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Revision 1.202 by root, Wed Apr 1 15:29:00 2009 UTC vs.
Revision 1.317 by root, Wed Mar 24 21:22:57 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
		6	and POE are various supported event loops/environments.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
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
…		…
320	In either case, if you care (and in most cases, you don't), then you	350	In either case, if you care (and in most cases, you don't), then you
321	can get whatever behaviour you want with any event loop, by taking the	351	can get whatever behaviour you want with any event loop, by taking the
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	353	account.
324		354
		355	=item AnyEvent->now_update
		356
		357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		358	the current time for each loop iteration (see the discussion of L<<
		359	AnyEvent->now >>, above).
		360
		361	When a callback runs for a long time (or when the process sleeps), then
		362	this "current" time will differ substantially from the real time, which
		363	might affect timers and time-outs.
		364
		365	When this is the case, you can call this method, which will update the
		366	event loop's idea of "current time".
		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
		375	Note that updating the time I<might> cause some events to be handled.
		376
325	=back	377	=back
326		378
327	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
		380
		381	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328		382
329	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
330	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
331	callback to be invoked whenever a signal occurs.	385	callback to be invoked whenever a signal occurs.
332		386
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	392	invocation, and callback invocation will be synchronous. Synchronous means
339	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,
340	but it is guaranteed not to interrupt any other callbacks.	394	but it is guaranteed not to interrupt any other callbacks.
341		395
342	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
343	between multiple watchers.	397	between multiple watchers, and AnyEvent will ensure that signals will not
		398	interrupt your program at bad times.
344		399
345	This watcher might use C<%SIG>, so programs overwriting those signals	400	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	401	so programs overwriting those signals directly will likely not work
		402	correctly.
347		403
348	Example: exit on SIGINT	404	Example: exit on SIGINT
349		405
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
		424
		425	=head3 Signal Races, Delays and Workarounds
		426
		427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		428	callbacks to signals in a generic way, which is a pity, as you cannot
		429	do race-free signal handling in perl, requiring C libraries for
		430	this. AnyEvent will try to do it's best, which means in some cases,
		431	signals will be delayed. The maximum time a signal might be delayed is
		432	specified in C<$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
352	=head2 CHILD PROCESS WATCHERS	445	=head2 CHILD PROCESS WATCHERS
353		446
		447	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		448
354	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.
355		450
356	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,
357	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
358	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
359	any trace events (stopped/continued).	454	finished and an exit status is available, not on any trace events
		455	(stopped/continued).
360		456
361	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
362	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
363	callback arguments.	459	callback arguments.
364		460
…		…
369		465
370	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
371	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
372	have exited already (and no SIGCHLD will be sent anymore).	468	have exited already (and no SIGCHLD will be sent anymore).
373		469
374	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
375	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
376	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.
377		476
378	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
379	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
380	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.
381		485
382	Example: fork a process and wait for it	486	Example: fork a process and wait for it
383		487
384	my $done = AnyEvent->condvar;	488	my $done = AnyEvent->condvar;
385		489
…		…
395	);	499	);
396		500
397	# do something else, then wait for process exit	501	# do something else, then wait for process exit
398	$done->recv;	502	$done->recv;
399		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
400	=head2 CONDITION VARIABLES	544	=head2 CONDITION VARIABLES
		545
		546	$cv = AnyEvent->condvar;
		547
		548	$cv->send (<list>);
		549	my @res = $cv->recv;
401		550
402	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
403	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
404	will actively watch for new events and call your callbacks.	553	will actively watch for new events and call your callbacks.
405		554
406	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
407	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).
408		557
409	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
410	because they represent a condition that must become true.	559	because they represent a condition that must become true.
411		560
		561	Now is probably a good time to look at the examples further below.
		562
412	Condition variables can be created by calling the C<< AnyEvent->condvar	563	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	564	>> method, usually without arguments. The only argument pair allowed is
414
415	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
416	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
417	the results).	567	the results).
418		568
419	After creation, the condition variable is "false" until it becomes "true"	569	After creation, the condition variable is "false" until it becomes "true"
…		…
424	Condition variables are similar to callbacks, except that you can	574	Condition variables are similar to callbacks, except that you can
425	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
426	in time where multiple outstanding events have been processed. And yet	576	in time where multiple outstanding events have been processed. And yet
427	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
428	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
429	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.
430		581
431	Condition variables are very useful to signal that something has finished,	582	Condition variables are very useful to signal that something has finished,
432	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,
433	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
434	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
…		…
468	after => 1,	619	after => 1,
469	cb => sub { $result_ready->send },	620	cb => sub { $result_ready->send },
470	);	621	);
471		622
472	# this "blocks" (while handling events) till the callback	623	# this "blocks" (while handling events) till the callback
473	# calls send	624	# calls ->send
474	$result_ready->recv;	625	$result_ready->recv;
475		626
476	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
477	condition variables are also code references.	628	variables are also callable directly.
478		629
479	my $done = AnyEvent->condvar;	630	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	631	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	632	$done->recv;
482		633
…		…
488		639
489	...	640	...
490		641
491	my @info = $couchdb->info->recv;	642	my @info = $couchdb->info->recv;
492		643
493	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
494	results are available:	645	results are available:
495		646
496	$couchdb->info->cb (sub {	647	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	648	my @info = $_[0]->recv;
498	});	649	});
…		…
516	immediately from within send.	667	immediately from within send.
517		668
518	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
519	future C<< ->recv >> calls.	670	future C<< ->recv >> calls.
