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Revision 1.205 by root, Sun Apr 19 12:09:46 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
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
33		41
34	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
35	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
36	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.
37		53
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		55
40	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
41	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
165	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
166	declared.	182	declared.
167		183
168	=head2 I/O WATCHERS	184	=head2 I/O WATCHERS
169		185
		186	$w = AnyEvent->io (
		187	fh => <filehandle_or_fileno>,
		188	poll => <"r" or "w">,
		189	cb => <callback>,
		190	);
		191
170	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
171	with the following mandatory key-value pairs as arguments:	193	with the following mandatory key-value pairs as arguments:
172		194
173	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
174	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
175	handle). Note that only file handles pointing to things for which	197	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	198	non-blocking operation makes sense are allowed. This includes sockets,
177	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
178	or block devices.	200	or block devices.
…		…
203	undef $w;	225	undef $w;
204	});	226	});
205		227
206	=head2 TIME WATCHERS	228	=head2 TIME WATCHERS
207		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
208	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 >>
209	method with the following mandatory arguments:	239	method with the following mandatory arguments:
210		240
211	C<after> specifies after how many seconds (fractional values are	241	C<after> specifies after how many seconds (fractional values are
212	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
…		…
333	might affect timers and time-outs.	363	might affect timers and time-outs.
334		364
335	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
336	event loop's idea of "current time".	366	event loop's idea of "current time".
337		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
338	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.
339		376
340	=back	377	=back
341		378
342	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
343		382
344	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
345	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
346	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
347		386
…		…
353	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
354	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,
355	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
356		395
357	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
358	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
359		399
360	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
361	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
362		403
363	Example: exit on SIGINT	404	Example: exit on SIGINT
364		405
365	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
366		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$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
367	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
368		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
369	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.
370		450
371	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,
372	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
373	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
374	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
375		456
376	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
377	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
378	callback arguments.	459	callback arguments.
379		460
…		…
384		465
385	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
386	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
387	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
388		469
389	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
390	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
391	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.
392		476
393	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
394	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
395	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.
396		485
397	Example: fork a process and wait for it	486	Example: fork a process and wait for it
398		487
399	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
400		489
…		…
410	);	499	);
411		500
412	# do something else, then wait for process exit	501	# do something else, then wait for process exit
413	$done->recv;	502	$done->recv;
414		503
		504	=head2 IDLE WATCHERS
		505
		506	$w = AnyEvent->idle (cb => <callback>);
		507
		508	Repeatedly invoke the callback after the process becomes idle, until
		509	either the watcher is destroyed or new events have been detected.
		510
		511	Idle watchers are useful when there is a need to do something, but it
		512	is not so important (or wise) to do it instantly. The callback will be
		513	invoked only when there is "nothing better to do", which is usually
		514	defined as "all outstanding events have been handled and no new events
		515	have been detected". That means that idle watchers ideally get invoked
		516	when the event loop has just polled for new events but none have been
		517	detected. Instead of blocking to wait for more events, the idle watchers
		518	will be invoked.
		519
		520	Unfortunately, most event loops do not really support idle watchers (only
		521	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		522	will simply call the callback "from time to time".
		523
		524	Example: read lines from STDIN, but only process them when the
		525	program is otherwise idle:
		526
		527	my @lines; # read data
		528	my $idle_w;
		529	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		530	push @lines, scalar <STDIN>;
		531
		532	# start an idle watcher, if not already done
		533	$idle_w ||= AnyEvent->idle (cb => sub {
		534	# handle only one line, when there are lines left
		535	if (my $line = shift @lines) {
		536	print "handled when idle: $line";
		537	} else {
		538	# otherwise disable the idle watcher again
		539	undef $idle_w;
		540	}
		541	});
		542	});
		543
415	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
416		550
417	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
418	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
419	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
420		554
421	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
422	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).
423		557
424	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
425	because they represent a condition that must become true.	559	because they represent a condition that must become true.
426		560
		561	Now is probably a good time to look at the examples further below.
		562
427	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
428	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
429
430	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
431	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
432	the results).	567	the results).
433		568
434	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
439	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
440	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
441	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
442	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
443	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
444	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.
445		581
446	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
447	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,
448	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
449	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
…		…
483	after => 1,	619	after => 1,
484	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
485	);	621	);
486		622
487	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
488	# calls send	624	# calls ->send
489	$result_ready->recv;	625	$result_ready->recv;
490		626
491	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
492	condition variables are also code references.	628	variables are also callable directly.
