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Revision 1.323 by root, Thu May 20 21:22:20 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 and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		56
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		58
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
173	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
174	declared.	185	declared.
175		186
176	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
177		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
180		197
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	198	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
182	for events (AnyEvent might or might not keep a reference to this file	199	for events (AnyEvent might or might not keep a reference to this file
183	handle). Note that only file handles pointing to things for which	200	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	201	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	202	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	203	or block devices.
…		…
211	undef $w;	228	undef $w;
212	});	229	});
213		230
214	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
215		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	242	method with the following mandatory arguments:
218		243
219	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	245	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
341	might affect timers and time-outs.	366	might affect timers and time-outs.
342		367
343	When this is the case, you can call this method, which will update the	368	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	369	event loop's idea of "current time".
345		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
346	Note that updating the time I<might> cause some events to be handled.	378	Note that updating the time I<might> cause some events to be handled.
347		379
348	=back	380	=back
349		381
350	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		385
352	You can watch for signals using a signal watcher, C<signal> is the signal	386	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
355		389
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	395	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	396	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	397	but it is guaranteed not to interrupt any other callbacks.
364		398
365	The main advantage of using these watchers is that you can share a signal	399	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	400	between multiple watchers, and AnyEvent will ensure that signals will not
		401	interrupt your program at bad times.
367		402
368	This watcher might use C<%SIG>, so programs overwriting those signals	403	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	404	so programs overwriting those signals directly will likely not work
		405	correctly.
370		406
371	Example: exit on SIGINT	407	Example: exit on SIGINT
372		408
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
		430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		431	callbacks to signals in a generic way, which is a pity, as you cannot
		432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
		434	signals will be delayed. The maximum time a signal might be delayed is
		435	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		436	variable can be changed only before the first signal watcher is created,
		437	and should be left alone otherwise. This variable determines how often
		438	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		439	will cause fewer spurious wake-ups, which is better for power and CPU
		440	saving.
		441
		442	All these problems can be avoided by installing the optional
		443	L<Async::Interrupt> module, which works with most event loops. It will not
		444	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		445	(and not with L<POE> currently, as POE does it's own workaround with
		446	one-second latency). For those, you just have to suffer the delays.
		447
375	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
376		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
377	You can also watch on a child process exit and catch its exit status.	452	You can also watch on a child process exit and catch its exit status.
378		453
379	The child process is specified by the C<pid> argument (if set to C<0>, it	454	The child process is specified by the C<pid> argument (one some backends,
380	watches for any child process exit). The watcher will triggered only when	455	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	456	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
383		459
384	The callback will be called with the pid and exit status (as returned by	460	The callback will be called with the pid and exit status (as returned by
385	waitpid), so unlike other watcher types, you I<can> rely on child watcher	461	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	462	callback arguments.
387		463
…		…
392		468
393	There is a slight catch to child watchers, however: you usually start them	469	There is a slight catch to child watchers, however: you usually start them
394	I<after> the child process was created, and this means the process could	470	I<after> the child process was created, and this means the process could
395	have exited already (and no SIGCHLD will be sent anymore).	471	have exited already (and no SIGCHLD will be sent anymore).
396		472
397	Not all event models handle this correctly (POE doesn't), but even for	473	Not all event models handle this correctly (neither POE nor IO::Async do,
		474	see their AnyEvent::Impl manpages for details), but even for event models
398	event models that I<do> handle this correctly, they usually need to be	475	that I<do> handle this correctly, they usually need to be loaded before
399	loaded before the process exits (i.e. before you fork in the first place).	476	the process exits (i.e. before you fork in the first place). AnyEvent's
		477	pure perl event loop handles all cases correctly regardless of when you
		478	start the watcher.
400		479
401	This means you cannot create a child watcher as the very first thing in an	480	This means you cannot create a child watcher as the very first
402	AnyEvent program, you I<have> to create at least one watcher before you	481	thing in an AnyEvent program, you I<have> to create at least one
403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	482	watcher before you C<fork> the child (alternatively, you can call
		483	C<AnyEvent::detect>).
		484
		485	As most event loops do not support waiting for child events, they will be
		486	emulated by AnyEvent in most cases, in which the latency and race problems
		487	mentioned in the description of signal watchers apply.
404		488
405	Example: fork a process and wait for it	489	Example: fork a process and wait for it
406		490
407	my $done = AnyEvent->condvar;	491	my $done = AnyEvent->condvar;
408		492
…		…
420	# do something else, then wait for process exit	504	# do something else, then wait for process exit
421	$done->recv;	505	$done->recv;
422		506
423	=head2 IDLE WATCHERS	507	=head2 IDLE WATCHERS
424		508
425	Sometimes there is a need to do something, but it is not so important	509	$w = AnyEvent->idle (cb => <callback>);
426	to do it instantly, but only when there is nothing better to do. This
427	"nothing better to do" is usually defined to be "no other events need
428	attention by the event loop".
429		510
430	Idle watchers ideally get invoked when the event loop has nothing	511	Repeatedly invoke the callback after the process becomes idle, until
431	better to do, just before it would block the process to wait for new	512	either the watcher is destroyed or new events have been detected.
432	events. Instead of blocking, the idle watcher is invoked.
433		513
434	Most event loops unfortunately do not really support idle watchers (only	514	Idle watchers are useful when there is a need to do something, but it
		515	is not so important (or wise) to do it instantly. The callback will be
		516	invoked only when there is "nothing better to do", which is usually
		517	defined as "all outstanding events have been handled and no new events
		518	have been detected". That means that idle watchers ideally get invoked
		519	when the event loop has just polled for new events but none have been
		520	detected. Instead of blocking to wait for more events, the idle watchers
		521	will be invoked.
		522
		523	Unfortunately, most event loops do not really support idle watchers (only
435	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	524	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
436	will simply call the callback "from time to time".	525	will simply call the callback "from time to time".
437		526
438	Example: read lines from STDIN, but only process them when the	527	Example: read lines from STDIN, but only process them when the
439	program is otherwise idle:	528	program is otherwise idle:
…		…
455	});	544	});
456	});	545	});
457		546
458	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
459		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
		553
460	If you are familiar with some event loops you will know that all of them	554	If you are familiar with some event loops you will know that all of them
461	require you to run some blocking "loop", "run" or similar function that	555	require you to run some blocking "loop", "run" or similar function that
462	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
463		557
464	AnyEvent is different, it expects somebody else to run the event loop and	558	AnyEvent is slightly different: it expects somebody else to run the event
465	will only block when necessary (usually when told by the user).	559	loop and will only block when necessary (usually when told by the user).
466		560
467	The instrument to do that is called a "condition variable", so called	561	The instrument to do that is called a "condition variable", so called
468	because they represent a condition that must become true.	562	because they represent a condition that must become true.
469		563
		564	Now is probably a good time to look at the examples further below.
		565
470	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
471	>> method, usually without arguments. The only argument pair allowed is	567	>> method, usually without arguments. The only argument pair allowed is
472
473	C<cb>, which specifies a callback to be called when the condition variable	568	C<cb>, which specifies a callback to be called when the condition variable
474	becomes true, with the condition variable as the first argument (but not	569	becomes true, with the condition variable as the first argument (but not
475	the results).	570	the results).
476		571
477	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
…		…
482	Condition variables are similar to callbacks, except that you can	577	Condition variables are similar to callbacks, except that you can
483	optionally wait for them. They can also be called merge points - points	578	optionally wait for them. They can also be called merge points - points
484	in time where multiple outstanding events have been processed. And yet	579	in time where multiple outstanding events have been processed. And yet
485	another way to call them is transactions - each condition variable can be	580	another way to call them is transactions - each condition variable can be
486	used to represent a transaction, which finishes at some point and delivers	581	used to represent a transaction, which finishes at some point and delivers
487	a result.	582	a result. And yet some people know them as "futures" - a promise to
		583	compute/deliver something that you can wait for.
488		584
489	Condition variables are very useful to signal that something has finished,	585	Condition variables are very useful to signal that something has finished,
490	for example, if you write a module that does asynchronous http requests,	586	for example, if you write a module that does asynchronous http requests,
491	then a condition variable would be the ideal candidate to signal the	587	then a condition variable would be the ideal candidate to signal the
492	availability of results. The user can either act when the callback is	588	availability of results. The user can either act when the callback is
…		…
513	eventually calls C<< -> send >>, and the "consumer side", which waits	609	eventually calls C<< -> send >>, and the "consumer side", which waits
514	for the send to occur.	610	for the send to occur.
515		611
516	Example: wait for a timer.	612	Example: wait for a timer.
517		613
518	# wait till the result is ready	614	# condition: "wait till the timer is fired"
519	my $result_ready = AnyEvent->condvar;	615	my $timer_fired = AnyEvent->condvar;
520		616
521	# do something such as adding a timer	617	# create the timer - we could wait for, say
522	# or socket watcher the calls $result_ready->send	618	# a handle becomign ready, or even an
523	# when the "result" is ready.	619	# AnyEvent::HTTP request to finish, but
524	# in this case, we simply use a timer:	620	# in this case, we simply use a timer:
525	my $w = AnyEvent->timer (	621	my $w = AnyEvent->timer (
526	after => 1,	622	after => 1,
527	cb => sub { $result_ready->send },	623	cb => sub { $timer_fired->send },
528	);	624	);
529		625
530	# this "blocks" (while handling events) till the callback	626	# this "blocks" (while handling events) till the callback
531	# calls send	627	# calls ->send
532	$result_ready->recv;	628	$timer_fired->recv;
533		629
534	Example: wait for a timer, but take advantage of the fact that	630	Example: wait for a timer, but take advantage of the fact that condition
535	condition variables are also code references.	631	variables are also callable directly.
