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Revision 1.208 by root, Sun Apr 26 18:12:53 2009 UTC vs.
Revision 1.316 by root, Mon Mar 15 18:51:30 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
…		…
39	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
40		41
41	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
42	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
43	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Repository>, at L<http://anyevent.schmorp.de>, for more info.
44		53
45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
46		55
47	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
48	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
172	my variables are only visible after the statement in which they are	181	my variables are only visible after the statement in which they are
173	declared.	182	declared.
174		183
175	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
176		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	192	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
178	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
179		194
180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	195	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
181	for events (AnyEvent might or might not keep a reference to this file	196	for events (AnyEvent might or might not keep a reference to this file
182	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
183	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
184	most character devices, pipes, fifos and so on, but not for example files	199	most character devices, pipes, fifos and so on, but not for example files
185	or block devices.	200	or block devices.
…		…
210	undef $w;	225	undef $w;
211	});	226	});
212		227
213	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
214		229
		230	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		231
		232	$w = AnyEvent->timer (
		233	after => <fractional_seconds>,
		234	interval => <fractional_seconds>,
		235	cb => <callback>,
		236	);
		237
215	You can create a time watcher by calling the C<< AnyEvent->timer >>	238	You can create a time watcher by calling the C<< AnyEvent->timer >>
216	method with the following mandatory arguments:	239	method with the following mandatory arguments:
217		240
218	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
219	supported) the callback should be invoked. C<cb> is the callback to invoke	242	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
340	might affect timers and time-outs.	363	might affect timers and time-outs.
341		364
342	When this is the case, you can call this method, which will update the	365	When this is the case, you can call this method, which will update the
343	event loop's idea of "current time".	366	event loop's idea of "current time".
344		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
345	Note that updating the time I<might> cause some events to be handled.	375	Note that updating the time I<might> cause some events to be handled.
346		376
347	=back	377	=back
348		378
349	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
350		382
351	You can watch for signals using a signal watcher, C<signal> is the signal	383	You can watch for signals using a signal watcher, C<signal> is the signal
352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	384	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
353	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
354		386
…		…
360	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
361	that it might take a while until the signal gets handled by the process,	393	that it might take a while until the signal gets handled by the process,
362	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
363		395
364	The main advantage of using these watchers is that you can share a signal	396	The main advantage of using these watchers is that you can share a signal
365	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
366		399
367	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
368	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
369		403
370	Example: exit on SIGINT	404	Example: exit on SIGINT
371		405
372	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
373		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		433	variable can be changed only before the first signal watcher is created,
		434	and should be left alone otherwise. This variable determines how often
		435	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		436	will cause fewer spurious wake-ups, which is better for power and CPU
		437	saving.
		438
		439	All these problems can be avoided by installing the optional
		440	L<Async::Interrupt> module, which works with most event loops. It will not
		441	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		442	(and not with L<POE> currently, as POE does it's own workaround with
		443	one-second latency). For those, you just have to suffer the delays.
		444
374	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
375		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
376	You can also watch on a child process exit and catch its exit status.	449	You can also watch on a child process exit and catch its exit status.
377		450
378	The child process is specified by the C<pid> argument (if set to C<0>, it	451	The child process is specified by the C<pid> argument (one some backends,
379	watches for any child process exit). The watcher will triggered only when	452	using C<0> watches for any child process exit, on others this will
380	the child process has finished and an exit status is available, not on	453	croak). The watcher will be triggered only when the child process has
381	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
382		456
383	The callback will be called with the pid and exit status (as returned by	457	The callback will be called with the pid and exit status (as returned by
384	waitpid), so unlike other watcher types, you I<can> rely on child watcher	458	waitpid), so unlike other watcher types, you I<can> rely on child watcher
385	callback arguments.	459	callback arguments.
386		460
…		…
391		465
392	There is a slight catch to child watchers, however: you usually start them	466	There is a slight catch to child watchers, however: you usually start them
393	I<after> the child process was created, and this means the process could	467	I<after> the child process was created, and this means the process could
394	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
395		469
396	Not all event models handle this correctly (POE doesn't), but even for	470	Not all event models handle this correctly (neither POE nor IO::Async do,
		471	see their AnyEvent::Impl manpages for details), but even for event models
397	event models that I<do> handle this correctly, they usually need to be	472	that I<do> handle this correctly, they usually need to be loaded before
398	loaded before the process exits (i.e. before you fork in the first place).	473	the process exits (i.e. before you fork in the first place). AnyEvent's
		474	pure perl event loop handles all cases correctly regardless of when you
		475	start the watcher.
399		476
400	This means you cannot create a child watcher as the very first thing in an	477	This means you cannot create a child watcher as the very first
401	AnyEvent program, you I<have> to create at least one watcher before you	478	thing in an AnyEvent program, you I<have> to create at least one
402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	479	watcher before you C<fork> the child (alternatively, you can call
		480	C<AnyEvent::detect>).
		481
		482	As most event loops do not support waiting for child events, they will be
		483	emulated by AnyEvent in most cases, in which the latency and race problems
		484	mentioned in the description of signal watchers apply.
403		485
404	Example: fork a process and wait for it	486	Example: fork a process and wait for it
405		487
406	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
407		489
…		…
419	# do something else, then wait for process exit	501	# do something else, then wait for process exit
420	$done->recv;	502	$done->recv;
421		503
422	=head2 IDLE WATCHERS	504	=head2 IDLE WATCHERS
423		505
424	Sometimes there is a need to do something, but it is not so important	506	$w = AnyEvent->idle (cb => <callback>);
425	to do it instantly, but only when there is nothing better to do. This
426	"nothing better to do" is usually defined to be "no other events need
427	attention by the event loop".
428		507
429	Idle watchers ideally get invoked when the event loop has nothing	508	Repeatedly invoke the callback after the process becomes idle, until
430	better to do, just before it would block the process to wait for new	509	either the watcher is destroyed or new events have been detected.
431	events. Instead of blocking, the idle watcher is invoked.
432		510
433	Most event loops unfortunately do not really support idle watchers (only	511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
435	will simply call the callback "from time to time".	522	will simply call the callback "from time to time".
436		523
437	Example: read lines from STDIN, but only process them when the	524	Example: read lines from STDIN, but only process them when the
438	program is otherwise idle:	525	program is otherwise idle:
…		…
454	});	541	});
455	});	542	});
456		543
457	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
458		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
		550
459	If you are familiar with some event loops you will know that all of them	551	If you are familiar with some event loops you will know that all of them
460	require you to run some blocking "loop", "run" or similar function that	552	require you to run some blocking "loop", "run" or similar function that
461	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
462		554
463	AnyEvent is different, it expects somebody else to run the event loop and	555	AnyEvent is slightly different: it expects somebody else to run the event
464	will only block when necessary (usually when told by the user).	556	loop and will only block when necessary (usually when told by the user).
465		557
466	The instrument to do that is called a "condition variable", so called	558	The instrument to do that is called a "condition variable", so called
467	because they represent a condition that must become true.	559	because they represent a condition that must become true.
468		560
		561	Now is probably a good time to look at the examples further below.
		562
469	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
470	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
471
472	C<cb>, which specifies a callback to be called when the condition variable	565	C<cb>, which specifies a callback to be called when the condition variable
473	becomes true, with the condition variable as the first argument (but not	566	becomes true, with the condition variable as the first argument (but not
474	the results).	567	the results).
475		568
476	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
481	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
482	optionally wait for them. They can also be called merge points - points	575	optionally wait for them. They can also be called merge points - points
483	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
484	another way to call them is transactions - each condition variable can be	577	another way to call them is transactions - each condition variable can be
485	used to represent a transaction, which finishes at some point and delivers	578	used to represent a transaction, which finishes at some point and delivers
486	a result.	579	a result. And yet some people know them as "futures" - a promise to
		580	compute/deliver something that you can wait for.
487		581
488	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
489	for example, if you write a module that does asynchronous http requests,	583	for example, if you write a module that does asynchronous http requests,
490	then a condition variable would be the ideal candidate to signal the	584	then a condition variable would be the ideal candidate to signal the
491	availability of results. The user can either act when the callback is	585	availability of results. The user can either act when the callback is
…		…
525	after => 1,	619	after => 1,
526	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
527	);	621	);
528		622
529	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
530	# calls send	624	# calls ->send
531	$result_ready->recv;	625	$result_ready->recv;
532		626
533	Example: wait for a timer, but take advantage of the fact that	627	Example: wait for a timer, but take advantage of the fact that condition
534	condition variables are also code references.	628	variables are also callable directly.