493		629
494	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
495	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
496	$done->recv;	632	$done->recv;
497		633
…		…
503		639
504	...	640	...
505		641
506	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
507		643
508	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
509	results are available:	645	results are available:
510		646
511	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
512	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
513	});	649	});
…		…
531	immediately from within send.	667	immediately from within send.
532		668
533	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
534	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
535		671
536	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
537	(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
538	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
539	overloading, so as tempting as it may be, passing a condition variable
540	instead of a callback does not work. Both the pure perl and EV loops
541	support overloading, however, as well as all functions that use perl to
542	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
543	example).
544		675
545	=item $cv->croak ($error)	676	=item $cv->croak ($error)
546		677
547	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
548	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
549		680
550	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
551	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.
552		687
553	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
554		689
555	=item $cv->end	690	=item $cv->end
556
557	These two methods are EXPERIMENTAL and MIGHT CHANGE.
558		691
559	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
560	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
561	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
562		695
563	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
564	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
565	>>, 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
566	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
567	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.
568		702
569	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:
570		710
571	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
572		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
573	my %result;	737	my %result;
574	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
575		739
576	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
577	$cv->begin;	741	$cv->begin;
578	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
579	$result{$host} = ...;	743	$result{$host} = ...;
…		…
594	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
595	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
596	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
597	doesn't execute once).	761	doesn't execute once).
598		762
599	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
600	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
601	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
602	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>.
603		768
604	=back	769	=back
605		770
606	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
607		772
…		…
623	function will call C<croak>.	788	function will call C<croak>.
624		789
625	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,
626	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
627		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
628	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
629	(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
630	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
631	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
632	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
633	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,
634	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
635		807
636	Another reason I<never> to C<< ->recv >> in a module is that you cannot
637	sensibly have two C<< ->recv >>'s in parallel, as that would require
638	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
639	can supply.
640
641	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
642	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
643	versions and also integrates coroutines into AnyEvent, making blocking
644	C<< ->recv >> calls perfectly safe as long as they are done from another
645	coroutine (one that doesn't run the event loop).
646
647	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
648	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
649	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
650	waits otherwise.	811	waits otherwise.
651		812
…		…
657	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
658		819
659	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
660	replaces it before doing so.	821	replaces it before doing so.
661		822
662	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)
663	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
664	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>
665	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
666		827
667	=back	828	=back
668		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
669	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
670		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
671	=over 4	903	=over 4
672		904
673	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
674		906
675	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
676	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
677	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
678	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
679	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
680		914	will be C<urxvt::anyevent>).
681	The known classes so far are:
682
683	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
684	AnyEvent::Impl::Event based on Event, second best choice.
685	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
686	AnyEvent::Impl::Glib based on Glib, third-best choice.
687	AnyEvent::Impl::Tk based on Tk, very bad choice.
688	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
689	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
690	AnyEvent::Impl::POE based on POE, not generic enough for full support.
691
692	There is no support for WxWidgets, as WxWidgets has no support for
693	watching file handles. However, you can use WxWidgets through the
694	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
695	second, which was considered to be too horrible to even consider for
696	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
697	it's adaptor.
698
699	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
700	autodetecting them.
701		915
702	=item AnyEvent::detect	916	=item AnyEvent::detect
703		917
704	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
705	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
706	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
707	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>.
708		925
709	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
710		927
711	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
712	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
713		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$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
714	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
715	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
716	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 ||= $guard;
717		962
718	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
719		964
720	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
721	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
722	the event loop has been chosen.	967	the event loop has been chosen.
723		968
724	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
725	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
726	and the array will be ignored.	971	array will be ignored.
727		972
728	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	}
729		993
730	=back	994	=back
731		995
732	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
733		997
…		…
788		1052
789		1053
790	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
791		1055
792	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
793	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
794	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
795	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
796		1060
797	=over 4	1061	=over 4
798		1062
799	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
800		1064
…		…
809		1073
810	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
811		1075
812	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
813	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
814	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
815		1079
816	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
817		1081
818	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
819		1083
…		…
847		1111
848	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
849		1113
850	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
851		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
852	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
853		1126
854	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
855	L<App::IGS>).	1128	L<App::IGS>).
856		1129
857	=item L<AnyEvent::IRC>
858
859	AnyEvent based IRC client module family (replacing the older Net::IRC3).
860
861	=item L<Net::XMPP2>
862
863	AnyEvent based XMPP (Jabber protocol) module family.
864
865	=item L<Net::FCP>	1130	=item L<Net::FCP>
866		1131
867	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
868	of AnyEvent.	1133	of AnyEvent.