536		632
537	my $done = AnyEvent->condvar;	633	my $done = AnyEvent->condvar;
538	my $delay = AnyEvent->timer (after => 5, cb => $done);	634	my $delay = AnyEvent->timer (after => 5, cb => $done);
539	$done->recv;	635	$done->recv;
540		636
…		…
546		642
547	...	643	...
548		644
549	my @info = $couchdb->info->recv;	645	my @info = $couchdb->info->recv;
550		646
551	And this is how you would just ste a callback to be called whenever the	647	And this is how you would just set a callback to be called whenever the
552	results are available:	648	results are available:
553		649
554	$couchdb->info->cb (sub {	650	$couchdb->info->cb (sub {
555	my @info = $_[0]->recv;	651	my @info = $_[0]->recv;
556	});	652	});
…		…
574	immediately from within send.	670	immediately from within send.
575		671
576	Any arguments passed to the C<send> call will be returned by all	672	Any arguments passed to the C<send> call will be returned by all
577	future C<< ->recv >> calls.	673	future C<< ->recv >> calls.
578		674
579	Condition variables are overloaded so one can call them directly	675	Condition variables are overloaded so one can call them directly (as if
580	(as a code reference). Calling them directly is the same as calling	676	they were a code reference). Calling them directly is the same as calling
581	C<send>. Note, however, that many C-based event loops do not handle	677	C<send>.
582	overloading, so as tempting as it may be, passing a condition variable
583	instead of a callback does not work. Both the pure perl and EV loops
584	support overloading, however, as well as all functions that use perl to
585	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
586	example).
587		678
588	=item $cv->croak ($error)	679	=item $cv->croak ($error)
589		680
590	Similar to send, but causes all call's to C<< ->recv >> to invoke	681	Similar to send, but causes all call's to C<< ->recv >> to invoke
591	C<Carp::croak> with the given error message/object/scalar.	682	C<Carp::croak> with the given error message/object/scalar.
592		683
593	This can be used to signal any errors to the condition variable	684	This can be used to signal any errors to the condition variable
594	user/consumer.	685	user/consumer. Doing it this way instead of calling C<croak> directly
		686	delays the error detetcion, but has the overwhelmign advantage that it
		687	diagnoses the error at the place where the result is expected, and not
		688	deep in some event clalback without connection to the actual code causing
		689	the problem.
595		690
596	=item $cv->begin ([group callback])	691	=item $cv->begin ([group callback])
597		692
598	=item $cv->end	693	=item $cv->end
599
600	These two methods are EXPERIMENTAL and MIGHT CHANGE.
601		694
602	These two methods can be used to combine many transactions/events into	695	These two methods can be used to combine many transactions/events into
603	one. For example, a function that pings many hosts in parallel might want	696	one. For example, a function that pings many hosts in parallel might want
604	to use a condition variable for the whole process.	697	to use a condition variable for the whole process.
605		698
606	Every call to C<< ->begin >> will increment a counter, and every call to	699	Every call to C<< ->begin >> will increment a counter, and every call to
607	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	700	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
608	>>, the (last) callback passed to C<begin> will be executed. That callback	701	>>, the (last) callback passed to C<begin> will be executed, passing the
609	is I<supposed> to call C<< ->send >>, but that is not required. If no	702	condvar as first argument. That callback is I<supposed> to call C<< ->send
610	callback was set, C<send> will be called without any arguments.	703	>>, but that is not required. If no group callback was set, C<send> will
		704	be called without any arguments.
611		705
612	Let's clarify this with the ping example:	706	You can think of C<< $cv->send >> giving you an OR condition (one call
		707	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		708	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		709
		710	Let's start with a simple example: you have two I/O watchers (for example,
		711	STDOUT and STDERR for a program), and you want to wait for both streams to
		712	close before activating a condvar:
613		713
614	my $cv = AnyEvent->condvar;	714	my $cv = AnyEvent->condvar;
615		715
		716	$cv->begin; # first watcher
		717	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		718	defined sysread $fh1, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->begin; # second watcher
		723	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		724	defined sysread $fh2, my $buf, 4096
		725	or $cv->end;
		726	});
		727
		728	$cv->recv;
		729
		730	This works because for every event source (EOF on file handle), there is
		731	one call to C<begin>, so the condvar waits for all calls to C<end> before
		732	sending.
		733
		734	The ping example mentioned above is slightly more complicated, as the
		735	there are results to be passwd back, and the number of tasks that are
		736	begung can potentially be zero:
		737
		738	my $cv = AnyEvent->condvar;
		739
616	my %result;	740	my %result;
617	$cv->begin (sub { $cv->send (\%result) });	741	$cv->begin (sub { shift->send (\%result) });
618		742
619	for my $host (@list_of_hosts) {	743	for my $host (@list_of_hosts) {
620	$cv->begin;	744	$cv->begin;
621	ping_host_then_call_callback $host, sub {	745	ping_host_then_call_callback $host, sub {
622	$result{$host} = ...;	746	$result{$host} = ...;
…		…
637	loop, which serves two important purposes: first, it sets the callback	761	loop, which serves two important purposes: first, it sets the callback
638	to be called once the counter reaches C<0>, and second, it ensures that	762	to be called once the counter reaches C<0>, and second, it ensures that
639	C<send> is called even when C<no> hosts are being pinged (the loop	763	C<send> is called even when C<no> hosts are being pinged (the loop
640	doesn't execute once).	764	doesn't execute once).
641		765
642	This is the general pattern when you "fan out" into multiple subrequests:	766	This is the general pattern when you "fan out" into multiple (but
643	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	767	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
644	is called at least once, and then, for each subrequest you start, call	768	the callback and ensure C<end> is called at least once, and then, for each
645	C<begin> and for each subrequest you finish, call C<end>.	769	subrequest you start, call C<begin> and for each subrequest you finish,
		770	call C<end>.
646		771
647	=back	772	=back
648		773
649	=head3 METHODS FOR CONSUMERS	774	=head3 METHODS FOR CONSUMERS
650		775
…		…
666	function will call C<croak>.	791	function will call C<croak>.
667		792
668	In list context, all parameters passed to C<send> will be returned,	793	In list context, all parameters passed to C<send> will be returned,
669	in scalar context only the first one will be returned.	794	in scalar context only the first one will be returned.
670		795
		796	Note that doing a blocking wait in a callback is not supported by any
		797	event loop, that is, recursive invocation of a blocking C<< ->recv
		798	>> is not allowed, and the C<recv> call will C<croak> if such a
		799	condition is detected. This condition can be slightly loosened by using
		800	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		801	any thread that doesn't run the event loop itself.
		802
671	Not all event models support a blocking wait - some die in that case	803	Not all event models support a blocking wait - some die in that case
672	(programs might want to do that to stay interactive), so I<if you are	804	(programs might want to do that to stay interactive), so I<if you are
673	using this from a module, never require a blocking wait>, but let the	805	using this from a module, never require a blocking wait>. Instead, let the
674	caller decide whether the call will block or not (for example, by coupling	806	caller decide whether the call will block or not (for example, by coupling
675	condition variables with some kind of request results and supporting	807	condition variables with some kind of request results and supporting
676	callbacks so the caller knows that getting the result will not block,	808	callbacks so the caller knows that getting the result will not block,
677	while still supporting blocking waits if the caller so desires).	809	while still supporting blocking waits if the caller so desires).
678		810
679	Another reason I<never> to C<< ->recv >> in a module is that you cannot
680	sensibly have two C<< ->recv >>'s in parallel, as that would require
681	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
682	can supply.
683
684	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
685	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
686	versions and also integrates coroutines into AnyEvent, making blocking
687	C<< ->recv >> calls perfectly safe as long as they are done from another
688	coroutine (one that doesn't run the event loop).
689
690	You can ensure that C<< -recv >> never blocks by setting a callback and	811	You can ensure that C<< -recv >> never blocks by setting a callback and
691	only calling C<< ->recv >> from within that callback (or at a later	812	only calling C<< ->recv >> from within that callback (or at a later
692	time). This will work even when the event loop does not support blocking	813	time). This will work even when the event loop does not support blocking
693	waits otherwise.	814	waits otherwise.
694		815
…		…
700	=item $cb = $cv->cb ($cb->($cv))	821	=item $cb = $cv->cb ($cb->($cv))
701		822
702	This is a mutator function that returns the callback set and optionally	823	This is a mutator function that returns the callback set and optionally
703	replaces it before doing so.	824	replaces it before doing so.
704		825
705	The callback will be called when the condition becomes "true", i.e. when	826	The callback will be called when the condition becomes (or already was)
706	C<send> or C<croak> are called, with the only argument being the condition	827	"true", i.e. when C<send> or C<croak> are called (or were called), with
707	variable itself. Calling C<recv> inside the callback or at any later time	828	the only argument being the condition variable itself. Calling C<recv>
708	is guaranteed not to block.	829	inside the callback or at any later time is guaranteed not to block.
