to be called when the condition variable	538	C<cb>, which specifies a callback to be called when the condition variable
385	becomes true.	539	becomes true, with the condition variable as the first argument (but not
		540	the results).
386		541
387	After creation, the condition variable is "false" until it becomes "true"	542	After creation, the condition variable is "false" until it becomes "true"
388	by calling the C<send> method (or calling the condition variable as if it	543	by calling the C<send> method (or calling the condition variable as if it
389	were a callback, read about the caveats in the description for the C<<	544	were a callback, read about the caveats in the description for the C<<
390	->send >> method).	545	->send >> method).
…		…
392	Condition variables are similar to callbacks, except that you can	547	Condition variables are similar to callbacks, except that you can
393	optionally wait for them. They can also be called merge points - points	548	optionally wait for them. They can also be called merge points - points
394	in time where multiple outstanding events have been processed. And yet	549	in time where multiple outstanding events have been processed. And yet
395	another way to call them is transactions - each condition variable can be	550	another way to call them is transactions - each condition variable can be
396	used to represent a transaction, which finishes at some point and delivers	551	used to represent a transaction, which finishes at some point and delivers
397	a result.	552	a result. And yet some people know them as "futures" - a promise to
		553	compute/deliver something that you can wait for.
398		554
399	Condition variables are very useful to signal that something has finished,	555	Condition variables are very useful to signal that something has finished,
400	for example, if you write a module that does asynchronous http requests,	556	for example, if you write a module that does asynchronous http requests,
401	then a condition variable would be the ideal candidate to signal the	557	then a condition variable would be the ideal candidate to signal the
402	availability of results. The user can either act when the callback is	558	availability of results. The user can either act when the callback is
…		…
436	after => 1,	592	after => 1,
437	cb => sub { $result_ready->send },	593	cb => sub { $result_ready->send },
438	);	594	);
439		595
440	# this "blocks" (while handling events) till the callback	596	# this "blocks" (while handling events) till the callback
441	# calls send	597	# calls -<send
442	$result_ready->recv;	598	$result_ready->recv;
443		599
444	Example: wait for a timer, but take advantage of the fact that	600	Example: wait for a timer, but take advantage of the fact that condition
445	condition variables are also code references.	601	variables are also callable directly.
446		602
447	my $done = AnyEvent->condvar;	603	my $done = AnyEvent->condvar;
448	my $delay = AnyEvent->timer (after => 5, cb => $done);	604	my $delay = AnyEvent->timer (after => 5, cb => $done);
449	$done->recv;	605	$done->recv;
		606
		607	Example: Imagine an API that returns a condvar and doesn't support
		608	callbacks. This is how you make a synchronous call, for example from
		609	the main program:
		610
		611	use AnyEvent::CouchDB;
		612
		613	...
		614
		615	my @info = $couchdb->info->recv;
		616
		617	And this is how you would just set a callback to be called whenever the
		618	results are available:
		619
		620	$couchdb->info->cb (sub {
		621	my @info = $_[0]->recv;
		622	});
450		623
451	=head3 METHODS FOR PRODUCERS	624	=head3 METHODS FOR PRODUCERS
452		625
453	These methods should only be used by the producing side, i.e. the	626	These methods should only be used by the producing side, i.e. the
454	code/module that eventually sends the signal. Note that it is also	627	code/module that eventually sends the signal. Note that it is also
…		…
467	immediately from within send.	640	immediately from within send.
468		641
469	Any arguments passed to the C<send> call will be returned by all	642	Any arguments passed to the C<send> call will be returned by all
470	future C<< ->recv >> calls.	643	future C<< ->recv >> calls.
471		644
472	Condition variables are overloaded so one can call them directly	645	Condition variables are overloaded so one can call them directly (as if
473	(as a code reference). Calling them directly is the same as calling	646	they were a code reference). Calling them directly is the same as calling
474	C<send>. Note, however, that many C-based event loops do not handle	647	C<send>.
475	overloading, so as tempting as it may be, passing a condition variable
476	instead of a callback does not work. Both the pure perl and EV loops
477	support overloading, however, as well as all functions that use perl to
478	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
479	example).
480		648
481	=item $cv->croak ($error)	649	=item $cv->croak ($error)
482		650
483	Similar to send, but causes all call's to C<< ->recv >> to invoke	651	Similar to send, but causes all call's to C<< ->recv >> to invoke
484	C<Carp::croak> with the given error message/object/scalar.	652	C<Carp::croak> with the given error message/object/scalar.
485		653
486	This can be used to signal any errors to the condition variable	654	This can be used to signal any errors to the condition variable
487	user/consumer.	655	user/consumer. Doing it this way instead of calling C<croak> directly
		656	delays the error detetcion, but has the overwhelmign advantage that it
		657	diagnoses the error at the place where the result is expected, and not
		658	deep in some event clalback without connection to the actual code causing
		659	the problem.
488		660
489	=item $cv->begin ([group callback])	661	=item $cv->begin ([group callback])
490		662
491	=item $cv->end	663	=item $cv->end
492
493	These two methods are EXPERIMENTAL and MIGHT CHANGE.
494		664
495	These two methods can be used to combine many transactions/events into	665	These two methods can be used to combine many transactions/events into
496	one. For example, a function that pings many hosts in parallel might want	666	one. For example, a function that pings many hosts in parallel might want
497	to use a condition variable for the whole process.	667	to use a condition variable for the whole process.
498		668
…		…
500	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
501	>>, the (last) callback passed to C<begin> will be executed. That callback	671	>>, the (last) callback passed to C<begin> will be executed. That callback
502	is I<supposed> to call C<< ->send >>, but that is not required. If no	672	is I<supposed> to call C<< ->send >>, but that is not required. If no
503	callback was set, C<send> will be called without any arguments.	673	callback was set, C<send> will be called without any arguments.
504		674
505	Let's clarify this with the ping example:	675	You can think of C<< $cv->send >> giving you an OR condition (one call
		676	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		677	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		678
		679	Let's start with a simple example: you have two I/O watchers (for example,
		680	STDOUT and STDERR for a program), and you want to wait for both streams to
		681	close before activating a condvar:
		682
		683	my $cv = AnyEvent->condvar;
		684
		685	$cv->begin; # first watcher
		686	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		687	defined sysread $fh1, my $buf, 4096
		688	or $cv->end;
		689	});
		690
		691	$cv->begin; # second watcher
		692	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		693	defined sysread $fh2, my $buf, 4096
		694	or $cv->end;
		695	});
		696
		697	$cv->recv;
		698
		699	This works because for every event source (EOF on file handle), there is
		700	one call to C<begin>, so the condvar waits for all calls to C<end> before
		701	sending.
		702
		703	The ping example mentioned above is slightly more complicated, as the
		704	there are results to be passwd back, and the number of tasks that are
		705	begung can potentially be zero:
506		706
507	my $cv = AnyEvent->condvar;	707	my $cv = AnyEvent->condvar;
508		708
509	my %result;	709	my %result;
510	$cv->begin (sub { $cv->send (\%result) });	710	$cv->begin (sub { $cv->send (\%result) });
…		…
530	loop, which serves two important purposes: first, it sets the callback	730	loop, which serves two important purposes: first, it sets the callback
531	to be called once the counter reaches C<0>, and second, it ensures that	731	to be called once the counter reaches C<0>, and second, it ensures that
532	C<send> is called even when C<no> hosts are being pinged (the loop	732	C<send> is called even when C<no> hosts are being pinged (the loop
533	doesn't execute once).	733	doesn't execute once).
534		734
535	This is the general pattern when you "fan out" into multiple subrequests:	735	This is the general pattern when you "fan out" into multiple (but
536	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	736	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
537	is called at least once, and then, for each subrequest you start, call	737	the callback and ensure C<end> is called at least once, and then, for each
538	C<begin> and for each subrequest you finish, call C<end>.	738	subrequest you start, call C<begin> and for each subrequest you finish,
		739	call C<end>.
539		740
540	=back	741	=back
541		742
542	=head3 METHODS FOR CONSUMERS	743	=head3 METHODS FOR CONSUMERS
543		744
…		…
559	function will call C<croak>.	760	function will call C<croak>.