869		1134
…		…
873		1138
874	=item L<Coro>	1139	=item L<Coro>
875		1140
876	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
877		1142
878	=item L<IO::Lambda>
879
880	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
881
882	=back	1143	=back
883		1144
884	=cut	1145	=cut
885		1146
886	package AnyEvent;	1147	package AnyEvent;
887		1148
888	no warnings;	1149	# basically a tuned-down version of common::sense
889	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	}
890		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
891	use Carp;	1159	use Carp ();
892		1160
893	our $VERSION = 4.351;	1161	our $VERSION = '5.251';
894	our $MODEL;	1162	our $MODEL;
895		1163
896	our $AUTOLOAD;	1164	our $AUTOLOAD;
897	our @ISA;	1165	our @ISA;
898		1166
899	our @REGISTRY;	1167	our @REGISTRY;
900		1168
901	our $WIN32;	1169	our $VERBOSE;
902		1170
903	BEGIN {	1171	BEGIN {
904	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
905	eval "sub WIN32(){ $win32 }";
906	}
907		1173
		1174	eval "sub TAINT (){" . (${^TAINT} *1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
908	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
909		1184
910	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
911		1186
912	{	1187	{
913	my $idx;	1188	my $idx;
…		…
915	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
916	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
917	}	1192	}
918		1193
919	my @models = (	1194	my @models = (
920	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
921	[Event:: => AnyEvent::Impl::Event::],
922	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
923	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
924	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
925	# 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
926	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
927	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
928	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
929	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
930	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
931	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
932	[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
933	);	1217	);
934		1218
935	our %method = map +($_ => 1),	1219	our %method = map +($_ => 1),
936	qw(io timer time now now_update signal child condvar one_event DESTROY);	1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
937		1221
938	our @post_detect;	1222	our @post_detect;
939		1223
940	sub post_detect(&) {	1224	sub post_detect(&) {
941	my ($cb) = @_;	1225	my ($cb) = @_;
942		1226
943	if ($MODEL) {	1227	if ($MODEL) {
944	$cb->();	1228	$cb->();
945		1229
946	1	1230	undef
947	} else {	1231	} else {
948	push @post_detect, $cb;	1232	push @post_detect, $cb;
949		1233
950	defined wantarray	1234	defined wantarray
951	? bless \$cb, "AnyEvent::Util::PostDetect"	1235	? bless \$cb, "AnyEvent::Util::postdetect"
952	: ()	1236	: ()
953	}	1237	}
954	}	1238	}
955		1239
956	sub AnyEvent::Util::PostDetect::DESTROY {	1240	sub AnyEvent::Util::postdetect::DESTROY {
957	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1241	@post_detect = grep $_ != ${$_[0]}, @post_detect;
958	}	1242	}
959		1243
960	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 $VERBOSE;
		1258	}
		1259	}
		1260
		1261	# check for already loaded models
961	unless ($MODEL) {	1262	unless ($MODEL) {
962	no strict 'refs';	1263	for (@REGISTRY, @models) {
963	local $SIG{__DIE__};	1264	my ($package, $model) = @$_;
964		1265	if (${"$package\::VERSION"} > 0) {
965	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
966	my $model = "AnyEvent::Impl::$1";
967	if (eval "require $model") {	1266	if (eval "require $model") {
968	$MODEL = $model;	1267	$MODEL = $model;
969	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1268	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
970	} else {	1269	last;
971	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1270	}
972	}	1271	}
973	}	1272	}
974		1273
975	# check for already loaded models
976	unless ($MODEL) {	1274	unless ($MODEL) {
		1275	# try to autoload a model