535		629
536	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
537	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
538	$done->recv;	632	$done->recv;
539		633
…		…
545		639
546	...	640	...
547		641
548	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
549		643
550	And this is how you would just ste a callback to be called whenever the	644	And this is how you would just set a callback to be called whenever the
551	results are available:	645	results are available:
552		646
553	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
554	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
555	});	649	});
…		…
573	immediately from within send.	667	immediately from within send.
574		668
575	Any arguments passed to the C<send> call will be returned by all	669	Any arguments passed to the C<send> call will be returned by all
576	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
577		671
578	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
579	(as a code reference). Calling them directly is the same as calling	673	they were a code reference). Calling them directly is the same as calling
580	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
581	overloading, so as tempting as it may be, passing a condition variable
582	instead of a callback does not work. Both the pure perl and EV loops
583	support overloading, however, as well as all functions that use perl to
584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
585	example).
586		675
587	=item $cv->croak ($error)	676	=item $cv->croak ($error)
588		677
589	Similar to send, but causes all call's to C<< ->recv >> to invoke	678	Similar to send, but causes all call's to C<< ->recv >> to invoke
590	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
591		680
592	This can be used to signal any errors to the condition variable	681	This can be used to signal any errors to the condition variable
593	user/consumer.	682	user/consumer. Doing it this way instead of calling C<croak> directly
		683	delays the error detetcion, but has the overwhelmign advantage that it
		684	diagnoses the error at the place where the result is expected, and not
		685	deep in some event clalback without connection to the actual code causing
		686	the problem.
594		687
595	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
596		689
597	=item $cv->end	690	=item $cv->end
598
599	These two methods are EXPERIMENTAL and MIGHT CHANGE.
600		691
601	These two methods can be used to combine many transactions/events into	692	These two methods can be used to combine many transactions/events into
602	one. For example, a function that pings many hosts in parallel might want	693	one. For example, a function that pings many hosts in parallel might want
603	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
604		695
605	Every call to C<< ->begin >> will increment a counter, and every call to	696	Every call to C<< ->begin >> will increment a counter, and every call to
606	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	697	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
607	>>, the (last) callback passed to C<begin> will be executed. That callback	698	>>, the (last) callback passed to C<begin> will be executed, passing the
608	is I<supposed> to call C<< ->send >>, but that is not required. If no	699	condvar as first argument. That callback is I<supposed> to call C<< ->send
609	callback was set, C<send> will be called without any arguments.	700	>>, but that is not required. If no group callback was set, C<send> will
		701	be called without any arguments.
610		702
611	Let's clarify this with the ping example:	703	You can think of C<< $cv->send >> giving you an OR condition (one call
		704	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		705	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		706
		707	Let's start with a simple example: you have two I/O watchers (for example,
		708	STDOUT and STDERR for a program), and you want to wait for both streams to
		709	close before activating a condvar:
612		710
613	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
614		712
		713	$cv->begin; # first watcher
		714	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		715	defined sysread $fh1, my $buf, 4096
		716	or $cv->end;
		717	});
		718
		719	$cv->begin; # second watcher
		720	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		721	defined sysread $fh2, my $buf, 4096
		722	or $cv->end;
		723	});
		724
		725	$cv->recv;
		726
		727	This works because for every event source (EOF on file handle), there is
		728	one call to C<begin>, so the condvar waits for all calls to C<end> before
		729	sending.
		730
		731	The ping example mentioned above is slightly more complicated, as the
		732	there are results to be passwd back, and the number of tasks that are
		733	begung can potentially be zero:
		734
		735	my $cv = AnyEvent->condvar;
		736
615	my %result;	737	my %result;
616	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
617		739
618	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
619	$cv->begin;	741	$cv->begin;
620	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
621	$result{$host} = ...;	743	$result{$host} = ...;
…		…
636	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
637	to be called once the counter reaches C<0>, and second, it ensures that	759	to be called once the counter reaches C<0>, and second, it ensures that
638	C<send> is called even when C<no> hosts are being pinged (the loop	760	C<send> is called even when C<no> hosts are being pinged (the loop
639	doesn't execute once).	761	doesn't execute once).
640		762
641	This is the general pattern when you "fan out" into multiple subrequests:	763	This is the general pattern when you "fan out" into multiple (but
642	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	764	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
643	is called at least once, and then, for each subrequest you start, call	765	the callback and ensure C<end> is called at least once, and then, for each
644	C<begin> and for each subrequest you finish, call C<end>.	766	subrequest you start, call C<begin> and for each subrequest you finish,
		767	call C<end>.
645		768
646	=back	769	=back
647		770
648	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
649		772
…		…
665	function will call C<croak>.	788	function will call C<croak>.
666		789
667	In list context, all parameters passed to C<send> will be returned,	790	In list context, all parameters passed to C<send> will be returned,
668	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
669		792
		793	Note that doing a blocking wait in a callback is not supported by any
		794	event loop, that is, recursive invocation of a blocking C<< ->recv
		795	>> is not allowed, and the C<recv> call will C<croak> if such a
		796	condition is detected. This condition can be slightly loosened by using
		797	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		798	any thread that doesn't run the event loop itself.
		799
670	Not all event models support a blocking wait - some die in that case	800	Not all event models support a blocking wait - some die in that case
671	(programs might want to do that to stay interactive), so I<if you are	801	(programs might want to do that to stay interactive), so I<if you are
672	using this from a module, never require a blocking wait>, but let the	802	using this from a module, never require a blocking wait>. Instead, let the
673	caller decide whether the call will block or not (for example, by coupling	803	caller decide whether the call will block or not (for example, by coupling
674	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
675	callbacks so the caller knows that getting the result will not block,	805	callbacks so the caller knows that getting the result will not block,
676	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
677		807
678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
679	sensibly have two C<< ->recv >>'s in parallel, as that would require
680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
681	can supply.
682
683	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
684	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
685	versions and also integrates coroutines into AnyEvent, making blocking
686	C<< ->recv >> calls perfectly safe as long as they are done from another
687	coroutine (one that doesn't run the event loop).
688
689	You can ensure that C<< -recv >> never blocks by setting a callback and	808	You can ensure that C<< -recv >> never blocks by setting a callback and
690	only calling C<< ->recv >> from within that callback (or at a later	809	only calling C<< ->recv >> from within that callback (or at a later
691	time). This will work even when the event loop does not support blocking	810	time). This will work even when the event loop does not support blocking
692	waits otherwise.	811	waits otherwise.
693		812
…		…
699	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
700		819
701	This is a mutator function that returns the callback set and optionally	820	This is a mutator function that returns the callback set and optionally
702	replaces it before doing so.	821	replaces it before doing so.
703		822
704	The callback will be called when the condition becomes "true", i.e. when	823	The callback will be called when the condition becomes (or already was)
705	C<send> or C<croak> are called, with the only argument being the condition	824	"true", i.e. when C<send> or C<croak> are called (or were called), with
706	variable itself. Calling C<recv> inside the callback or at any later time	825	the only argument being the condition variable itself. Calling C<recv>
707	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
708		827
709	=back	828	=back
710		829
		830	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		831
		832	The available backend classes are (every class has its own manpage):
		833
		834	=over 4
		835
		836	=item Backends that are autoprobed when no other event loop can be found.
		837
		838	EV is the preferred backend when no other event loop seems to be in
		839	use. If EV is not installed, then AnyEvent will fall back to its own
		840	pure-perl implementation, which is available everywhere as it comes with
		841	AnyEvent itself.
		842
		843	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		844	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		845
		846	=item Backends that are transparently being picked up when they are used.
		847
		848	These will be used when they are currently loaded when the first watcher
		849	is created, in which case it is assumed that the application is using
		850	them. This means that AnyEvent will automatically pick the right backend
		851	when the main program loads an event module before anything starts to
		852	create watchers. Nothing special needs to be done by the main program.
		853
		854	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		855	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		856	AnyEvent::Impl::Tk based on Tk, very broken.
		857	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		858	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		859	AnyEvent::Impl::Irssi used when running within irssi.
		860
		861	=item Backends with special needs.
		862
		863	Qt requires the Qt::Application to be instantiated first, but will
		864	otherwise be picked up automatically. As long as the main program
		865	instantiates the application before any AnyEvent watchers are created,
		866	everything should just work.