560		761
561	In list context, all parameters passed to C<send> will be returned,	762	In list context, all parameters passed to C<send> will be returned,
562	in scalar context only the first one will be returned.	763	in scalar context only the first one will be returned.
563		764
		765	Note that doing a blocking wait in a callback is not supported by any
		766	event loop, that is, recursive invocation of a blocking C<< ->recv
		767	>> is not allowed, and the C<recv> call will C<croak> if such a
		768	condition is detected. This condition can be slightly loosened by using
		769	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		770	any thread that doesn't run the event loop itself.
		771
564	Not all event models support a blocking wait - some die in that case	772	Not all event models support a blocking wait - some die in that case
565	(programs might want to do that to stay interactive), so I<if you are	773	(programs might want to do that to stay interactive), so I<if you are
566	using this from a module, never require a blocking wait>, but let the	774	using this from a module, never require a blocking wait>. Instead, let the
567	caller decide whether the call will block or not (for example, by coupling	775	caller decide whether the call will block or not (for example, by coupling
568	condition variables with some kind of request results and supporting	776	condition variables with some kind of request results and supporting
569	callbacks so the caller knows that getting the result will not block,	777	callbacks so the caller knows that getting the result will not block,
570	while still supporting blocking waits if the caller so desires).	778	while still supporting blocking waits if the caller so desires).
571		779
572	Another reason I<never> to C<< ->recv >> in a module is that you cannot
573	sensibly have two C<< ->recv >>'s in parallel, as that would require
574	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
575	can supply.
576
577	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
578	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
579	versions and also integrates coroutines into AnyEvent, making blocking
580	C<< ->recv >> calls perfectly safe as long as they are done from another
581	coroutine (one that doesn't run the event loop).
582
583	You can ensure that C<< -recv >> never blocks by setting a callback and	780	You can ensure that C<< -recv >> never blocks by setting a callback and
584	only calling C<< ->recv >> from within that callback (or at a later	781	only calling C<< ->recv >> from within that callback (or at a later
585	time). This will work even when the event loop does not support blocking	782	time). This will work even when the event loop does not support blocking
586	waits otherwise.	783	waits otherwise.
587		784
588	=item $bool = $cv->ready	785	=item $bool = $cv->ready
589		786
590	Returns true when the condition is "true", i.e. whether C<send> or	787	Returns true when the condition is "true", i.e. whether C<send> or
591	C<croak> have been called.	788	C<croak> have been called.
592		789
593	=item $cb = $cv->cb ([new callback])	790	=item $cb = $cv->cb ($cb->($cv))
594		791
595	This is a mutator function that returns the callback set and optionally	792	This is a mutator function that returns the callback set and optionally
596	replaces it before doing so.	793	replaces it before doing so.
597		794
598	The callback will be called when the condition becomes "true", i.e. when	795	The callback will be called when the condition becomes (or already was)
599	C<send> or C<croak> are called, with the only argument being the condition	796	"true", i.e. when C<send> or C<croak> are called (or were called), with
600	variable itself. Calling C<recv> inside the callback or at any later time	797	the only argument being the condition variable itself. Calling C<recv>
601	is guaranteed not to block.	798	inside the callback or at any later time is guaranteed not to block.
602		799
603	=back	800	=back
604		801
		802	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		803
		804	The available backend classes are (every class has its own manpage):
		805
		806	=over 4
		807
		808	=item Backends that are autoprobed when no other event loop can be found.
		809
		810	EV is the preferred backend when no other event loop seems to be in
		811	use. If EV is not installed, then AnyEvent will fall back to its own
		812	pure-perl implementation, which is available everywhere as it comes with
		813	AnyEvent itself.
		814
		815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		816	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		817
		818	=item Backends that are transparently being picked up when they are used.
		819
		820	These will be used when they are currently loaded when the first watcher
		821	is created, in which case it is assumed that the application is using
		822	them. This means that AnyEvent will automatically pick the right backend
		823	when the main program loads an event module before anything starts to
		824	create watchers. Nothing special needs to be done by the main program.
		825
		826	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		827	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		828	AnyEvent::Impl::Tk based on Tk, very broken.
		829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		830	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		831	AnyEvent::Impl::Irssi used when running within irssi.
		832
		833	=item Backends with special needs.
		834
		835	Qt requires the Qt::Application to be instantiated first, but will
		836	otherwise be picked up automatically. As long as the main program
		837	instantiates the application before any AnyEvent watchers are created,
		838	everything should just work.
		839
		840	AnyEvent::Impl::Qt based on Qt.
		841
		842	Support for IO::Async can only be partial, as it is too broken and
		843	architecturally limited to even support the AnyEvent API. It also
		844	is the only event loop that needs the loop to be set explicitly, so
		845	it can only be used by a main program knowing about AnyEvent. See
		846	L<AnyEvent::Impl::Async> for the gory details.
		847
		848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		849
		850	=item Event loops that are indirectly supported via other backends.
		851
		852	Some event loops can be supported via other modules:
		853
		854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		855
		856	B<WxWidgets> has no support for watching file handles. However, you can
		857	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		858	polls 20 times per second, which was considered to be too horrible to even
		859	consider for AnyEvent.
		860
		861	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		862	backend, so it can be supported through POE.
		863
		864	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		865	load L<POE> when detecting them, in the hope that POE will pick them up,
		866	in which case everything will be automatic.
		867
		868	=back
		869
605	=head1 GLOBAL VARIABLES AND FUNCTIONS	870	=head1 GLOBAL VARIABLES AND FUNCTIONS
606		871
		872	These are not normally required to use AnyEvent, but can be useful to
		873	write AnyEvent extension modules.
		874
607	=over 4	875	=over 4
608		876
609	=item $AnyEvent::MODEL	877	=item $AnyEvent::MODEL
610		878
611	Contains C<undef> until the first watcher is being created. Then it	879	Contains C<undef> until the first watcher is being created, before the
		880	backend has been autodetected.
		881
612	contains the event model that is being used, which is the name of the	882	Afterwards it contains the event model that is being used, which is the
613	Perl class implementing the model. This class is usually one of the	883	name of the Perl class implementing the model. This class is usually one
614	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
615	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
616		886	will be C<urxvt::anyevent>).
617	The known classes so far are:
618
619	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
620	AnyEvent::Impl::Event based on Event, second best choice.
621	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
622	AnyEvent::Impl::Glib based on Glib, third-best choice.
623	AnyEvent::Impl::Tk based on Tk, very bad choice.
624	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
625	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
626	AnyEvent::Impl::POE based on POE, not generic enough for full support.
627
628	There is no support for WxWidgets, as WxWidgets has no support for
629	watching file handles. However, you can use WxWidgets through the
630	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
631	second, which was considered to be too horrible to even consider for
632	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
633	it's adaptor.
634
635	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
636	autodetecting them.
637		887
638	=item AnyEvent::detect	888	=item AnyEvent::detect
639		889
640	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
641	if necessary. You should only call this function right before you would	891	if necessary. You should only call this function right before you would
642	have created an AnyEvent watcher anyway, that is, as late as possible at	892	have created an AnyEvent watcher anyway, that is, as late as possible at
643	runtime.	893	runtime, and not e.g. while initialising of your module.
		894
		895	If you need to do some initialisation before AnyEvent watchers are
		896	created, use C<post_detect>.
644		897
645	=item $guard = AnyEvent::post_detect { BLOCK }	898	=item $guard = AnyEvent::post_detect { BLOCK }
646		899
647	Arranges for the code block to be executed as soon as the event model is	900	Arranges for the code block to be executed as soon as the event model is
648	autodetected (or immediately if this has already happened).	901	autodetected (or immediately if this has already happened).
649		902
		903	The block will be executed I<after> the actual backend has been detected
		904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		906	other initialisations - see the sources of L<AnyEvent::Strict> or
		907	L<AnyEvent::AIO> to see how this is used.
		908
		909	The most common usage is to create some global watchers, without forcing
		910	event module detection too early, for example, L<AnyEvent::AIO> creates
		911	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		912	avoid autodetecting the event module at load time.