977	for (@REGISTRY, @models) {	1276	for (@REGISTRY, @models) {
978	my ($package, $model) = @$_;	1277	my ($package, $model, $autoload) = @$_;
		1278	if (
		1279	$autoload
		1280	and eval "require $package"
979	if (${"$package\::VERSION"} > 0) {	1281	and ${"$package\::VERSION"} > 0
980	if (eval "require $model") {	1282	and eval "require $model"
		1283	) {
981	$MODEL = $model;	1284	$MODEL = $model;
982	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1285	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
983	last;	1286	last;
984	}
985	}	1287	}
986	}	1288	}
987		1289
988	unless ($MODEL) {
989	# try to load a model
990
991	for (@REGISTRY, @models) {
992	my ($package, $model) = @$_;
993	if (eval "require $package"
994	and ${"$package\::VERSION"} > 0
995	and eval "require $model") {
996	$MODEL = $model;
997	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
998	last;
999	}
1000	}
1001
1002	$MODEL	1290	$MODEL
1003	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1291	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1004	}
1005	}	1292	}
1006
1007	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1008
1009	unshift @ISA, $MODEL;
1010
1011	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1012
1013	(shift @post_detect)->() while @post_detect;
1014	}	1293	}
		1294
		1295	@models = (); # free probe data
		1296
		1297	push @{"$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;
1015		1303
1016	$MODEL	1304	$MODEL
1017	}	1305	}
1018		1306
1019	sub AUTOLOAD {	1307	sub AUTOLOAD {
1020	(my $func = $AUTOLOAD) =~ s/.*://;	1308	(my $func = $AUTOLOAD) =~ s/.*://;
1021		1309
1022	$method{$func}	1310	$method{$func}
1023	or croak "$func: not a valid method for AnyEvent objects";	1311	or Carp::croak "$func: not a valid AnyEvent class method";
1024		1312
1025	detect unless $MODEL;	1313	detect;
1026		1314
1027	my $class = shift;	1315	my $class = shift;
1028	$class->$func (@_);	1316	$class->$func (@_);
1029	}	1317	}
1030		1318
1031	# 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
1032	# to support binding more than one watcher per filehandle (they usually	1320	# to support binding more than one watcher per filehandle (they usually
1033	# 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).
1034	sub _dupfh($$$$) {	1322	sub _dupfh($$;$$) {
1035	my ($poll, $fh, $r, $w) = @_;	1323	my ($poll, $fh, $r, $w) = @_;
1036		1324
1037	# cygwin requires the fh mode to be matching, unix doesn't	1325	# cygwin requires the fh mode to be matching, unix doesn't
1038	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1326	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1039	: $poll eq "w" ? ($w, ">")
1040	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1041		1327
1042	open my $fh2, "$mode&" . fileno $fh	1328	open my $fh2, $mode, $fh
1043	or die "cannot dup() filehandle: $!,";	1329	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1044		1330
1045	# we assume CLOEXEC is already set by perl in all important cases	1331	# we assume CLOEXEC is already set by perl in all important cases
1046		1332
1047	($fh2, $rw)	1333	($fh2, $rw)
1048	}	1334	}
1049		1335
		1336	=head1 SIMPLIFIED AE API
		1337
		1338	Starting with version 5.0, AnyEvent officially supports a second, much
		1339	simpler, API that is designed to reduce the calling, typing and memory
		1340	overhead.
		1341
		1342	See the L<AE> manpage for details.
		1343
		1344	=cut
		1345
		1346	package AE;
		1347
		1348	our $VERSION = $AnyEvent::VERSION;
		1349
		1350	sub io($$$) {
		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
1050	package AnyEvent::Base;	1386	package AnyEvent::Base;
1051		1387
1052	# default implementations for many methods	1388	# default implementations for many methods
1053		1389
1054	BEGIN {	1390	sub _time() {
		1391	eval q{ # poor man's autoloading
		1392	# probe for availability of Time::HiRes
1055	if (eval "use 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;
1056	*_time = \&Time::HiRes::time;	1395	*_time = \&Time::HiRes::time;
1057	# if (eval "use POSIX (); (POSIX::times())...	1396	# if (eval "use POSIX (); (POSIX::times())...