709		830
710	=back	831	=back
711		832
		833	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		834
		835	The available backend classes are (every class has its own manpage):
		836
		837	=over 4
		838
		839	=item Backends that are autoprobed when no other event loop can be found.
		840
		841	EV is the preferred backend when no other event loop seems to be in
		842	use. If EV is not installed, then AnyEvent will fall back to its own
		843	pure-perl implementation, which is available everywhere as it comes with
		844	AnyEvent itself.
		845
		846	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		847	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		848
		849	=item Backends that are transparently being picked up when they are used.
		850
		851	These will be used when they are currently loaded when the first watcher
		852	is created, in which case it is assumed that the application is using
		853	them. This means that AnyEvent will automatically pick the right backend
		854	when the main program loads an event module before anything starts to
		855	create watchers. Nothing special needs to be done by the main program.
		856
		857	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		858	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		859	AnyEvent::Impl::Tk based on Tk, very broken.
		860	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		861	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		862	AnyEvent::Impl::Irssi used when running within irssi.
		863
		864	=item Backends with special needs.
		865
		866	Qt requires the Qt::Application to be instantiated first, but will
		867	otherwise be picked up automatically. As long as the main program
		868	instantiates the application before any AnyEvent watchers are created,
		869	everything should just work.
		870
		871	AnyEvent::Impl::Qt based on Qt.
		872
		873	Support for IO::Async can only be partial, as it is too broken and
		874	architecturally limited to even support the AnyEvent API. It also
		875	is the only event loop that needs the loop to be set explicitly, so
		876	it can only be used by a main program knowing about AnyEvent. See
		877	L<AnyEvent::Impl::Async> for the gory details.
		878
		879	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		880
		881	=item Event loops that are indirectly supported via other backends.
		882
		883	Some event loops can be supported via other modules:
		884
		885	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		886
		887	B<WxWidgets> has no support for watching file handles. However, you can
		888	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		889	polls 20 times per second, which was considered to be too horrible to even
		890	consider for AnyEvent.
		891
		892	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		893	backend, so it can be supported through POE.
		894
		895	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		896	load L<POE> when detecting them, in the hope that POE will pick them up,
		897	in which case everything will be automatic.
		898
		899	=back
		900
712	=head1 GLOBAL VARIABLES AND FUNCTIONS	901	=head1 GLOBAL VARIABLES AND FUNCTIONS
713		902
		903	These are not normally required to use AnyEvent, but can be useful to
		904	write AnyEvent extension modules.
		905
714	=over 4	906	=over 4
715		907
716	=item $AnyEvent::MODEL	908	=item $AnyEvent::MODEL
717		909
718	Contains C<undef> until the first watcher is being created. Then it	910	Contains C<undef> until the first watcher is being created, before the
		911	backend has been autodetected.
		912
719	contains the event model that is being used, which is the name of the	913	Afterwards it contains the event model that is being used, which is the
720	Perl class implementing the model. This class is usually one of the	914	name of the Perl class implementing the model. This class is usually one
721	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	915	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
722	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	916	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
723		917	will be C<urxvt::anyevent>).
724	The known classes so far are:
725
726	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
727	AnyEvent::Impl::Event based on Event, second best choice.
728	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
729	AnyEvent::Impl::Glib based on Glib, third-best choice.
730	AnyEvent::Impl::Tk based on Tk, very bad choice.
731	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
732	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
733	AnyEvent::Impl::POE based on POE, not generic enough for full support.
734
735	There is no support for WxWidgets, as WxWidgets has no support for
736	watching file handles. However, you can use WxWidgets through the
737	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
738	second, which was considered to be too horrible to even consider for
739	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
740	it's adaptor.
741
742	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
743	autodetecting them.
744		918
745	=item AnyEvent::detect	919	=item AnyEvent::detect
746		920
747	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	921	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
748	if necessary. You should only call this function right before you would	922	if necessary. You should only call this function right before you would
749	have created an AnyEvent watcher anyway, that is, as late as possible at	923	have created an AnyEvent watcher anyway, that is, as late as possible at
750	runtime.	924	runtime, and not e.g. while initialising of your module.
		925
		926	If you need to do some initialisation before AnyEvent watchers are
		927	created, use C<post_detect>.
751		928
752	=item $guard = AnyEvent::post_detect { BLOCK }	929	=item $guard = AnyEvent::post_detect { BLOCK }
753		930
754	Arranges for the code block to be executed as soon as the event model is	931	Arranges for the code block to be executed as soon as the event model is
755	autodetected (or immediately if this has already happened).	932	autodetected (or immediately if this has already happened).
756		933
		934	The block will be executed I<after> the actual backend has been detected
		935	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		936	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		937	other initialisations - see the sources of L<AnyEvent::Strict> or
		938	L<AnyEvent::AIO> to see how this is used.
		939
		940	The most common usage is to create some global watchers, without forcing
		941	event module detection too early, for example, L<AnyEvent::AIO> creates
		942	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		943	avoid autodetecting the event module at load time.
		944
757	If called in scalar or list context, then it creates and returns an object	945	If called in scalar or list context, then it creates and returns an object
758	that automatically removes the callback again when it is destroyed. See	946	that automatically removes the callback again when it is destroyed (or
		947	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
759	L<Coro::BDB> for a case where this is useful.	948	a case where this is useful.
		949
		950	Example: Create a watcher for the IO::AIO module and store it in
		951	C<$WATCHER>. Only do so after the event loop is initialised, though.
		952
		953	our WATCHER;
		954
		955	my $guard = AnyEvent::post_detect {
		956	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		957	};
		958
		959	# the ||= is important in case post_detect immediately runs the block,
		960	# as to not clobber the newly-created watcher. assigning both watcher and
		961	# post_detect guard to the same variable has the advantage of users being
		962	# able to just C<undef $WATCHER> if the watcher causes them grief.
		963
		964	$WATCHER ||= $guard;
760		965
761	=item @AnyEvent::post_detect	966	=item @AnyEvent::post_detect
762		967
763	If there are any code references in this array (you can C<push> to it	968	If there are any code references in this array (you can C<push> to it
764	before or after loading AnyEvent), then they will called directly after	969	before or after loading AnyEvent), then they will called directly after
765	the event loop has been chosen.	970	the event loop has been chosen.
766		971
767	You should check C<$AnyEvent::MODEL> before adding to this array, though:	972	You should check C<$AnyEvent::MODEL> before adding to this array, though:
768	if it contains a true value then the event loop has already been detected,	973	if it is defined then the event loop has already been detected, and the
769	and the array will be ignored.	974	array will be ignored.
770		975
771	Best use C<AnyEvent::post_detect { BLOCK }> instead.	976	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		977	it, as it takes care of these details.
		978
		979	This variable is mainly useful for modules that can do something useful
		980	when AnyEvent is used and thus want to know when it is initialised, but do
		981	not need to even load it by default. This array provides the means to hook
		982	into AnyEvent passively, without loading it.
		983
		984	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		985	together, you could put this into Coro (this is the actual code used by
		986	Coro to accomplish this):
		987
		988	if (defined $AnyEvent::MODEL) {
		989	# AnyEvent already initialised, so load Coro::AnyEvent
		990	require Coro::AnyEvent;
		991	} else {
		992	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		993	# as soon as it is
		994	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		995	}
772		996
773	=back	997	=back
774		998
775	=head1 WHAT TO DO IN A MODULE	999	=head1 WHAT TO DO IN A MODULE
776		1000
…		…
831		1055
832		1056
833	=head1 OTHER MODULES	1057	=head1 OTHER MODULES
834		1058
835	The following is a non-exhaustive list of additional modules that use	1059	The following is a non-exhaustive list of additional modules that use
836	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1060	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
837	in the same program. Some of the modules come with AnyEvent, some are	1061	modules and other event loops in the same program. Some of the modules
838	available via CPAN.	1062	come with AnyEvent, most are available via CPAN.
839		1063
840	=over 4	1064	=over 4
841		1065
842	=item L<AnyEvent::Util>	1066	=item L<AnyEvent::Util>
843		1067
…		…
852		1076
853	=item L<AnyEvent::Handle>	1077	=item L<AnyEvent::Handle>
854		1078
855	Provide read and write buffers, manages watchers for reads and writes,	1079	Provide read and write buffers, manages watchers for reads and writes,
856	supports raw and formatted I/O, I/O queued and fully transparent and	1080	supports raw and formatted I/O, I/O queued and fully transparent and
857	non-blocking SSL/TLS.	1081	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
858		1082
859	=item L<AnyEvent::DNS>	1083	=item L<AnyEvent::DNS>
860		1084
861	Provides rich asynchronous DNS resolver capabilities.	1085	Provides rich asynchronous DNS resolver capabilities.
862		1086
		1087	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1088
		1089	Implement event-based interfaces to the protocols of the same name (for
		1090	the curious, IGS is the International Go Server and FCP is the Freenet
		1091	Client Protocol).
		1092
		1093	=item L<AnyEvent::Handle::UDP>
		1094
		1095	Here be danger!
		1096
		1097	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1098	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1099	it's use of a stream-based API with a protocol that isn't streamable, that
		1100	the only way to improve it is to delete it.