		913
650	If called in scalar or list context, then it creates and returns an object	914	If called in scalar or list context, then it creates and returns an object
651	that automatically removes the callback again when it is destroyed. See	915	that automatically removes the callback again when it is destroyed (or
		916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
652	L<Coro::BDB> for a case where this is useful.	917	a case where this is useful.
		918
		919	Example: Create a watcher for the IO::AIO module and store it in
		920	C<$WATCHER>. Only do so after the event loop is initialised, though.
		921
		922	our WATCHER;
		923
		924	my $guard = AnyEvent::post_detect {
		925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		926	};
		927
		928	# the ||= is important in case post_detect immediately runs the block,
		929	# as to not clobber the newly-created watcher. assigning both watcher and
		930	# post_detect guard to the same variable has the advantage of users being
		931	# able to just C<undef $WATCHER> if the watcher causes them grief.
		932
		933	$WATCHER ||= $guard;
653		934
654	=item @AnyEvent::post_detect	935	=item @AnyEvent::post_detect
655		936
656	If there are any code references in this array (you can C<push> to it	937	If there are any code references in this array (you can C<push> to it
657	before or after loading AnyEvent), then they will called directly after	938	before or after loading AnyEvent), then they will called directly after
658	the event loop has been chosen.	939	the event loop has been chosen.
659		940
660	You should check C<$AnyEvent::MODEL> before adding to this array, though:	941	You should check C<$AnyEvent::MODEL> before adding to this array, though:
661	if it contains a true value then the event loop has already been detected,	942	if it is defined then the event loop has already been detected, and the
662	and the array will be ignored.	943	array will be ignored.
663		944
664	Best use C<AnyEvent::post_detect { BLOCK }> instead.	945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		946	it,as it takes care of these details.
		947
		948	This variable is mainly useful for modules that can do something useful
		949	when AnyEvent is used and thus want to know when it is initialised, but do
		950	not need to even load it by default. This array provides the means to hook
		951	into AnyEvent passively, without loading it.
665		952
666	=back	953	=back
667		954
668	=head1 WHAT TO DO IN A MODULE	955	=head1 WHAT TO DO IN A MODULE
669		956
…		…
724		1011
725		1012
726	=head1 OTHER MODULES	1013	=head1 OTHER MODULES
727		1014
728	The following is a non-exhaustive list of additional modules that use	1015	The following is a non-exhaustive list of additional modules that use
729	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
730	in the same program. Some of the modules come with AnyEvent, some are	1017	modules and other event loops in the same program. Some of the modules
731	available via CPAN.	1018	come with AnyEvent, most are available via CPAN.
732		1019
733	=over 4	1020	=over 4
734		1021
735	=item L<AnyEvent::Util>	1022	=item L<AnyEvent::Util>
736		1023
…		…
745		1032
746	=item L<AnyEvent::Handle>	1033	=item L<AnyEvent::Handle>
747		1034
748	Provide read and write buffers, manages watchers for reads and writes,	1035	Provide read and write buffers, manages watchers for reads and writes,
749	supports raw and formatted I/O, I/O queued and fully transparent and	1036	supports raw and formatted I/O, I/O queued and fully transparent and
750	non-blocking SSL/TLS.	1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
751		1038
752	=item L<AnyEvent::DNS>	1039	=item L<AnyEvent::DNS>
753		1040
754	Provides rich asynchronous DNS resolver capabilities.	1041	Provides rich asynchronous DNS resolver capabilities.
755		1042
…		…
783		1070
784	=item L<AnyEvent::GPSD>	1071	=item L<AnyEvent::GPSD>
785		1072
786	A non-blocking interface to gpsd, a daemon delivering GPS information.	1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
787		1074
		1075	=item L<AnyEvent::IRC>
		1076
		1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1078
		1079	=item L<AnyEvent::XMPP>
		1080
		1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1082	Net::XMPP2>.
		1083
788	=item L<AnyEvent::IGS>	1084	=item L<AnyEvent::IGS>
789		1085
790	A non-blocking interface to the Internet Go Server protocol (used by	1086	A non-blocking interface to the Internet Go Server protocol (used by
791	L<App::IGS>).	1087	L<App::IGS>).
792		1088
793	=item L<Net::IRC3>
794
795	AnyEvent based IRC client module family.
796
797	=item L<Net::XMPP2>
798
799	AnyEvent based XMPP (Jabber protocol) module family.
800
801	=item L<Net::FCP>	1089	=item L<Net::FCP>
802		1090
803	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
804	of AnyEvent.	1092	of AnyEvent.
805		1093
…		…
809		1097
810	=item L<Coro>	1098	=item L<Coro>
811		1099
812	Has special support for AnyEvent via L<Coro::AnyEvent>.	1100	Has special support for AnyEvent via L<Coro::AnyEvent>.
813		1101
814	=item L<IO::Lambda>
815
816	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
817
818	=back	1102	=back
819		1103
820	=cut	1104	=cut
821		1105
822	package AnyEvent;	1106	package AnyEvent;
823		1107
		1108	# basically a tuned-down version of common::sense
		1109	sub common_sense {
824	no warnings;	1110	# no warnings
825	use strict;	1111	${^WARNING_BITS} ^= ${^WARNING_BITS};
		1112	# use strict vars subs
		1113	$^H |= 0x00000600;
		1114	}
826		1115
		1116	BEGIN { AnyEvent::common_sense }
		1117
827	use Carp;	1118	use Carp ();
828		1119
829	our $VERSION = 4.2;	1120	our $VERSION = '5.0';
830	our $MODEL;	1121	our $MODEL;
831		1122
832	our $AUTOLOAD;	1123	our $AUTOLOAD;
833	our @ISA;	1124	our @ISA;
834		1125
835	our @REGISTRY;	1126	our @REGISTRY;
836		1127
837	our $WIN32;	1128	our $WIN32;
838		1129
		1130	our $VERBOSE;
		1131
839	BEGIN {	1132	BEGIN {
840	my $win32 = ! ! ($^O =~ /mswin32/i);	1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
841	eval "sub WIN32(){ $win32 }";	1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
842	}
843		1135
		1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1137	if ${^TAINT};
		1138
844	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1140
		1141	}
		1142
		1143	our $MAX_SIGNAL_LATENCY = 10;
845		1144
846	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1145	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
847		1146
848	{	1147	{
849	my $idx;	1148	my $idx;
…		…
851	for reverse split /\s*,\s*/,	1150	for reverse split /\s*,\s*/,
852	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
853	}	1152	}
854		1153
855	my @models = (	1154	my @models = (
856	[EV:: => AnyEvent::Impl::EV::],	1155	[EV:: => AnyEvent::Impl::EV:: , 1],
857	[Event:: => AnyEvent::Impl::Event::],
858	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1156	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
859	# everything below here will not be autoprobed	1157	# everything below here will not (normally) be autoprobed
860	# as the pureperl backend should work everywhere	1158	# as the pureperl backend should work everywhere
861	# and is usually faster	1159	# and is usually faster
		1160	[Event:: => AnyEvent::Impl::Event::, 1],
		1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
862	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
863	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
864	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
865	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
866	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
867	[Wx:: => AnyEvent::Impl::POE::],	1167	[Wx:: => AnyEvent::Impl::POE::],
868	[Prima:: => AnyEvent::Impl::POE::],	1168	[Prima:: => AnyEvent::Impl::POE::],
		1169	# IO::Async is just too broken - we would need workarounds for its
		1170	# byzantine signal and broken child handling, among others.
		1171	# IO::Async is rather hard to detect, as it doesn't have any
		1172	# obvious default class.