520		671
521	Condition variables are overloaded so one can call them directly	672	Condition variables are overloaded so one can call them directly (as if
522	(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
523	C<send>. Note, however, that many C-based event loops do not handle	674	C<send>.
524	overloading, so as tempting as it may be, passing a condition variable
525	instead of a callback does not work. Both the pure perl and EV loops
526	support overloading, however, as well as all functions that use perl to
527	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
528	example).
529		675
530	=item $cv->croak ($error)	676	=item $cv->croak ($error)
531		677
532	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
533	C<Carp::croak> with the given error message/object/scalar.	679	C<Carp::croak> with the given error message/object/scalar.
534		680
535	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
536	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.
537		687
538	=item $cv->begin ([group callback])	688	=item $cv->begin ([group callback])
539		689
540	=item $cv->end	690	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		691
544	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
545	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
546	to use a condition variable for the whole process.	694	to use a condition variable for the whole process.
547		695
548	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
549	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
550	>>, 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
551	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
552	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.
553		702
554	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:
555		710
556	my $cv = AnyEvent->condvar;	711	my $cv = AnyEvent->condvar;
557		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
558	my %result;	737	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	738	$cv->begin (sub { shift->send (\%result) });
560		739
561	for my $host (@list_of_hosts) {	740	for my $host (@list_of_hosts) {
562	$cv->begin;	741	$cv->begin;
563	ping_host_then_call_callback $host, sub {	742	ping_host_then_call_callback $host, sub {
564	$result{$host} = ...;	743	$result{$host} = ...;
…		…
579	loop, which serves two important purposes: first, it sets the callback	758	loop, which serves two important purposes: first, it sets the callback
580	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
581	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
582	doesn't execute once).	761	doesn't execute once).
583		762
584	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
585	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
586	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
587	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>.
588		768
589	=back	769	=back
590		770
591	=head3 METHODS FOR CONSUMERS	771	=head3 METHODS FOR CONSUMERS
592		772
…		…
608	function will call C<croak>.	788	function will call C<croak>.
609		789
610	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,
611	in scalar context only the first one will be returned.	791	in scalar context only the first one will be returned.
612		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
613	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
614	(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
615	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
616	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
617	condition variables with some kind of request results and supporting	804	condition variables with some kind of request results and supporting
618	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,
619	while still supporting blocking waits if the caller so desires).	806	while still supporting blocking waits if the caller so desires).
620		807
621	Another reason I<never> to C<< ->recv >> in a module is that you cannot
622	sensibly have two C<< ->recv >>'s in parallel, as that would require
623	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
624	can supply.
625
626	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
627	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
628	versions and also integrates coroutines into AnyEvent, making blocking
629	C<< ->recv >> calls perfectly safe as long as they are done from another
630	coroutine (one that doesn't run the event loop).
631
632	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
633	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
634	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
635	waits otherwise.	811	waits otherwise.
636		812
…		…
642	=item $cb = $cv->cb ($cb->($cv))	818	=item $cb = $cv->cb ($cb->($cv))
643		819
644	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
645	replaces it before doing so.	821	replaces it before doing so.
646		822
647	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)
648	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
649	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>
650	is guaranteed not to block.	826	inside the callback or at any later time is guaranteed not to block.
651		827
652	=back	828	=back
653		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
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	898	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		899
		900	These are not normally required to use AnyEvent, but can be useful to
		901	write AnyEvent extension modules.
		902
656	=over 4	903	=over 4
657		904
658	=item $AnyEvent::MODEL	905	=item $AnyEvent::MODEL
659		906
660	Contains C<undef> until the first watcher is being created. Then it	907	Contains C<undef> until the first watcher is being created, before the
		908	backend has been autodetected.
		909
661	contains the event model that is being used, which is the name of the	910	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	911	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	912	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	913	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		914	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		915
687	=item AnyEvent::detect	916	=item AnyEvent::detect
688		917
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	918	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	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
691	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
692	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>.
693		925
694	=item $guard = AnyEvent::post_detect { BLOCK }	926	=item $guard = AnyEvent::post_detect { BLOCK }
695		927
696	Arranges for the code block to be executed as soon as the event model is	928	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	929	autodetected (or immediately if this has already happened).
698		930
		931	The block will be executed I<after> the actual backend has been detected
		932	(C<$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
699	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
700	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
701	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 ||= $guard;
702		962
703	=item @AnyEvent::post_detect	963	=item @AnyEvent::post_detect
704		964
705	If there are any code references in this array (you can C<push> to it	965	If there are any code references in this array (you can C<push> to it
706	before or after loading AnyEvent), then they will called directly after	966	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	967	the event loop has been chosen.
708		968
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	969	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	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
711	and the array will be ignored.	971	array will be ignored.
712		972
713	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	}
714		993
715	=back	994	=back
716		995
717	=head1 WHAT TO DO IN A MODULE	996	=head1 WHAT TO DO IN A MODULE
718		997
…		…
773		1052
774		1053
775	=head1 OTHER MODULES	1054	=head1 OTHER MODULES
776		1055
777	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
778	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
779	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
780	available via CPAN.	1059	come with AnyEvent, most are available via CPAN.
781		1060
782	=over 4	1061	=over 4
783		1062
784	=item L<AnyEvent::Util>	1063	=item L<AnyEvent::Util>
785		1064
…		…
794		1073
795	=item L<AnyEvent::Handle>	1074	=item L<AnyEvent::Handle>
796		1075
797	Provide read and write buffers, manages watchers for reads and writes,	1076	Provide read and write buffers, manages watchers for reads and writes,
798	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
799	non-blocking SSL/TLS.	1078	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		1079
801	=item L<AnyEvent::DNS>	1080	=item L<AnyEvent::DNS>
802		1081
803	Provides rich asynchronous DNS resolver capabilities.	1082	Provides rich asynchronous DNS resolver capabilities.
804		1083
…		…
832		1111
833	=item L<AnyEvent::GPSD>	1112	=item L<AnyEvent::GPSD>
834		1113
835	A non-blocking interface to gpsd, a daemon delivering GPS information.	1114	A non-blocking interface to gpsd, a daemon delivering GPS information.
