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Revision 1.317 by root, Wed Mar 24 21:22:57 2010 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 { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
27	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
28		53
29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
30		55
31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
32	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
128	These watchers are normal Perl objects with normal Perl lifetime. After	153	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	154	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	155	callback when the event occurs (of course, only when the event model
131	is in control).	156	is in control).
132		157
		158	Note that B<callbacks must not permanently change global variables>
		159	potentially in use by the event loop (such as C<$_> 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
133	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
134	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
135	to it).	166	to it).
136		167
137	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.
…		…
150	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
151	declared.	182	declared.
152		183
153	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
154		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
155	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
156	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
157		194
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	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
160	must be a string that is either C<r> or C<w>, which creates a watcher	202	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	203	watcher waiting for "r"eadable or "w"ritable events, respectively.
		204
162	callback to invoke each time the file handle becomes ready.	205	C<cb> is the callback to invoke each time the file handle becomes ready.
163		206
164	Although the callback might get passed parameters, their value and	207	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	208	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	209	callbacks cannot use arguments passed to I/O watcher callbacks.
167		210
…		…
182	undef $w;	225	undef $w;
183	});	226	});
184		227
185	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
186		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
187	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 >>
188	method with the following mandatory arguments:	239	method with the following mandatory arguments:
189		240
190	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
191	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
…		…
299	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
300	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
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	353	account.
303		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	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
		375	Note that updating the time I<might> cause some events to be handled.
		376
304	=back	377	=back
305		378
306	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
307		382
308	You can watch for signals using a signal watcher, C<signal> is the signal	383	You can watch for signals using a signal watcher, C<signal> is the signal
309	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
310	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
311		386
…		…
317	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
318	that it might take a while until the signal gets handled by the process,	393	that it might take a while until the signal gets handled by the process,
319	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
320		395
321	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
322	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
323		399
324	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
325	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
326		403
327	Example: exit on SIGINT	404	Example: exit on SIGINT
328		405
329	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
330		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		433	variable can be changed only before the first signal watcher is created,
		434	and should be left alone otherwise. This variable determines how often
		435	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		436	will cause fewer spurious wake-ups, which is better for power and CPU
		437	saving.
		438
		439	All these problems can be avoided by installing the optional
		440	L<Async::Interrupt> module, which works with most event loops. It will not
		441	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		442	(and not with L<POE> currently, as POE does it's own workaround with
		443	one-second latency). For those, you just have to suffer the delays.
		444
331	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
332		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
333	You can also watch on a child process exit and catch its exit status.	449	You can also watch on a child process exit and catch its exit status.
334		450
335	The child process is specified by the C<pid> argument (if set to C<0>, it	451	The child process is specified by the C<pid> argument (one some backends,
336	watches for any child process exit). The watcher will trigger as often	452	using C<0> watches for any child process exit, on others this will
337	as status change for the child are received. This works by installing a	453	croak). The watcher will be triggered only when the child process has
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	454	finished and an exit status is available, not on any trace events
339	and exit status (as returned by waitpid), so unlike other watcher types,	455	(stopped/continued).
340	you I<can> rely on child watcher callback arguments.	456
		457	The callback will be called with the pid and exit status (as returned by
		458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		459	callback arguments.
		460
		461	This watcher type works by installing a signal handler for C<SIGCHLD>,
		462	and since it cannot be shared, nothing else should use SIGCHLD or reap
		463	random child processes (waiting for specific child processes, e.g. inside
		464	C<system>, is just fine).
341		465
342	There is a slight catch to child watchers, however: you usually start them	466	There is a slight catch to child watchers, however: you usually start them
343	I<after> the child process was created, and this means the process could	467	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
345		469
346	Not all event models handle this correctly (POE doesn't), but even for	470	Not all event models handle this correctly (neither POE nor IO::Async do,
		471	see their AnyEvent::Impl manpages for details), but even for event models
347	event models that I<do> handle this correctly, they usually need to be	472	that I<do> handle this correctly, they usually need to be loaded before
348	loaded before the process exits (i.e. before you fork in the first place).	473	the process exits (i.e. before you fork in the first place). AnyEvent's
		474	pure perl event loop handles all cases correctly regardless of when you
		475	start the watcher.
349		476
350	This means you cannot create a child watcher as the very first thing in an	477	This means you cannot create a child watcher as the very first
351	AnyEvent program, you I<have> to create at least one watcher before you	478	thing in an AnyEvent program, you I<have> to create at least one
352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	479	watcher before you C<fork> the child (alternatively, you can call
		480	C<AnyEvent::detect>).
		481
		482	As most event loops do not support waiting for child events, they will be
		483	emulated by AnyEvent in most cases, in which the latency and race problems
		484	mentioned in the description of signal watchers apply.
353		485
354	Example: fork a process and wait for it	486	Example: fork a process and wait for it
355		487
356	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
357		489
…		…
367	);	499	);
368		500
369	# do something else, then wait for process exit	501	# do something else, then wait for process exit
370	$done->recv;	502	$done->recv;
371		503
		504	=head2 IDLE WATCHERS
		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
		508	Repeatedly invoke the callback after the process becomes idle, until
		509	either the watcher is destroyed or new events have been detected.
		510
		511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
		521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		522	will simply call the callback "from time to time".
		523
		524	Example: read lines from STDIN, but only process them when the
		525	program is otherwise idle:
		526
		527	my @lines; # read data
		528	my $idle_w;
		529	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		530	push @lines, scalar <STDIN>;
		531
		532	# start an idle watcher, if not already done
		533	$idle_w ||= AnyEvent->idle (cb => sub {
		534	# handle only one line, when there are lines left
		535	if (my $line = shift @lines) {
		536	print "handled when idle: $line";
		537	} else {
		538	# otherwise disable the idle watcher again
		539	undef $idle_w;
		540	}
		541	});
		542	});
		543
372	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
373		550
374	If you are familiar with some event loops you will know that all of them	551	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	552	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
377		554
378	AnyEvent is different, it expects somebody else to run the event loop and	555	AnyEvent is slightly different: it expects somebody else to run the event
379	will only block when necessary (usually when told by the user).	556	loop and will only block when necessary (usually when told by the user).
380		557
381	The instrument to do that is called a "condition variable", so called	558	The instrument to do that is called a "condition variable", so called
382	because they represent a condition that must become true.	559	because they represent a condition that must become true.
		560
		561	Now is probably a good time to look at the examples further below.
383		562
384	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
386	C<cb>, which specifies a callback to be called when the condition variable	565	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	566	becomes true, with the condition variable as the first argument (but not
		567	the results).
388		568
389	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	570	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	571	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	572	->send >> method).
…		…
394	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
395	optionally wait for them. They can also be called merge points - points	575	optionally wait for them. They can also be called merge points - points
396	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
397	another way to call them is transactions - each condition variable can be	577	another way to call them is transactions - each condition variable can be
398	used to represent a transaction, which finishes at some point and delivers	578	used to represent a transaction, which finishes at some point and delivers
399	a result.	579	a result. And yet some people know them as "futures" - a promise to
		580	compute/deliver something that you can wait for.
400		581
401	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
402	for example, if you write a module that does asynchronous http requests,	583	for example, if you write a module that does asynchronous http requests,
403	then a condition variable would be the ideal candidate to signal the	584	then a condition variable would be the ideal candidate to signal the
404	availability of results. The user can either act when the callback is	585	availability of results. The user can either act when the callback is
…		…
438	after => 1,	619	after => 1,
439	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
440	);	621	);
441		622
442	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
443	# calls send	624	# calls ->send
444	$result_ready->recv;	625	$result_ready->recv;
445		626
446	Example: wait for a timer, but take advantage of the fact that	627	Example: wait for a timer, but take advantage of the fact that condition
447	condition variables are also code references.	628	variables are also callable directly.
448		629
449	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	632	$done->recv;
		633
		634	Example: Imagine an API that returns a condvar and doesn't support
		635	callbacks. This is how you make a synchronous call, for example from
		636	the main program:
		637
		638	use AnyEvent::CouchDB;
		639
		640	...
		641
		642	my @info = $couchdb->info->recv;
		643
		644	And this is how you would just set a callback to be called whenever the
		645	results are available:
		646
		647	$couchdb->info->cb (sub {
		648	my @info = $_[0]->recv;
		649	});
452		650
453	=head3 METHODS FOR PRODUCERS	651	=head3 METHODS FOR PRODUCERS
454		652
455	These methods should only be used by the producing side, i.e. the	653	These methods should only be used by the producing side, i.e. the
456	code/module that eventually sends the signal. Note that it is also	654	code/module that eventually sends the signal. Note that it is also
…		…
469	immediately from within send.	667	immediately from within send.