		1173	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1174	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1175	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1176	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
869	);	1177	);
870		1178
871	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1179	our %method = map +($_ => 1),
		1180	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
872		1181
873	our @post_detect;	1182	our @post_detect;
874		1183
875	sub post_detect(&) {	1184	sub post_detect(&) {
876	my ($cb) = @_;	1185	my ($cb) = @_;
877		1186
878	if ($MODEL) {	1187	if ($MODEL) {
879	$cb->();	1188	$cb->();
880		1189
881	1	1190	undef
882	} else {	1191	} else {
883	push @post_detect, $cb;	1192	push @post_detect, $cb;
884		1193
885	defined wantarray	1194	defined wantarray
886	? bless \$cb, "AnyEvent::Util::PostDetect"	1195	? bless \$cb, "AnyEvent::Util::postdetect"
887	: ()	1196	: ()
888	}	1197	}
889	}	1198	}
890		1199
891	sub AnyEvent::Util::PostDetect::DESTROY {	1200	sub AnyEvent::Util::postdetect::DESTROY {
892	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1201	@post_detect = grep $_ != ${$_[0]}, @post_detect;
893	}	1202	}
894		1203
895	sub detect() {	1204	sub detect() {
896	unless ($MODEL) {	1205	unless ($MODEL) {
897	no strict 'refs';
898	local $SIG{__DIE__};	1206	local $SIG{__DIE__};
899		1207
900	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1208	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
901	my $model = "AnyEvent::Impl::$1";	1209	my $model = "AnyEvent::Impl::$1";
902	if (eval "require $model") {	1210	if (eval "require $model") {
903	$MODEL = $model;	1211	$MODEL = $model;
904	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1212	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
905	} else {	1213	} else {
906	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1214	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
907	}	1215	}
908	}	1216	}
909		1217
910	# check for already loaded models	1218	# check for already loaded models
911	unless ($MODEL) {	1219	unless ($MODEL) {
912	for (@REGISTRY, @models) {	1220	for (@REGISTRY, @models) {
913	my ($package, $model) = @$_;	1221	my ($package, $model) = @$_;
914	if (${"$package\::VERSION"} > 0) {	1222	if (${"$package\::VERSION"} > 0) {
915	if (eval "require $model") {	1223	if (eval "require $model") {
916	$MODEL = $model;	1224	$MODEL = $model;
917	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1225	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
918	last;	1226	last;
919	}	1227	}
920	}	1228	}
921	}	1229	}
922		1230
923	unless ($MODEL) {	1231	unless ($MODEL) {
924	# try to load a model	1232	# try to autoload a model
925
926	for (@REGISTRY, @models) {	1233	for (@REGISTRY, @models) {
927	my ($package, $model) = @$_;	1234	my ($package, $model, $autoload) = @$_;
		1235	if (
		1236	$autoload
928	if (eval "require $package"	1237	and eval "require $package"
929	and ${"$package\::VERSION"} > 0	1238	and ${"$package\::VERSION"} > 0
930	and eval "require $model") {	1239	and eval "require $model"
		1240	) {
931	$MODEL = $model;	1241	$MODEL = $model;
932	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1242	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
933	last;	1243	last;
934	}	1244	}
935	}	1245	}
936		1246
937	$MODEL	1247	$MODEL
938	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1248	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
939	}	1249	}
940	}	1250	}
941		1251
		1252	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1253
942	unshift @ISA, $MODEL;	1254	unshift @ISA, $MODEL;
943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1255
		1256	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
944		1257
945	(shift @post_detect)->() while @post_detect;	1258	(shift @post_detect)->() while @post_detect;
946	}	1259	}
947		1260
948	$MODEL	1261	$MODEL
…		…
950		1263
951	sub AUTOLOAD {	1264	sub AUTOLOAD {
952	(my $func = $AUTOLOAD) =~ s/.*://;	1265	(my $func = $AUTOLOAD) =~ s/.*://;
953		1266
954	$method{$func}	1267	$method{$func}
955	or croak "$func: not a valid method for AnyEvent objects";	1268	or Carp::croak "$func: not a valid method for AnyEvent objects";
956		1269
957	detect unless $MODEL;	1270	detect unless $MODEL;
958		1271
959	my $class = shift;	1272	my $class = shift;
960	$class->$func (@_);	1273	$class->$func (@_);
961	}	1274	}
962		1275
		1276	# utility function to dup a filehandle. this is used by many backends
		1277	# to support binding more than one watcher per filehandle (they usually
		1278	# allow only one watcher per fd, so we dup it to get a different one).
		1279	sub _dupfh($$;$$) {
		1280	my ($poll, $fh, $r, $w) = @_;
		1281
		1282	# cygwin requires the fh mode to be matching, unix doesn't
		1283	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
		1284
		1285	open my $fh2, $mode, $fh
		1286	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
		1287
		1288	# we assume CLOEXEC is already set by perl in all important cases
		1289
		1290	($fh2, $rw)
		1291	}
		1292
		1293	=head1 SIMPLIFIED AE API
		1294
		1295	Starting with version 5.0, AnyEvent officially supports a second, much
		1296	simpler, API that is designed to reduce the calling, typing and memory
		1297	overhead.
		1298
		1299	See the L<AE> manpage for details.
		1300
		1301	=cut
		1302
		1303	package AE;
		1304
		1305	our $VERSION = $AnyEvent::VERSION;
		1306
		1307	sub io($$$) {
		1308	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1309	}
		1310
		1311	sub timer($$$) {
		1312	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1313	}
		1314
		1315	sub signal($$) {
		1316	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1317	}
		1318
		1319	sub child($$) {
		1320	AnyEvent->child (pid => $_[0], cb => $_[1])
		1321	}
		1322
		1323	sub idle($) {
		1324	AnyEvent->idle (cb => $_[0])
		1325	}
		1326
		1327	sub cv(;&) {
		1328	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1329	}
		1330
		1331	sub now() {
		1332	AnyEvent->now
		1333	}
		1334
		1335	sub now_update() {
		1336	AnyEvent->now_update
		1337	}
		1338
		1339	sub time() {
		1340	AnyEvent->time
		1341	}
		1342
963	package AnyEvent::Base;	1343	package AnyEvent::Base;
964		1344
965	# default implementation for now and time	1345	# default implementations for many methods
966		1346
967	use Time::HiRes ();	1347	sub _time {
		1348	# probe for availability of Time::HiRes
		1349	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1350	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1351	*_time = \&Time::HiRes::time;
		1352	# if (eval "use POSIX (); (POSIX::times())...
		1353	} else {
		1354	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
		1355	*_time = sub { time }; # epic fail
		1356	}
968		1357
969	sub time { Time::HiRes::time }	1358	&_time
970	sub now { Time::HiRes::time }	1359	}
		1360
		1361	sub time { _time }
		1362	sub now { _time }
		1363	sub now_update { }
971		1364
972	# default implementation for ->condvar	1365	# default implementation for ->condvar
973		1366
974	sub condvar {	1367	sub condvar {
975	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1368	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
976	}	1369	}
977		1370
978	# default implementation for ->signal	1371	# default implementation for ->signal
979		1372
980	our %SIG_CB;	1373	our $HAVE_ASYNC_INTERRUPT;
		1374
		1375	sub _have_async_interrupt() {
		1376	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1377	&& eval "use Async::Interrupt 1.0 (); 1")
		1378	unless defined $HAVE_ASYNC_INTERRUPT;
		1379
		1380	$HAVE_ASYNC_INTERRUPT
		1381	}
		1382
		1383	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1384	our (%SIG_ASY, %SIG_ASY_W);
		1385	our ($SIG_COUNT, $SIG_TW);
		1386
		1387	sub _signal_exec {
		1388	$HAVE_ASYNC_INTERRUPT
		1389	? $SIGPIPE_R->drain
		1390	: sysread $SIGPIPE_R, my $dummy, 9;
		1391
		1392	while (%SIG_EV) {
		1393	for (keys %SIG_EV) {
		1394	delete $SIG_EV{$_};
		1395	$_->() for values %{ $SIG_CB{$_} || {} };
		1396	}
		1397	}
		1398	}
		1399
		1400	# install a dummy wakeup watcher to reduce signal catching latency
		1401	sub _sig_add() {
		1402	unless ($SIG_COUNT++) {
		1403	# try to align timer on a full-second boundary, if possible
		1404	my $NOW = AE::now;
		1405
		1406	$SIG_TW = AE::timer
		1407	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1408	$MAX_SIGNAL_LATENCY,
		1409	sub { } # just for the PERL_ASYNC_CHECK
		1410	;
		1411	}
		1412	}
		1413
		1414	sub _sig_del {
		1415	undef $SIG_TW
		1416	unless --$SIG_COUNT;
		1417	}
		1418
		1419	our $_sig_name_init; $_sig_name_init = sub {
		1420	eval q{ # poor man's autoloading
		1421	undef $_sig_name_init;
		1422
		1423	if (_have_async_interrupt) {
		1424	*sig2num = \&Async::Interrupt::sig2num;
		1425	*sig2name = \&Async::Interrupt::sig2name;
		1426	} else {
		1427	require Config;
		1428
		1429	my %signame2num;
		1430	@signame2num{ split ' ', $Config::Config{sig_name} }
		1431	= split ' ', $Config::Config{sig_num};
		1432
		1433	my @signum2name;
		1434	@signum2name[values %signame2num] = keys %signame2num;
		1435
		1436	*sig2num = sub($) {
		1437	$_[0] > 0 ? shift : $signame2num{+shift}
		1438	};
		1439	*sig2name = sub ($) {
		1440	$_[0] > 0 ? $signum2name[+shift] : shift
		1441	};
		1442	}
		1443	};
		1444	die if $@;
		1445	};
		1446
		1447	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1448	sub sig2name($) { &$_sig_name_init; &sig2name }
981		1449
982	sub signal {	1450	sub signal {
		1451	eval q{ # poor man's autoloading {}
		1452	# probe for availability of Async::Interrupt
		1453	if (_have_async_interrupt) {
		1454	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1455
		1456	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1457	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1458
		1459	} else {
		1460	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1461
		1462	require Fcntl;
		1463
		1464	if (AnyEvent::WIN32) {
		1465	require AnyEvent::Util;
		1466
		1467	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1468	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1469	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1470	} else {
		1471	pipe $SIGPIPE_R, $SIGPIPE_W;
		1472	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1473	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1474
		1475	# not strictly required, as $^F is normally 2, but let's make sure...