836		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
837	=item L<AnyEvent::IGS>	1125	=item L<AnyEvent::IGS>
838		1126
839	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
840	L<App::IGS>).	1128	L<App::IGS>).
841		1129
842	=item L<AnyEvent::IRC>
843
844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
845
846	=item L<Net::XMPP2>
847
848	AnyEvent based XMPP (Jabber protocol) module family.
849
850	=item L<Net::FCP>	1130	=item L<Net::FCP>
851		1131
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1132	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.	1133	of AnyEvent.
854		1134
…		…
858		1138
859	=item L<Coro>	1139	=item L<Coro>
860		1140
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1141	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1142
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1143	=back
868		1144
869	=cut	1145	=cut
870		1146
871	package AnyEvent;	1147	package AnyEvent;
872		1148
873	no warnings;	1149	# basically a tuned-down version of common::sense
874	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	}
875		1156
		1157	BEGIN { AnyEvent::common_sense }
		1158
876	use Carp;	1159	use Carp ();
877		1160
878	our $VERSION = 4.35;	1161	our $VERSION = '5.251';
879	our $MODEL;	1162	our $MODEL;
880		1163
881	our $AUTOLOAD;	1164	our $AUTOLOAD;
882	our @ISA;	1165	our @ISA;
883		1166
884	our @REGISTRY;	1167	our @REGISTRY;
885		1168
886	our $WIN32;	1169	our $VERBOSE;
887		1170
888	BEGIN {	1171	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1172	require "AnyEvent/constants.pl";
890	eval "sub WIN32(){ $win32 }";
891	}
892		1173
		1174	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1175
		1176	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1177	if ${^TAINT};
		1178
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1179	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1180
		1181	}
		1182
		1183	our $MAX_SIGNAL_LATENCY = 10;
894		1184
895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1185	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896		1186
897	{	1187	{
898	my $idx;	1188	my $idx;
…		…
900	for reverse split /\s*,\s*/,	1190	for reverse split /\s*,\s*/,
901	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1191	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902	}	1192	}
903		1193
904	my @models = (	1194	my @models = (
905	[EV:: => AnyEvent::Impl::EV::],	1195	[EV:: => AnyEvent::Impl::EV:: , 1],
906	[Event:: => AnyEvent::Impl::Event::],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1196	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908	# everything below here will not be autoprobed	1197	# everything below here will not (normally) be autoprobed
909	# as the pureperl backend should work everywhere	1198	# as the pureperl backend should work everywhere
910	# 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
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1204	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1205	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1206	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1207	[Wx:: => AnyEvent::Impl::POE::],
917	[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
918	);	1217	);
919		1218
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1219	our %method = map +($_ => 1),
		1220	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1221
922	our @post_detect;	1222	our @post_detect;
923		1223
924	sub post_detect(&) {	1224	sub post_detect(&) {
925	my ($cb) = @_;	1225	my ($cb) = @_;
926		1226
927	if ($MODEL) {
928	$cb->();
929
930	1
931	} else {
932	push @post_detect, $cb;	1227	push @post_detect, $cb;
933		1228
934	defined wantarray	1229	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1230	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1231	: ()
		1232	}
		1233
		1234	sub AnyEvent::Util::postdetect::DESTROY {
		1235	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1236	}
		1237
		1238	sub detect() {
		1239	# free some memory
		1240	*detect = sub () { $MODEL };
		1241
		1242	local $!; # for good measure
		1243	local $SIG{__DIE__};
		1244
		1245	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1246	my $model = "AnyEvent::Impl::$1";
		1247	if (eval "require $model") {
		1248	$MODEL = $model;
		1249	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1250	} else {
		1251	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1252	}
937	}	1253	}
938	}
939		1254
940	sub AnyEvent::Util::PostDetect::DESTROY {	1255	# check for already loaded models
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}
943
944	sub detect() {
945	unless ($MODEL) {	1256	unless ($MODEL) {
946	no strict 'refs';	1257	for (@REGISTRY, @models) {
947	local $SIG{__DIE__};	1258	my ($package, $model) = @$_;
948		1259	if (${"$package\::VERSION"} > 0) {
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1260	if (eval "require $model") {
952	$MODEL = $model;	1261	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1262	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
954	} else {	1263	last;
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1264	}
956	}	1265	}
957	}	1266	}
958		1267
959	# check for already loaded models
960	unless ($MODEL) {	1268	unless ($MODEL) {
		1269	# try to autoload a model
961	for (@REGISTRY, @models) {	1270	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1271	my ($package, $model, $autoload) = @$_;
		1272	if (
		1273	$autoload
		1274	and eval "require $package"
963	if (${"$package\::VERSION"} > 0) {	1275	and ${"$package\::VERSION"} > 0
964	if (eval "require $model") {	1276	and eval "require $model"
		1277	) {
965	$MODEL = $model;	1278	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1279	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1280	last;
968	}
969	}	1281	}
970	}	1282	}
971		1283
972	unless ($MODEL) {
973	# try to load a model
974
975	for (@REGISTRY, @models) {
976	my ($package, $model) = @$_;
977	if (eval "require $package"
978	and ${"$package\::VERSION"} > 0
979	and eval "require $model") {
980	$MODEL = $model;
981	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
982	last;
983	}
984	}
985
986	$MODEL	1284	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1285	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}
989	}	1286	}
990
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992
993	unshift @ISA, $MODEL;
994
995	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
996
997	(shift @post_detect)->() while @post_detect;
998	}	1287	}
		1288
		1289	@models = (); # free probe data
		1290
		1291	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1292	unshift @ISA, $MODEL;
		1293
		1294	# now nuke some methods that are overriden by the backend.