470		668
471	Any arguments passed to the C<send> call will be returned by all	669	Any arguments passed to the C<send> call will be returned by all
472	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
473		671
474	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
475	(as a code reference). Calling them directly is the same as calling	673	they were a code reference). Calling them directly is the same as calling
476	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
477	overloading, so as tempting as it may be, passing a condition variable
478	instead of a callback does not work. Both the pure perl and EV loops
479	support overloading, however, as well as all functions that use perl to
480	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
481	example).
482		675
483	=item $cv->croak ($error)	676	=item $cv->croak ($error)
484		677
485	Similar to send, but causes all call's to C<< ->recv >> to invoke	678	Similar to send, but causes all call's to C<< ->recv >> to invoke
486	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
487		680
488	This can be used to signal any errors to the condition variable	681	This can be used to signal any errors to the condition variable
489	user/consumer.	682	user/consumer. Doing it this way instead of calling C<croak> directly
		683	delays the error detetcion, but has the overwhelmign advantage that it
		684	diagnoses the error at the place where the result is expected, and not
		685	deep in some event clalback without connection to the actual code causing
		686	the problem.
490		687
491	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
492		689
493	=item $cv->end	690	=item $cv->end
494
495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
496		691
497	These two methods can be used to combine many transactions/events into	692	These two methods can be used to combine many transactions/events into
498	one. For example, a function that pings many hosts in parallel might want	693	one. For example, a function that pings many hosts in parallel might want
499	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
500		695
501	Every call to C<< ->begin >> will increment a counter, and every call to	696	Every call to C<< ->begin >> will increment a counter, and every call to
502	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	697	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
503	>>, the (last) callback passed to C<begin> will be executed. That callback	698	>>, the (last) callback passed to C<begin> will be executed, passing the
504	is I<supposed> to call C<< ->send >>, but that is not required. If no	699	condvar as first argument. That callback is I<supposed> to call C<< ->send
505	callback was set, C<send> will be called without any arguments.	700	>>, but that is not required. If no group callback was set, C<send> will
		701	be called without any arguments.
506		702
507	Let's clarify this with the ping example:	703	You can think of C<< $cv->send >> giving you an OR condition (one call
		704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		706
		707	Let's start with a simple example: you have two I/O watchers (for example,
		708	STDOUT and STDERR for a program), and you want to wait for both streams to
		709	close before activating a condvar:
508		710
509	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
510		712
		713	$cv->begin; # first watcher
		714	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		715	defined sysread $fh1, my $buf, 4096
		716	or $cv->end;
		717	});
		718
		719	$cv->begin; # second watcher
		720	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		721	defined sysread $fh2, my $buf, 4096
		722	or $cv->end;
		723	});
		724
		725	$cv->recv;
		726
		727	This works because for every event source (EOF on file handle), there is
		728	one call to C<begin>, so the condvar waits for all calls to C<end> before
		729	sending.
		730
		731	The ping example mentioned above is slightly more complicated, as the
		732	there are results to be passwd back, and the number of tasks that are
		733	begung can potentially be zero:
		734
		735	my $cv = AnyEvent->condvar;
		736
511	my %result;	737	my %result;
512	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
513		739
514	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
515	$cv->begin;	741	$cv->begin;
516	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
517	$result{$host} = ...;	743	$result{$host} = ...;
…		…
532	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
533	to be called once the counter reaches C<0>, and second, it ensures that	759	to be called once the counter reaches C<0>, and second, it ensures that
534	C<send> is called even when C<no> hosts are being pinged (the loop	760	C<send> is called even when C<no> hosts are being pinged (the loop
535	doesn't execute once).	761	doesn't execute once).
536		762
537	This is the general pattern when you "fan out" into multiple subrequests:	763	This is the general pattern when you "fan out" into multiple (but
538	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	764	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
539	is called at least once, and then, for each subrequest you start, call	765	the callback and ensure C<end> is called at least once, and then, for each
540	C<begin> and for each subrequest you finish, call C<end>.	766	subrequest you start, call C<begin> and for each subrequest you finish,
		767	call C<end>.
541		768
542	=back	769	=back
543		770
544	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
545		772
…		…
561	function will call C<croak>.	788	function will call C<croak>.
562		789
563	In list context, all parameters passed to C<send> will be returned,	790	In list context, all parameters passed to C<send> will be returned,
564	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
565		792
		793	Note that doing a blocking wait in a callback is not supported by any
		794	event loop, that is, recursive invocation of a blocking C<< ->recv
		795	>> is not allowed, and the C<recv> call will C<croak> if such a
		796	condition is detected. This condition can be slightly loosened by using
		797	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		798	any thread that doesn't run the event loop itself.
		799
566	Not all event models support a blocking wait - some die in that case	800	Not all event models support a blocking wait - some die in that case
567	(programs might want to do that to stay interactive), so I<if you are	801	(programs might want to do that to stay interactive), so I<if you are
568	using this from a module, never require a blocking wait>, but let the	802	using this from a module, never require a blocking wait>. Instead, let the
569	caller decide whether the call will block or not (for example, by coupling	803	caller decide whether the call will block or not (for example, by coupling
570	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
571	callbacks so the caller knows that getting the result will not block,	805	callbacks so the caller knows that getting the result will not block,
572	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
573		807
574	Another reason I<never> to C<< ->recv >> in a module is that you cannot
575	sensibly have two C<< ->recv >>'s in parallel, as that would require
576	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
577	can supply.
578
579	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
580	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
581	versions and also integrates coroutines into AnyEvent, making blocking
582	C<< ->recv >> calls perfectly safe as long as they are done from another
583	coroutine (one that doesn't run the event loop).
584
585	You can ensure that C<< -recv >> never blocks by setting a callback and	808	You can ensure that C<< -recv >> never blocks by setting a callback and
586	only calling C<< ->recv >> from within that callback (or at a later	809	only calling C<< ->recv >> from within that callback (or at a later
587	time). This will work even when the event loop does not support blocking	810	time). This will work even when the event loop does not support blocking
588	waits otherwise.	811	waits otherwise.
589		812
590	=item $bool = $cv->ready	813	=item $bool = $cv->ready
591		814
592	Returns true when the condition is "true", i.e. whether C<send> or	815	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	816	C<croak> have been called.
594		817
595	=item $cb = $cv->cb ([new callback])	818	=item $cb = $cv->cb ($cb->($cv))
596		819
597	This is a mutator function that returns the callback set and optionally	820	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	821	replaces it before doing so.
599		822
600	The callback will be called when the condition becomes "true", i.e. when	823	The callback will be called when the condition becomes (or already was)
601	C<send> or C<croak> are called, with the only argument being the condition	824	"true", i.e. when C<send> or C<croak> are called (or were called), with
602	variable itself. Calling C<recv> inside the callback or at any later time	825	the only argument being the condition variable itself. Calling C<recv>
603	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
604		827
605	=back	828	=back
606		829
		830	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		831
		832	The available backend classes are (every class has its own manpage):
		833
		834	=over 4
		835
		836	=item Backends that are autoprobed when no other event loop can be found.
		837
		838	EV is the preferred backend when no other event loop seems to be in
		839	use. If EV is not installed, then AnyEvent will fall back to its own
		840	pure-perl implementation, which is available everywhere as it comes with
		841	AnyEvent itself.
		842
		843	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		844	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		845
		846	=item Backends that are transparently being picked up when they are used.
		847
		848	These will be used when they are currently loaded when the first watcher
		849	is created, in which case it is assumed that the application is using
		850	them. This means that AnyEvent will automatically pick the right backend
		851	when the main program loads an event module before anything starts to
		852	create watchers. Nothing special needs to be done by the main program.
		853
		854	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		855	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		856	AnyEvent::Impl::Tk based on Tk, very broken.
		857	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		858	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		859	AnyEvent::Impl::Irssi used when running within irssi.
		860
		861	=item Backends with special needs.
		862
		863	Qt requires the Qt::Application to be instantiated first, but will
		864	otherwise be picked up automatically. As long as the main program
		865	instantiates the application before any AnyEvent watchers are created,
		866	everything should just work.
		867
		868	AnyEvent::Impl::Qt based on Qt.
		869
		870	Support for IO::Async can only be partial, as it is too broken and
		871	architecturally limited to even support the AnyEvent API. It also
		872	is the only event loop that needs the loop to be set explicitly, so
		873	it can only be used by a main program knowing about AnyEvent. See
		874	L<AnyEvent::Impl::Async> for the gory details.
		875
		876	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		877
		878	=item Event loops that are indirectly supported via other backends.