		867
		868	AnyEvent::Impl::Qt based on Qt.
		869
		870	Support for IO::Async can only be partial, as it is too broken and
		871	architecturally limited to even support the AnyEvent API. It also
		872	is the only event loop that needs the loop to be set explicitly, so
		873	it can only be used by a main program knowing about AnyEvent. See
		874	L<AnyEvent::Impl::Async> for the gory details.
		875
		876	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		877
		878	=item Event loops that are indirectly supported via other backends.
		879
		880	Some event loops can be supported via other modules:
		881
		882	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		883
		884	B<WxWidgets> has no support for watching file handles. However, you can
		885	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		886	polls 20 times per second, which was considered to be too horrible to even
		887	consider for AnyEvent.
		888
		889	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		890	backend, so it can be supported through POE.
		891
		892	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		893	load L<POE> when detecting them, in the hope that POE will pick them up,
		894	in which case everything will be automatic.
		895
		896	=back
		897
711	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
712		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
713	=over 4	903	=over 4
714		904
715	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
716		906
717	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
718	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
719	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
720	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
721	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
722		914	will be C<urxvt::anyevent>).
723	The known classes so far are:
724
725	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
726	AnyEvent::Impl::Event based on Event, second best choice.
727	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
728	AnyEvent::Impl::Glib based on Glib, third-best choice.
729	AnyEvent::Impl::Tk based on Tk, very bad choice.
730	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
731	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
732	AnyEvent::Impl::POE based on POE, not generic enough for full support.
733
734	There is no support for WxWidgets, as WxWidgets has no support for
735	watching file handles. However, you can use WxWidgets through the
736	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
737	second, which was considered to be too horrible to even consider for
738	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
739	it's adaptor.
740
741	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
742	autodetecting them.
743		915
744	=item AnyEvent::detect	916	=item AnyEvent::detect
745		917
746	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
747	if necessary. You should only call this function right before you would	919	if necessary. You should only call this function right before you would
748	have created an AnyEvent watcher anyway, that is, as late as possible at	920	have created an AnyEvent watcher anyway, that is, as late as possible at
749	runtime.	921	runtime, and not e.g. while initialising of your module.
		922
		923	If you need to do some initialisation before AnyEvent watchers are
		924	created, use C<post_detect>.
750		925
751	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
752		927
753	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
754	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
755		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		933	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		934	other initialisations - see the sources of L<AnyEvent::Strict> or
		935	L<AnyEvent::AIO> to see how this is used.
		936
		937	The most common usage is to create some global watchers, without forcing
		938	event module detection too early, for example, L<AnyEvent::AIO> creates
		939	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		940	avoid autodetecting the event module at load time.
		941
756	If called in scalar or list context, then it creates and returns an object	942	If called in scalar or list context, then it creates and returns an object
757	that automatically removes the callback again when it is destroyed. See	943	that automatically removes the callback again when it is destroyed (or
		944	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
758	L<Coro::BDB> for a case where this is useful.	945	a case where this is useful.
		946
		947	Example: Create a watcher for the IO::AIO module and store it in
		948	C<$WATCHER>. Only do so after the event loop is initialised, though.
		949
		950	our WATCHER;
		951
		952	my $guard = AnyEvent::post_detect {
		953	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		954	};
		955
		956	# the ||= is important in case post_detect immediately runs the block,
		957	# as to not clobber the newly-created watcher. assigning both watcher and
		958	# post_detect guard to the same variable has the advantage of users being
		959	# able to just C<undef $WATCHER> if the watcher causes them grief.
		960
		961	$WATCHER ||= $guard;
759		962
760	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
761		964
762	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
763	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
764	the event loop has been chosen.	967	the event loop has been chosen.
765		968
766	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
767	if it contains a true value then the event loop has already been detected,	970	if it is defined then the event loop has already been detected, and the
768	and the array will be ignored.	971	array will be ignored.
769		972
770	Best use C<AnyEvent::post_detect { BLOCK }> instead.	973	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		974	it, as it takes care of these details.
		975
		976	This variable is mainly useful for modules that can do something useful
		977	when AnyEvent is used and thus want to know when it is initialised, but do
		978	not need to even load it by default. This array provides the means to hook
		979	into AnyEvent passively, without loading it.
		980
		981	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		982	together, you could put this into Coro (this is the actual code used by
		983	Coro to accomplish this):
		984
		985	if (defined $AnyEvent::MODEL) {
		986	# AnyEvent already initialised, so load Coro::AnyEvent
		987	require Coro::AnyEvent;
		988	} else {
		989	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		990	# as soon as it is
		991	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		992	}
771		993
772	=back	994	=back
773		995
774	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
775		997
…		…
830		1052
831		1053
832	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
833		1055
834	The following is a non-exhaustive list of additional modules that use	1056	The following is a non-exhaustive list of additional modules that use
835	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1057	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
836	in the same program. Some of the modules come with AnyEvent, some are	1058	modules and other event loops in the same program. Some of the modules
837	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
838		1060
839	=over 4	1061	=over 4
840		1062
841	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
842		1064
…		…
851		1073
852	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
853		1075
854	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
855	supports raw and formatted I/O, I/O queued and fully transparent and	1077	supports raw and formatted I/O, I/O queued and fully transparent and
856	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
857		1079
858	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
859		1081
860	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
861		1083
…		…
889		1111
890	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
891		1113
892	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
893		1115
		1116	=item L<AnyEvent::IRC>
		1117
		1118	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1119
		1120	=item L<AnyEvent::XMPP>
		1121
		1122	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1123	Net::XMPP2>.
		1124
894	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
895		1126
896	A non-blocking interface to the Internet Go Server protocol (used by	1127	A non-blocking interface to the Internet Go Server protocol (used by
897	L<App::IGS>).	1128	L<App::IGS>).
898		1129
899	=item L<AnyEvent::IRC>
900
901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
902
903	=item L<Net::XMPP2>
904
905	AnyEvent based XMPP (Jabber protocol) module family.
906
907	=item L<Net::FCP>	1130	=item L<Net::FCP>
908		1131
909	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
910	of AnyEvent.	1133	of AnyEvent.
911		1134
…		…
915		1138
916	=item L<Coro>	1139	=item L<Coro>
917		1140
918	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
919		1142
920	=item L<IO::Lambda>
921
922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
923
924	=back	1143	=back
925		1144
926	=cut	1145	=cut
927		1146
928	package AnyEvent;	1147	package AnyEvent;
929		1148
930	no warnings;	1149	# basically a tuned-down version of common::sense
931	use strict qw(vars subs);	1150	sub common_sense {
		1151	# from common:.sense 1.0
		1152	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1153	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1154	$^H |= 0x00000600;
		1155	}
932		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
933	use Carp;	1159	use Carp ();
934		1160
935	our $VERSION = 4.4;	1161	our $VERSION = '5.251';
936	our $MODEL;	1162	our $MODEL;
937		1163
938	our $AUTOLOAD;	1164	our $AUTOLOAD;
939	our @ISA;	1165	our @ISA;
940		1166
941	our @REGISTRY;	1167	our @REGISTRY;
942		1168
943	our $WIN32;	1169	our $VERBOSE;
944		1170
945	BEGIN {	1171	BEGIN {
946	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
947	eval "sub WIN32(){ $win32 }";
948	}
949		1173
		1174	eval "sub TAINT (){" . (${^TAINT} *1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
951		1184
952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
953		1186
954	{	1187	{
955	my $idx;	1188	my $idx;
…		…
957	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
959	}	1192	}
960		1193
961	my @models = (	1194	my @models = (
962	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
963	[Event:: => AnyEvent::Impl::Event::],
964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
965	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
966	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
967	# and is usually faster	1199	# and is usually faster
		1200	[Event:: => AnyEvent::Impl::Event::, 1],
		1201	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1202	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1203	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
973	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
974	[Prima:: => AnyEvent::Impl::POE::],	1208	[Prima:: => AnyEvent::Impl::POE::],
		1209	# IO::Async is just too broken - we would need workarounds for its
		1210	# byzantine signal and broken child handling, among others.
		1211	# IO::Async is rather hard to detect, as it doesn't have any
		1212	# obvious default class.