		1476	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1477	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1478	}
		1479
		1480	$SIGPIPE_R
		1481	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1482
		1483	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1484	}
		1485
		1486	*signal = sub {
983	my (undef, %arg) = @_;	1487	my (undef, %arg) = @_;
984		1488
985	my $signal = uc $arg{signal}	1489	my $signal = uc $arg{signal}
986	or Carp::croak "required option 'signal' is missing";	1490	or Carp::croak "required option 'signal' is missing";
987		1491
		1492	if ($HAVE_ASYNC_INTERRUPT) {
		1493	# async::interrupt
		1494
		1495	$signal = sig2num $signal;
988	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1496	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1497
		1498	$SIG_ASY{$signal} ||= new Async::Interrupt
		1499	cb => sub { undef $SIG_EV{$signal} },
		1500	signal => $signal,
		1501	pipe => [$SIGPIPE_R->filenos],
		1502	pipe_autodrain => 0,
		1503	;
		1504
		1505	} else {
		1506	# pure perl
		1507
		1508	# AE::Util has been loaded in signal
		1509	$signal = sig2name $signal;
		1510	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1511
989	$SIG{$signal} ||= sub {	1512	$SIG{$signal} ||= sub {
990	$_->() for values %{ $SIG_CB{$signal} || {} };	1513	local $!;
		1514	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1515	undef $SIG_EV{$signal};
		1516	};
		1517
		1518	# can't do signal processing without introducing races in pure perl,
		1519	# so limit the signal latency.
		1520	_sig_add;
		1521	}
		1522
		1523	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1524	};
		1525
		1526	*AnyEvent::Base::signal::DESTROY = sub {
		1527	my ($signal, $cb) = @{$_[0]};
		1528
		1529	_sig_del;
		1530
		1531	delete $SIG_CB{$signal}{$cb};
		1532
		1533	$HAVE_ASYNC_INTERRUPT
		1534	? delete $SIG_ASY{$signal}
		1535	: # delete doesn't work with older perls - they then
		1536	# print weird messages, or just unconditionally exit
		1537	# instead of getting the default action.
		1538	undef $SIG{$signal}
		1539	unless keys %{ $SIG_CB{$signal} };
		1540	};
991	};	1541	};
992		1542	die if $@;
993	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1543	&signal
994	}
995
996	sub AnyEvent::Base::Signal::DESTROY {
997	my ($signal, $cb) = @{$_[0]};
998
999	delete $SIG_CB{$signal}{$cb};
1000
1001	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1002	}	1544	}
1003		1545
1004	# default implementation for ->child	1546	# default implementation for ->child
1005		1547
1006	our %PID_CB;	1548	our %PID_CB;
1007	our $CHLD_W;	1549	our $CHLD_W;
1008	our $CHLD_DELAY_W;	1550	our $CHLD_DELAY_W;
1009	our $PID_IDLE;
1010	our $WNOHANG;	1551	our $WNOHANG;
1011		1552
1012	sub _child_wait {	1553	sub _emit_childstatus($$) {
1013	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1554	my (undef, $rpid, $rstatus) = @_;
		1555
		1556	$_->($rpid, $rstatus)
1014	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1557	for values %{ $PID_CB{$rpid} || {} },
1015	(values %{ $PID_CB{0} || {} });	1558	values %{ $PID_CB{0} || {} };
1016	}
1017
1018	undef $PID_IDLE;
1019	}	1559	}
1020		1560
1021	sub _sigchld {	1561	sub _sigchld {
1022	# make sure we deliver these changes "synchronous" with the event loop.	1562	my $pid;
1023	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {	1563
1024	undef $CHLD_DELAY_W;	1564	AnyEvent->_emit_childstatus ($pid, $?)
1025	&_child_wait;	1565	while ($pid = waitpid -1, $WNOHANG) > 0;
1026	});
1027	}	1566	}
1028		1567
1029	sub child {	1568	sub child {
1030	my (undef, %arg) = @_;	1569	my (undef, %arg) = @_;
1031		1570
1032	defined (my $pid = $arg{pid} + 0)	1571	defined (my $pid = $arg{pid} + 0)
1033	or Carp::croak "required option 'pid' is missing";	1572	or Carp::croak "required option 'pid' is missing";
1034		1573
1035	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1574	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1036		1575
1037	unless ($WNOHANG) {	1576	# WNOHANG is almost cetrainly 1 everywhere
		1577	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1578	? 1
1038	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1579	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1039	}
1040		1580
1041	unless ($CHLD_W) {	1581	unless ($CHLD_W) {
1042	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1582	$CHLD_W = AE::signal CHLD => \&_sigchld;
1043	# child could be a zombie already, so make at least one round	1583	# child could be a zombie already, so make at least one round
1044	&_sigchld;	1584	&_sigchld;
1045	}	1585	}
1046		1586
1047	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1587	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1048	}	1588	}
1049		1589
1050	sub AnyEvent::Base::Child::DESTROY {	1590	sub AnyEvent::Base::child::DESTROY {
1051	my ($pid, $cb) = @{$_[0]};	1591	my ($pid, $cb) = @{$_[0]};
1052		1592
1053	delete $PID_CB{$pid}{$cb};	1593	delete $PID_CB{$pid}{$cb};
1054	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1594	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1055		1595
1056	undef $CHLD_W unless keys %PID_CB;	1596	undef $CHLD_W unless keys %PID_CB;
1057	}	1597	}
1058		1598
		1599	# idle emulation is done by simply using a timer, regardless
		1600	# of whether the process is idle or not, and not letting
		1601	# the callback use more than 50% of the time.
		1602	sub idle {
		1603	my (undef, %arg) = @_;
		1604
		1605	my ($cb, $w, $rcb) = $arg{cb};
		1606
		1607	$rcb = sub {
		1608	if ($cb) {
		1609	$w = _time;
		1610	&$cb;
		1611	$w = _time - $w;
		1612
		1613	# never use more then 50% of the time for the idle watcher,
		1614	# within some limits
		1615	$w = 0.0001 if $w < 0.0001;
		1616	$w = 5 if $w > 5;
		1617
		1618	$w = AE::timer $w, 0, $rcb;
		1619	} else {
		1620	# clean up...