		879
		880	Some event loops can be supported via other modules:
		881
		882	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		883
		884	B<WxWidgets> has no support for watching file handles. However, you can
		885	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		886	polls 20 times per second, which was considered to be too horrible to even
		887	consider for AnyEvent.
		888
		889	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		890	backend, so it can be supported through POE.
		891
		892	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		893	load L<POE> when detecting them, in the hope that POE will pick them up,
		894	in which case everything will be automatic.
		895
		896	=back
		897
607	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
608		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
609	=over 4	903	=over 4
610		904
611	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
612		906
613	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
614	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
615	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
616	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
617	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
618		914	will be C<urxvt::anyevent>).
619	The known classes so far are:
620
621	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
622	AnyEvent::Impl::Event based on Event, second best choice.
623	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
624	AnyEvent::Impl::Glib based on Glib, third-best choice.
625	AnyEvent::Impl::Tk based on Tk, very bad choice.
626	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
627	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
628	AnyEvent::Impl::POE based on POE, not generic enough for full support.
629
630	There is no support for WxWidgets, as WxWidgets has no support for
631	watching file handles. However, you can use WxWidgets through the
632	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
633	second, which was considered to be too horrible to even consider for
634	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
635	it's adaptor.
636
637	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
638	autodetecting them.
639		915
640	=item AnyEvent::detect	916	=item AnyEvent::detect
641		917
642	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
643	if necessary. You should only call this function right before you would	919	if necessary. You should only call this function right before you would
644	have created an AnyEvent watcher anyway, that is, as late as possible at	920	have created an AnyEvent watcher anyway, that is, as late as possible at
645	runtime.	921	runtime, and not e.g. while initialising of your module.
		922
		923	If you need to do some initialisation before AnyEvent watchers are
		924	created, use C<post_detect>.
646		925
647	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
648		927
649	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
650	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
651		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		933	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		934	other initialisations - see the sources of L<AnyEvent::Strict> or
		935	L<AnyEvent::AIO> to see how this is used.
		936
		937	The most common usage is to create some global watchers, without forcing
		938	event module detection too early, for example, L<AnyEvent::AIO> creates
		939	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		940	avoid autodetecting the event module at load time.
		941
652	If called in scalar or list context, then it creates and returns an object	942	If called in scalar or list context, then it creates and returns an object
653	that automatically removes the callback again when it is destroyed. See	943	that automatically removes the callback again when it is destroyed (or
		944	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
654	L<Coro::BDB> for a case where this is useful.	945	a case where this is useful.
		946
		947	Example: Create a watcher for the IO::AIO module and store it in
		948	C<$WATCHER>. Only do so after the event loop is initialised, though.
		949
		950	our WATCHER;
		951
		952	my $guard = AnyEvent::post_detect {
		953	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		954	};
		955
		956	# the ||= is important in case post_detect immediately runs the block,
		957	# as to not clobber the newly-created watcher. assigning both watcher and
		958	# post_detect guard to the same variable has the advantage of users being
		959	# able to just C<undef $WATCHER> if the watcher causes them grief.
		960
		961	$WATCHER ||= $guard;
655		962
656	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
657		964
658	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
659	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
660	the event loop has been chosen.	967	the event loop has been chosen.
661		968
662	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
663	if it contains a true value then the event loop has already been detected,	970	if it is defined then the event loop has already been detected, and the
664	and the array will be ignored.	971	array will be ignored.
665		972
666	Best use C<AnyEvent::post_detect { BLOCK }> instead.	973	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		974	it, as it takes care of these details.
		975
		976	This variable is mainly useful for modules that can do something useful
		977	when AnyEvent is used and thus want to know when it is initialised, but do
		978	not need to even load it by default. This array provides the means to hook
		979	into AnyEvent passively, without loading it.
		980
		981	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		982	together, you could put this into Coro (this is the actual code used by
		983	Coro to accomplish this):
		984
		985	if (defined $AnyEvent::MODEL) {
		986	# AnyEvent already initialised, so load Coro::AnyEvent
		987	require Coro::AnyEvent;
		988	} else {
		989	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		990	# as soon as it is
		991	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		992	}
667		993
668	=back	994	=back
669		995
670	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
671		997
…		…
726		1052
727		1053
728	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
729		1055
730	The following is a non-exhaustive list of additional modules that use	1056	The following is a non-exhaustive list of additional modules that use
731	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1057	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
732	in the same program. Some of the modules come with AnyEvent, some are	1058	modules and other event loops in the same program. Some of the modules
733	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
734		1060
735	=over 4	1061	=over 4
736		1062
737	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
738		1064
…		…
747		1073
748	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
749		1075
750	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
751	supports raw and formatted I/O, I/O queued and fully transparent and	1077	supports raw and formatted I/O, I/O queued and fully transparent and
752	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
753		1079
754	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
755		1081
756	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
757		1083
…		…
785		1111
786	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
787		1113
788	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
789		1115
		1116	=item L<AnyEvent::IRC>
		1117
		1118	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1119
		1120	=item L<AnyEvent::XMPP>
		1121
		1122	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1123	Net::XMPP2>.
		1124
790	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
791		1126
792	A non-blocking interface to the Internet Go Server protocol (used by	1127	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).	1128	L<App::IGS>).
794		1129
795	=item L<Net::IRC3>
796
797	AnyEvent based IRC client module family.
798
799	=item L<Net::XMPP2>
800
801	AnyEvent based XMPP (Jabber protocol) module family.
802
803	=item L<Net::FCP>	1130	=item L<Net::FCP>
804		1131
805	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
806	of AnyEvent.	1133	of AnyEvent.
807		1134
…		…
811		1138
812	=item L<Coro>	1139	=item L<Coro>
813		1140
814	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
815		1142
816	=item L<IO::Lambda>
817
818	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
819
820	=back	1143	=back
821		1144
822	=cut	1145	=cut
823		1146
824	package AnyEvent;	1147	package AnyEvent;
825		1148
826	no warnings;	1149	# basically a tuned-down version of common::sense
827	use strict;	1150	sub common_sense {
		1151	# from common:.sense 1.0
		1152	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1153	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1154	$^H |= 0x00000600;
		1155	}
828		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
829	use Carp;	1159	use Carp ();
830		1160
831	our $VERSION = 4.21;	1161	our $VERSION = '5.251';
832	our $MODEL;	1162	our $MODEL;
833		1163
834	our $AUTOLOAD;	1164	our $AUTOLOAD;
835	our @ISA;	1165	our @ISA;
836		1166
837	our @REGISTRY;	1167	our @REGISTRY;
838		1168
839	our $WIN32;	1169	our $VERBOSE;
840		1170
841	BEGIN {	1171	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
843	eval "sub WIN32(){ $win32 }";
844	}
845		1173
		1174	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
847		1184
848	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
849		1186
850	{	1187	{
851	my $idx;	1188	my $idx;
…		…
853	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
854	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
855	}	1192	}
856		1193
857	my @models = (	1194	my @models = (
858	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
859	[Event:: => AnyEvent::Impl::Event::],
860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
861	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
862	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
863	# and is usually faster	1199	# and is usually faster
		1200	[Event:: => AnyEvent::Impl::Event::, 1],
		1201	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1202	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1203	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	1208	[Prima:: => AnyEvent::Impl::POE::],
		1209	# IO::Async is just too broken - we would need workarounds for its
		1210	# byzantine signal and broken child handling, among others.
		1211	# IO::Async is rather hard to detect, as it doesn't have any
		1212	# obvious default class.