		1295	# SUPER is not allowed.
		1296	for (qw(time signal child idle)) {
		1297	undef &{"AnyEvent::Base::$_"}
		1298	if defined &{"$MODEL\::$_"};
		1299	}
		1300
		1301	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1302
		1303	(shift @post_detect)->() while @post_detect;
		1304
		1305	*post_detect = sub(&) {
		1306	shift->();
		1307
		1308	undef
		1309	};
999		1310
1000	$MODEL	1311	$MODEL
1001	}	1312	}
1002		1313
1003	sub AUTOLOAD {	1314	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1315	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1316
1006	$method{$func}	1317	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1318	or Carp::croak "$func: not a valid AnyEvent class method";
1008		1319
1009	detect unless $MODEL;	1320	detect;
1010		1321
1011	my $class = shift;	1322	my $class = shift;
1012	$class->$func (@_);	1323	$class->$func (@_);
1013	}	1324	}
1014		1325
1015	# utility function to dup a filehandle. this is used by many backends	1326	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1327	# to support binding more than one watcher per filehandle (they usually
1017	# allow only one watcher per fd, so we dup it to get a different one).	1328	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1329	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1330	my ($poll, $fh, $r, $w) = @_;
1020		1331
1021	# cygwin requires the fh mode to be matching, unix doesn't	1332	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1333	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023	: $poll eq "w" ? ($w, ">")
1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025		1334
1026	open my $fh2, "$mode&" . fileno $fh	1335	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1336	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1337
1029	# we assume CLOEXEC is already set by perl in all important cases	1338	# we assume CLOEXEC is already set by perl in all important cases
1030		1339
1031	($fh2, $rw)	1340	($fh2, $rw)
1032	}	1341	}
1033		1342
		1343	=head1 SIMPLIFIED AE API
		1344
		1345	Starting with version 5.0, AnyEvent officially supports a second, much
		1346	simpler, API that is designed to reduce the calling, typing and memory
		1347	overhead.
		1348
		1349	See the L<AE> manpage for details.
		1350
		1351	=cut
		1352
		1353	package AE;
		1354
		1355	our $VERSION = $AnyEvent::VERSION;
		1356
		1357	sub io($$$) {
		1358	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1359	}
		1360
		1361	sub timer($$$) {
		1362	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1363	}
		1364
		1365	sub signal($$) {
		1366	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1367	}
		1368
		1369	sub child($$) {
		1370	AnyEvent->child (pid => $_[0], cb => $_[1])
		1371	}
		1372
		1373	sub idle($) {
		1374	AnyEvent->idle (cb => $_[0])
		1375	}
		1376
		1377	sub cv(;&) {
		1378	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1379	}
		1380
		1381	sub now() {
		1382	AnyEvent->now
		1383	}
		1384
		1385	sub now_update() {
		1386	AnyEvent->now_update
		1387	}
		1388
		1389	sub time() {
		1390	AnyEvent->time
		1391	}
		1392
1034	package AnyEvent::Base;	1393	package AnyEvent::Base;
1035		1394
1036	# default implementation for now and time	1395	# default implementations for many methods
1037		1396
1038	BEGIN {	1397	sub time {
		1398	eval q{ # poor man's autoloading {}
		1399	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1400	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1401	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1402	*AE::time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1403	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1404	} else {
		1405	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1406	*AE::time = sub (){ time }; # epic fail
		1407	}
		1408
		1409	*time = sub { AE::time }; # different prototypes
		1410	};
		1411	die if $@;
		1412
		1413	&time
		1414	}
		1415
		1416	*now = \&time;
		1417
		1418	sub now_update { }
		1419
		1420	# default implementation for ->condvar
		1421
		1422	sub condvar {
		1423	eval q{ # poor man's autoloading {}
		1424	*condvar = sub {
		1425	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1426	};
		1427
		1428	*AE::cv = sub (;&) {
		1429	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1430	};
		1431	};
		1432	die if $@;
		1433
		1434	&condvar
		1435	}
		1436
		1437	# default implementation for ->signal
		1438
		1439	our $HAVE_ASYNC_INTERRUPT;
		1440
		1441	sub _have_async_interrupt() {
		1442	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1443	&& eval "use Async::Interrupt 1.02 (); 1")
		1444	unless defined $HAVE_ASYNC_INTERRUPT;
		1445
		1446	$HAVE_ASYNC_INTERRUPT
		1447	}
		1448
		1449	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1450	our (%SIG_ASY, %SIG_ASY_W);
		1451	our ($SIG_COUNT, $SIG_TW);
		1452
		1453	# install a dummy wakeup watcher to reduce signal catching latency
		1454	# used by Impls
		1455	sub _sig_add() {
		1456	unless ($SIG_COUNT++) {
		1457	# try to align timer on a full-second boundary, if possible
		1458	my $NOW = AE::now;
		1459
		1460	$SIG_TW = AE::timer
		1461	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1462	$MAX_SIGNAL_LATENCY,