		1101
		1102	It features data corruption (but typically only under load) and general
		1103	confusion. On top, the author is not only clueless about UDP but also
		1104	fact-resistant - some gems of his understanding: "connect doesn't work
		1105	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1106	packets", "I don't need to implement proper error checking as UDP doesn't
		1107	support error checking" and so on - he doesn't even understand what's
		1108	wrong with his module when it is explained to him.
		1109
863	=item L<AnyEvent::HTTP>	1110	=item L<AnyEvent::DBI>
864		1111
865	A simple-to-use HTTP library that is capable of making a lot of concurrent	1112	Executes L<DBI> requests asynchronously in a proxy process for you,
866	HTTP requests.	1113	notifying you in an event-bnased way when the operation is finished.
		1114
		1115	=item L<AnyEvent::AIO>
		1116
		1117	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1118	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1119	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1120	file I/O, and much more.
867		1121
868	=item L<AnyEvent::HTTPD>	1122	=item L<AnyEvent::HTTPD>
869		1123
870	Provides a simple web application server framework.	1124	A simple embedded webserver.
871		1125
872	=item L<AnyEvent::FastPing>	1126	=item L<AnyEvent::FastPing>
873		1127
874	The fastest ping in the west.	1128	The fastest ping in the west.
875		1129
876	=item L<AnyEvent::DBI>
877
878	Executes L<DBI> requests asynchronously in a proxy process.
879
880	=item L<AnyEvent::AIO>
881
882	Truly asynchronous I/O, should be in the toolbox of every event
883	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
884	together.
885
886	=item L<AnyEvent::BDB>
887
888	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
889	L<BDB> and AnyEvent together.
890
891	=item L<AnyEvent::GPSD>
892
893	A non-blocking interface to gpsd, a daemon delivering GPS information.
894
895	=item L<AnyEvent::IGS>
896
897	A non-blocking interface to the Internet Go Server protocol (used by
898	L<App::IGS>).
899
900	=item L<AnyEvent::IRC>
901
902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
903
904	=item L<Net::XMPP2>
905
906	AnyEvent based XMPP (Jabber protocol) module family.
907
908	=item L<Net::FCP>
909
910	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
911	of AnyEvent.
912
913	=item L<Event::ExecFlow>
914
915	High level API for event-based execution flow control.
916
917	=item L<Coro>	1130	=item L<Coro>
918		1131
919	Has special support for AnyEvent via L<Coro::AnyEvent>.	1132	Has special support for AnyEvent via L<Coro::AnyEvent>.
920		1133
921	=item L<IO::Lambda>
922
923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
924
925	=back	1134	=back
926		1135
927	=cut	1136	=cut
928		1137
929	package AnyEvent;	1138	package AnyEvent;
930		1139
931	no warnings;	1140	# basically a tuned-down version of common::sense
932	use strict qw(vars subs);	1141	sub common_sense {
		1142	# from common:.sense 1.0
		1143	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1144	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1145	$^H |= 0x00000600;
		1146	}
933		1147
		1148	BEGIN { AnyEvent::common_sense }
		1149
934	use Carp;	1150	use Carp ();
935		1151
936	our $VERSION = 4.412;	1152	our $VERSION = '5.261';
937	our $MODEL;	1153	our $MODEL;
938		1154
939	our $AUTOLOAD;	1155	our $AUTOLOAD;
940	our @ISA;	1156	our @ISA;
941		1157
942	our @REGISTRY;	1158	our @REGISTRY;
943		1159
944	our $WIN32;	1160	our $VERBOSE;
945		1161
946	BEGIN {	1162	BEGIN {
947	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1163	require "AnyEvent/constants.pl";
		1164
948	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1165	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
949		1166
950	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1167	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
951	if ${^TAINT};	1168	if ${^TAINT};
952	}
953		1169
954	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1170	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1171
		1172	}
		1173
		1174	our $MAX_SIGNAL_LATENCY = 10;
955		1175
956	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1176	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
957		1177
958	{	1178	{
959	my $idx;	1179	my $idx;
…		…
961	for reverse split /\s*,\s*/,	1181	for reverse split /\s*,\s*/,
962	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1182	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
963	}	1183	}
964		1184
965	my @models = (	1185	my @models = (
966	[EV:: => AnyEvent::Impl::EV::],	1186	[EV:: => AnyEvent::Impl::EV:: , 1],
967	[Event:: => AnyEvent::Impl::Event::],
968	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1187	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
969	# everything below here will not be autoprobed	1188	# everything below here will not (normally) be autoprobed
970	# as the pureperl backend should work everywhere	1189	# as the pureperl backend should work everywhere
971	# and is usually faster	1190	# and is usually faster
		1191	[Event:: => AnyEvent::Impl::Event::, 1],
		1192	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1193	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1194	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
972	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1195	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
973	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
974	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
975	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1196	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
976	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1197	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
977	[Wx:: => AnyEvent::Impl::POE::],	1198	[Wx:: => AnyEvent::Impl::POE::],
978	[Prima:: => AnyEvent::Impl::POE::],	1199	[Prima:: => AnyEvent::Impl::POE::],
		1200	# IO::Async is just too broken - we would need workarounds for its
		1201	# byzantine signal and broken child handling, among others.
		1202	# IO::Async is rather hard to detect, as it doesn't have any
		1203	# obvious default class.
		1204	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1205	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1206	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1207	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
979	);	1208	);
980		1209
981	our %method = map +($_ => 1),	1210	our %method = map +($_ => 1),
982	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1211	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
983		1212
984	our @post_detect;	1213	our @post_detect;
985		1214
986	sub post_detect(&) {	1215	sub post_detect(&) {
987	my ($cb) = @_;	1216	my ($cb) = @_;
988		1217
989	if ($MODEL) {
990	$cb->();
991
992	1
993	} else {
994	push @post_detect, $cb;	1218	push @post_detect, $cb;
995		1219
996	defined wantarray	1220	defined wantarray
997	? bless \$cb, "AnyEvent::Util::postdetect"	1221	? bless \$cb, "AnyEvent::Util::postdetect"
998	: ()	1222	: ()
999	}
1000	}	1223	}
1001		1224
1002	sub AnyEvent::Util::postdetect::DESTROY {	1225	sub AnyEvent::Util::postdetect::DESTROY {
1003	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1226	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1004	}	1227	}
1005		1228
1006	sub detect() {	1229	sub detect() {
		1230	# free some memory
		1231	*detect = sub () { $MODEL };
		1232
		1233	local $!; # for good measure
		1234	local $SIG{__DIE__};
		1235
		1236	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1237	my $model = "AnyEvent::Impl::$1";
		1238	if (eval "require $model") {
		1239	$MODEL = $model;
		1240	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1241	} else {
		1242	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1243	}
		1244	}
		1245
		1246	# check for already loaded models
1007	unless ($MODEL) {	1247	unless ($MODEL) {
1008	no strict 'refs';	1248	for (@REGISTRY, @models) {
1009	local $SIG{__DIE__};	1249	my ($package, $model) = @$_;
1010		1250	if (${"$package\::VERSION"} > 0) {
1011	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1012	my $model = "AnyEvent::Impl::$1";
1013	if (eval "require $model") {	1251	if (eval "require $model") {
1014	$MODEL = $model;	1252	$MODEL = $model;
1015	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1253	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1016	} else {	1254	last;
1017	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1255	}
1018	}	1256	}
1019	}	1257	}
1020		1258
1021	# check for already loaded models
1022	unless ($MODEL) {	1259	unless ($MODEL) {
		1260	# try to autoload a model
1023	for (@REGISTRY, @models) {	1261	for (@REGISTRY, @models) {
1024	my ($package, $model) = @$_;	1262	my ($package, $model, $autoload) = @$_;
		1263	if (
		1264	$autoload
		1265	and eval "require $package"
1025	if (${"$package\::VERSION"} > 0) {	1266	and ${"$package\::VERSION"} > 0
1026	if (eval "require $model") {	1267	and eval "require $model"
		1268	) {
1027	$MODEL = $model;	1269	$MODEL = $model;
1028	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1029	last;	1271	last;
1030	}
1031	}	1272	}
1032	}	1273	}
1033		1274
1034	unless ($MODEL) {
1035	# try to load a model
1036
1037	for (@REGISTRY, @models) {
1038	my ($package, $model) = @$_;
1039	if (eval "require $package"
1040	and ${"$package\::VERSION"} > 0
1041	and eval "require $model") {
1042	$MODEL = $model;
1043	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1044	last;
1045	}
1046	}
1047
1048	$MODEL	1275	$MODEL
1049	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1276	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1050	}
1051	}	1277	}
1052
1053	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1054
1055	unshift @ISA, $MODEL;
1056
1057	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1058
1059	(shift @post_detect)->() while @post_detect;
1060	}	1278	}
		1279
		1280	@models = (); # free probe data
		1281
		1282	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1283	unshift @ISA, $MODEL;
		1284
		1285	# now nuke some methods that are overriden by the backend.
		1286	# SUPER is not allowed.