		1213	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1215	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1216	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
975	);	1217	);
976		1218
977	our %method = map +($_ => 1),	1219	our %method = map +($_ => 1),
978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
979		1221
…		…
983	my ($cb) = @_;	1225	my ($cb) = @_;
984		1226
985	if ($MODEL) {	1227	if ($MODEL) {
986	$cb->();	1228	$cb->();
987		1229
988	1	1230	undef
989	} else {	1231	} else {
990	push @post_detect, $cb;	1232	push @post_detect, $cb;
991		1233
992	defined wantarray	1234	defined wantarray
993	? bless \$cb, "AnyEvent::Util::postdetect"	1235	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
998	sub AnyEvent::Util::postdetect::DESTROY {	1240	sub AnyEvent::Util::postdetect::DESTROY {
999	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1241	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1000	}	1242	}
1001		1243
1002	sub detect() {	1244	sub detect() {
		1245	# free some memory
		1246	*detect = sub () { $MODEL };
		1247
		1248	local $!; # for good measure
		1249	local $SIG{__DIE__};
		1250
		1251	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1252	my $model = "AnyEvent::Impl::$1";
		1253	if (eval "require $model") {
		1254	$MODEL = $model;
		1255	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1256	} else {
		1257	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1258	}
		1259	}
		1260
		1261	# check for already loaded models
1003	unless ($MODEL) {	1262	unless ($MODEL) {
1004	no strict 'refs';	1263	for (@REGISTRY, @models) {
1005	local $SIG{__DIE__};	1264	my ($package, $model) = @$_;
1006		1265	if (${"$package\::VERSION"} > 0) {
1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1008	my $model = "AnyEvent::Impl::$1";
1009	if (eval "require $model") {	1266	if (eval "require $model") {
1010	$MODEL = $model;	1267	$MODEL = $model;
1011	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1268	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1012	} else {	1269	last;
1013	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1270	}
1014	}	1271	}
1015	}	1272	}
1016		1273
1017	# check for already loaded models
1018	unless ($MODEL) {	1274	unless ($MODEL) {
		1275	# try to autoload a model
1019	for (@REGISTRY, @models) {	1276	for (@REGISTRY, @models) {
1020	my ($package, $model) = @$_;	1277	my ($package, $model, $autoload) = @$_;
		1278	if (
		1279	$autoload
		1280	and eval "require $package"
1021	if (${"$package\::VERSION"} > 0) {	1281	and ${"$package\::VERSION"} > 0
1022	if (eval "require $model") {	1282	and eval "require $model"
		1283	) {
1023	$MODEL = $model;	1284	$MODEL = $model;
1024	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1285	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1025	last;	1286	last;
1026	}
1027	}	1287	}
1028	}	1288	}
1029		1289
1030	unless ($MODEL) {
1031	# try to load a model
1032
1033	for (@REGISTRY, @models) {
1034	my ($package, $model) = @$_;
1035	if (eval "require $package"
1036	and ${"$package\::VERSION"} > 0
1037	and eval "require $model") {
1038	$MODEL = $model;
1039	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1040	last;
1041	}
1042	}
1043
1044	$MODEL	1290	$MODEL
1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1291	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1046	}
1047	}	1292	}
1048
1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1050
1051	unshift @ISA, $MODEL;
1052
1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1054
1055	(shift @post_detect)->() while @post_detect;
1056	}	1293	}
		1294
		1295	@models = (); # free probe data
		1296
		1297	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1298	unshift @ISA, $MODEL;
		1299
		1300	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1301
		1302	(shift @post_detect)->() while @post_detect;
1057		1303
1058	$MODEL	1304	$MODEL
1059	}	1305	}
1060		1306
1061	sub AUTOLOAD {	1307	sub AUTOLOAD {
1062	(my $func = $AUTOLOAD) =~ s/.*://;	1308	(my $func = $AUTOLOAD) =~ s/.*://;
1063		1309
1064	$method{$func}	1310	$method{$func}
1065	or croak "$func: not a valid method for AnyEvent objects";	1311	or Carp::croak "$func: not a valid AnyEvent class method";
1066		1312
1067	detect unless $MODEL;	1313	detect;
1068		1314
1069	my $class = shift;	1315	my $class = shift;
1070	$class->$func (@_);	1316	$class->$func (@_);
1071	}	1317	}
1072		1318
1073	# utility function to dup a filehandle. this is used by many backends	1319	# utility function to dup a filehandle. this is used by many backends
1074	# to support binding more than one watcher per filehandle (they usually	1320	# to support binding more than one watcher per filehandle (they usually
1075	# allow only one watcher per fd, so we dup it to get a different one).	1321	# allow only one watcher per fd, so we dup it to get a different one).
1076	sub _dupfh($$$$) {	1322	sub _dupfh($$;$$) {
1077	my ($poll, $fh, $r, $w) = @_;	1323	my ($poll, $fh, $r, $w) = @_;
1078		1324
1079	# cygwin requires the fh mode to be matching, unix doesn't	1325	# cygwin requires the fh mode to be matching, unix doesn't
1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1326	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1081	: $poll eq "w" ? ($w, ">")
1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1083		1327
1084	open my $fh2, "$mode&" . fileno $fh	1328	open my $fh2, $mode, $fh
1085	or die "cannot dup() filehandle: $!,";	1329	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1086		1330
1087	# we assume CLOEXEC is already set by perl in all important cases	1331	# we assume CLOEXEC is already set by perl in all important cases
1088		1332
1089	($fh2, $rw)	1333	($fh2, $rw)
1090	}	1334	}
1091		1335
		1336	=head1 SIMPLIFIED AE API
		1337
		1338	Starting with version 5.0, AnyEvent officially supports a second, much
		1339	simpler, API that is designed to reduce the calling, typing and memory
		1340	overhead.
		1341
		1342	See the L<AE> manpage for details.
		1343
		1344	=cut
		1345
		1346	package AE;
		1347
		1348	our $VERSION = $AnyEvent::VERSION;
		1349
		1350	sub io($$$) {
		1351	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1352	}
		1353
		1354	sub timer($$$) {
		1355	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1356	}
		1357
		1358	sub signal($$) {
		1359	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1360	}
		1361
		1362	sub child($$) {
		1363	AnyEvent->child (pid => $_[0], cb => $_[1])
		1364	}
		1365
		1366	sub idle($) {
		1367	AnyEvent->idle (cb => $_[0])
		1368	}
		1369
		1370	sub cv(;&) {
		1371	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1372	}
		1373
		1374	sub now() {
		1375	AnyEvent->now
		1376	}
		1377
		1378	sub now_update() {
		1379	AnyEvent->now_update
		1380	}
		1381
		1382	sub time() {
		1383	AnyEvent->time
		1384	}
		1385
1092	package AnyEvent::Base;	1386	package AnyEvent::Base;
1093		1387
1094	# default implementations for many methods	1388	# default implementations for many methods
1095		1389
1096	BEGIN {	1390	sub _time() {
		1391	eval q{ # poor man's autoloading
		1392	# probe for availability of Time::HiRes
1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1393	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1394	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1098	*_time = \&Time::HiRes::time;	1395	*_time = \&Time::HiRes::time;
1099	# if (eval "use POSIX (); (POSIX::times())...	1396	# if (eval "use POSIX (); (POSIX::times())...