		1621	undef $w;
		1622	undef $rcb;
		1623	}
		1624	};
		1625
		1626	$w = AE::timer 0.05, 0, $rcb;
		1627
		1628	bless \\$cb, "AnyEvent::Base::idle"
		1629	}
		1630
		1631	sub AnyEvent::Base::idle::DESTROY {
		1632	undef $${$_[0]};
		1633	}
		1634
1059	package AnyEvent::CondVar;	1635	package AnyEvent::CondVar;
1060		1636
1061	our @ISA = AnyEvent::CondVar::Base::;	1637	our @ISA = AnyEvent::CondVar::Base::;
1062		1638
1063	package AnyEvent::CondVar::Base;	1639	package AnyEvent::CondVar::Base;
1064		1640
1065	use overload	1641	#use overload
1066	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1642	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1067	fallback => 1;	1643	# fallback => 1;
		1644
		1645	# save 300+ kilobytes by dirtily hardcoding overloading
		1646	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1647	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1648	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1649	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1650
		1651	our $WAITING;
1068		1652
1069	sub _send {	1653	sub _send {
1070	# nop	1654	# nop
1071	}	1655	}
1072		1656
…		…
1085	sub ready {	1669	sub ready {
1086	$_[0]{_ae_sent}	1670	$_[0]{_ae_sent}
1087	}	1671	}
1088		1672
1089	sub _wait {	1673	sub _wait {
		1674	$WAITING
		1675	and !$_[0]{_ae_sent}
		1676	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1677
		1678	local $WAITING = 1;
1090	AnyEvent->one_event while !$_[0]{_ae_sent};	1679	AnyEvent->one_event while !$_[0]{_ae_sent};
1091	}	1680	}
1092		1681
1093	sub recv {	1682	sub recv {
1094	$_[0]->_wait;	1683	$_[0]->_wait;
…		…
1096	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1685	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1097	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1686	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1098	}	1687	}
1099		1688
1100	sub cb {	1689	sub cb {
1101	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1690	my $cv = shift;
		1691
		1692	@_
		1693	and $cv->{_ae_cb} = shift
		1694	and $cv->{_ae_sent}
		1695	and (delete $cv->{_ae_cb})->($cv);
		1696
1102	$_[0]{_ae_cb}	1697	$cv->{_ae_cb}
1103	}	1698	}
1104		1699
1105	sub begin {	1700	sub begin {
1106	++$_[0]{_ae_counter};	1701	++$_[0]{_ae_counter};
1107	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1702	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1113	}	1708	}
1114		1709
1115	# undocumented/compatibility with pre-3.4	1710	# undocumented/compatibility with pre-3.4
1116	*broadcast = \&send;	1711	*broadcast = \&send;
1117	*wait = \&_wait;	1712	*wait = \&_wait;
		1713
		1714	=head1 ERROR AND EXCEPTION HANDLING
		1715
		1716	In general, AnyEvent does not do any error handling - it relies on the
		1717	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1718	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1719	checking of all AnyEvent methods, however, which is highly useful during
		1720	development.
		1721
		1722	As for exception handling (i.e. runtime errors and exceptions thrown while
		1723	executing a callback), this is not only highly event-loop specific, but
		1724	also not in any way wrapped by this module, as this is the job of the main
		1725	program.
		1726
		1727	The pure perl event loop simply re-throws the exception (usually
		1728	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1729	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1730	so on.
		1731
		1732	=head1 ENVIRONMENT VARIABLES
		1733
		1734	The following environment variables are used by this module or its
		1735	submodules.
		1736
		1737	Note that AnyEvent will remove I<all> environment variables starting with
		1738	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1739	enabled.
		1740
		1741	=over 4
		1742
		1743	=item C<PERL_ANYEVENT_VERBOSE>
		1744
		1745	By default, AnyEvent will be completely silent except in fatal
		1746	conditions. You can set this environment variable to make AnyEvent more
		1747	talkative.
		1748
		1749	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1750	conditions, such as not being able to load the event model specified by
		1751	C<PERL_ANYEVENT_MODEL>.
		1752
		1753	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1754	model it chooses.
		1755
		1756	When set to C<8> or higher, then AnyEvent will report extra information on
		1757	which optional modules it loads and how it implements certain features.
		1758
		1759	=item C<PERL_ANYEVENT_STRICT>
		1760
		1761	AnyEvent does not do much argument checking by default, as thorough
		1762	argument checking is very costly. Setting this variable to a true value
		1763	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1764	check the arguments passed to most method calls. If it finds any problems,
		1765	it will croak.
		1766
		1767	In other words, enables "strict" mode.
		1768
		1769	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
		1770	>>, it is definitely recommended to keep it off in production. Keeping
		1771	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1772	can be very useful, however.
		1773
		1774	=item C<PERL_ANYEVENT_MODEL>
		1775
		1776	This can be used to specify the event model to be used by AnyEvent, before
		1777	auto detection and -probing kicks in. It must be a string consisting
		1778	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1779	and the resulting module name is loaded and if the load was successful,
		1780	used as event model. If it fails to load AnyEvent will proceed with
		1781	auto detection and -probing.
		1782
		1783	This functionality might change in future versions.
		1784
		1785	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1786	could start your program like this:
		1787
		1788	PERL_ANYEVENT_MODEL=Perl perl ...
		1789
		1790	=item C<PERL_ANYEVENT_PROTOCOLS>
		1791
		1792	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1793	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1794	of auto probing).
		1795
		1796	Must be set to a comma-separated list of protocols or address families,
		1797	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1798	used, and preference will be given to protocols mentioned earlier in the
		1799	list.
		1800
		1801	This variable can effectively be used for denial-of-service attacks
		1802	against local programs (e.g. when setuid), although the impact is likely
		1803	small, as the program has to handle conenction and other failures anyways.
		1804
		1805	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1806	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1807	- only support IPv4, never try to resolve or contact IPv6
		1808	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1809	IPv6, but prefer IPv6 over IPv4.
		1810
		1811	=item C<PERL_ANYEVENT_EDNS0>
		1812
		1813	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1814	for DNS. This extension is generally useful to reduce DNS traffic, but
		1815	some (broken) firewalls drop such DNS packets, which is why it is off by
		1816	default.
		1817
		1818	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1819	EDNS0 in its DNS requests.
		1820
		1821	=item C<PERL_ANYEVENT_MAX_FORKS>
		1822
		1823	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1824	will create in parallel.
		1825
		1826	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1827
		1828	The default value for the C<max_outstanding> parameter for the default DNS
		1829	resolver - this is the maximum number of parallel DNS requests that are
		1830	sent to the DNS server.
		1831
		1832	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1833
		1834	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1835	configuration) in the default resolver. When set to the empty string, no
		1836	default config will be used.
		1837
		1838	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1839
		1840	When neither C<ca_file> nor C<ca_path> was specified during
		1841	L<AnyEvent::TLS> context creation, and either of these environment
		1842	variables exist, they will be used to specify CA certificate locations
		1843	instead of a system-dependent default.
		1844
		1845	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1846
		1847	When these are set to C<1>, then the respective modules are not
		1848	loaded. Mostly good for testing AnyEvent itself.
		1849
		1850	=back
1118		1851
1119	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1852	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1120		1853
1121	This is an advanced topic that you do not normally need to use AnyEvent in	1854	This is an advanced topic that you do not normally need to use AnyEvent in
1122	a module. This section is only of use to event loop authors who want to	1855	a module. This section is only of use to event loop authors who want to
…		…
1156		1889
1157	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1890	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1158	condition variables: code blocking while waiting for a condition will	1891	condition variables: code blocking while waiting for a condition will
1159	C<die>. This still works with most modules/usages, and blocking calls must	1892	C<die>. This still works with most modules/usages, and blocking calls must
1160	not be done in an interactive application, so it makes sense.	1893	not be done in an interactive application, so it makes sense.
1161
1162	=head1 ENVIRONMENT VARIABLES
1163
1164	The following environment variables are used by this module:
1165
1166	=over 4
1167
1168	=item C<PERL_ANYEVENT_VERBOSE>
1169
1170	By default, AnyEvent will be completely silent except in fatal
1171	conditions. You can set this environment variable to make AnyEvent more
1172	talkative.
1173
1174	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1175	conditions, such as not being able to load the event model specified by
1176	C<PERL_ANYEVENT_MODEL>.
1177
1178	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1179	model it chooses.
1180
1181	=item C<PERL_ANYEVENT_MODEL>
1182
1183	This can be used to specify the event model to be used by AnyEvent, before
1184	auto detection and -probing kicks in. It must be a string consisting
1185	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1186	and the resulting module name is loaded and if the load was successful,
1187	used as event model. If it fails to load AnyEvent will proceed with
1188	auto detection and -probing.
1189
1190	This functionality might change in future versions.
1191
1192	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1193	could start your program like this:
1194
1195	PERL_ANYEVENT_MODEL=Perl perl ...
1196
1197	=item C<PERL_ANYEVENT_PROTOCOLS>
1198
1199	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1200	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1201	of auto probing).