1058	} else {	1397	} else {
		1398	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1059	*_time = sub { time }; # epic fail	1399	*_time = sub (){ time }; # epic fail
		1400	}
1060	}	1401	};
		1402	die if $@;
		1403
		1404	&_time
1061	}	1405	}
1062		1406
1063	sub time { _time }	1407	sub time { _time }
1064	sub now { _time }	1408	sub now { _time }
1065	sub now_update { }	1409	sub now_update { }
1066		1410
1067	# default implementation for ->condvar	1411	# default implementation for ->condvar
1068		1412
1069	sub condvar {	1413	sub condvar {
1070	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1414	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1071	}	1415	}
1072		1416
1073	# default implementation for ->signal	1417	# default implementation for ->signal
1074		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
1075	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);
1076		1432
1077	sub _signal_exec {	1433	# install a dummy wakeup watcher to reduce signal catching latency
1078	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;
1079		1439
1080	while (%SIG_EV) {	1440	$SIG_TW = AE::timer
1081	for (keys %SIG_EV) {	1441	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1082	delete $SIG_EV{$_};	1442	$MAX_SIGNAL_LATENCY,
1083	$_->() 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	};
1084	}	1476	}
1085	}	1477	};
1086	}	1478	die if $@;
		1479	};
		1480
		1481	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1482	sub sig2name($) { &$_sig_name_init; &sig2name }
1087		1483
1088	sub signal {	1484	sub signal {
1089	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;
1090		1489
1091	unless ($SIGPIPE_R) {	1490	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1092	require Fcntl;	1491	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1093		1492
1094	if (AnyEvent::WIN32) {
1095	require AnyEvent::Util;
1096
1097	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1098	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1099	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1100	} 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 {
1101	pipe $SIGPIPE_R, $SIGPIPE_W;	1503	pipe $SIGPIPE_R, $SIGPIPE_W;
1102	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;
1103	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;
1104	}	1516	}
1105		1517
1106	$SIGPIPE_R	1518	*signal = sub {
1107	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1519	my (undef, %arg) = @_;
1108		1520
1109	# not strictly required, as $^F is normally 2, but let's make sure...
1110	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1111	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1112
1113	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1114	}
1115
1116	my $signal = uc $arg{signal}	1521	my $signal = uc $arg{signal}
1117	or Carp::croak "required option 'signal' is missing";	1522	or Carp::croak "required option 'signal' is missing";
1118		1523
		1524	if ($HAVE_ASYNC_INTERRUPT) {
		1525	# async::interrupt
		1526
		1527	$signal = sig2num $signal;
1119	$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
1120	$SIG{$signal} ||= sub {	1544	$SIG{$signal} ||= sub {
1121	local $!;	1545	local $!;
1122	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1546	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1123	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	};
1124	};	1586	};
		1587	die if $@;
1125		1588
1126	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1589	&signal
1127	}
1128
1129	sub AnyEvent::Base::Signal::DESTROY {
1130	my ($signal, $cb) = @{$_[0]};
1131
1132	delete $SIG_CB{$signal}{$cb};
1133
1134	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1135	}	1590	}
1136		1591
1137	# default implementation for ->child	1592	# default implementation for ->child
1138		1593
1139	our %PID_CB;	1594	our %PID_CB;
1140	our $CHLD_W;	1595	our $CHLD_W;
1141	our $CHLD_DELAY_W;	1596	our $CHLD_DELAY_W;
1142	our $PID_IDLE;
1143	our $WNOHANG;	1597	our $WNOHANG;
1144		1598
1145	sub _child_wait {	1599	# used by many Impl's
1146	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1600	sub _emit_childstatus($$) {
		1601	my (undef, $rpid, $rstatus) = @_;
		1602
		1603	$_->($rpid, $rstatus)
1147	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1604	for values %{ $PID_CB{$rpid} || {} },
1148	(values %{ $PID_CB{0} || {} });	1605	values %{ $PID_CB{0} || {} };
1149	}
1150
1151	undef $PID_IDLE;
1152	}
1153
1154	sub _sigchld {
1155	# make sure we deliver these changes "synchronous" with the event loop.
1156	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1157	undef $CHLD_DELAY_W;
1158	&_child_wait;
1159	});
1160	}	1606	}
1161		1607
1162	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 {
1163	my (undef, %arg) = @_;	1618	my (undef, %arg) = @_;
1164		1619
1165	defined (my $pid = $arg{pid} + 0)	1620	defined (my $pid = $arg{pid} + 0)
1166	or Carp::croak "required option 'pid' is missing";	1621	or Carp::croak "required option 'pid' is missing";
1167		1622
1168	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1623	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1169		1624
1170	unless ($WNOHANG) {	1625	# WNOHANG is almost cetrainly 1 everywhere
		1626	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1627	? 1
1171	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1628	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1172	}
1173		1629
1174	unless ($CHLD_W) {	1630	unless ($CHLD_W) {
1175	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1631	$CHLD_W = AE::signal CHLD => \&_sigchld;
1176	# child could be a zombie already, so make at least one round	1632	# child could be a zombie already, so make at least one round
1177	&_sigchld;	1633	&_sigchld;
1178	}	1634	}
1179		1635
1180	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1636	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1181	}	1637	};
1182		1638
1183	sub AnyEvent::Base::Child::DESTROY {	1639	*AnyEvent::Base::child::DESTROY = sub {
1184	my ($pid, $cb) = @{$_[0]};	1640	my ($pid, $cb) = @{$_[0]};
1185		1641
1186	delete $PID_CB{$pid}{$cb};	1642	delete $PID_CB{$pid}{$cb};
1187	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1643	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1188		1644
1189	undef $CHLD_W unless keys %PID_CB;	1645	undef $CHLD_W unless keys %PID_CB;
		1646	};
		1647	};
		1648	die if $@;
		1649
		1650	&child
		1651	}
		1652
		1653	# idle emulation is done by simply using a timer, regardless
		1654	# of whether the process is idle or not, and not letting
		1655	# the callback use more than 50% of the time.