1100	} else {	1397	} else {
		1398	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1101	*_time = sub { time }; # epic fail	1399	*_time = sub (){ time }; # epic fail
		1400	}
1102	}	1401	};
		1402	die if $@;
		1403
		1404	&_time
1103	}	1405	}
1104		1406
1105	sub time { _time }	1407	sub time { _time }
1106	sub now { _time }	1408	sub now { _time }
1107	sub now_update { }	1409	sub now_update { }
…		…
1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1414	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1113	}	1415	}
1114		1416
1115	# default implementation for ->signal	1417	# default implementation for ->signal
1116		1418
		1419	our $HAVE_ASYNC_INTERRUPT;
		1420
		1421	sub _have_async_interrupt() {
		1422	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1423	&& eval "use Async::Interrupt 1.02 (); 1")
		1424	unless defined $HAVE_ASYNC_INTERRUPT;
		1425
		1426	$HAVE_ASYNC_INTERRUPT
		1427	}
		1428
1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1429	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1430	our (%SIG_ASY, %SIG_ASY_W);
		1431	our ($SIG_COUNT, $SIG_TW);
1118		1432
1119	sub _signal_exec {	1433	# install a dummy wakeup watcher to reduce signal catching latency
1120	sysread $SIGPIPE_R, my $dummy, 4;	1434	# used by Impls
		1435	sub _sig_add() {
		1436	unless ($SIG_COUNT++) {
		1437	# try to align timer on a full-second boundary, if possible
		1438	my $NOW = AE::now;
1121		1439
1122	while (%SIG_EV) {	1440	$SIG_TW = AE::timer
1123	for (keys %SIG_EV) {	1441	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1124	delete $SIG_EV{$_};	1442	$MAX_SIGNAL_LATENCY,
1125	$_->() for values %{ $SIG_CB{$_} || {} };	1443	sub { } # just for the PERL_ASYNC_CHECK
		1444	;
		1445	}
		1446	}
		1447
		1448	sub _sig_del {
		1449	undef $SIG_TW
		1450	unless --$SIG_COUNT;
		1451	}
		1452
		1453	our $_sig_name_init; $_sig_name_init = sub {
		1454	eval q{ # poor man's autoloading
		1455	undef $_sig_name_init;
		1456
		1457	if (_have_async_interrupt) {
		1458	*sig2num = \&Async::Interrupt::sig2num;
		1459	*sig2name = \&Async::Interrupt::sig2name;
		1460	} else {
		1461	require Config;
		1462
		1463	my %signame2num;
		1464	@signame2num{ split ' ', $Config::Config{sig_name} }
		1465	= split ' ', $Config::Config{sig_num};
		1466
		1467	my @signum2name;
		1468	@signum2name[values %signame2num] = keys %signame2num;
		1469
		1470	*sig2num = sub($) {
		1471	$_[0] > 0 ? shift : $signame2num{+shift}
		1472	};
		1473	*sig2name = sub ($) {
		1474	$_[0] > 0 ? $signum2name[+shift] : shift
		1475	};
1126	}	1476	}
1127	}	1477	};
1128	}	1478	die if $@;
		1479	};
		1480
		1481	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1482	sub sig2name($) { &$_sig_name_init; &sig2name }
1129		1483
1130	sub signal {	1484	sub signal {
1131	my (undef, %arg) = @_;	1485	eval q{ # poor man's autoloading {}
		1486	# probe for availability of Async::Interrupt
		1487	if (_have_async_interrupt) {
		1488	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1132		1489
1133	unless ($SIGPIPE_R) {	1490	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1134	require Fcntl;	1491	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1135		1492
1136	if (AnyEvent::WIN32) {
1137	require AnyEvent::Util;
1138
1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1142	} else {	1493	} else {
		1494	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1495
		1496	if (AnyEvent::WIN32) {
		1497	require AnyEvent::Util;
		1498
		1499	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1500	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1501	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1502	} else {
1143	pipe $SIGPIPE_R, $SIGPIPE_W;	1503	pipe $SIGPIPE_R, $SIGPIPE_W;
1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1504	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1505	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1506
		1507	# not strictly required, as $^F is normally 2, but let's make sure...
		1508	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1509	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1510	}
		1511
		1512	$SIGPIPE_R
		1513	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1514
		1515	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1146	}	1516	}
1147		1517
1148	$SIGPIPE_R	1518	*signal = sub {
1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1519	my (undef, %arg) = @_;
1150		1520
1151	# not strictly required, as $^F is normally 2, but let's make sure...
1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1154
1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1156	}
1157
1158	my $signal = uc $arg{signal}	1521	my $signal = uc $arg{signal}
1159	or Carp::croak "required option 'signal' is missing";	1522	or Carp::croak "required option 'signal' is missing";
1160		1523
		1524	if ($HAVE_ASYNC_INTERRUPT) {
		1525	# async::interrupt
		1526
		1527	$signal = sig2num $signal;
1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1528	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1529
		1530	$SIG_ASY{$signal} ||= new Async::Interrupt
		1531	cb => sub { undef $SIG_EV{$signal} },
		1532	signal => $signal,
		1533	pipe => [$SIGPIPE_R->filenos],
		1534	pipe_autodrain => 0,
		1535	;
		1536
		1537	} else {
		1538	# pure perl
		1539
		1540	# AE::Util has been loaded in signal
		1541	$signal = sig2name $signal;
		1542	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1543
1162	$SIG{$signal} ||= sub {	1544	$SIG{$signal} ||= sub {
1163	local $!;	1545	local $!;
1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1546	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1165	undef $SIG_EV{$signal};	1547	undef $SIG_EV{$signal};
		1548	};
		1549
		1550	# can't do signal processing without introducing races in pure perl,
		1551	# so limit the signal latency.
		1552	_sig_add;
		1553	}
		1554
		1555	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1556	};
		1557
		1558	*AnyEvent::Base::signal::DESTROY = sub {
		1559	my ($signal, $cb) = @{$_[0]};
		1560
		1561	_sig_del;
		1562
		1563	delete $SIG_CB{$signal}{$cb};
		1564
		1565	$HAVE_ASYNC_INTERRUPT
		1566	? delete $SIG_ASY{$signal}
		1567	: # delete doesn't work with older perls - they then
		1568	# print weird messages, or just unconditionally exit
		1569	# instead of getting the default action.
		1570	undef $SIG{$signal}
		1571	unless keys %{ $SIG_CB{$signal} };
		1572	};
		1573
		1574	*_signal_exec = sub {
		1575	$HAVE_ASYNC_INTERRUPT
		1576	? $SIGPIPE_R->drain
		1577	: sysread $SIGPIPE_R, (my $dummy), 9;
		1578
		1579	while (%SIG_EV) {
		1580	for (keys %SIG_EV) {
		1581	delete $SIG_EV{$_};
		1582	$_->() for values %{ $SIG_CB{$_} || {} };
		1583	}
		1584	}
		1585	};
1166	};	1586	};
		1587	die if $@;
1167		1588
1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1589	&signal
1169	}
1170
1171	sub AnyEvent::Base::signal::DESTROY {
1172	my ($signal, $cb) = @{$_[0]};
1173
1174	delete $SIG_CB{$signal}{$cb};
1175
1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1177	}	1590	}
1178		1591
1179	# default implementation for ->child	1592	# default implementation for ->child
1180		1593
1181	our %PID_CB;	1594	our %PID_CB;
1182	our $CHLD_W;	1595	our $CHLD_W;
1183	our $CHLD_DELAY_W;	1596	our $CHLD_DELAY_W;
1184	our $PID_IDLE;
1185	our $WNOHANG;	1597	our $WNOHANG;
1186		1598
1187	sub _child_wait {	1599	# used by many Impl's
1188	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1600	sub _emit_childstatus($$) {
		1601	my (undef, $rpid, $rstatus) = @_;
		1602
		1603	$_->($rpid, $rstatus)
1189	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1604	for values %{ $PID_CB{$rpid} || {} },
1190	(values %{ $PID_CB{0} || {} });	1605	values %{ $PID_CB{0} || {} };
1191	}
1192
1193	undef $PID_IDLE;
1194	}
1195
1196	sub _sigchld {
1197	# make sure we deliver these changes "synchronous" with the event loop.
1198	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1199	undef $CHLD_DELAY_W;
1200	&_child_wait;
1201	});
1202	}	1606	}
1203		1607
1204	sub child {	1608	sub child {
		1609	eval q{ # poor man's autoloading {}
		1610	*_sigchld = sub {
		1611	my $pid;
		1612
		1613	AnyEvent->_emit_childstatus ($pid, $?)
		1614	while ($pid = waitpid -1, $WNOHANG) > 0;
		1615	};
		1616
		1617	*child = sub {
1205	my (undef, %arg) = @_;	1618	my (undef, %arg) = @_;
1206		1619
1207	defined (my $pid = $arg{pid} + 0)	1620	defined (my $pid = $arg{pid} + 0)
1208	or Carp::croak "required option 'pid' is missing";	1621	or Carp::croak "required option 'pid' is missing";
1209		1622
1210	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1623	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1211		1624
1212	unless ($WNOHANG) {	1625	# WNOHANG is almost cetrainly 1 everywhere
		1626	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1627	? 1
1213	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1628	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1214	}
1215		1629
1216	unless ($CHLD_W) {	1630	unless ($CHLD_W) {
1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1631	$CHLD_W = AE::signal CHLD => \&_sigchld;
1218	# child could be a zombie already, so make at least one round	1632	# child could be a zombie already, so make at least one round
1219	&_sigchld;	1633	&_sigchld;
1220	}	1634	}
1221		1635
1222	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1636	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1223	}	1637	};
1224		1638
1225	sub AnyEvent::Base::child::DESTROY {	1639	*AnyEvent::Base::child::DESTROY = sub {
1226	my ($pid, $cb) = @{$_[0]};	1640	my ($pid, $cb) = @{$_[0]};
1227		1641
1228	delete $PID_CB{$pid}{$cb};	1642	delete $PID_CB{$pid}{$cb};
1229	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1643	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1230		1644
1231	undef $CHLD_W unless keys %PID_CB;	1645	undef $CHLD_W unless keys %PID_CB;
		1646	};
		1647	};
		1648	die if $@;
		1649
		1650	&child
1232	}	1651	}
1233		1652
1234	# idle emulation is done by simply using a timer, regardless	1653	# idle emulation is done by simply using a timer, regardless
1235	# of whether the proces sis idle or not, and not letting	1654	# of whether the process is idle or not, and not letting
1236	# the callback use more than 50% of the time.	1655	# the callback use more than 50% of the time.