		1213	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1215	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1216	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
871	);	1217	);
872		1218
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1219	our %method = map +($_ => 1),
		1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
874		1221
875	our @post_detect;	1222	our @post_detect;
876		1223
877	sub post_detect(&) {	1224	sub post_detect(&) {
878	my ($cb) = @_;	1225	my ($cb) = @_;
879		1226
880	if ($MODEL) {
881	$cb->();
882
883	1
884	} else {
885	push @post_detect, $cb;	1227	push @post_detect, $cb;
886		1228
887	defined wantarray	1229	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"	1230	? bless \$cb, "AnyEvent::Util::postdetect"
889	: ()	1231	: ()
		1232	}
		1233
		1234	sub AnyEvent::Util::postdetect::DESTROY {
		1235	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1236	}
		1237
		1238	sub detect() {
		1239	# free some memory
		1240	*detect = sub () { $MODEL };
		1241
		1242	local $!; # for good measure
		1243	local $SIG{__DIE__};
		1244
		1245	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1246	my $model = "AnyEvent::Impl::$1";
		1247	if (eval "require $model") {
		1248	$MODEL = $model;
		1249	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1250	} else {
		1251	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1252	}
890	}	1253	}
891	}
892		1254
893	sub AnyEvent::Util::PostDetect::DESTROY {	1255	# check for already loaded models
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}
896
897	sub detect() {
898	unless ($MODEL) {	1256	unless ($MODEL) {
899	no strict 'refs';	1257	for (@REGISTRY, @models) {
900	local $SIG{__DIE__};	1258	my ($package, $model) = @$_;
901		1259	if (${"$package\::VERSION"} > 0) {
902	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
903	my $model = "AnyEvent::Impl::$1";
904	if (eval "require $model") {	1260	if (eval "require $model") {
905	$MODEL = $model;	1261	$MODEL = $model;
906	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1262	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
907	} else {	1263	last;
908	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1264	}
909	}	1265	}
910	}	1266	}
911		1267
912	# check for already loaded models
913	unless ($MODEL) {	1268	unless ($MODEL) {
		1269	# try to autoload a model
914	for (@REGISTRY, @models) {	1270	for (@REGISTRY, @models) {
915	my ($package, $model) = @$_;	1271	my ($package, $model, $autoload) = @$_;
		1272	if (
		1273	$autoload
		1274	and eval "require $package"
916	if (${"$package\::VERSION"} > 0) {	1275	and ${"$package\::VERSION"} > 0
917	if (eval "require $model") {	1276	and eval "require $model"
		1277	) {
918	$MODEL = $model;	1278	$MODEL = $model;
919	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1279	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
920	last;	1280	last;
921	}
922	}	1281	}
923	}	1282	}
924		1283
925	unless ($MODEL) {
926	# try to load a model
927
928	for (@REGISTRY, @models) {
929	my ($package, $model) = @$_;
930	if (eval "require $package"
931	and ${"$package\::VERSION"} > 0
932	and eval "require $model") {
933	$MODEL = $model;
934	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
935	last;
936	}
937	}
938
939	$MODEL	1284	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1285	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}
942	}	1286	}
943
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945
946	unshift @ISA, $MODEL;
947
948	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
949
950	(shift @post_detect)->() while @post_detect;
951	}	1287	}
		1288
		1289	@models = (); # free probe data
		1290
		1291	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1292	unshift @ISA, $MODEL;
		1293
		1294	# now nuke some methods that are overriden by the backend.
		1295	# SUPER is not allowed.
		1296	for (qw(time signal child idle)) {
		1297	undef &{"AnyEvent::Base::$_"}
		1298	if defined &{"$MODEL\::$_"};
		1299	}
		1300
		1301	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1302
		1303	(shift @post_detect)->() while @post_detect;
		1304
		1305	*post_detect = sub(&) {
		1306	shift->();
		1307
		1308	undef
		1309	};
952		1310
953	$MODEL	1311	$MODEL
954	}	1312	}
955		1313
956	sub AUTOLOAD {	1314	sub AUTOLOAD {
957	(my $func = $AUTOLOAD) =~ s/.*://;	1315	(my $func = $AUTOLOAD) =~ s/.*://;
958		1316
959	$method{$func}	1317	$method{$func}
960	or croak "$func: not a valid method for AnyEvent objects";	1318	or Carp::croak "$func: not a valid AnyEvent class method";
961		1319
962	detect unless $MODEL;	1320	detect;
963		1321
964	my $class = shift;	1322	my $class = shift;
965	$class->$func (@_);	1323	$class->$func (@_);
966	}	1324	}
967		1325
968	# utility function to dup a filehandle. this is used by many backends	1326	# utility function to dup a filehandle. this is used by many backends
969	# to support binding more than one watcher per filehandle (they usually	1327	# to support binding more than one watcher per filehandle (they usually
970	# allow only one watcher per fd, so we dup it to get a different one).	1328	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1329	sub _dupfh($$;$$) {
972	my ($poll, $fh, $r, $w) = @_;	1330	my ($poll, $fh, $r, $w) = @_;
973		1331
974	require Fcntl;
975
976	# cygwin requires the fh mode to be matching, unix doesn't	1332	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1333	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
978	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1334
981	open my $fh2, "$mode&" . fileno $fh	1335	open my $fh2, $mode, $fh
982	or die "cannot dup() filehandle: $!";	1336	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
983		1337
984	# we assume CLOEXEC is already set by perl in all important cases	1338	# we assume CLOEXEC is already set by perl in all important cases
985		1339
986	($fh2, $rw)	1340	($fh2, $rw)
987	}	1341	}
988		1342
		1343	=head1 SIMPLIFIED AE API
		1344
		1345	Starting with version 5.0, AnyEvent officially supports a second, much
		1346	simpler, API that is designed to reduce the calling, typing and memory
		1347	overhead.
		1348
		1349	See the L<AE> manpage for details.
		1350
		1351	=cut
		1352
		1353	package AE;
		1354
		1355	our $VERSION = $AnyEvent::VERSION;
		1356
		1357	sub io($$$) {
		1358	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1359	}
		1360
		1361	sub timer($$$) {
		1362	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1363	}
		1364
		1365	sub signal($$) {
		1366	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1367	}
		1368
		1369	sub child($$) {
		1370	AnyEvent->child (pid => $_[0], cb => $_[1])
		1371	}
		1372
		1373	sub idle($) {
		1374	AnyEvent->idle (cb => $_[0])
		1375	}
		1376
		1377	sub cv(;&) {
		1378	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1379	}
		1380
		1381	sub now() {
		1382	AnyEvent->now
		1383	}
		1384
		1385	sub now_update() {
		1386	AnyEvent->now_update
		1387	}
		1388
		1389	sub time() {
		1390	AnyEvent->time
		1391	}
		1392
989	package AnyEvent::Base;	1393	package AnyEvent::Base;
990		1394
991	# default implementation for now and time	1395	# default implementations for many methods
992		1396
993	use Time::HiRes ();	1397	sub time {
		1398	eval q{ # poor man's autoloading {}
		1399	# probe for availability of Time::HiRes
		1400	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1401	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
		1402	*AE::time = \&Time::HiRes::time;
		1403	# if (eval "use POSIX (); (POSIX::times())...
		1404	} else {
		1405	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
		1406	*AE::time = sub (){ time }; # epic fail
		1407	}
994		1408
995	sub time { Time::HiRes::time }	1409	*time = sub { AE::time }; # different prototypes
996	sub now { Time::HiRes::time }	1410	};
		1411	die if $@;
		1412
		1413	&time
		1414	}
		1415
		1416	*now = \&time;
		1417
		1418	sub now_update { }
997		1419
998	# default implementation for ->condvar	1420	# default implementation for ->condvar
999		1421
1000	sub condvar {	1422	sub condvar {
		1423	eval q{ # poor man's autoloading {}
		1424	*condvar = sub {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1425	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1426	};
		1427
		1428	*AE::cv = sub (;&) {
		1429	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1430	};
		1431	};
		1432	die if $@;
		1433
		1434	&condvar
1002	}	1435	}
1003		1436
1004	# default implementation for ->signal	1437	# default implementation for ->signal
1005		1438
1006	our %SIG_CB;	1439	our $HAVE_ASYNC_INTERRUPT;
		1440
		1441	sub _have_async_interrupt() {
		1442	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1443	&& eval "use Async::Interrupt 1.02 (); 1")
		1444	unless defined $HAVE_ASYNC_INTERRUPT;
		1445
		1446	$HAVE_ASYNC_INTERRUPT
		1447	}
		1448
		1449	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1450	our (%SIG_ASY, %SIG_ASY_W);
		1451	our ($SIG_COUNT, $SIG_TW);
		1452
		1453	# install a dummy wakeup watcher to reduce signal catching latency
		1454	# used by Impls
		1455	sub _sig_add() {
		1456	unless ($SIG_COUNT++) {
		1457	# try to align timer on a full-second boundary, if possible
		1458	my $NOW = AE::now;
		1459
		1460	$SIG_TW = AE::timer
		1461	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1462	$MAX_SIGNAL_LATENCY,
		1463	sub { } # just for the PERL_ASYNC_CHECK
		1464	;
		1465	}
		1466	}
		1467
		1468	sub _sig_del {
		1469	undef $SIG_TW
		1470	unless --$SIG_COUNT;
		1471	}
		1472
		1473	our $_sig_name_init; $_sig_name_init = sub {
		1474	eval q{ # poor man's autoloading {}
		1475	undef $_sig_name_init;
		1476
		1477	if (_have_async_interrupt) {
		1478	*sig2num = \&Async::Interrupt::sig2num;
		1479	*sig2name = \&Async::Interrupt::sig2name;
		1480	} else {
		1481	require Config;
		1482
		1483	my %signame2num;
		1484	@signame2num{ split ' ', $Config::Config{sig_name} }
		1485	= split ' ', $Config::Config{sig_num};
		1486
		1487	my @signum2name;
		1488	@signum2name[values %signame2num] = keys %signame2num;
		1489
		1490	*sig2num = sub($) {
		1491	$_[0] > 0 ? shift : $signame2num{+shift}
		1492	};
		1493	*sig2name = sub ($) {
		1494	$_[0] > 0 ? $signum2name[+shift] : shift
		1495	};
		1496	}
		1497	};
		1498	die if $@;
		1499	};
		1500
		1501	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1502	sub sig2name($) { &$_sig_name_init; &sig2name }
1007		1503
1008	sub signal {	1504	sub signal {
		1505	eval q{ # poor man's autoloading {}
		1506	# probe for availability of Async::Interrupt
		1507	if (_have_async_interrupt) {
		1508	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
		1509
		1510	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1511	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
		1512
		1513	} else {
		1514	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1515
		1516	if (AnyEvent::WIN32) {
		1517	require AnyEvent::Util;
		1518
		1519	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1520	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1521	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1522	} else {
		1523	pipe $SIGPIPE_R, $SIGPIPE_W;
		1524	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1525	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1526
		1527	# not strictly required, as $^F is normally 2, but let's make sure...