		1656	sub idle {
		1657	eval q{ # poor man's autoloading {}
		1658	*idle = sub {
		1659	my (undef, %arg) = @_;
		1660
		1661	my ($cb, $w, $rcb) = $arg{cb};
		1662
		1663	$rcb = sub {
		1664	if ($cb) {
		1665	$w = _time;
		1666	&$cb;
		1667	$w = _time - $w;
		1668
		1669	# never use more then 50% of the time for the idle watcher,
		1670	# within some limits
		1671	$w = 0.0001 if $w < 0.0001;
		1672	$w = 5 if $w > 5;
		1673
		1674	$w = AE::timer $w, 0, $rcb;
		1675	} else {
		1676	# clean up...
		1677	undef $w;
		1678	undef $rcb;
		1679	}
		1680	};
		1681
		1682	$w = AE::timer 0.05, 0, $rcb;
		1683
		1684	bless \\$cb, "AnyEvent::Base::idle"
		1685	};
		1686
		1687	*AnyEvent::Base::idle::DESTROY = sub {
		1688	undef $${$_[0]};
		1689	};
		1690	};
		1691	die if $@;
		1692
		1693	&idle
1190	}	1694	}
1191		1695
1192	package AnyEvent::CondVar;	1696	package AnyEvent::CondVar;
1193		1697
1194	our @ISA = AnyEvent::CondVar::Base::;	1698	our @ISA = AnyEvent::CondVar::Base::;
1195		1699
1196	package AnyEvent::CondVar::Base;	1700	package AnyEvent::CondVar::Base;
1197		1701
1198	use overload	1702	#use overload
1199	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1703	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1200	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;
1201		1713
1202	sub _send {	1714	sub _send {
1203	# nop	1715	# nop
1204	}	1716	}
1205		1717
…		…
1218	sub ready {	1730	sub ready {
1219	$_[0]{_ae_sent}	1731	$_[0]{_ae_sent}
1220	}	1732	}
1221		1733
1222	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 $WAITING = 1;
1223	AnyEvent->one_event while !$_[0]{_ae_sent};	1740	AnyEvent->one_event while !$_[0]{_ae_sent};
1224	}	1741	}
1225		1742
1226	sub recv {	1743	sub recv {
1227	$_[0]->_wait;	1744	$_[0]->_wait;
…		…
1229	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1746	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1230	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1747	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1231	}	1748	}
1232		1749
1233	sub cb {	1750	sub cb {
1234	$_[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
1235	$_[0]{_ae_cb}	1758	$cv->{_ae_cb}
1236	}	1759	}
1237		1760
1238	sub begin {	1761	sub begin {
1239	++$_[0]{_ae_counter};	1762	++$_[0]{_ae_counter};
1240	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1763	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1268	so on.	1791	so on.
1269		1792
1270	=head1 ENVIRONMENT VARIABLES	1793	=head1 ENVIRONMENT VARIABLES
1271		1794
1272	The following environment variables are used by this module or its	1795	The following environment variables are used by this module or its
1273	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.
1274		1801
1275	=over 4	1802	=over 4
1276		1803
1277	=item C<PERL_ANYEVENT_VERBOSE>	1804	=item C<PERL_ANYEVENT_VERBOSE>
1278		1805
…		…
1285	C<PERL_ANYEVENT_MODEL>.	1812	C<PERL_ANYEVENT_MODEL>.
1286		1813
1287	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
1288	model it chooses.	1815	model it chooses.