		1463	sub { } # just for the PERL_ASYNC_CHECK
		1464	;
1044	}	1465	}
1045	}	1466	}
1046		1467
1047	sub time { _time }	1468	sub _sig_del {
1048	sub now { _time }	1469	undef $SIG_TW
1049		1470	unless --$SIG_COUNT;
1050	# default implementation for ->condvar
1051
1052	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1054	}	1471	}
1055		1472
1056	# default implementation for ->signal	1473	our $_sig_name_init; $_sig_name_init = sub {
		1474	eval q{ # poor man's autoloading {}
		1475	undef $_sig_name_init;
1057		1476
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1477	if (_have_async_interrupt) {
		1478	*sig2num = \&Async::Interrupt::sig2num;
		1479	*sig2name = \&Async::Interrupt::sig2name;
		1480	} else {
		1481	require Config;
1059		1482
1060	sub _signal_exec {	1483	my %signame2num;
1061	sysread $SIGPIPE_R, my $dummy, 4;	1484	@signame2num{ split ' ', $Config::Config{sig_name} }
		1485	= split ' ', $Config::Config{sig_num};
1062		1486
1063	while (%SIG_EV) {	1487	my @signum2name;
1064	for (keys %SIG_EV) {	1488	@signum2name[values %signame2num] = keys %signame2num;
1065	delete $SIG_EV{$_};	1489
1066	$_->() for values %{ $SIG_CB{$_} || {} };	1490	*sig2num = sub($) {
		1491	$_[0] > 0 ? shift : $signame2num{+shift}
		1492	};
		1493	*sig2name = sub ($) {
		1494	$_[0] > 0 ? $signum2name[+shift] : shift
		1495	};
1067	}	1496	}
1068	}	1497	};
1069	}	1498	die if $@;
		1499	};
		1500
		1501	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1502	sub sig2name($) { &$_sig_name_init; &sig2name }
1070		1503
1071	sub signal {	1504	sub signal {
1072	my (undef, %arg) = @_;	1505	eval q{ # poor man's autoloading {}
		1506	# probe for availability of Async::Interrupt
		1507	if (_have_async_interrupt) {
		1508	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1509
1074	unless ($SIGPIPE_R) {	1510	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1075	require Fcntl;	1511	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1076		1512
1077	if (AnyEvent::WIN32) {
1078	require AnyEvent::Util;
1079
1080	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1081	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083	} else {	1513	} else {
		1514	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1515
		1516	if (AnyEvent::WIN32) {
		1517	require AnyEvent::Util;
		1518
		1519	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1520	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1521	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1522	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1523	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1524	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1525	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1526
		1527	# not strictly required, as $^F is normally 2, but let's make sure...
		1528	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1529	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1530	}
		1531
		1532	$SIGPIPE_R
		1533	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1534
		1535	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1087	}	1536	}
1088		1537
1089	$SIGPIPE_R	1538	*signal = $HAVE_ASYNC_INTERRUPT
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1539	? sub {
		1540	my (undef, %arg) = @_;
1091		1541
1092	# not strictly required, as $^F is normally 2, but let's make sure...	1542	# async::interrupt
1093	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1095
1096	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1097	}
1098
1099	my $signal = uc $arg{signal}	1543	my $signal = sig2num $arg{signal};
1100	or Carp::croak "required option 'signal' is missing";
1101
1102	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1544	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1545
		1546	$SIG_ASY{$signal} ||= new Async::Interrupt
		1547	cb => sub { undef $SIG_EV{$signal} },
		1548	signal => $signal,
		1549	pipe => [$SIGPIPE_R->filenos],
		1550	pipe_autodrain => 0,
		1551	;
		1552
		1553	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1554	}
		1555	: sub {
		1556	my (undef, %arg) = @_;
		1557
		1558	# pure perl
		1559	my $signal = sig2name $arg{signal};
		1560	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1561
1103	$SIG{$signal} ||= sub {	1562	$SIG{$signal} ||= sub {
1104	local $!;	1563	local $!;
1105	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1564	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1106	undef $SIG_EV{$signal};	1565	undef $SIG_EV{$signal};
		1566	};
		1567
		1568	# can't do signal processing without introducing races in pure perl,
		1569	# so limit the signal latency.
		1570	_sig_add;
		1571
		1572	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1573	}
		1574	;
		1575
		1576	*AnyEvent::Base::signal::DESTROY = sub {
		1577	my ($signal, $cb) = @{$_[0]};
		1578
		1579	_sig_del;
		1580
		1581	delete $SIG_CB{$signal}{$cb};
		1582
		1583	$HAVE_ASYNC_INTERRUPT
		1584	? delete $SIG_ASY{$signal}
		1585	: # delete doesn't work with older perls - they then
		1586	# print weird messages, or just unconditionally exit
		1587	# instead of getting the default action.