		1528	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1529	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1530	}
		1531
		1532	$SIGPIPE_R
		1533	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1534
		1535	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1536	}
		1537
		1538	*signal = $HAVE_ASYNC_INTERRUPT
		1539	? sub {
1009	my (undef, %arg) = @_;	1540	my (undef, %arg) = @_;
1010		1541
		1542	# async::interrupt
1011	my $signal = uc $arg{signal}	1543	my $signal = sig2num $arg{signal};
1012	or Carp::croak "required option 'signal' is missing";
1013
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1545
		1546	$SIG_ASY{$signal} ||= new Async::Interrupt
		1547	cb => sub { undef $SIG_EV{$signal} },
		1548	signal => $signal,
		1549	pipe => [$SIGPIPE_R->filenos],
		1550	pipe_autodrain => 0,
		1551	;
		1552
		1553	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1554	}
		1555	: sub {
		1556	my (undef, %arg) = @_;
		1557
		1558	# pure perl
		1559	my $signal = sig2name $arg{signal};
		1560	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1561
1015	$SIG{$signal} ||= sub {	1562	$SIG{$signal} ||= sub {
		1563	local $!;
		1564	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1565	undef $SIG_EV{$signal};
		1566	};
		1567
		1568	# can't do signal processing without introducing races in pure perl,
		1569	# so limit the signal latency.
		1570	_sig_add;
		1571
		1572	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1573	}
		1574	;
		1575
		1576	*AnyEvent::Base::signal::DESTROY = sub {
		1577	my ($signal, $cb) = @{$_[0]};
		1578
		1579	_sig_del;
		1580
		1581	delete $SIG_CB{$signal}{$cb};
		1582
		1583	$HAVE_ASYNC_INTERRUPT
		1584	? delete $SIG_ASY{$signal}
		1585	: # delete doesn't work with older perls - they then
		1586	# print weird messages, or just unconditionally exit
		1587	# instead of getting the default action.
		1588	undef $SIG{$signal}
		1589	unless keys %{ $SIG_CB{$signal} };
		1590	};
		1591
		1592	*_signal_exec = sub {
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? $SIGPIPE_R->drain
		1595	: sysread $SIGPIPE_R, (my $dummy), 9;
		1596
		1597	while (%SIG_EV) {
		1598	for (keys %SIG_EV) {
		1599	delete $SIG_EV{$_};
1016	$_->() for values %{ $SIG_CB{$signal} || {} };	1600	$_->() for values %{ $SIG_CB{$_} || {} };
		1601	}
		1602	}
		1603	};
1017	};	1604	};
		1605	die if $@;
1018		1606
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1607	&signal
1020	}
1021
1022	sub AnyEvent::Base::Signal::DESTROY {
1023	my ($signal, $cb) = @{$_[0]};
1024
1025	delete $SIG_CB{$signal}{$cb};
1026
1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1028	}	1608	}
1029		1609
1030	# default implementation for ->child	1610	# default implementation for ->child
1031		1611
1032	our %PID_CB;	1612	our %PID_CB;
1033	our $CHLD_W;	1613	our $CHLD_W;
1034	our $CHLD_DELAY_W;	1614	our $CHLD_DELAY_W;
1035	our $PID_IDLE;
1036	our $WNOHANG;	1615	our $WNOHANG;
1037		1616
1038	sub _child_wait {	1617	# used by many Impl's
1039	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1618	sub _emit_childstatus($$) {
		1619	my (undef, $rpid, $rstatus) = @_;
		1620
		1621	$_->($rpid, $rstatus)
1040	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1622	for values %{ $PID_CB{$rpid} || {} },
1041	(values %{ $PID_CB{0} || {} });	1623	values %{ $PID_CB{0} || {} };
1042	}
1043
1044	undef $PID_IDLE;
1045	}
1046
1047	sub _sigchld {
1048	# make sure we deliver these changes "synchronous" with the event loop.
1049	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1050	undef $CHLD_DELAY_W;
1051	&_child_wait;
1052	});
1053	}	1624	}
1054		1625
1055	sub child {	1626	sub child {
		1627	eval q{ # poor man's autoloading {}
		1628	*_sigchld = sub {
		1629	my $pid;
		1630
		1631	AnyEvent->_emit_childstatus ($pid, $?)
		1632	while ($pid = waitpid -1, $WNOHANG) > 0;
		1633	};
		1634
		1635	*child = sub {
1056	my (undef, %arg) = @_;	1636	my (undef, %arg) = @_;
1057		1637
1058	defined (my $pid = $arg{pid} + 0)	1638	defined (my $pid = $arg{pid} + 0)
1059	or Carp::croak "required option 'pid' is missing";	1639	or Carp::croak "required option 'pid' is missing";
1060		1640
1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1641	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1062		1642
1063	unless ($WNOHANG) {	1643	# WNOHANG is almost cetrainly 1 everywhere
		1644	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1645	? 1
1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1646	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1065	}
1066		1647
1067	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1069	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1070	&_sigchld;	1651	&_sigchld;
1071	}	1652	}
1072		1653
1073	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1074	}	1655	};
1075		1656
1076	sub AnyEvent::Base::Child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1077	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1078		1659
1079	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1081		1662
1082	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
		1669	}
		1670
		1671	# idle emulation is done by simply using a timer, regardless
		1672	# of whether the process is idle or not, and not letting
		1673	# the callback use more than 50% of the time.
		1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
		1677	my (undef, %arg) = @_;
		1678
		1679	my ($cb, $w, $rcb) = $arg{cb};
		1680
		1681	$rcb = sub {
		1682	if ($cb) {
		1683	$w = _time;
		1684	&$cb;
		1685	$w = _time - $w;
		1686
		1687	# never use more then 50% of the time for the idle watcher,
		1688	# within some limits
		1689	$w = 0.0001 if $w < 0.0001;
		1690	$w = 5 if $w > 5;
		1691
		1692	$w = AE::timer $w, 0, $rcb;
		1693	} else {
		1694	# clean up...
		1695	undef $w;
		1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
		1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
		1708	};
		1709	die if $@;
		1710
		1711	&idle
1083	}	1712	}
1084		1713
1085	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1086		1715
1087	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
1088		1717
1089	package AnyEvent::CondVar::Base;	1718	package AnyEvent::CondVar::Base;
1090		1719
1091	use overload	1720	#use overload
1092	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1721	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1093	fallback => 1;	1722	# fallback => 1;
		1723
		1724	# save 300+ kilobytes by dirtily hardcoding overloading
		1725	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1726	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1727	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1728	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1729
		1730	our $WAITING;
1094		1731
1095	sub _send {	1732	sub _send {
1096	# nop	1733	# nop
1097	}	1734	}
1098		1735
…		…
1111	sub ready {	1748	sub ready {
1112	$_[0]{_ae_sent}	1749	$_[0]{_ae_sent}
1113	}	1750	}
1114		1751
1115	sub _wait {	1752	sub _wait {
		1753	$WAITING
		1754	and !$_[0]{_ae_sent}
		1755	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1756
		1757	local $WAITING = 1;
1116	AnyEvent->one_event while !$_[0]{_ae_sent};	1758	AnyEvent->one_event while !$_[0]{_ae_sent};
1117	}	1759	}
1118		1760
1119	sub recv {	1761	sub recv {
1120	$_[0]->_wait;	1762	$_[0]->_wait;
…		…
1122	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1764	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1123	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1765	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1124	}	1766	}
1125		1767
1126	sub cb {	1768	sub cb {
1127	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1769	my $cv = shift;
		1770
		1771	@_
		1772	and $cv->{_ae_cb} = shift
		1773	and $cv->{_ae_sent}
		1774	and (delete $cv->{_ae_cb})->($cv);
		1775
1128	$_[0]{_ae_cb}	1776	$cv->{_ae_cb}
1129	}	1777	}
1130		1778
1131	sub begin {	1779	sub begin {
1132	++$_[0]{_ae_counter};	1780	++$_[0]{_ae_counter};
1133	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1781	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1139	}	1787	}
1140		1788
1141	# undocumented/compatibility with pre-3.4	1789	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	1790	*broadcast = \&send;
1143	*wait = \&_wait;	1791	*wait = \&_wait;
		1792
		1793	=head1 ERROR AND EXCEPTION HANDLING
		1794
		1795	In general, AnyEvent does not do any error handling - it relies on the
		1796	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1797	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1798	checking of all AnyEvent methods, however, which is highly useful during
		1799	development.