		1287	for (qw(time signal child idle)) {
		1288	undef &{"AnyEvent::Base::$_"}
		1289	if defined &{"$MODEL\::$_"};
		1290	}
		1291
		1292	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1293
		1294	(shift @post_detect)->() while @post_detect;
		1295
		1296	*post_detect = sub(&) {
		1297	shift->();
		1298
		1299	undef
		1300	};
1061		1301
1062	$MODEL	1302	$MODEL
1063	}	1303	}
1064		1304
1065	sub AUTOLOAD {	1305	sub AUTOLOAD {
1066	(my $func = $AUTOLOAD) =~ s/.*://;	1306	(my $func = $AUTOLOAD) =~ s/.*://;
1067		1307
1068	$method{$func}	1308	$method{$func}
1069	or croak "$func: not a valid method for AnyEvent objects";	1309	or Carp::croak "$func: not a valid AnyEvent class method";
1070		1310
1071	detect unless $MODEL;	1311	detect;
1072		1312
1073	my $class = shift;	1313	my $class = shift;
1074	$class->$func (@_);	1314	$class->$func (@_);
1075	}	1315	}
1076		1316
1077	# utility function to dup a filehandle. this is used by many backends	1317	# utility function to dup a filehandle. this is used by many backends
1078	# to support binding more than one watcher per filehandle (they usually	1318	# to support binding more than one watcher per filehandle (they usually
1079	# allow only one watcher per fd, so we dup it to get a different one).	1319	# allow only one watcher per fd, so we dup it to get a different one).
1080	sub _dupfh($$$$) {	1320	sub _dupfh($$;$$) {
1081	my ($poll, $fh, $r, $w) = @_;	1321	my ($poll, $fh, $r, $w) = @_;
1082		1322
1083	# cygwin requires the fh mode to be matching, unix doesn't	1323	# cygwin requires the fh mode to be matching, unix doesn't
1084	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1324	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1085	: $poll eq "w" ? ($w, ">")
1086	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1087		1325
1088	open my $fh2, "$mode&" . fileno $fh	1326	open my $fh2, $mode, $fh
1089	or die "cannot dup() filehandle: $!,";	1327	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1090		1328
1091	# we assume CLOEXEC is already set by perl in all important cases	1329	# we assume CLOEXEC is already set by perl in all important cases
1092		1330
1093	($fh2, $rw)	1331	($fh2, $rw)
1094	}	1332	}
1095		1333
		1334	=head1 SIMPLIFIED AE API
		1335
		1336	Starting with version 5.0, AnyEvent officially supports a second, much
		1337	simpler, API that is designed to reduce the calling, typing and memory
		1338	overhead by using function call syntax and a fixed number of parameters.
		1339
		1340	See the L<AE> manpage for details.
		1341
		1342	=cut
		1343
		1344	package AE;
		1345
		1346	our $VERSION = $AnyEvent::VERSION;
		1347
		1348	# fall back to the main API by default - backends and AnyEvent::Base
		1349	# implementations can overwrite these.
		1350
		1351	sub io($$$) {
		1352	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1353	}
		1354
		1355	sub timer($$$) {
		1356	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1357	}
		1358
		1359	sub signal($$) {
		1360	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1361	}
		1362
		1363	sub child($$) {
		1364	AnyEvent->child (pid => $_[0], cb => $_[1])
		1365	}
		1366
		1367	sub idle($) {
		1368	AnyEvent->idle (cb => $_[0])
		1369	}
		1370
		1371	sub cv(;&) {
		1372	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1373	}
		1374
		1375	sub now() {
		1376	AnyEvent->now
		1377	}
		1378
		1379	sub now_update() {
		1380	AnyEvent->now_update
		1381	}
		1382
		1383	sub time() {
		1384	AnyEvent->time
		1385	}
		1386
1096	package AnyEvent::Base;	1387	package AnyEvent::Base;
1097		1388
1098	# default implementations for many methods	1389	# default implementations for many methods
1099		1390
1100	BEGIN {	1391	sub time {
		1392	eval q{ # poor man's autoloading {}
		1393	# probe for availability of Time::HiRes
1101	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1394	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1395	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1102	*_time = \&Time::HiRes::time;	1396	*AE::time = \&Time::HiRes::time;
1103	# if (eval "use POSIX (); (POSIX::times())...	1397	# if (eval "use POSIX (); (POSIX::times())...
1104	} else {	1398	} else {
		1399	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1105	*_time = sub { time }; # epic fail	1400	*AE::time = sub (){ time }; # epic fail
		1401	}
		1402
		1403	*time = sub { AE::time }; # different prototypes
		1404	};
		1405	die if $@;
		1406
		1407	&time
		1408	}
		1409
		1410	*now = \&time;
		1411
		1412	sub now_update { }
		1413
		1414	# default implementation for ->condvar
		1415
		1416	sub condvar {
		1417	eval q{ # poor man's autoloading {}
		1418	*condvar = sub {
		1419	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1420	};
		1421
		1422	*AE::cv = sub (;&) {
		1423	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1424	};
		1425	};
		1426	die if $@;
		1427
		1428	&condvar
		1429	}
		1430
		1431	# default implementation for ->signal
		1432
		1433	our $HAVE_ASYNC_INTERRUPT;
		1434
		1435	sub _have_async_interrupt() {
		1436	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1437	&& eval "use Async::Interrupt 1.02 (); 1")
		1438	unless defined $HAVE_ASYNC_INTERRUPT;
		1439
		1440	$HAVE_ASYNC_INTERRUPT
		1441	}
		1442
		1443	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1444	our (%SIG_ASY, %SIG_ASY_W);
		1445	our ($SIG_COUNT, $SIG_TW);
		1446
		1447	# install a dummy wakeup watcher to reduce signal catching latency
		1448	# used by Impls
		1449	sub _sig_add() {
		1450	unless ($SIG_COUNT++) {
		1451	# try to align timer on a full-second boundary, if possible
		1452	my $NOW = AE::now;
		1453
		1454	$SIG_TW = AE::timer
		1455	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1456	$MAX_SIGNAL_LATENCY,
		1457	sub { } # just for the PERL_ASYNC_CHECK
		1458	;
1106	}	1459	}
1107	}	1460	}
1108		1461
1109	sub time { _time }	1462	sub _sig_del {
1110	sub now { _time }	1463	undef $SIG_TW
1111	sub now_update { }	1464	unless --$SIG_COUNT;
1112
1113	# default implementation for ->condvar
1114
1115	sub condvar {
1116	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1117	}	1465	}
1118		1466
1119	# default implementation for ->signal	1467	our $_sig_name_init; $_sig_name_init = sub {
		1468	eval q{ # poor man's autoloading {}
		1469	undef $_sig_name_init;
1120		1470
1121	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1471	if (_have_async_interrupt) {
		1472	*sig2num = \&Async::Interrupt::sig2num;
		1473	*sig2name = \&Async::Interrupt::sig2name;
		1474	} else {
		1475	require Config;
1122		1476
1123	sub _signal_exec {	1477	my %signame2num;
1124	sysread $SIGPIPE_R, my $dummy, 4;	1478	@signame2num{ split ' ', $Config::Config{sig_name} }
		1479	= split ' ', $Config::Config{sig_num};
1125		1480
1126	while (%SIG_EV) {	1481	my @signum2name;
1127	for (keys %SIG_EV) {	1482	@signum2name[values %signame2num] = keys %signame2num;
1128	delete $SIG_EV{$_};	1483
1129	$_->() for values %{ $SIG_CB{$_} || {} };	1484	*sig2num = sub($) {
		1485	$_[0] > 0 ? shift : $signame2num{+shift}
		1486	};
		1487	*sig2name = sub ($) {
		1488	$_[0] > 0 ? $signum2name[+shift] : shift
		1489	};
1130	}	1490	}
1131	}	1491	};
1132	}	1492	die if $@;
		1493	};
		1494
		1495	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1496	sub sig2name($) { &$_sig_name_init; &sig2name }
1133		1497
1134	sub signal {	1498	sub signal {
1135	my (undef, %arg) = @_;	1499	eval q{ # poor man's autoloading {}
		1500	# probe for availability of Async::Interrupt
		1501	if (_have_async_interrupt) {
		1502	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1136		1503
1137	unless ($SIGPIPE_R) {	1504	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1138	require Fcntl;	1505	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1139		1506
1140	if (AnyEvent::WIN32) {
1141	require AnyEvent::Util;
1142
1143	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1144	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1145	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1146	} else {	1507	} else {
		1508	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1509
		1510	if (AnyEvent::WIN32) {
		1511	require AnyEvent::Util;
		1512
		1513	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1514	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1515	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1516	} else {
1147	pipe $SIGPIPE_R, $SIGPIPE_W;	1517	pipe $SIGPIPE_R, $SIGPIPE_W;
1148	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1518	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1149	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1519	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1150		1520
1151	# not strictly required, as $^F is normally 2, but let's make sure...	1521	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1522	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1523	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1524	}
		1525
		1526	$SIGPIPE_R
		1527	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1528
		1529	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1154	}	1530	}
1155		1531
1156	$SIGPIPE_R	1532	*signal = $HAVE_ASYNC_INTERRUPT
1157	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1533	? sub {
		1534	my (undef, %arg) = @_;
1158		1535
1159	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1536	# async::interrupt
1160	}
1161
1162	my $signal = uc $arg{signal}	1537	my $signal = sig2num $arg{signal};
1163	or Carp::croak "required option 'signal' is missing";
1164
1165	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1538	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1539
		1540	$SIG_ASY{$signal} ||= new Async::Interrupt
		1541	cb => sub { undef $SIG_EV{$signal} },
		1542	signal => $signal,
		1543	pipe => [$SIGPIPE_R->filenos],
		1544	pipe_autodrain => 0,
		1545	;
		1546
		1547	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1548	}
		1549	: sub {
		1550	my (undef, %arg) = @_;
		1551
		1552	# pure perl
		1553	my $signal = sig2name $arg{signal};
		1554	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1555
1166	$SIG{$signal} ||= sub {	1556	$SIG{$signal} ||= sub {
1167	local $!;	1557	local $!;
1168	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1558	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1169	undef $SIG_EV{$signal};	1559	undef $SIG_EV{$signal};
		1560	};
		1561
		1562	# can't do signal processing without introducing races in pure perl,
		1563	# so limit the signal latency.