1237	sub idle {	1656	sub idle {
		1657	eval q{ # poor man's autoloading {}
		1658	*idle = sub {
1238	my (undef, %arg) = @_;	1659	my (undef, %arg) = @_;
1239		1660
1240	my ($cb, $w, $rcb) = $arg{cb};	1661	my ($cb, $w, $rcb) = $arg{cb};
1241		1662
1242	$rcb = sub {	1663	$rcb = sub {
1243	if ($cb) {	1664	if ($cb) {
1244	$w = _time;	1665	$w = _time;
1245	&$cb;	1666	&$cb;
1246	$w = _time - $w;	1667	$w = _time - $w;
1247		1668
1248	# never use more then 50% of the time for the idle watcher,	1669	# never use more then 50% of the time for the idle watcher,
1249	# within some limits	1670	# within some limits
1250	$w = 0.0001 if $w < 0.0001;	1671	$w = 0.0001 if $w < 0.0001;
1251	$w = 5 if $w > 5;	1672	$w = 5 if $w > 5;
1252		1673
1253	$w = AnyEvent->timer (after => $w, cb => $rcb);	1674	$w = AE::timer $w, 0, $rcb;
1254	} else {	1675	} else {
1255	# clean up...	1676	# clean up...
1256	undef $w;	1677	undef $w;
1257	undef $rcb;	1678	undef $rcb;
		1679	}
		1680	};
		1681
		1682	$w = AE::timer 0.05, 0, $rcb;
		1683
		1684	bless \\$cb, "AnyEvent::Base::idle"
1258	}	1685	};
		1686
		1687	*AnyEvent::Base::idle::DESTROY = sub {
		1688	undef $${$_[0]};
		1689	};
1259	};	1690	};
		1691	die if $@;
1260		1692
1261	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1693	&idle
1262
1263	bless \\$cb, "AnyEvent::Base::idle"
1264	}
1265
1266	sub AnyEvent::Base::idle::DESTROY {
1267	undef $${$_[0]};
1268	}	1694	}
1269		1695
1270	package AnyEvent::CondVar;	1696	package AnyEvent::CondVar;
1271		1697
1272	our @ISA = AnyEvent::CondVar::Base::;	1698	our @ISA = AnyEvent::CondVar::Base::;
1273		1699
1274	package AnyEvent::CondVar::Base;	1700	package AnyEvent::CondVar::Base;
1275		1701
1276	use overload	1702	#use overload
1277	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1703	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1278	fallback => 1;	1704	# fallback => 1;
		1705
		1706	# save 300+ kilobytes by dirtily hardcoding overloading
		1707	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1708	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1709	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1710	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1711
		1712	our $WAITING;
1279		1713
1280	sub _send {	1714	sub _send {
1281	# nop	1715	# nop
1282	}	1716	}
1283		1717
…		…
1296	sub ready {	1730	sub ready {
1297	$_[0]{_ae_sent}	1731	$_[0]{_ae_sent}
1298	}	1732	}
1299		1733
1300	sub _wait {	1734	sub _wait {
		1735	$WAITING
		1736	and !$_[0]{_ae_sent}
		1737	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1738
		1739	local $WAITING = 1;
1301	AnyEvent->one_event while !$_[0]{_ae_sent};	1740	AnyEvent->one_event while !$_[0]{_ae_sent};
1302	}	1741	}
1303		1742
1304	sub recv {	1743	sub recv {
1305	$_[0]->_wait;	1744	$_[0]->_wait;
…		…
1307	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1746	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1308	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1747	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1309	}	1748	}
1310		1749
1311	sub cb {	1750	sub cb {
1312	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1751	my $cv = shift;
		1752
		1753	@_
		1754	and $cv->{_ae_cb} = shift
		1755	and $cv->{_ae_sent}
		1756	and (delete $cv->{_ae_cb})->($cv);
		1757
1313	$_[0]{_ae_cb}	1758	$cv->{_ae_cb}
1314	}	1759	}
1315		1760
1316	sub begin {	1761	sub begin {
1317	++$_[0]{_ae_counter};	1762	++$_[0]{_ae_counter};
1318	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1763	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1346	so on.	1791	so on.
1347		1792
1348	=head1 ENVIRONMENT VARIABLES	1793	=head1 ENVIRONMENT VARIABLES
1349		1794
1350	The following environment variables are used by this module or its	1795	The following environment variables are used by this module or its
1351	submodules:	1796	submodules.
		1797
		1798	Note that AnyEvent will remove I<all> environment variables starting with
		1799	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1800	enabled.
1352		1801
1353	=over 4	1802	=over 4
1354		1803
1355	=item C<PERL_ANYEVENT_VERBOSE>	1804	=item C<PERL_ANYEVENT_VERBOSE>
1356		1805
…		…
1363	C<PERL_ANYEVENT_MODEL>.	1812	C<PERL_ANYEVENT_MODEL>.
1364		1813
1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1814	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1366	model it chooses.	1815	model it chooses.
1367		1816
		1817	When set to C<8> or higher, then AnyEvent will report extra information on
		1818	which optional modules it loads and how it implements certain features.
		1819
1368	=item C<PERL_ANYEVENT_STRICT>	1820	=item C<PERL_ANYEVENT_STRICT>
1369		1821
1370	AnyEvent does not do much argument checking by default, as thorough	1822	AnyEvent does not do much argument checking by default, as thorough
1371	argument checking is very costly. Setting this variable to a true value	1823	argument checking is very costly. Setting this variable to a true value
1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1824	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1373	check the arguments passed to most method calls. If it finds any problems	1825	check the arguments passed to most method calls. If it finds any problems,
1374	it will croak.	1826	it will croak.
1375		1827
1376	In other words, enables "strict" mode.	1828	In other words, enables "strict" mode.
1377		1829
1378	Unlike C<use strict>, it is definitely recommended ot keep it off in	1830	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1831	>>, it is definitely recommended to keep it off in production. Keeping
1380	developing programs can be very useful, however.	1832	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1833	can be very useful, however.
1381		1834
1382	=item C<PERL_ANYEVENT_MODEL>	1835	=item C<PERL_ANYEVENT_MODEL>
1383		1836
1384	This can be used to specify the event model to be used by AnyEvent, before	1837	This can be used to specify the event model to be used by AnyEvent, before
1385	auto detection and -probing kicks in. It must be a string consisting	1838	auto detection and -probing kicks in. It must be a string consisting
…		…
1428		1881
1429	=item C<PERL_ANYEVENT_MAX_FORKS>	1882	=item C<PERL_ANYEVENT_MAX_FORKS>
1430		1883
1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1884	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1432	will create in parallel.	1885	will create in parallel.
		1886
		1887	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1888
		1889	The default value for the C<max_outstanding> parameter for the default DNS
		1890	resolver - this is the maximum number of parallel DNS requests that are
		1891	sent to the DNS server.
		1892
		1893	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1894
		1895	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1896	configuration) in the default resolver. When set to the empty string, no
		1897	default config will be used.
		1898
		1899	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1900
		1901	When neither C<ca_file> nor C<ca_path> was specified during
		1902	L<AnyEvent::TLS> context creation, and either of these environment
		1903	variables exist, they will be used to specify CA certificate locations
		1904	instead of a system-dependent default.
		1905
		1906	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1907
		1908	When these are set to C<1>, then the respective modules are not
		1909	loaded. Mostly good for testing AnyEvent itself.