		1800
		1801	As for exception handling (i.e. runtime errors and exceptions thrown while
		1802	executing a callback), this is not only highly event-loop specific, but
		1803	also not in any way wrapped by this module, as this is the job of the main
		1804	program.
		1805
		1806	The pure perl event loop simply re-throws the exception (usually
		1807	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1808	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1809	so on.
		1810
		1811	=head1 ENVIRONMENT VARIABLES
		1812
		1813	The following environment variables are used by this module or its
		1814	submodules.
		1815
		1816	Note that AnyEvent will remove I<all> environment variables starting with
		1817	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1818	enabled.
		1819
		1820	=over 4
		1821
		1822	=item C<PERL_ANYEVENT_VERBOSE>
		1823
		1824	By default, AnyEvent will be completely silent except in fatal
		1825	conditions. You can set this environment variable to make AnyEvent more
		1826	talkative.
		1827
		1828	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1829	conditions, such as not being able to load the event model specified by
		1830	C<PERL_ANYEVENT_MODEL>.
		1831
		1832	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1833	model it chooses.
		1834
		1835	When set to C<8> or higher, then AnyEvent will report extra information on
		1836	which optional modules it loads and how it implements certain features.
		1837
		1838	=item C<PERL_ANYEVENT_STRICT>
		1839
		1840	AnyEvent does not do much argument checking by default, as thorough
		1841	argument checking is very costly. Setting this variable to a true value
		1842	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1843	check the arguments passed to most method calls. If it finds any problems,
		1844	it will croak.
		1845
		1846	In other words, enables "strict" mode.
		1847
		1848	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
		1849	>>, it is definitely recommended to keep it off in production. Keeping
		1850	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1851	can be very useful, however.
		1852
		1853	=item C<PERL_ANYEVENT_MODEL>
		1854
		1855	This can be used to specify the event model to be used by AnyEvent, before
		1856	auto detection and -probing kicks in. It must be a string consisting
		1857	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1858	and the resulting module name is loaded and if the load was successful,
		1859	used as event model. If it fails to load AnyEvent will proceed with
		1860	auto detection and -probing.
		1861
		1862	This functionality might change in future versions.
		1863
		1864	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1865	could start your program like this:
		1866
		1867	PERL_ANYEVENT_MODEL=Perl perl ...
		1868
		1869	=item C<PERL_ANYEVENT_PROTOCOLS>
		1870
		1871	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1872	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1873	of auto probing).
		1874
		1875	Must be set to a comma-separated list of protocols or address families,
		1876	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1877	used, and preference will be given to protocols mentioned earlier in the
		1878	list.
		1879
		1880	This variable can effectively be used for denial-of-service attacks
		1881	against local programs (e.g. when setuid), although the impact is likely
		1882	small, as the program has to handle conenction and other failures anyways.
		1883
		1884	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1885	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1886	- only support IPv4, never try to resolve or contact IPv6
		1887	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1888	IPv6, but prefer IPv6 over IPv4.
		1889
		1890	=item C<PERL_ANYEVENT_EDNS0>
		1891
		1892	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1893	for DNS. This extension is generally useful to reduce DNS traffic, but
		1894	some (broken) firewalls drop such DNS packets, which is why it is off by
		1895	default.
		1896
		1897	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1898	EDNS0 in its DNS requests.
		1899
		1900	=item C<PERL_ANYEVENT_MAX_FORKS>
		1901
		1902	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1903	will create in parallel.
		1904
		1905	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1906
		1907	The default value for the C<max_outstanding> parameter for the default DNS
		1908	resolver - this is the maximum number of parallel DNS requests that are
		1909	sent to the DNS server.
		1910
		1911	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1912
		1913	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1914	configuration) in the default resolver. When set to the empty string, no
		1915	default config will be used.
		1916
		1917	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1918
		1919	When neither C<ca_file> nor C<ca_path> was specified during
		1920	L<AnyEvent::TLS> context creation, and either of these environment
		1921	variables exist, they will be used to specify CA certificate locations
		1922	instead of a system-dependent default.
		1923
		1924	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1925
		1926	When these are set to C<1>, then the respective modules are not
		1927	loaded. Mostly good for testing AnyEvent itself.
		1928
		1929	=back
1144		1930
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1931	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		1932
1147	This is an advanced topic that you do not normally need to use AnyEvent in	1933	This is an advanced topic that you do not normally need to use AnyEvent in
1148	a module. This section is only of use to event loop authors who want to	1934	a module. This section is only of use to event loop authors who want to
…		…
1182		1968
1183	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1969	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1184	condition variables: code blocking while waiting for a condition will	1970	condition variables: code blocking while waiting for a condition will
1185	C<die>. This still works with most modules/usages, and blocking calls must	1971	C<die>. This still works with most modules/usages, and blocking calls must
1186	not be done in an interactive application, so it makes sense.	1972	not be done in an interactive application, so it makes sense.
1187
1188	=head1 ENVIRONMENT VARIABLES
1189
1190	The following environment variables are used by this module:
1191
1192	=over 4
1193
1194	=item C<PERL_ANYEVENT_VERBOSE>
1195
1196	By default, AnyEvent will be completely silent except in fatal
1197	conditions. You can set this environment variable to make AnyEvent more
1198	talkative.
1199
1200	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1201	conditions, such as not being able to load the event model specified by
1202	C<PERL_ANYEVENT_MODEL>.
1203
1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1205	model it chooses.
1206
1207	=item C<PERL_ANYEVENT_STRICT>
1208
1209	AnyEvent does not do much argument checking by default, as thorough
1210	argument checking is very costly. Setting this variable to a true value
1211	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1212	check the arguments passed to most method calls. If it finds any problems
1213	it will croak.
1214
1215	In other words, enables "strict" mode.
1216
1217	Unlike C<use strict> it is definitely recommended ot keep it off in
1218	production.
1219
1220	=item C<PERL_ANYEVENT_MODEL>
1221
1222	This can be used to specify the event model to be used by AnyEvent, before
1223	auto detection and -probing kicks in. It must be a string consisting
1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1225	and the resulting module name is loaded and if the load was successful,
1226	used as event model. If it fails to load AnyEvent will proceed with
1227	auto detection and -probing.
1228
1229	This functionality might change in future versions.
1230
1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1232	could start your program like this:
1233
1234	PERL_ANYEVENT_MODEL=Perl perl ...
1235
1236	=item C<PERL_ANYEVENT_PROTOCOLS>
1237
1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1240	of auto probing).
1241
1242	Must be set to a comma-separated list of protocols or address families,
1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1244	used, and preference will be given to protocols mentioned earlier in the
1245	list.
1246
1247	This variable can effectively be used for denial-of-service attacks
1248	against local programs (e.g. when setuid), although the impact is likely
1249	small, as the program has to handle connection errors already-
1250
1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1253	- only support IPv4, never try to resolve or contact IPv6
1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1255	IPv6, but prefer IPv6 over IPv4.
1256
1257	=item C<PERL_ANYEVENT_EDNS0>
1258
1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1260	for DNS. This extension is generally useful to reduce DNS traffic, but
1261	some (broken) firewalls drop such DNS packets, which is why it is off by
1262	default.
1263
1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1265	EDNS0 in its DNS requests.
1266
1267	=item C<PERL_ANYEVENT_MAX_FORKS>
1268
1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1270	will create in parallel.