1202
1203	Must be set to a comma-separated list of protocols or address families,
1204	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1205	used, and preference will be given to protocols mentioned earlier in the
1206	list.
1207
1208	This variable can effectively be used for denial-of-service attacks
1209	against local programs (e.g. when setuid), although the impact is likely
1210	small, as the program has to handle connection errors already-
1211
1212	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1213	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1214	- only support IPv4, never try to resolve or contact IPv6
1215	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1216	IPv6, but prefer IPv6 over IPv4.
1217
1218	=item C<PERL_ANYEVENT_EDNS0>
1219
1220	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1221	for DNS. This extension is generally useful to reduce DNS traffic, but
1222	some (broken) firewalls drop such DNS packets, which is why it is off by
1223	default.
1224
1225	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1226	EDNS0 in its DNS requests.
1227
1228	=item C<PERL_ANYEVENT_MAX_FORKS>
1229
1230	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1231	will create in parallel.
1232
1233	=back
1234		1894
1235	=head1 EXAMPLE PROGRAM	1895	=head1 EXAMPLE PROGRAM
1236		1896
1237	The following program uses an I/O watcher to read data from STDIN, a timer	1897	The following program uses an I/O watcher to read data from STDIN, a timer
1238	to display a message once per second, and a condition variable to quit the	1898	to display a message once per second, and a condition variable to quit the
…		…
1401	through AnyEvent. The benchmark creates a lot of timers (with a zero	2061	through AnyEvent. The benchmark creates a lot of timers (with a zero
1402	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2062	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1403	which it is), lets them fire exactly once and destroys them again.	2063	which it is), lets them fire exactly once and destroys them again.
1404		2064
1405	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2065	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1406	distribution.	2066	distribution. It uses the L<AE> interface, which makes a real difference
		2067	for the EV and Perl backends only.
1407		2068
1408	=head3 Explanation of the columns	2069	=head3 Explanation of the columns
1409		2070
1410	I<watcher> is the number of event watchers created/destroyed. Since	2071	I<watcher> is the number of event watchers created/destroyed. Since
1411	different event models feature vastly different performances, each event	2072	different event models feature vastly different performances, each event
…		…
1432	watcher.	2093	watcher.
1433		2094
1434	=head3 Results	2095	=head3 Results
1435		2096
1436	name watchers bytes create invoke destroy comment	2097	name watchers bytes create invoke destroy comment
1437	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2098	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1438	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2099	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1439	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2100	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1440	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2101	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1441	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2102	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1442	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2103	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2104	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2105	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1443	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2106	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1444	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2107	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1445	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2108	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1446	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2109	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1447		2110
1448	=head3 Discussion	2111	=head3 Discussion
1449		2112
1450	The benchmark does I<not> measure scalability of the event loop very	2113	The benchmark does I<not> measure scalability of the event loop very
1451	well. For example, a select-based event loop (such as the pure perl one)	2114	well. For example, a select-based event loop (such as the pure perl one)
…		…
1463	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2126	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1464	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2127	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1465	cycles with POE.	2128	cycles with POE.
1466		2129
1467	C<EV> is the sole leader regarding speed and memory use, which are both	2130	C<EV> is the sole leader regarding speed and memory use, which are both
1468	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2131	maximal/minimal, respectively. When using the L<AE> API there is zero
		2132	overhead (when going through the AnyEvent API create is about 5-6 times
		2133	slower, with other times being equal, so still uses far less memory than
1469	far less memory than any other event loop and is still faster than Event	2134	any other event loop and is still faster than Event natively).
1470	natively.
1471		2135
1472	The pure perl implementation is hit in a few sweet spots (both the	2136	The pure perl implementation is hit in a few sweet spots (both the
1473	constant timeout and the use of a single fd hit optimisations in the perl	2137	constant timeout and the use of a single fd hit optimisations in the perl
1474	interpreter and the backend itself). Nevertheless this shows that it	2138	interpreter and the backend itself). Nevertheless this shows that it
1475	adds very little overhead in itself. Like any select-based backend its	2139	adds very little overhead in itself. Like any select-based backend its
1476	performance becomes really bad with lots of file descriptors (and few of	2140	performance becomes really bad with lots of file descriptors (and few of
1477	them active), of course, but this was not subject of this benchmark.	2141	them active), of course, but this was not subject of this benchmark.
1478		2142
1479	The C<Event> module has a relatively high setup and callback invocation	2143	The C<Event> module has a relatively high setup and callback invocation
1480	cost, but overall scores in on the third place.	2144	cost, but overall scores in on the third place.
		2145
		2146	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2147	when using its pure perl backend.
1481		2148
1482	C<Glib>'s memory usage is quite a bit higher, but it features a	2149	C<Glib>'s memory usage is quite a bit higher, but it features a
1483	faster callback invocation and overall ends up in the same class as	2150	faster callback invocation and overall ends up in the same class as
1484	C<Event>. However, Glib scales extremely badly, doubling the number of	2151	C<Event>. However, Glib scales extremely badly, doubling the number of
1485	watchers increases the processing time by more than a factor of four,	2152	watchers increases the processing time by more than a factor of four,
…		…
1546	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2213	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1547	(1%) are active. This mirrors the activity of large servers with many	2214	(1%) are active. This mirrors the activity of large servers with many
1548	connections, most of which are idle at any one point in time.	2215	connections, most of which are idle at any one point in time.
1549		2216
1550	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2217	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1551	distribution.	2218	distribution. It uses the L<AE> interface, which makes a real difference
		2219	for the EV and Perl backends only.
1552		2220
1553	=head3 Explanation of the columns	2221	=head3 Explanation of the columns
1554		2222
1555	I<sockets> is the number of sockets, and twice the number of "servers" (as	2223	I<sockets> is the number of sockets, and twice the number of "servers" (as
1556	each server has a read and write socket end).	2224	each server has a read and write socket end).
…		…
1563	it to another server. This includes deleting the old timeout and creating	2231	it to another server. This includes deleting the old timeout and creating
1564	a new one that moves the timeout into the future.	2232	a new one that moves the timeout into the future.
1565		2233
1566	=head3 Results	2234	=head3 Results
1567		2235
1568	name sockets create request	2236	name sockets create request
1569	EV 20000 69.01 11.16	2237	EV 20000 62.66 7.99
1570	Perl 20000 73.32 35.87	2238	Perl 20000 68.32 32.64
1571	Event 20000 212.62 257.32	2239	IOAsync 20000 174.06 101.15 epoll
1572	Glib 20000 651.16 1896.30	2240	IOAsync 20000 174.67 610.84 poll
		2241	Event 20000 202.69 242.91
		2242	Glib 20000 557.01 1689.52
1573	POE 20000 349.67 12317.24 uses POE::Loop::Event	2243	POE 20000 341.54 12086.32 uses POE::Loop::Event
1574		2244
1575	=head3 Discussion	2245	=head3 Discussion
1576		2246
1577	This benchmark I<does> measure scalability and overall performance of the	2247	This benchmark I<does> measure scalability and overall performance of the
1578	particular event loop.	2248	particular event loop.
…		…
1580	EV is again fastest. Since it is using epoll on my system, the setup time	2250	EV is again fastest. Since it is using epoll on my system, the setup time
1581	is relatively high, though.	2251	is relatively high, though.
1582		2252
1583	Perl surprisingly comes second. It is much faster than the C-based event	2253	Perl surprisingly comes second. It is much faster than the C-based event
1584	loops Event and Glib.	2254	loops Event and Glib.
		2255
		2256	IO::Async performs very well when using its epoll backend, and still quite
		2257	good compared to Glib when using its pure perl backend.
1585		2258
1586	Event suffers from high setup time as well (look at its code and you will	2259	Event suffers from high setup time as well (look at its code and you will
1587	understand why). Callback invocation also has a high overhead compared to	2260	understand why). Callback invocation also has a high overhead compared to
1588	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2261	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1589	uses select or poll in basically all documented configurations.	2262	uses select or poll in basically all documented configurations.
…		…
1652	=item * C-based event loops perform very well with small number of	2325	=item * C-based event loops perform very well with small number of
1653	watchers, as the management overhead dominates.	2326	watchers, as the management overhead dominates.