		1588	undef $SIG{$signal}
		1589	unless keys %{ $SIG_CB{$signal} };
		1590	};
		1591
		1592	*_signal_exec = sub {
		1593	$HAVE_ASYNC_INTERRUPT
		1594	? $SIGPIPE_R->drain
		1595	: sysread $SIGPIPE_R, (my $dummy), 9;
		1596
		1597	while (%SIG_EV) {
		1598	for (keys %SIG_EV) {
		1599	delete $SIG_EV{$_};
		1600	$_->() for values %{ $SIG_CB{$_} || {} };
		1601	}
		1602	}
		1603	};
1107	};	1604	};
		1605	die if $@;
1108		1606
1109	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1607	&signal
1110	}
1111
1112	sub AnyEvent::Base::Signal::DESTROY {
1113	my ($signal, $cb) = @{$_[0]};
1114
1115	delete $SIG_CB{$signal}{$cb};
1116
1117	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1118	}	1608	}
1119		1609
1120	# default implementation for ->child	1610	# default implementation for ->child
1121		1611
1122	our %PID_CB;	1612	our %PID_CB;
1123	our $CHLD_W;	1613	our $CHLD_W;
1124	our $CHLD_DELAY_W;	1614	our $CHLD_DELAY_W;
1125	our $PID_IDLE;
1126	our $WNOHANG;	1615	our $WNOHANG;
1127		1616
1128	sub _child_wait {	1617	# used by many Impl's
1129	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1618	sub _emit_childstatus($$) {
		1619	my (undef, $rpid, $rstatus) = @_;
		1620
		1621	$_->($rpid, $rstatus)
1130	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1622	for values %{ $PID_CB{$rpid} || {} },
1131	(values %{ $PID_CB{0} || {} });	1623	values %{ $PID_CB{0} || {} };
1132	}
1133
1134	undef $PID_IDLE;
1135	}
1136
1137	sub _sigchld {
1138	# make sure we deliver these changes "synchronous" with the event loop.
1139	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1140	undef $CHLD_DELAY_W;
1141	&_child_wait;
1142	});
1143	}	1624	}
1144		1625
1145	sub child {	1626	sub child {
		1627	eval q{ # poor man's autoloading {}
		1628	*_sigchld = sub {
		1629	my $pid;
		1630
		1631	AnyEvent->_emit_childstatus ($pid, $?)
		1632	while ($pid = waitpid -1, $WNOHANG) > 0;
		1633	};
		1634
		1635	*child = sub {
1146	my (undef, %arg) = @_;	1636	my (undef, %arg) = @_;
1147		1637
1148	defined (my $pid = $arg{pid} + 0)	1638	defined (my $pid = $arg{pid} + 0)
1149	or Carp::croak "required option 'pid' is missing";	1639	or Carp::croak "required option 'pid' is missing";
1150		1640
1151	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1641	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1152		1642
1153	unless ($WNOHANG) {	1643	# WNOHANG is almost cetrainly 1 everywhere
		1644	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1645	? 1
1154	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1646	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1155	}
1156		1647
1157	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1158	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1159	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1160	&_sigchld;	1651	&_sigchld;
1161	}	1652	}
1162		1653
1163	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1164	}	1655	};
1165		1656
1166	sub AnyEvent::Base::Child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1167	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1168		1659
1169	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1170	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1171		1662
1172	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
		1669	}
		1670
		1671	# idle emulation is done by simply using a timer, regardless
		1672	# of whether the process is idle or not, and not letting
		1673	# the callback use more than 50% of the time.
		1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
		1677	my (undef, %arg) = @_;
		1678
		1679	my ($cb, $w, $rcb) = $arg{cb};
		1680
		1681	$rcb = sub {
		1682	if ($cb) {
		1683	$w = _time;
		1684	&$cb;
		1685	$w = _time - $w;
		1686
		1687	# never use more then 50% of the time for the idle watcher,
		1688	# within some limits
		1689	$w = 0.0001 if $w < 0.0001;
		1690	$w = 5 if $w > 5;
		1691
		1692	$w = AE::timer $w, 0, $rcb;
		1693	} else {
		1694	# clean up...
		1695	undef $w;
		1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
		1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
		1708	};
		1709	die if $@;
		1710
		1711	&idle
1173	}	1712	}
1174		1713
1175	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1176		1715
1177	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
1178		1717
1179	package AnyEvent::CondVar::Base;	1718	package AnyEvent::CondVar::Base;
1180		1719
1181	use overload	1720	#use overload
1182	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1721	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1183	fallback => 1;	1722	# fallback => 1;
		1723
		1724	# save 300+ kilobytes by dirtily hardcoding overloading
		1725	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1726	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1727	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1728	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1729
		1730	our $WAITING;
1184		1731
1185	sub _send {	1732	sub _send {
1186	# nop	1733	# nop
1187	}	1734	}
1188		1735
…		…
1201	sub ready {	1748	sub ready {
1202	$_[0]{_ae_sent}	1749	$_[0]{_ae_sent}
1203	}	1750	}
1204		1751
1205	sub _wait {	1752	sub _wait {
		1753	$WAITING
		1754	and !$_[0]{_ae_sent}
		1755	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1756
		1757	local $WAITING = 1;
1206	AnyEvent->one_event while !$_[0]{_ae_sent};	1758	AnyEvent->one_event while !$_[0]{_ae_sent};
1207	}	1759	}
1208		1760
1209	sub recv {	1761	sub recv {
1210	$_[0]->_wait;	1762	$_[0]->_wait;
…		…
1212	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1764	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1213	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1765	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1214	}	1766	}
1215		1767
1216	sub cb {	1768	sub cb {
1217	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1769	my $cv = shift;
		1770
		1771	@_
		1772	and $cv->{_ae_cb} = shift
		1773	and $cv->{_ae_sent}
		1774	and (delete $cv->{_ae_cb})->($cv);
		1775
1218	$_[0]{_ae_cb}	1776	$cv->{_ae_cb}
1219	}	1777	}
1220		1778
1221	sub begin {	1779	sub begin {
1222	++$_[0]{_ae_counter};	1780	++$_[0]{_ae_counter};
1223	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1781	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1251	so on.	1809	so on.
1252		1810
1253	=head1 ENVIRONMENT VARIABLES	1811	=head1 ENVIRONMENT VARIABLES
1254		1812
1255	The following environment variables are used by this module or its	1813	The following environment variables are used by this module or its
1256	submodules:	1814	submodules.