1271
1272	=back
1273		1973
1274	=head1 EXAMPLE PROGRAM	1974	=head1 EXAMPLE PROGRAM
1275		1975
1276	The following program uses an I/O watcher to read data from STDIN, a timer	1976	The following program uses an I/O watcher to read data from STDIN, a timer
1277	to display a message once per second, and a condition variable to quit the	1977	to display a message once per second, and a condition variable to quit the
…		…
1290	warn "read: $input\n"; # output what has been read	1990	warn "read: $input\n"; # output what has been read
1291	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1991	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1292	},	1992	},
1293	);	1993	);
1294		1994
1295	my $time_watcher; # can only be used once
1296
1297	sub new_timer {
1298	$timer = AnyEvent->timer (after => 1, cb => sub {	1995	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1299	warn "timeout\n"; # print 'timeout' about every second	1996	warn "timeout\n"; # print 'timeout' at most every second
1300	&new_timer; # and restart the time
1301	});	1997	});
1302	}
1303
1304	new_timer; # create first timer
1305		1998
1306	$cv->recv; # wait until user enters /^q/i	1999	$cv->recv; # wait until user enters /^q/i
1307		2000
1308	=head1 REAL-WORLD EXAMPLE	2001	=head1 REAL-WORLD EXAMPLE
1309		2002
…		…
1440	through AnyEvent. The benchmark creates a lot of timers (with a zero	2133	through AnyEvent. The benchmark creates a lot of timers (with a zero
1441	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2134	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1442	which it is), lets them fire exactly once and destroys them again.	2135	which it is), lets them fire exactly once and destroys them again.
1443		2136
1444	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2137	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1445	distribution.	2138	distribution. It uses the L<AE> interface, which makes a real difference
		2139	for the EV and Perl backends only.
1446		2140
1447	=head3 Explanation of the columns	2141	=head3 Explanation of the columns
1448		2142
1449	I<watcher> is the number of event watchers created/destroyed. Since	2143	I<watcher> is the number of event watchers created/destroyed. Since
1450	different event models feature vastly different performances, each event	2144	different event models feature vastly different performances, each event
…		…
1471	watcher.	2165	watcher.
1472		2166
1473	=head3 Results	2167	=head3 Results
1474		2168
1475	name watchers bytes create invoke destroy comment	2169	name watchers bytes create invoke destroy comment
1476	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	2170	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1477	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	2171	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1478	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	2172	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1479	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	2173	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1480	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	2174	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1481	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	2175	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2176	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2177	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1482	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	2178	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1483	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	2179	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1484	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	2180	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1485	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	2181	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1486		2182
1487	=head3 Discussion	2183	=head3 Discussion
1488		2184
1489	The benchmark does I<not> measure scalability of the event loop very	2185	The benchmark does I<not> measure scalability of the event loop very
1490	well. For example, a select-based event loop (such as the pure perl one)	2186	well. For example, a select-based event loop (such as the pure perl one)
…		…
1502	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2198	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1503	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2199	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1504	cycles with POE.	2200	cycles with POE.
1505		2201
1506	C<EV> is the sole leader regarding speed and memory use, which are both	2202	C<EV> is the sole leader regarding speed and memory use, which are both
1507	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2203	maximal/minimal, respectively. When using the L<AE> API there is zero
		2204	overhead (when going through the AnyEvent API create is about 5-6 times
		2205	slower, with other times being equal, so still uses far less memory than
1508	far less memory than any other event loop and is still faster than Event	2206	any other event loop and is still faster than Event natively).
1509	natively.
1510		2207
1511	The pure perl implementation is hit in a few sweet spots (both the	2208	The pure perl implementation is hit in a few sweet spots (both the
1512	constant timeout and the use of a single fd hit optimisations in the perl	2209	constant timeout and the use of a single fd hit optimisations in the perl
1513	interpreter and the backend itself). Nevertheless this shows that it	2210	interpreter and the backend itself). Nevertheless this shows that it
1514	adds very little overhead in itself. Like any select-based backend its	2211	adds very little overhead in itself. Like any select-based backend its
1515	performance becomes really bad with lots of file descriptors (and few of	2212	performance becomes really bad with lots of file descriptors (and few of
1516	them active), of course, but this was not subject of this benchmark.	2213	them active), of course, but this was not subject of this benchmark.
1517		2214
1518	The C<Event> module has a relatively high setup and callback invocation	2215	The C<Event> module has a relatively high setup and callback invocation
1519	cost, but overall scores in on the third place.	2216	cost, but overall scores in on the third place.
		2217
		2218	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2219	when using its pure perl backend.
1520		2220
1521	C<Glib>'s memory usage is quite a bit higher, but it features a	2221	C<Glib>'s memory usage is quite a bit higher, but it features a
1522	faster callback invocation and overall ends up in the same class as	2222	faster callback invocation and overall ends up in the same class as
1523	C<Event>. However, Glib scales extremely badly, doubling the number of	2223	C<Event>. However, Glib scales extremely badly, doubling the number of
1524	watchers increases the processing time by more than a factor of four,	2224	watchers increases the processing time by more than a factor of four,
…		…
1585	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2285	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1586	(1%) are active. This mirrors the activity of large servers with many	2286	(1%) are active. This mirrors the activity of large servers with many
1587	connections, most of which are idle at any one point in time.	2287	connections, most of which are idle at any one point in time.
1588		2288
1589	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2289	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1590	distribution.	2290	distribution. It uses the L<AE> interface, which makes a real difference
		2291	for the EV and Perl backends only.
1591		2292
1592	=head3 Explanation of the columns	2293	=head3 Explanation of the columns
1593		2294
1594	I<sockets> is the number of sockets, and twice the number of "servers" (as	2295	I<sockets> is the number of sockets, and twice the number of "servers" (as
1595	each server has a read and write socket end).	2296	each server has a read and write socket end).
…		…
1602	it to another server. This includes deleting the old timeout and creating	2303	it to another server. This includes deleting the old timeout and creating
1603	a new one that moves the timeout into the future.	2304	a new one that moves the timeout into the future.
1604		2305
1605	=head3 Results	2306	=head3 Results
1606		2307
1607	name sockets create request	2308	name sockets create request
1608	EV 20000 69.01 11.16	2309	EV 20000 62.66 7.99
1609	Perl 20000 73.32 35.87	2310	Perl 20000 68.32 32.64
1610	Event 20000 212.62 257.32	2311	IOAsync 20000 174.06 101.15 epoll
1611	Glib 20000 651.16 1896.30	2312	IOAsync 20000 174.67 610.84 poll
		2313	Event 20000 202.69 242.91
		2314	Glib 20000 557.01 1689.52
1612	POE 20000 349.67 12317.24 uses POE::Loop::Event	2315	POE 20000 341.54 12086.32 uses POE::Loop::Event
1613		2316
1614	=head3 Discussion	2317	=head3 Discussion
1615		2318
1616	This benchmark I<does> measure scalability and overall performance of the	2319	This benchmark I<does> measure scalability and overall performance of the
1617	particular event loop.	2320	particular event loop.
…		…
1619	EV is again fastest. Since it is using epoll on my system, the setup time	2322	EV is again fastest. Since it is using epoll on my system, the setup time
1620	is relatively high, though.	2323	is relatively high, though.
1621		2324
1622	Perl surprisingly comes second. It is much faster than the C-based event	2325	Perl surprisingly comes second. It is much faster than the C-based event
1623	loops Event and Glib.	2326	loops Event and Glib.
		2327
		2328	IO::Async performs very well when using its epoll backend, and still quite
		2329	good compared to Glib when using its pure perl backend.
1624		2330
1625	Event suffers from high setup time as well (look at its code and you will	2331	Event suffers from high setup time as well (look at its code and you will
1626	understand why). Callback invocation also has a high overhead compared to	2332	understand why). Callback invocation also has a high overhead compared to
1627	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2333	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1628	uses select or poll in basically all documented configurations.	2334	uses select or poll in basically all documented configurations.
…		…
1691	=item * C-based event loops perform very well with small number of	2397	=item * C-based event loops perform very well with small number of
1692	watchers, as the management overhead dominates.	2398	watchers, as the management overhead dominates.
1693		2399
1694	=back	2400	=back
1695		2401
		2402	=head2 THE IO::Lambda BENCHMARK
		2403
		2404	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2405	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2406	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2407	shouldn't come as a surprise to anybody). As such, the benchmark is
		2408	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2409	very optimal. But how would AnyEvent compare when used without the extra
		2410	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2411
		2412	The benchmark itself creates an echo-server, and then, for 500 times,
		2413	connects to the echo server, sends a line, waits for the reply, and then
		2414	creates the next connection. This is a rather bad benchmark, as it doesn't
		2415	test the efficiency of the framework or much non-blocking I/O, but it is a
		2416	benchmark nevertheless.