		1564	_sig_add;
		1565
		1566	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1567	}
		1568	;
		1569
		1570	*AnyEvent::Base::signal::DESTROY = sub {
		1571	my ($signal, $cb) = @{$_[0]};
		1572
		1573	_sig_del;
		1574
		1575	delete $SIG_CB{$signal}{$cb};
		1576
		1577	$HAVE_ASYNC_INTERRUPT
		1578	? delete $SIG_ASY{$signal}
		1579	: # delete doesn't work with older perls - they then
		1580	# print weird messages, or just unconditionally exit
		1581	# instead of getting the default action.
		1582	undef $SIG{$signal}
		1583	unless keys %{ $SIG_CB{$signal} };
		1584	};
		1585
		1586	*_signal_exec = sub {
		1587	$HAVE_ASYNC_INTERRUPT
		1588	? $SIGPIPE_R->drain
		1589	: sysread $SIGPIPE_R, (my $dummy), 9;
		1590
		1591	while (%SIG_EV) {
		1592	for (keys %SIG_EV) {
		1593	delete $SIG_EV{$_};
		1594	$_->() for values %{ $SIG_CB{$_} || {} };
		1595	}
		1596	}
		1597	};
1170	};	1598	};
		1599	die if $@;
1171		1600
1172	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1601	&signal
1173	}
1174
1175	sub AnyEvent::Base::signal::DESTROY {
1176	my ($signal, $cb) = @{$_[0]};
1177
1178	delete $SIG_CB{$signal}{$cb};
1179
1180	# delete doesn't work with older perls - they then
1181	# print weird messages, or just unconditionally exit
1182	# instead of getting the default action.
1183	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1184	}	1602	}
1185		1603
1186	# default implementation for ->child	1604	# default implementation for ->child
1187		1605
1188	our %PID_CB;	1606	our %PID_CB;
1189	our $CHLD_W;	1607	our $CHLD_W;
1190	our $CHLD_DELAY_W;	1608	our $CHLD_DELAY_W;
1191	our $WNOHANG;	1609	our $WNOHANG;
1192		1610
1193	sub _sigchld {	1611	# used by many Impl's
1194	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1612	sub _emit_childstatus($$) {
		1613	my (undef, $rpid, $rstatus) = @_;
		1614
		1615	$_->($rpid, $rstatus)
1195	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1616	for values %{ $PID_CB{$rpid} || {} },
1196	(values %{ $PID_CB{0} || {} });	1617	values %{ $PID_CB{0} || {} };
1197	}
1198	}	1618	}
1199		1619
1200	sub child {	1620	sub child {
		1621	eval q{ # poor man's autoloading {}
		1622	*_sigchld = sub {
		1623	my $pid;
		1624
		1625	AnyEvent->_emit_childstatus ($pid, $?)
		1626	while ($pid = waitpid -1, $WNOHANG) > 0;
		1627	};
		1628
		1629	*child = sub {
1201	my (undef, %arg) = @_;	1630	my (undef, %arg) = @_;
1202		1631
1203	defined (my $pid = $arg{pid} + 0)	1632	defined (my $pid = $arg{pid} + 0)
1204	or Carp::croak "required option 'pid' is missing";	1633	or Carp::croak "required option 'pid' is missing";
1205		1634
1206	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1635	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1207		1636
		1637	# WNOHANG is almost cetrainly 1 everywhere
		1638	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1639	? 1
1208	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1640	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1209		1641
1210	unless ($CHLD_W) {	1642	unless ($CHLD_W) {
1211	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1643	$CHLD_W = AE::signal CHLD => \&_sigchld;
1212	# child could be a zombie already, so make at least one round	1644	# child could be a zombie already, so make at least one round
1213	&_sigchld;	1645	&_sigchld;
1214	}	1646	}
1215		1647
1216	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1648	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1217	}	1649	};
1218		1650
1219	sub AnyEvent::Base::child::DESTROY {	1651	*AnyEvent::Base::child::DESTROY = sub {
1220	my ($pid, $cb) = @{$_[0]};	1652	my ($pid, $cb) = @{$_[0]};
1221		1653
1222	delete $PID_CB{$pid}{$cb};	1654	delete $PID_CB{$pid}{$cb};
1223	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1655	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1224		1656
1225	undef $CHLD_W unless keys %PID_CB;	1657	undef $CHLD_W unless keys %PID_CB;
		1658	};
		1659	};
		1660	die if $@;
		1661
		1662	&child
1226	}	1663	}
1227		1664
1228	# idle emulation is done by simply using a timer, regardless	1665	# idle emulation is done by simply using a timer, regardless
1229	# of whether the process is idle or not, and not letting	1666	# of whether the process is idle or not, and not letting
1230	# the callback use more than 50% of the time.	1667	# the callback use more than 50% of the time.
1231	sub idle {	1668	sub idle {
		1669	eval q{ # poor man's autoloading {}
		1670	*idle = sub {
1232	my (undef, %arg) = @_;	1671	my (undef, %arg) = @_;
1233		1672
1234	my ($cb, $w, $rcb) = $arg{cb};	1673	my ($cb, $w, $rcb) = $arg{cb};
1235		1674
1236	$rcb = sub {	1675	$rcb = sub {
1237	if ($cb) {	1676	if ($cb) {
1238	$w = _time;	1677	$w = _time;
1239	&$cb;	1678	&$cb;
1240	$w = _time - $w;	1679	$w = _time - $w;
1241		1680
1242	# never use more then 50% of the time for the idle watcher,	1681	# never use more then 50% of the time for the idle watcher,
1243	# within some limits	1682	# within some limits
1244	$w = 0.0001 if $w < 0.0001;	1683	$w = 0.0001 if $w < 0.0001;
1245	$w = 5 if $w > 5;	1684	$w = 5 if $w > 5;
1246		1685
1247	$w = AnyEvent->timer (after => $w, cb => $rcb);	1686	$w = AE::timer $w, 0, $rcb;
1248	} else {	1687	} else {
1249	# clean up...	1688	# clean up...
1250	undef $w;	1689	undef $w;
1251	undef $rcb;	1690	undef $rcb;
		1691	}
		1692	};
		1693
		1694	$w = AE::timer 0.05, 0, $rcb;
		1695
		1696	bless \\$cb, "AnyEvent::Base::idle"
1252	}	1697	};
		1698
		1699	*AnyEvent::Base::idle::DESTROY = sub {
		1700	undef $${$_[0]};
		1701	};
1253	};	1702	};
		1703	die if $@;
1254		1704
1255	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1705	&idle
1256
1257	bless \\$cb, "AnyEvent::Base::idle"
1258	}
1259
1260	sub AnyEvent::Base::idle::DESTROY {
1261	undef $${$_[0]};
1262	}	1706	}
1263		1707
1264	package AnyEvent::CondVar;	1708	package AnyEvent::CondVar;
1265		1709
1266	our @ISA = AnyEvent::CondVar::Base::;	1710	our @ISA = AnyEvent::CondVar::Base::;
1267		1711
1268	package AnyEvent::CondVar::Base;	1712	package AnyEvent::CondVar::Base;
1269		1713
1270	use overload	1714	#use overload
1271	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1715	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1272	fallback => 1;	1716	# fallback => 1;
		1717
		1718	# save 300+ kilobytes by dirtily hardcoding overloading
		1719	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1720	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1721	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1722	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1723
		1724	our $WAITING;
1273		1725
1274	sub _send {	1726	sub _send {
1275	# nop	1727	# nop
1276	}	1728	}
1277		1729
…		…
1290	sub ready {	1742	sub ready {
1291	$_[0]{_ae_sent}	1743	$_[0]{_ae_sent}
1292	}	1744	}
1293		1745
1294	sub _wait {	1746	sub _wait {
		1747	$WAITING
		1748	and !$_[0]{_ae_sent}
		1749	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1750
		1751	local $WAITING = 1;
1295	AnyEvent->one_event while !$_[0]{_ae_sent};	1752	AnyEvent->one_event while !$_[0]{_ae_sent};
1296	}	1753	}
1297		1754
1298	sub recv {	1755	sub recv {
1299	$_[0]->_wait;	1756	$_[0]->_wait;
…		…
1301	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1758	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1302	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1759	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1303	}	1760	}
1304		1761
1305	sub cb {	1762	sub cb {
1306	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1763	my $cv = shift;
		1764
		1765	@_
		1766	and $cv->{_ae_cb} = shift
		1767	and $cv->{_ae_sent}
		1768	and (delete $cv->{_ae_cb})->($cv);
		1769
1307	$_[0]{_ae_cb}	1770	$cv->{_ae_cb}
1308	}	1771	}
1309		1772
1310	sub begin {	1773	sub begin {
1311	++$_[0]{_ae_counter};	1774	++$_[0]{_ae_counter};
1312	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1775	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	C<PERL_ANYEVENT_MODEL>.	1824	C<PERL_ANYEVENT_MODEL>.