		1815
		1816	Note that AnyEvent will remove I<all> environment variables starting with
		1817	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1818	enabled.
1257		1819
1258	=over 4	1820	=over 4
1259		1821
1260	=item C<PERL_ANYEVENT_VERBOSE>	1822	=item C<PERL_ANYEVENT_VERBOSE>
1261		1823
…		…
1268	C<PERL_ANYEVENT_MODEL>.	1830	C<PERL_ANYEVENT_MODEL>.
1269		1831
1270	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1832	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1271	model it chooses.	1833	model it chooses.
1272		1834
		1835	When set to C<8> or higher, then AnyEvent will report extra information on
		1836	which optional modules it loads and how it implements certain features.
		1837
1273	=item C<PERL_ANYEVENT_STRICT>	1838	=item C<PERL_ANYEVENT_STRICT>
1274		1839
1275	AnyEvent does not do much argument checking by default, as thorough	1840	AnyEvent does not do much argument checking by default, as thorough
1276	argument checking is very costly. Setting this variable to a true value	1841	argument checking is very costly. Setting this variable to a true value
1277	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1842	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1278	check the arguments passed to most method calls. If it finds any problems	1843	check the arguments passed to most method calls. If it finds any problems,
1279	it will croak.	1844	it will croak.
1280		1845
1281	In other words, enables "strict" mode.	1846	In other words, enables "strict" mode.
1282		1847
1283	Unlike C<use strict>, it is definitely recommended ot keep it off in	1848	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1284	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1849	>>, it is definitely recommended to keep it off in production. Keeping
1285	developing programs can be very useful, however.	1850	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1851	can be very useful, however.
1286		1852
1287	=item C<PERL_ANYEVENT_MODEL>	1853	=item C<PERL_ANYEVENT_MODEL>
1288		1854
1289	This can be used to specify the event model to be used by AnyEvent, before	1855	This can be used to specify the event model to be used by AnyEvent, before
1290	auto detection and -probing kicks in. It must be a string consisting	1856	auto detection and -probing kicks in. It must be a string consisting
…		…
1333		1899
1334	=item C<PERL_ANYEVENT_MAX_FORKS>	1900	=item C<PERL_ANYEVENT_MAX_FORKS>
1335		1901
1336	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1902	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1337	will create in parallel.	1903	will create in parallel.
		1904
		1905	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1906
		1907	The default value for the C<max_outstanding> parameter for the default DNS
		1908	resolver - this is the maximum number of parallel DNS requests that are
		1909	sent to the DNS server.
		1910
		1911	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1912
		1913	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1914	configuration) in the default resolver. When set to the empty string, no
		1915	default config will be used.
		1916
		1917	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1918
		1919	When neither C<ca_file> nor C<ca_path> was specified during
		1920	L<AnyEvent::TLS> context creation, and either of these environment
		1921	variables exist, they will be used to specify CA certificate locations
		1922	instead of a system-dependent default.
		1923
		1924	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1925
		1926	When these are set to C<1>, then the respective modules are not
		1927	loaded. Mostly good for testing AnyEvent itself.
1338		1928
1339	=back	1929	=back
1340		1930
1341	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1931	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1342		1932
…		…
1400	warn "read: $input\n"; # output what has been read	1990	warn "read: $input\n"; # output what has been read
1401	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1991	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1402	},	1992	},
1403	);	1993	);
1404		1994
1405	my $time_watcher; # can only be used once
1406
1407	sub new_timer {
1408	$timer = AnyEvent->timer (after => 1, cb => sub {	1995	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1409	warn "timeout\n"; # print 'timeout' about every second	1996	warn "timeout\n"; # print 'timeout' at most every second
1410	&new_timer; # and restart the time
1411	});	1997	});
1412	}
1413
1414	new_timer; # create first timer
1415		1998
1416	$cv->recv; # wait until user enters /^q/i	1999	$cv->recv; # wait until user enters /^q/i
1417		2000
1418	=head1 REAL-WORLD EXAMPLE	2001	=head1 REAL-WORLD EXAMPLE
1419		2002
…		…
1550	through AnyEvent. The benchmark creates a lot of timers (with a zero	2133	through AnyEvent. The benchmark creates a lot of timers (with a zero
1551	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2134	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1552	which it is), lets them fire exactly once and destroys them again.	2135	which it is), lets them fire exactly once and destroys them again.
1553		2136
1554	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2137	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1555	distribution.	2138	distribution. It uses the L<AE> interface, which makes a real difference
		2139	for the EV and Perl backends only.
1556		2140
1557	=head3 Explanation of the columns	2141	=head3 Explanation of the columns
1558		2142
1559	I<watcher> is the number of event watchers created/destroyed. Since	2143	I<watcher> is the number of event watchers created/destroyed. Since
1560	different event models feature vastly different performances, each event	2144	different event models feature vastly different performances, each event
…		…
1581	watcher.	2165	watcher.
1582		2166
1583	=head3 Results	2167	=head3 Results
1584		2168
1585	name watchers bytes create invoke destroy comment	2169	name watchers bytes create invoke destroy comment
1586	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2170	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1587	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2171	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1588	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2172	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1589	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2173	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1590	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2174	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1591	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2175	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2176	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2177	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1592	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2178	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1593	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2179	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1594	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2180	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1595	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2181	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1596		2182
1597	=head3 Discussion	2183	=head3 Discussion
1598		2184
1599	The benchmark does I<not> measure scalability of the event loop very	2185	The benchmark does I<not> measure scalability of the event loop very
1600	well. For example, a select-based event loop (such as the pure perl one)	2186	well. For example, a select-based event loop (such as the pure perl one)
…		…
1612	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2198	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1613	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2199	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1614	cycles with POE.	2200	cycles with POE.