1289		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
1290	=item C<PERL_ANYEVENT_STRICT>	1820	=item C<PERL_ANYEVENT_STRICT>
1291		1821
1292	AnyEvent does not do much argument checking by default, as thorough	1822	AnyEvent does not do much argument checking by default, as thorough
1293	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
1294	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
1295	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,
1296	it will croak.	1826	it will croak.
1297		1827
1298	In other words, enables "strict" mode.	1828	In other words, enables "strict" mode.
1299		1829
1300	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>
1301	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1831	>>, it is definitely recommended to keep it off in production. Keeping
1302	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.
1303		1834
1304	=item C<PERL_ANYEVENT_MODEL>	1835	=item C<PERL_ANYEVENT_MODEL>
1305		1836
1306	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
1307	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
…		…
1350		1881
1351	=item C<PERL_ANYEVENT_MAX_FORKS>	1882	=item C<PERL_ANYEVENT_MAX_FORKS>
1352		1883
1353	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>
1354	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.
1355		1910
1356	=back	1911	=back
1357		1912
1358	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1913	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1359		1914
…		…
1417	warn "read: $input\n"; # output what has been read	1972	warn "read: $input\n"; # output what has been read
1418	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1973	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1419	},	1974	},
1420	);	1975	);
1421		1976
1422	my $time_watcher; # can only be used once
1423
1424	sub new_timer {
1425	$timer = AnyEvent->timer (after => 1, cb => sub {	1977	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1426	warn "timeout\n"; # print 'timeout' about every second	1978	warn "timeout\n"; # print 'timeout' at most every second
1427	&new_timer; # and restart the time
1428	});	1979	});
1429	}
1430
1431	new_timer; # create first timer
1432		1980
1433	$cv->recv; # wait until user enters /^q/i	1981	$cv->recv; # wait until user enters /^q/i
1434		1982
1435	=head1 REAL-WORLD EXAMPLE	1983	=head1 REAL-WORLD EXAMPLE
1436		1984
…		…
1567	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
1568	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,
1569	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.
1570		2118
1571	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
1572	distribution.	2120	distribution. It uses the L<AE> interface, which makes a real difference
		2121	for the EV and Perl backends only.
1573		2122
1574	=head3 Explanation of the columns	2123	=head3 Explanation of the columns
1575		2124
1576	I<watcher> is the number of event watchers created/destroyed. Since	2125	I<watcher> is the number of event watchers created/destroyed. Since
1577	different event models feature vastly different performances, each event	2126	different event models feature vastly different performances, each event
…		…
1598	watcher.	2147	watcher.
1599		2148
1600	=head3 Results	2149	=head3 Results
1601		2150
1602	name watchers bytes create invoke destroy comment	2151	name watchers bytes create invoke destroy comment
1603	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
1604	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
1605	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
1606	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
1607	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
1608	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
1609	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
1610	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
1611	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
1612	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
1613		2164
1614	=head3 Discussion	2165	=head3 Discussion
1615		2166
1616	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
1617	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)
…		…
1629	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2180	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1630	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
1631	cycles with POE.	2182	cycles with POE.
1632		2183
1633	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
1634	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
1635	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).
1636	natively.
1637		2189
1638	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
1639	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
1640	interpreter and the backend itself). Nevertheless this shows that it	2192	interpreter and the backend itself). Nevertheless this shows that it
1641	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
1642	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
1643	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.
1644		2196
1645	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
1646	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.
1647		2202
1648	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
1649	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
1650	C<Event>. However, Glib scales extremely badly, doubling the number of	2205	C<Event>. However, Glib scales extremely badly, doubling the number of
1651	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,
…		…
1712	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
1713	(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
1714	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.
1715		2270
1716	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
1717	distribution.	2272	distribution. It uses the L<AE> interface, which makes a real difference
		2273	for the EV and Perl backends only.
1718		2274
1719	=head3 Explanation of the columns	2275	=head3 Explanation of the columns
1720		2276
1721	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
1722	each server has a read and write socket end).	2278	each server has a read and write socket end).
…		…
1729	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
1730	a new one that moves the timeout into the future.	2286	a new one that moves the timeout into the future.