1654		2327
1655	=back	2328	=back
1656		2329
		2330	=head2 THE IO::Lambda BENCHMARK
		2331
		2332	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2333	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2334	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2335	shouldn't come as a surprise to anybody). As such, the benchmark is
		2336	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2337	very optimal. But how would AnyEvent compare when used without the extra
		2338	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2339
		2340	The benchmark itself creates an echo-server, and then, for 500 times,
		2341	connects to the echo server, sends a line, waits for the reply, and then
		2342	creates the next connection. This is a rather bad benchmark, as it doesn't
		2343	test the efficiency of the framework or much non-blocking I/O, but it is a
		2344	benchmark nevertheless.
		2345
		2346	name runtime
		2347	Lambda/select 0.330 sec
		2348	+ optimized 0.122 sec
		2349	Lambda/AnyEvent 0.327 sec
		2350	+ optimized 0.138 sec
		2351	Raw sockets/select 0.077 sec
		2352	POE/select, components 0.662 sec
		2353	POE/select, raw sockets 0.226 sec
		2354	POE/select, optimized 0.404 sec
		2355
		2356	AnyEvent/select/nb 0.085 sec
		2357	AnyEvent/EV/nb 0.068 sec
		2358	+state machine 0.134 sec
		2359
		2360	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2361	benchmarks actually make blocking connects and use 100% blocking I/O,
		2362	defeating the purpose of an event-based solution. All of the newly
		2363	written AnyEvent benchmarks use 100% non-blocking connects (using
		2364	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2365	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2366	generally require a lot more bookkeeping and event handling than blocking
		2367	connects (which involve a single syscall only).
		2368
		2369	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2370	offers similar expressive power as POE and IO::Lambda, using conventional
		2371	Perl syntax. This means that both the echo server and the client are 100%
		2372	non-blocking, further placing it at a disadvantage.
		2373
		2374	As you can see, the AnyEvent + EV combination even beats the
		2375	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2376	backend easily beats IO::Lambda and POE.
		2377
		2378	And even the 100% non-blocking version written using the high-level (and
		2379	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2380	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2381	in a non-blocking way.
		2382
		2383	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2384	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2385	part of the IO::lambda distribution and were used without any changes.
		2386
		2387
		2388	=head1 SIGNALS
		2389
		2390	AnyEvent currently installs handlers for these signals:
		2391
		2392	=over 4
		2393
		2394	=item SIGCHLD
		2395
		2396	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2397	emulation for event loops that do not support them natively. Also, some
		2398	event loops install a similar handler.
		2399
		2400	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2401	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2402
		2403	=item SIGPIPE
		2404
		2405	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2406	when AnyEvent gets loaded.
		2407
		2408	The rationale for this is that AnyEvent users usually do not really depend
		2409	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2410	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2411	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2412	some random socket.
		2413
		2414	The rationale for installing a no-op handler as opposed to ignoring it is
		2415	that this way, the handler will be restored to defaults on exec.
		2416
		2417	Feel free to install your own handler, or reset it to defaults.
		2418
		2419	=back
		2420
		2421	=cut
		2422
		2423	undef $SIG{CHLD}
		2424	if $SIG{CHLD} eq 'IGNORE';
		2425
		2426	$SIG{PIPE} = sub { }
		2427	unless defined $SIG{PIPE};
		2428
		2429	=head1 RECOMMENDED/OPTIONAL MODULES
		2430
		2431	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2432	it's built-in modules) are required to use it.
		2433
		2434	That does not mean that AnyEvent won't take advantage of some additional
		2435	modules if they are installed.
		2436
		2437	This section epxlains which additional modules will be used, and how they
		2438	affect AnyEvent's operetion.
		2439
		2440	=over 4
		2441
		2442	=item L<Async::Interrupt>
		2443
		2444	This slightly arcane module is used to implement fast signal handling: To
		2445	my knowledge, there is no way to do completely race-free and quick
		2446	signal handling in pure perl. To ensure that signals still get
		2447	delivered, AnyEvent will start an interval timer to wake up perl (and
		2448	catch the signals) with some delay (default is 10 seconds, look for
		2449	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2450
		2451	If this module is available, then it will be used to implement signal
		2452	catching, which means that signals will not be delayed, and the event loop
		2453	will not be interrupted regularly, which is more efficient (And good for
		2454	battery life on laptops).
		2455
		2456	This affects not just the pure-perl event loop, but also other event loops
		2457	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2458
		2459	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2460	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2461	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2462	does nothing for those backends.
		2463
		2464	=item L<EV>
		2465
		2466	This module isn't really "optional", as it is simply one of the backend
		2467	event loops that AnyEvent can use. However, it is simply the best event
		2468	loop available in terms of features, speed and stability: It supports
		2469	the AnyEvent API optimally, implements all the watcher types in XS, does
		2470	automatic timer adjustments even when no monotonic clock is available,
		2471	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2472	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2473	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2474
		2475	=item L<Guard>
		2476
		2477	The guard module, when used, will be used to implement
		2478	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2479	lot less memory), but otherwise doesn't affect guard operation much. It is
		2480	purely used for performance.
		2481
		2482	=item L<JSON> and L<JSON::XS>
		2483
		2484	This module is required when you want to read or write JSON data via
		2485	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2486	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2487
		2488	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2489	installed.
		2490
		2491	=item L<Net::SSLeay>
		2492
		2493	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2494	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2495	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2496
		2497	=item L<Time::HiRes>
		2498
		2499	This module is part of perl since release 5.008. It will be used when the
		2500	chosen event library does not come with a timing source on it's own. The
		2501	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2502	try to use a monotonic clock for timing stability.
		2503
		2504	=back
		2505
1657		2506
1658	=head1 FORK	2507	=head1 FORK
1659		2508
1660	Most event libraries are not fork-safe. The ones who are usually are	2509	Most event libraries are not fork-safe. The ones who are usually are
1661	because they rely on inefficient but fork-safe C<select> or C<poll>	2510	because they rely on inefficient but fork-safe C<select> or C<poll>
1662	calls. Only L<EV> is fully fork-aware.	2511	calls. Only L<EV> is fully fork-aware.
1663		2512
1664	If you have to fork, you must either do so I<before> creating your first	2513	If you have to fork, you must either do so I<before> creating your first
1665	watcher OR you must not use AnyEvent at all in the child.	2514	watcher OR you must not use AnyEvent at all in the child OR you must do
		2515	something completely out of the scope of AnyEvent.
1666		2516
1667		2517
1668	=head1 SECURITY CONSIDERATIONS	2518	=head1 SECURITY CONSIDERATIONS
1669		2519
1670	AnyEvent can be forced to load any event model via	2520	AnyEvent can be forced to load any event model via
…		…
1681		2531
1682	use AnyEvent;	2532	use AnyEvent;
1683		2533
1684	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2534	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1685	be used to probe what backend is used and gain other information (which is	2535	be used to probe what backend is used and gain other information (which is
1686	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	2536	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2537	$ENV{PERL_ANYEVENT_STRICT}.
		2538
		2539	Note that AnyEvent will remove I<all> environment variables starting with
		2540	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2541	enabled.
1687		2542
1688		2543
1689	=head1 BUGS	2544	=head1 BUGS
1690		2545
1691	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2546	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1692	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2547	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1693	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2548	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1694	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2549	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1695	pronounced).	2550	pronounced).
1696		2551
1697		2552
1698	=head1 SEE ALSO	2553	=head1 SEE ALSO
1699		2554
…		…
1703	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2558	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1704		2559
1705	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2560	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1706	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2561	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1707	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2562	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1708	L<AnyEvent::Impl::POE>.	2563	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1709		2564
1710	Non-blocking file handles, sockets, TCP clients and	2565	Non-blocking file handles, sockets, TCP clients and
1711	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2566	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1712		2567
1713	Asynchronous DNS: L<AnyEvent::DNS>.	2568	Asynchronous DNS: L<AnyEvent::DNS>.
1714		2569
1715	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2570	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2571	L<Coro::Event>,
1716		2572
1717	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2573	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2574	L<AnyEvent::HTTP>.
1718		2575
1719		2576
1720	=head1 AUTHOR	2577	=head1 AUTHOR
1721		2578
1722	Marc Lehmann <schmorp@schmorp.de>	2579	Marc Lehmann <schmorp@schmorp.de>

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