1362		1825
1363	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1826	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1364	model it chooses.	1827	model it chooses.
1365		1828
		1829	When set to C<8> or higher, then AnyEvent will report extra information on
		1830	which optional modules it loads and how it implements certain features.
		1831
1366	=item C<PERL_ANYEVENT_STRICT>	1832	=item C<PERL_ANYEVENT_STRICT>
1367		1833
1368	AnyEvent does not do much argument checking by default, as thorough	1834	AnyEvent does not do much argument checking by default, as thorough
1369	argument checking is very costly. Setting this variable to a true value	1835	argument checking is very costly. Setting this variable to a true value
1370	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1836	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1371	check the arguments passed to most method calls. If it finds any problems,	1837	check the arguments passed to most method calls. If it finds any problems,
1372	it will croak.	1838	it will croak.
1373		1839
1374	In other words, enables "strict" mode.	1840	In other words, enables "strict" mode.
1375		1841
1376	Unlike C<use strict>, it is definitely recommended to keep it off in	1842	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1377	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1843	>>, it is definitely recommended to keep it off in production. Keeping
1378	developing programs can be very useful, however.	1844	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1845	can be very useful, however.
1379		1846
1380	=item C<PERL_ANYEVENT_MODEL>	1847	=item C<PERL_ANYEVENT_MODEL>
1381		1848
1382	This can be used to specify the event model to be used by AnyEvent, before	1849	This can be used to specify the event model to be used by AnyEvent, before
1383	auto detection and -probing kicks in. It must be a string consisting	1850	auto detection and -probing kicks in. It must be a string consisting
…		…
1426		1893
1427	=item C<PERL_ANYEVENT_MAX_FORKS>	1894	=item C<PERL_ANYEVENT_MAX_FORKS>
1428		1895
1429	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1896	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1430	will create in parallel.	1897	will create in parallel.
		1898
		1899	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1900
		1901	The default value for the C<max_outstanding> parameter for the default DNS
		1902	resolver - this is the maximum number of parallel DNS requests that are
		1903	sent to the DNS server.
		1904
		1905	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1906
		1907	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1908	configuration) in the default resolver. When set to the empty string, no
		1909	default config will be used.
		1910
		1911	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1912
		1913	When neither C<ca_file> nor C<ca_path> was specified during
		1914	L<AnyEvent::TLS> context creation, and either of these environment
		1915	variables exist, they will be used to specify CA certificate locations
		1916	instead of a system-dependent default.
		1917
		1918	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1919
		1920	When these are set to C<1>, then the respective modules are not
		1921	loaded. Mostly good for testing AnyEvent itself.
1431		1922
1432	=back	1923	=back
1433		1924
1434	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1925	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1435		1926
…		…
1493	warn "read: $input\n"; # output what has been read	1984	warn "read: $input\n"; # output what has been read
1494	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1985	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1495	},	1986	},
1496	);	1987	);
1497		1988
1498	my $time_watcher; # can only be used once
1499
1500	sub new_timer {
1501	$timer = AnyEvent->timer (after => 1, cb => sub {	1989	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1502	warn "timeout\n"; # print 'timeout' about every second	1990	warn "timeout\n"; # print 'timeout' at most every second
1503	&new_timer; # and restart the time
1504	});	1991	});
1505	}
1506
1507	new_timer; # create first timer
1508		1992
1509	$cv->recv; # wait until user enters /^q/i	1993	$cv->recv; # wait until user enters /^q/i
1510		1994
1511	=head1 REAL-WORLD EXAMPLE	1995	=head1 REAL-WORLD EXAMPLE
1512		1996
…		…
1585		2069
1586	The actual code goes further and collects all errors (C<die>s, exceptions)	2070	The actual code goes further and collects all errors (C<die>s, exceptions)
1587	that occurred during request processing. The C<result> method detects	2071	that occurred during request processing. The C<result> method detects
1588	whether an exception as thrown (it is stored inside the $txn object)	2072	whether an exception as thrown (it is stored inside the $txn object)
1589	and just throws the exception, which means connection errors and other	2073	and just throws the exception, which means connection errors and other
1590	problems get reported tot he code that tries to use the result, not in a	2074	problems get reported to the code that tries to use the result, not in a
1591	random callback.	2075	random callback.
1592		2076
1593	All of this enables the following usage styles:	2077	All of this enables the following usage styles:
1594		2078
1595	1. Blocking:	2079	1. Blocking:
…		…
1643	through AnyEvent. The benchmark creates a lot of timers (with a zero	2127	through AnyEvent. The benchmark creates a lot of timers (with a zero
1644	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2128	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1645	which it is), lets them fire exactly once and destroys them again.	2129	which it is), lets them fire exactly once and destroys them again.
1646		2130
1647	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2131	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1648	distribution.	2132	distribution. It uses the L<AE> interface, which makes a real difference
		2133	for the EV and Perl backends only.
1649		2134
1650	=head3 Explanation of the columns	2135	=head3 Explanation of the columns
1651		2136
1652	I<watcher> is the number of event watchers created/destroyed. Since	2137	I<watcher> is the number of event watchers created/destroyed. Since
1653	different event models feature vastly different performances, each event	2138	different event models feature vastly different performances, each event
…		…
1674	watcher.	2159	watcher.
1675		2160
1676	=head3 Results	2161	=head3 Results
1677		2162
1678	name watchers bytes create invoke destroy comment	2163	name watchers bytes create invoke destroy comment
1679	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2164	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1680	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2165	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1681	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2166	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1682	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2167	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1683	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2168	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1684	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2169	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2170	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2171	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1685	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2172	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1686	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2173	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1687	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2174	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1688	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2175	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1689		2176
1690	=head3 Discussion	2177	=head3 Discussion
1691		2178
1692	The benchmark does I<not> measure scalability of the event loop very	2179	The benchmark does I<not> measure scalability of the event loop very
1693	well. For example, a select-based event loop (such as the pure perl one)	2180	well. For example, a select-based event loop (such as the pure perl one)
…		…
1705	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2192	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1706	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2193	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1707	cycles with POE.	2194	cycles with POE.
1708		2195
1709	C<EV> is the sole leader regarding speed and memory use, which are both	2196	C<EV> is the sole leader regarding speed and memory use, which are both
1710	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2197	maximal/minimal, respectively. When using the L<AE> API there is zero
		2198	overhead (when going through the AnyEvent API create is about 5-6 times
		2199	slower, with other times being equal, so still uses far less memory than
1711	far less memory than any other event loop and is still faster than Event	2200	any other event loop and is still faster than Event natively).
1712	natively.
1713		2201
1714	The pure perl implementation is hit in a few sweet spots (both the	2202	The pure perl implementation is hit in a few sweet spots (both the
1715	constant timeout and the use of a single fd hit optimisations in the perl	2203	constant timeout and the use of a single fd hit optimisations in the perl
1716	interpreter and the backend itself). Nevertheless this shows that it	2204	interpreter and the backend itself). Nevertheless this shows that it
1717	adds very little overhead in itself. Like any select-based backend its	2205	adds very little overhead in itself. Like any select-based backend its
1718	performance becomes really bad with lots of file descriptors (and few of	2206	performance becomes really bad with lots of file descriptors (and few of
1719	them active), of course, but this was not subject of this benchmark.	2207	them active), of course, but this was not subject of this benchmark.
1720		2208
1721	The C<Event> module has a relatively high setup and callback invocation	2209	The C<Event> module has a relatively high setup and callback invocation
1722	cost, but overall scores in on the third place.	2210	cost, but overall scores in on the third place.
		2211
		2212	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2213	when using its pure perl backend.
1723		2214
1724	C<Glib>'s memory usage is quite a bit higher, but it features a	2215	C<Glib>'s memory usage is quite a bit higher, but it features a
1725	faster callback invocation and overall ends up in the same class as	2216	faster callback invocation and overall ends up in the same class as
1726	C<Event>. However, Glib scales extremely badly, doubling the number of	2217	C<Event>. However, Glib scales extremely badly, doubling the number of
1727	watchers increases the processing time by more than a factor of four,	2218	watchers increases the processing time by more than a factor of four,
…		…
1788	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2279	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1789	(1%) are active. This mirrors the activity of large servers with many	2280	(1%) are active. This mirrors the activity of large servers with many
1790	connections, most of which are idle at any one point in time.	2281	connections, most of which are idle at any one point in time.
1791		2282
1792	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2283	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1793	distribution.	2284	distribution. It uses the L<AE> interface, which makes a real difference
		2285	for the EV and Perl backends only.
1794		2286
1795	=head3 Explanation of the columns	2287	=head3 Explanation of the columns
1796		2288
1797	I<sockets> is the number of sockets, and twice the number of "servers" (as	2289	I<sockets> is the number of sockets, and twice the number of "servers" (as
1798	each server has a read and write socket end).	2290	each server has a read and write socket end).