1433		1910
1434	=back	1911	=back
1435		1912
1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1913	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1437		1914
…		…
1495	warn "read: $input\n"; # output what has been read	1972	warn "read: $input\n"; # output what has been read
1496	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1973	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1497	},	1974	},
1498	);	1975	);
1499		1976
1500	my $time_watcher; # can only be used once
1501
1502	sub new_timer {
1503	$timer = AnyEvent->timer (after => 1, cb => sub {	1977	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1504	warn "timeout\n"; # print 'timeout' about every second	1978	warn "timeout\n"; # print 'timeout' at most every second
1505	&new_timer; # and restart the time
1506	});	1979	});
1507	}
1508
1509	new_timer; # create first timer
1510		1980
1511	$cv->recv; # wait until user enters /^q/i	1981	$cv->recv; # wait until user enters /^q/i
1512		1982
1513	=head1 REAL-WORLD EXAMPLE	1983	=head1 REAL-WORLD EXAMPLE
1514		1984
…		…
1645	through AnyEvent. The benchmark creates a lot of timers (with a zero	2115	through AnyEvent. The benchmark creates a lot of timers (with a zero
1646	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2116	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1647	which it is), lets them fire exactly once and destroys them again.	2117	which it is), lets them fire exactly once and destroys them again.
1648		2118
1649	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2119	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1650	distribution.	2120	distribution. It uses the L<AE> interface, which makes a real difference
		2121	for the EV and Perl backends only.
1651		2122
1652	=head3 Explanation of the columns	2123	=head3 Explanation of the columns
1653		2124
1654	I<watcher> is the number of event watchers created/destroyed. Since	2125	I<watcher> is the number of event watchers created/destroyed. Since
1655	different event models feature vastly different performances, each event	2126	different event models feature vastly different performances, each event
…		…
1676	watcher.	2147	watcher.
1677		2148
1678	=head3 Results	2149	=head3 Results
1679		2150
1680	name watchers bytes create invoke destroy comment	2151	name watchers bytes create invoke destroy comment
1681	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2152	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1682	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2153	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1683	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2154	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1684	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2155	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1685	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2156	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1686	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2157	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2158	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2159	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1687	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2160	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1688	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2161	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1689	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2162	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2163	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1691		2164
1692	=head3 Discussion	2165	=head3 Discussion
1693		2166
1694	The benchmark does I<not> measure scalability of the event loop very	2167	The benchmark does I<not> measure scalability of the event loop very
1695	well. For example, a select-based event loop (such as the pure perl one)	2168	well. For example, a select-based event loop (such as the pure perl one)
…		…
1707	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2180	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1708	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2181	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1709	cycles with POE.	2182	cycles with POE.
1710		2183
1711	C<EV> is the sole leader regarding speed and memory use, which are both	2184	C<EV> is the sole leader regarding speed and memory use, which are both
1712	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2185	maximal/minimal, respectively. When using the L<AE> API there is zero
		2186	overhead (when going through the AnyEvent API create is about 5-6 times
		2187	slower, with other times being equal, so still uses far less memory than
1713	far less memory than any other event loop and is still faster than Event	2188	any other event loop and is still faster than Event natively).
1714	natively.
1715		2189
1716	The pure perl implementation is hit in a few sweet spots (both the	2190	The pure perl implementation is hit in a few sweet spots (both the
1717	constant timeout and the use of a single fd hit optimisations in the perl	2191	constant timeout and the use of a single fd hit optimisations in the perl
1718	interpreter and the backend itself). Nevertheless this shows that it	2192	interpreter and the backend itself). Nevertheless this shows that it
1719	adds very little overhead in itself. Like any select-based backend its	2193	adds very little overhead in itself. Like any select-based backend its
1720	performance becomes really bad with lots of file descriptors (and few of	2194	performance becomes really bad with lots of file descriptors (and few of
1721	them active), of course, but this was not subject of this benchmark.	2195	them active), of course, but this was not subject of this benchmark.
1722		2196
1723	The C<Event> module has a relatively high setup and callback invocation	2197	The C<Event> module has a relatively high setup and callback invocation
1724	cost, but overall scores in on the third place.	2198	cost, but overall scores in on the third place.
		2199
		2200	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2201	when using its pure perl backend.
1725		2202
1726	C<Glib>'s memory usage is quite a bit higher, but it features a	2203	C<Glib>'s memory usage is quite a bit higher, but it features a
1727	faster callback invocation and overall ends up in the same class as	2204	faster callback invocation and overall ends up in the same class as
1728	C<Event>. However, Glib scales extremely badly, doubling the number of	2205	C<Event>. However, Glib scales extremely badly, doubling the number of
1729	watchers increases the processing time by more than a factor of four,	2206	watchers increases the processing time by more than a factor of four,
…		…
1790	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2267	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1791	(1%) are active. This mirrors the activity of large servers with many	2268	(1%) are active. This mirrors the activity of large servers with many
1792	connections, most of which are idle at any one point in time.	2269	connections, most of which are idle at any one point in time.
1793		2270
1794	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2271	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1795	distribution.	2272	distribution. It uses the L<AE> interface, which makes a real difference
		2273	for the EV and Perl backends only.
1796		2274
1797	=head3 Explanation of the columns	2275	=head3 Explanation of the columns
1798		2276
1799	I<sockets> is the number of sockets, and twice the number of "servers" (as	2277	I<sockets> is the number of sockets, and twice the number of "servers" (as
1800	each server has a read and write socket end).	2278	each server has a read and write socket end).
…		…
1807	it to another server. This includes deleting the old timeout and creating	2285	it to another server. This includes deleting the old timeout and creating
1808	a new one that moves the timeout into the future.	2286	a new one that moves the timeout into the future.
1809		2287
1810	=head3 Results	2288	=head3 Results
1811		2289
1812	name sockets create request	2290	name sockets create request
1813	EV 20000 69.01 11.16	2291	EV 20000 62.66 7.99
1814	Perl 20000 73.32 35.87	2292	Perl 20000 68.32 32.64
1815	Event 20000 212.62 257.32	2293	IOAsync 20000 174.06 101.15 epoll
1816	Glib 20000 651.16 1896.30	2294	IOAsync 20000 174.67 610.84 poll
		2295	Event 20000 202.69 242.91
		2296	Glib 20000 557.01 1689.52
1817	POE 20000 349.67 12317.24 uses POE::Loop::Event	2297	POE 20000 341.54 12086.32 uses POE::Loop::Event
1818		2298
1819	=head3 Discussion	2299	=head3 Discussion
1820		2300
1821	This benchmark I<does> measure scalability and overall performance of the	2301	This benchmark I<does> measure scalability and overall performance of the
1822	particular event loop.	2302	particular event loop.
…		…
1824	EV is again fastest. Since it is using epoll on my system, the setup time	2304	EV is again fastest. Since it is using epoll on my system, the setup time
1825	is relatively high, though.	2305	is relatively high, though.
1826		2306
1827	Perl surprisingly comes second. It is much faster than the C-based event	2307	Perl surprisingly comes second. It is much faster than the C-based event
1828	loops Event and Glib.	2308	loops Event and Glib.
		2309
		2310	IO::Async performs very well when using its epoll backend, and still quite
		2311	good compared to Glib when using its pure perl backend.
1829		2312
1830	Event suffers from high setup time as well (look at its code and you will	2313	Event suffers from high setup time as well (look at its code and you will
1831	understand why). Callback invocation also has a high overhead compared to	2314	understand why). Callback invocation also has a high overhead compared to
1832	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2315	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1833	uses select or poll in basically all documented configurations.	2316	uses select or poll in basically all documented configurations.
…		…
1896	=item * C-based event loops perform very well with small number of	2379	=item * C-based event loops perform very well with small number of
1897	watchers, as the management overhead dominates.	2380	watchers, as the management overhead dominates.
1898		2381
1899	=back	2382	=back
1900		2383
		2384	=head2 THE IO::Lambda BENCHMARK
		2385
		2386	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2387	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2388	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2389	shouldn't come as a surprise to anybody). As such, the benchmark is
		2390	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2391	very optimal. But how would AnyEvent compare when used without the extra
		2392	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2393
		2394	The benchmark itself creates an echo-server, and then, for 500 times,
		2395	connects to the echo server, sends a line, waits for the reply, and then
		2396	creates the next connection. This is a rather bad benchmark, as it doesn't
		2397	test the efficiency of the framework or much non-blocking I/O, but it is a
		2398	benchmark nevertheless.