1731		2287
1732	=head3 Results	2288	=head3 Results
1733		2289
1734	name sockets create request	2290	name sockets create request
1735	EV 20000 69.01 11.16	2291	EV 20000 62.66 7.99
1736	Perl 20000 73.32 35.87	2292	Perl 20000 68.32 32.64
1737	Event 20000 212.62 257.32	2293	IOAsync 20000 174.06 101.15 epoll
1738	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
1739	POE 20000 349.67 12317.24 uses POE::Loop::Event	2297	POE 20000 341.54 12086.32 uses POE::Loop::Event
1740		2298
1741	=head3 Discussion	2299	=head3 Discussion
1742		2300
1743	This benchmark I<does> measure scalability and overall performance of the	2301	This benchmark I<does> measure scalability and overall performance of the
1744	particular event loop.	2302	particular event loop.
…		…
1746	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
1747	is relatively high, though.	2305	is relatively high, though.
1748		2306
1749	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
1750	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.
1751		2312
1752	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
1753	understand why). Callback invocation also has a high overhead compared to	2314	understand why). Callback invocation also has a high overhead compared to
1754	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
1755	uses select or poll in basically all documented configurations.	2316	uses select or poll in basically all documented configurations.
…		…
1818	=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
1819	watchers, as the management overhead dominates.	2380	watchers, as the management overhead dominates.
1820		2381
1821	=back	2382	=back
1822		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
1823		2441
1824	=head1 SIGNALS	2442	=head1 SIGNALS
1825		2443
1826	AnyEvent currently installs handlers for these signals:	2444	AnyEvent currently installs handlers for these signals:
1827		2445
…		…
1830	=item SIGCHLD	2448	=item SIGCHLD
1831		2449
1832	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
1833	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
1834	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.
1835		2456
1836	=item SIGPIPE	2457	=item SIGPIPE
1837		2458
1838	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>
1839	when AnyEvent gets loaded.	2460	when AnyEvent gets loaded.
…		…
1851		2472
1852	=back	2473	=back
1853		2474
1854	=cut	2475	=cut
1855		2476
		2477	undef $SIG{CHLD}
		2478	if $SIG{CHLD} eq 'IGNORE';
		2479
1856	$SIG{PIPE} = sub { }	2480	$SIG{PIPE} = sub { }
1857	unless defined $SIG{PIPE};	2481	unless defined $SIG{PIPE};
1858		2482
		2483	=head1 RECOMMENDED/OPTIONAL MODULES
		2484
		2485	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2486	it's built-in modules) are required to use it.
		2487
		2488	That does not mean that AnyEvent won't take advantage of some additional
		2489	modules if they are installed.
		2490
		2491	This section explains which additional modules will be used, and how they
		2492	affect AnyEvent's operation.
		2493
		2494	=over 4
		2495
		2496	=item L<Async::Interrupt>
		2497
		2498	This slightly arcane module is used to implement fast signal handling: To
		2499	my knowledge, there is no way to do completely race-free and quick
		2500	signal handling in pure perl. To ensure that signals still get
		2501	delivered, AnyEvent will start an interval timer to wake up perl (and
		2502	catch the signals) with some delay (default is 10 seconds, look for
		2503	C<$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
1859		2560
1860	=head1 FORK	2561	=head1 FORK
1861		2562
1862	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
1863	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
1864	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).
1865		2575
1866	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
1867	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.
1868		2588
1869		2589
1870	=head1 SECURITY CONSIDERATIONS	2590	=head1 SECURITY CONSIDERATIONS
1871		2591
1872	AnyEvent can be forced to load any event model via	2592	AnyEvent can be forced to load any event model via
…		…
1884	use AnyEvent;	2604	use AnyEvent;
1885		2605
1886	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2606	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1887	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
1888	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
1889	$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.
1890		2614
1891		2615
1892	=head1 BUGS	2616	=head1 BUGS
1893		2617
1894	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
…		…
1906	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2630	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1907		2631
1908	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2632	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1909	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>,
1910	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2634	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1911	L<AnyEvent::Impl::POE>.	2635	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1912		2636
1913	Non-blocking file handles, sockets, TCP clients and	2637	Non-blocking file handles, sockets, TCP clients and
1914	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2638	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1915		2639
1916	Asynchronous DNS: L<AnyEvent::DNS>.	2640	Asynchronous DNS: L<AnyEvent::DNS>.
1917		2641
1918	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>,
1919		2644
1920	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>.
1921		2647
1922		2648
1923	=head1 AUTHOR	2649	=head1 AUTHOR
1924		2650
1925	Marc Lehmann <schmorp@schmorp.de>	2651	Marc Lehmann <schmorp@schmorp.de>

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