…		…
1805	it to another server. This includes deleting the old timeout and creating	2297	it to another server. This includes deleting the old timeout and creating
1806	a new one that moves the timeout into the future.	2298	a new one that moves the timeout into the future.
1807		2299
1808	=head3 Results	2300	=head3 Results
1809		2301
1810	name sockets create request	2302	name sockets create request
1811	EV 20000 69.01 11.16	2303	EV 20000 62.66 7.99
1812	Perl 20000 73.32 35.87	2304	Perl 20000 68.32 32.64
1813	Event 20000 212.62 257.32	2305	IOAsync 20000 174.06 101.15 epoll
1814	Glib 20000 651.16 1896.30	2306	IOAsync 20000 174.67 610.84 poll
		2307	Event 20000 202.69 242.91
		2308	Glib 20000 557.01 1689.52
1815	POE 20000 349.67 12317.24 uses POE::Loop::Event	2309	POE 20000 341.54 12086.32 uses POE::Loop::Event
1816		2310
1817	=head3 Discussion	2311	=head3 Discussion
1818		2312
1819	This benchmark I<does> measure scalability and overall performance of the	2313	This benchmark I<does> measure scalability and overall performance of the
1820	particular event loop.	2314	particular event loop.
…		…
1822	EV is again fastest. Since it is using epoll on my system, the setup time	2316	EV is again fastest. Since it is using epoll on my system, the setup time
1823	is relatively high, though.	2317	is relatively high, though.
1824		2318
1825	Perl surprisingly comes second. It is much faster than the C-based event	2319	Perl surprisingly comes second. It is much faster than the C-based event
1826	loops Event and Glib.	2320	loops Event and Glib.
		2321
		2322	IO::Async performs very well when using its epoll backend, and still quite
		2323	good compared to Glib when using its pure perl backend.
1827		2324
1828	Event suffers from high setup time as well (look at its code and you will	2325	Event suffers from high setup time as well (look at its code and you will
1829	understand why). Callback invocation also has a high overhead compared to	2326	understand why). Callback invocation also has a high overhead compared to
1830	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2327	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1831	uses select or poll in basically all documented configurations.	2328	uses select or poll in basically all documented configurations.
…		…
1943	As you can see, the AnyEvent + EV combination even beats the	2440	As you can see, the AnyEvent + EV combination even beats the
1944	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2441	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1945	backend easily beats IO::Lambda and POE.	2442	backend easily beats IO::Lambda and POE.
1946		2443
1947	And even the 100% non-blocking version written using the high-level (and	2444	And even the 100% non-blocking version written using the high-level (and
1948	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2445	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
1949	large margin, even though it does all of DNS, tcp-connect and socket I/O	2446	higher level ("unoptimised") abstractions by a large margin, even though
1950	in a non-blocking way.	2447	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
1951		2448
1952	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2449	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
1953	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2450	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
1954	part of the IO::lambda distribution and were used without any changes.	2451	part of the IO::Lambda distribution and were used without any changes.
1955		2452
1956		2453
1957	=head1 SIGNALS	2454	=head1 SIGNALS
1958		2455
1959	AnyEvent currently installs handlers for these signals:	2456	AnyEvent currently installs handlers for these signals:
…		…
1963	=item SIGCHLD	2460	=item SIGCHLD
1964		2461
1965	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2462	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1966	emulation for event loops that do not support them natively. Also, some	2463	emulation for event loops that do not support them natively. Also, some
1967	event loops install a similar handler.	2464	event loops install a similar handler.
		2465
		2466	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2467	AnyEvent will reset it to default, to avoid losing child exit statuses.
1968		2468
1969	=item SIGPIPE	2469	=item SIGPIPE
1970		2470
1971	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2471	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1972	when AnyEvent gets loaded.	2472	when AnyEvent gets loaded.
…		…
1984		2484
1985	=back	2485	=back
1986		2486
1987	=cut	2487	=cut
1988		2488
		2489	undef $SIG{CHLD}
		2490	if $SIG{CHLD} eq 'IGNORE';
		2491
1989	$SIG{PIPE} = sub { }	2492	$SIG{PIPE} = sub { }
1990	unless defined $SIG{PIPE};	2493	unless defined $SIG{PIPE};
1991		2494
		2495	=head1 RECOMMENDED/OPTIONAL MODULES
		2496
		2497	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2498	it's built-in modules) are required to use it.
		2499
		2500	That does not mean that AnyEvent won't take advantage of some additional
		2501	modules if they are installed.
		2502
		2503	This section explains which additional modules will be used, and how they
		2504	affect AnyEvent's operation.
		2505
		2506	=over 4
		2507
		2508	=item L<Async::Interrupt>
		2509
		2510	This slightly arcane module is used to implement fast signal handling: To
		2511	my knowledge, there is no way to do completely race-free and quick
		2512	signal handling in pure perl. To ensure that signals still get
		2513	delivered, AnyEvent will start an interval timer to wake up perl (and
		2514	catch the signals) with some delay (default is 10 seconds, look for
		2515	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2516
		2517	If this module is available, then it will be used to implement signal
		2518	catching, which means that signals will not be delayed, and the event loop
		2519	will not be interrupted regularly, which is more efficient (and good for
		2520	battery life on laptops).
		2521
		2522	This affects not just the pure-perl event loop, but also other event loops
		2523	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2524
		2525	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2526	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2527	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2528	does nothing for those backends.
		2529
		2530	=item L<EV>
		2531
		2532	This module isn't really "optional", as it is simply one of the backend
		2533	event loops that AnyEvent can use. However, it is simply the best event
		2534	loop available in terms of features, speed and stability: It supports
		2535	the AnyEvent API optimally, implements all the watcher types in XS, does
		2536	automatic timer adjustments even when no monotonic clock is available,
		2537	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2538	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2539	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2540
		2541	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2542	then this module will do nothing for you.
		2543
		2544	=item L<Guard>
		2545
		2546	The guard module, when used, will be used to implement
		2547	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2548	lot less memory), but otherwise doesn't affect guard operation much. It is
		2549	purely used for performance.
		2550
		2551	=item L<JSON> and L<JSON::XS>
		2552
		2553	One of these modules is required when you want to read or write JSON data
		2554	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2555	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2556
		2557	=item L<Net::SSLeay>
		2558
		2559	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2560	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2561	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2562
		2563	=item L<Time::HiRes>
		2564
		2565	This module is part of perl since release 5.008. It will be used when the
		2566	chosen event library does not come with a timing source on it's own. The
		2567	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2568	try to use a monotonic clock for timing stability.
		2569
		2570	=back
		2571
1992		2572
1993	=head1 FORK	2573	=head1 FORK
1994		2574
1995	Most event libraries are not fork-safe. The ones who are usually are	2575	Most event libraries are not fork-safe. The ones who are usually are
1996	because they rely on inefficient but fork-safe C<select> or C<poll>	2576	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1997	calls. Only L<EV> is fully fork-aware.	2577	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2578	are usually badly thought-out hacks that are incompatible with fork in
		2579	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2580	continue event-processing in both parent and child (or both, if you know
		2581	what you are doing).
		2582
		2583	This means that, in general, you cannot fork and do event processing in
		2584	the child if the event library was initialised before the fork (which
		2585	usually happens when the first AnyEvent watcher is created, or the library
		2586	is loaded).
1998		2587
1999	If you have to fork, you must either do so I<before> creating your first	2588	If you have to fork, you must either do so I<before> creating your first
2000	watcher OR you must not use AnyEvent at all in the child.	2589	watcher OR you must not use AnyEvent at all in the child OR you must do
		2590	something completely out of the scope of AnyEvent.
		2591
		2592	The problem of doing event processing in the parent I<and> the child
		2593	is much more complicated: even for backends that I<are> fork-aware or
		2594	fork-safe, their behaviour is not usually what you want: fork clones all
		2595	watchers, that means all timers, I/O watchers etc. are active in both
		2596	parent and child, which is almost never what you want. USing C<exec>
		2597	to start worker children from some kind of manage rprocess is usually
		2598	preferred, because it is much easier and cleaner, at the expense of having
		2599	to have another binary.
2001		2600
2002		2601
2003	=head1 SECURITY CONSIDERATIONS	2602	=head1 SECURITY CONSIDERATIONS
2004		2603
2005	AnyEvent can be forced to load any event model via	2604	AnyEvent can be forced to load any event model via
…		…
2043	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2642	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2044		2643
2045	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2644	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2046	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2645	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2047	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2646	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2048	L<AnyEvent::Impl::POE>.	2647	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2049		2648
2050	Non-blocking file handles, sockets, TCP clients and	2649	Non-blocking file handles, sockets, TCP clients and
2051	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2650	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2052		2651
2053	Asynchronous DNS: L<AnyEvent::DNS>.	2652	Asynchronous DNS: L<AnyEvent::DNS>.
2054		2653
2055	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2654	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2655	L<Coro::Event>,
2056		2656
2057	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2657	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2658	L<AnyEvent::HTTP>.
2058		2659
2059		2660
2060	=head1 AUTHOR	2661	=head1 AUTHOR
2061		2662
2062	Marc Lehmann <schmorp@schmorp.de>	2663	Marc Lehmann <schmorp@schmorp.de>

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