		2417
		2418	name runtime
		2419	Lambda/select 0.330 sec
		2420	+ optimized 0.122 sec
		2421	Lambda/AnyEvent 0.327 sec
		2422	+ optimized 0.138 sec
		2423	Raw sockets/select 0.077 sec
		2424	POE/select, components 0.662 sec
		2425	POE/select, raw sockets 0.226 sec
		2426	POE/select, optimized 0.404 sec
		2427
		2428	AnyEvent/select/nb 0.085 sec
		2429	AnyEvent/EV/nb 0.068 sec
		2430	+state machine 0.134 sec
		2431
		2432	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2433	benchmarks actually make blocking connects and use 100% blocking I/O,
		2434	defeating the purpose of an event-based solution. All of the newly
		2435	written AnyEvent benchmarks use 100% non-blocking connects (using
		2436	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2437	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2438	generally require a lot more bookkeeping and event handling than blocking
		2439	connects (which involve a single syscall only).
		2440
		2441	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2442	offers similar expressive power as POE and IO::Lambda, using conventional
		2443	Perl syntax. This means that both the echo server and the client are 100%
		2444	non-blocking, further placing it at a disadvantage.
		2445
		2446	As you can see, the AnyEvent + EV combination even beats the
		2447	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2448	backend easily beats IO::Lambda and POE.
		2449
		2450	And even the 100% non-blocking version written using the high-level (and
		2451	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2452	higher level ("unoptimised") abstractions by a large margin, even though
		2453	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2454
		2455	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2456	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2457	part of the IO::Lambda distribution and were used without any changes.
		2458
		2459
		2460	=head1 SIGNALS
		2461
		2462	AnyEvent currently installs handlers for these signals:
		2463
		2464	=over 4
		2465
		2466	=item SIGCHLD
		2467
		2468	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2469	emulation for event loops that do not support them natively. Also, some
		2470	event loops install a similar handler.
		2471
		2472	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2473	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2474
		2475	=item SIGPIPE
		2476
		2477	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2478	when AnyEvent gets loaded.
		2479
		2480	The rationale for this is that AnyEvent users usually do not really depend
		2481	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2482	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2483	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2484	some random socket.
		2485
		2486	The rationale for installing a no-op handler as opposed to ignoring it is
		2487	that this way, the handler will be restored to defaults on exec.
		2488
		2489	Feel free to install your own handler, or reset it to defaults.
		2490
		2491	=back
		2492
		2493	=cut
		2494
		2495	undef $SIG{CHLD}
		2496	if $SIG{CHLD} eq 'IGNORE';
		2497
		2498	$SIG{PIPE} = sub { }
		2499	unless defined $SIG{PIPE};
		2500
		2501	=head1 RECOMMENDED/OPTIONAL MODULES
		2502
		2503	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2504	it's built-in modules) are required to use it.
		2505
		2506	That does not mean that AnyEvent won't take advantage of some additional
		2507	modules if they are installed.
		2508
		2509	This section explains which additional modules will be used, and how they
		2510	affect AnyEvent's operation.
		2511
		2512	=over 4
		2513
		2514	=item L<Async::Interrupt>
		2515
		2516	This slightly arcane module is used to implement fast signal handling: To
		2517	my knowledge, there is no way to do completely race-free and quick
		2518	signal handling in pure perl. To ensure that signals still get
		2519	delivered, AnyEvent will start an interval timer to wake up perl (and
		2520	catch the signals) with some delay (default is 10 seconds, look for
		2521	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2522
		2523	If this module is available, then it will be used to implement signal
		2524	catching, which means that signals will not be delayed, and the event loop
		2525	will not be interrupted regularly, which is more efficient (and good for
		2526	battery life on laptops).
		2527
		2528	This affects not just the pure-perl event loop, but also other event loops
		2529	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2530
		2531	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2532	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2533	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2534	does nothing for those backends.
		2535
		2536	=item L<EV>
		2537
		2538	This module isn't really "optional", as it is simply one of the backend
		2539	event loops that AnyEvent can use. However, it is simply the best event
		2540	loop available in terms of features, speed and stability: It supports
		2541	the AnyEvent API optimally, implements all the watcher types in XS, does
		2542	automatic timer adjustments even when no monotonic clock is available,
		2543	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2544	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2545	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2546
		2547	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2548	then this module will do nothing for you.
		2549
		2550	=item L<Guard>
		2551
		2552	The guard module, when used, will be used to implement
		2553	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2554	lot less memory), but otherwise doesn't affect guard operation much. It is
		2555	purely used for performance.
		2556
		2557	=item L<JSON> and L<JSON::XS>
		2558
		2559	One of these modules is required when you want to read or write JSON data
		2560	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2561	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2562
		2563	=item L<Net::SSLeay>
		2564
		2565	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2566	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2567	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2568
		2569	=item L<Time::HiRes>
		2570
		2571	This module is part of perl since release 5.008. It will be used when the
		2572	chosen event library does not come with a timing source on it's own. The
		2573	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2574	try to use a monotonic clock for timing stability.
		2575
		2576	=back
		2577
1696		2578
1697	=head1 FORK	2579	=head1 FORK
1698		2580
1699	Most event libraries are not fork-safe. The ones who are usually are	2581	Most event libraries are not fork-safe. The ones who are usually are
1700	because they rely on inefficient but fork-safe C<select> or C<poll>	2582	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1701	calls. Only L<EV> is fully fork-aware.	2583	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2584	are usually badly thought-out hacks that are incompatible with fork in
		2585	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2586	continue event-processing in both parent and child (or both, if you know
		2587	what you are doing).
		2588
		2589	This means that, in general, you cannot fork and do event processing in
		2590	the child if the event library was initialised before the fork (which
		2591	usually happens when the first AnyEvent watcher is created, or the library
		2592	is loaded).
1702		2593
1703	If you have to fork, you must either do so I<before> creating your first	2594	If you have to fork, you must either do so I<before> creating your first
1704	watcher OR you must not use AnyEvent at all in the child.	2595	watcher OR you must not use AnyEvent at all in the child OR you must do
		2596	something completely out of the scope of AnyEvent.
		2597
		2598	The problem of doing event processing in the parent I<and> the child
		2599	is much more complicated: even for backends that I<are> fork-aware or
		2600	fork-safe, their behaviour is not usually what you want: fork clones all
		2601	watchers, that means all timers, I/O watchers etc. are active in both
		2602	parent and child, which is almost never what you want. USing C<exec>
		2603	to start worker children from some kind of manage rprocess is usually
		2604	preferred, because it is much easier and cleaner, at the expense of having
		2605	to have another binary.
1705		2606
1706		2607
1707	=head1 SECURITY CONSIDERATIONS	2608	=head1 SECURITY CONSIDERATIONS
1708		2609
1709	AnyEvent can be forced to load any event model via	2610	AnyEvent can be forced to load any event model via
…		…
1721	use AnyEvent;	2622	use AnyEvent;
1722		2623
1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2624	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1724	be used to probe what backend is used and gain other information (which is	2625	be used to probe what backend is used and gain other information (which is
1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2626	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1726	$ENV{PERL_ANYEGENT_STRICT}.	2627	$ENV{PERL_ANYEVENT_STRICT}.
		2628
		2629	Note that AnyEvent will remove I<all> environment variables starting with
		2630	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2631	enabled.
1727		2632
1728		2633
1729	=head1 BUGS	2634	=head1 BUGS
1730		2635
1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2636	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2637	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2638	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2639	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1735	pronounced).	2640	pronounced).
1736		2641
1737		2642
1738	=head1 SEE ALSO	2643	=head1 SEE ALSO
1739		2644
…		…
1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2648	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1744		2649
1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2650	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2651	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2652	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1748	L<AnyEvent::Impl::POE>.	2653	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1749		2654
1750	Non-blocking file handles, sockets, TCP clients and	2655	Non-blocking file handles, sockets, TCP clients and
1751	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2656	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1752		2657
1753	Asynchronous DNS: L<AnyEvent::DNS>.	2658	Asynchronous DNS: L<AnyEvent::DNS>.
1754		2659
1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2660	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2661	L<Coro::Event>,
1756		2662
1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2663	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2664	L<AnyEvent::HTTP>.
1758		2665
1759		2666
1760	=head1 AUTHOR	2667	=head1 AUTHOR
1761		2668
1762	Marc Lehmann <schmorp@schmorp.de>	2669	Marc Lehmann <schmorp@schmorp.de>

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