		2399
		2400	name runtime
		2401	Lambda/select 0.330 sec
		2402	+ optimized 0.122 sec
		2403	Lambda/AnyEvent 0.327 sec
		2404	+ optimized 0.138 sec
		2405	Raw sockets/select 0.077 sec
		2406	POE/select, components 0.662 sec
		2407	POE/select, raw sockets 0.226 sec
		2408	POE/select, optimized 0.404 sec
		2409
		2410	AnyEvent/select/nb 0.085 sec
		2411	AnyEvent/EV/nb 0.068 sec
		2412	+state machine 0.134 sec
		2413
		2414	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2415	benchmarks actually make blocking connects and use 100% blocking I/O,
		2416	defeating the purpose of an event-based solution. All of the newly
		2417	written AnyEvent benchmarks use 100% non-blocking connects (using
		2418	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2419	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2420	generally require a lot more bookkeeping and event handling than blocking
		2421	connects (which involve a single syscall only).
		2422
		2423	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2424	offers similar expressive power as POE and IO::Lambda, using conventional
		2425	Perl syntax. This means that both the echo server and the client are 100%
		2426	non-blocking, further placing it at a disadvantage.
		2427
		2428	As you can see, the AnyEvent + EV combination even beats the
		2429	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2430	backend easily beats IO::Lambda and POE.
		2431
		2432	And even the 100% non-blocking version written using the high-level (and
		2433	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2434	higher level ("unoptimised") abstractions by a large margin, even though
		2435	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2436
		2437	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2438	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2439	part of the IO::Lambda distribution and were used without any changes.
		2440
1901		2441
1902	=head1 SIGNALS	2442	=head1 SIGNALS
1903		2443
1904	AnyEvent currently installs handlers for these signals:	2444	AnyEvent currently installs handlers for these signals:
1905		2445
…		…
1908	=item SIGCHLD	2448	=item SIGCHLD
1909		2449
1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2450	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1911	emulation for event loops that do not support them natively. Also, some	2451	emulation for event loops that do not support them natively. Also, some
1912	event loops install a similar handler.	2452	event loops install a similar handler.
		2453
		2454	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2455	AnyEvent will reset it to default, to avoid losing child exit statuses.
1913		2456
1914	=item SIGPIPE	2457	=item SIGPIPE
1915		2458
1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2459	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1917	when AnyEvent gets loaded.	2460	when AnyEvent gets loaded.
…		…
1929		2472
1930	=back	2473	=back
1931		2474
1932	=cut	2475	=cut
1933		2476
		2477	undef $SIG{CHLD}
		2478	if $SIG{CHLD} eq 'IGNORE';
		2479
1934	$SIG{PIPE} = sub { }	2480	$SIG{PIPE} = sub { }
1935	unless defined $SIG{PIPE};	2481	unless defined $SIG{PIPE};
1936		2482
		2483	=head1 RECOMMENDED/OPTIONAL MODULES
		2484
		2485	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2486	it's built-in modules) are required to use it.
		2487
		2488	That does not mean that AnyEvent won't take advantage of some additional
		2489	modules if they are installed.
		2490
		2491	This section explains which additional modules will be used, and how they
		2492	affect AnyEvent's operation.
		2493
		2494	=over 4
		2495
		2496	=item L<Async::Interrupt>
		2497
		2498	This slightly arcane module is used to implement fast signal handling: To
		2499	my knowledge, there is no way to do completely race-free and quick
		2500	signal handling in pure perl. To ensure that signals still get
		2501	delivered, AnyEvent will start an interval timer to wake up perl (and
		2502	catch the signals) with some delay (default is 10 seconds, look for
		2503	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2504
		2505	If this module is available, then it will be used to implement signal
		2506	catching, which means that signals will not be delayed, and the event loop
		2507	will not be interrupted regularly, which is more efficient (and good for
		2508	battery life on laptops).
		2509
		2510	This affects not just the pure-perl event loop, but also other event loops
		2511	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2512
		2513	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2514	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2515	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2516	does nothing for those backends.
		2517
		2518	=item L<EV>
		2519
		2520	This module isn't really "optional", as it is simply one of the backend
		2521	event loops that AnyEvent can use. However, it is simply the best event
		2522	loop available in terms of features, speed and stability: It supports
		2523	the AnyEvent API optimally, implements all the watcher types in XS, does
		2524	automatic timer adjustments even when no monotonic clock is available,
		2525	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2526	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2527	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2528
		2529	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2530	then this module will do nothing for you.
		2531
		2532	=item L<Guard>
		2533
		2534	The guard module, when used, will be used to implement
		2535	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2536	lot less memory), but otherwise doesn't affect guard operation much. It is
		2537	purely used for performance.
		2538
		2539	=item L<JSON> and L<JSON::XS>
		2540
		2541	One of these modules is required when you want to read or write JSON data
		2542	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2543	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2544
		2545	=item L<Net::SSLeay>
		2546
		2547	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2548	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2549	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2550
		2551	=item L<Time::HiRes>
		2552
		2553	This module is part of perl since release 5.008. It will be used when the
		2554	chosen event library does not come with a timing source on it's own. The
		2555	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2556	try to use a monotonic clock for timing stability.
		2557
		2558	=back
		2559
1937		2560
1938	=head1 FORK	2561	=head1 FORK
1939		2562
1940	Most event libraries are not fork-safe. The ones who are usually are	2563	Most event libraries are not fork-safe. The ones who are usually are
1941	because they rely on inefficient but fork-safe C<select> or C<poll>	2564	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1942	calls. Only L<EV> is fully fork-aware.	2565	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2566	are usually badly thought-out hacks that are incompatible with fork in
		2567	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2568	continue event-processing in both parent and child (or both, if you know
		2569	what you are doing).
		2570
		2571	This means that, in general, you cannot fork and do event processing in
		2572	the child if the event library was initialised before the fork (which
		2573	usually happens when the first AnyEvent watcher is created, or the library
		2574	is loaded).
1943		2575
1944	If you have to fork, you must either do so I<before> creating your first	2576	If you have to fork, you must either do so I<before> creating your first
1945	watcher OR you must not use AnyEvent at all in the child.	2577	watcher OR you must not use AnyEvent at all in the child OR you must do
		2578	something completely out of the scope of AnyEvent.
		2579
		2580	The problem of doing event processing in the parent I<and> the child
		2581	is much more complicated: even for backends that I<are> fork-aware or
		2582	fork-safe, their behaviour is not usually what you want: fork clones all
		2583	watchers, that means all timers, I/O watchers etc. are active in both
		2584	parent and child, which is almost never what you want. USing C<exec>
		2585	to start worker children from some kind of manage rprocess is usually
		2586	preferred, because it is much easier and cleaner, at the expense of having
		2587	to have another binary.
1946		2588
1947		2589
1948	=head1 SECURITY CONSIDERATIONS	2590	=head1 SECURITY CONSIDERATIONS
1949		2591
1950	AnyEvent can be forced to load any event model via	2592	AnyEvent can be forced to load any event model via
…		…
1962	use AnyEvent;	2604	use AnyEvent;
1963		2605
1964	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2606	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1965	be used to probe what backend is used and gain other information (which is	2607	be used to probe what backend is used and gain other information (which is
1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2608	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1967	$ENV{PERL_ANYEGENT_STRICT}.	2609	$ENV{PERL_ANYEVENT_STRICT}.
		2610
		2611	Note that AnyEvent will remove I<all> environment variables starting with
		2612	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2613	enabled.
1968		2614
1969		2615
1970	=head1 BUGS	2616	=head1 BUGS
1971		2617
1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2618	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1984	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2630	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1985		2631
1986	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2632	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1987	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2633	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1988	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2634	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1989	L<AnyEvent::Impl::POE>.	2635	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1990		2636
1991	Non-blocking file handles, sockets, TCP clients and	2637	Non-blocking file handles, sockets, TCP clients and
1992	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2638	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1993		2639
1994	Asynchronous DNS: L<AnyEvent::DNS>.	2640	Asynchronous DNS: L<AnyEvent::DNS>.
1995		2641
1996	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2642	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2643	L<Coro::Event>,
1997		2644
1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2645	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2646	L<AnyEvent::HTTP>.
1999		2647
2000		2648
2001	=head1 AUTHOR	2649	=head1 AUTHOR
2002		2650
2003	Marc Lehmann <schmorp@schmorp.de>	2651	Marc Lehmann <schmorp@schmorp.de>

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