1615		2201
1616	C<EV> is the sole leader regarding speed and memory use, which are both	2202	C<EV> is the sole leader regarding speed and memory use, which are both
1617	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2203	maximal/minimal, respectively. When using the L<AE> API there is zero
		2204	overhead (when going through the AnyEvent API create is about 5-6 times
		2205	slower, with other times being equal, so still uses far less memory than
1618	far less memory than any other event loop and is still faster than Event	2206	any other event loop and is still faster than Event natively).
1619	natively.
1620		2207
1621	The pure perl implementation is hit in a few sweet spots (both the	2208	The pure perl implementation is hit in a few sweet spots (both the
1622	constant timeout and the use of a single fd hit optimisations in the perl	2209	constant timeout and the use of a single fd hit optimisations in the perl
1623	interpreter and the backend itself). Nevertheless this shows that it	2210	interpreter and the backend itself). Nevertheless this shows that it
1624	adds very little overhead in itself. Like any select-based backend its	2211	adds very little overhead in itself. Like any select-based backend its
1625	performance becomes really bad with lots of file descriptors (and few of	2212	performance becomes really bad with lots of file descriptors (and few of
1626	them active), of course, but this was not subject of this benchmark.	2213	them active), of course, but this was not subject of this benchmark.
1627		2214
1628	The C<Event> module has a relatively high setup and callback invocation	2215	The C<Event> module has a relatively high setup and callback invocation
1629	cost, but overall scores in on the third place.	2216	cost, but overall scores in on the third place.
		2217
		2218	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2219	when using its pure perl backend.
1630		2220
1631	C<Glib>'s memory usage is quite a bit higher, but it features a	2221	C<Glib>'s memory usage is quite a bit higher, but it features a
1632	faster callback invocation and overall ends up in the same class as	2222	faster callback invocation and overall ends up in the same class as
1633	C<Event>. However, Glib scales extremely badly, doubling the number of	2223	C<Event>. However, Glib scales extremely badly, doubling the number of
1634	watchers increases the processing time by more than a factor of four,	2224	watchers increases the processing time by more than a factor of four,
…		…
1695	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2285	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1696	(1%) are active. This mirrors the activity of large servers with many	2286	(1%) are active. This mirrors the activity of large servers with many
1697	connections, most of which are idle at any one point in time.	2287	connections, most of which are idle at any one point in time.
1698		2288
1699	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2289	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1700	distribution.	2290	distribution. It uses the L<AE> interface, which makes a real difference
		2291	for the EV and Perl backends only.
1701		2292
1702	=head3 Explanation of the columns	2293	=head3 Explanation of the columns
1703		2294
1704	I<sockets> is the number of sockets, and twice the number of "servers" (as	2295	I<sockets> is the number of sockets, and twice the number of "servers" (as
1705	each server has a read and write socket end).	2296	each server has a read and write socket end).
…		…
1712	it to another server. This includes deleting the old timeout and creating	2303	it to another server. This includes deleting the old timeout and creating
1713	a new one that moves the timeout into the future.	2304	a new one that moves the timeout into the future.
1714		2305
1715	=head3 Results	2306	=head3 Results
1716		2307
1717	name sockets create request	2308	name sockets create request
1718	EV 20000 69.01 11.16	2309	EV 20000 62.66 7.99
1719	Perl 20000 73.32 35.87	2310	Perl 20000 68.32 32.64
1720	Event 20000 212.62 257.32	2311	IOAsync 20000 174.06 101.15 epoll
1721	Glib 20000 651.16 1896.30	2312	IOAsync 20000 174.67 610.84 poll
		2313	Event 20000 202.69 242.91
		2314	Glib 20000 557.01 1689.52
1722	POE 20000 349.67 12317.24 uses POE::Loop::Event	2315	POE 20000 341.54 12086.32 uses POE::Loop::Event
1723		2316
1724	=head3 Discussion	2317	=head3 Discussion
1725		2318
1726	This benchmark I<does> measure scalability and overall performance of the	2319	This benchmark I<does> measure scalability and overall performance of the
1727	particular event loop.	2320	particular event loop.
…		…
1729	EV is again fastest. Since it is using epoll on my system, the setup time	2322	EV is again fastest. Since it is using epoll on my system, the setup time
1730	is relatively high, though.	2323	is relatively high, though.
1731		2324
1732	Perl surprisingly comes second. It is much faster than the C-based event	2325	Perl surprisingly comes second. It is much faster than the C-based event
1733	loops Event and Glib.	2326	loops Event and Glib.
		2327
		2328	IO::Async performs very well when using its epoll backend, and still quite
		2329	good compared to Glib when using its pure perl backend.
1734		2330
1735	Event suffers from high setup time as well (look at its code and you will	2331	Event suffers from high setup time as well (look at its code and you will
1736	understand why). Callback invocation also has a high overhead compared to	2332	understand why). Callback invocation also has a high overhead compared to
1737	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2333	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1738	uses select or poll in basically all documented configurations.	2334	uses select or poll in basically all documented configurations.
…		…
1801	=item * C-based event loops perform very well with small number of	2397	=item * C-based event loops perform very well with small number of
1802	watchers, as the management overhead dominates.	2398	watchers, as the management overhead dominates.
1803		2399
1804	=back	2400	=back
1805		2401
		2402	=head2 THE IO::Lambda BENCHMARK
		2403
		2404	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2405	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2406	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2407	shouldn't come as a surprise to anybody). As such, the benchmark is
		2408	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2409	very optimal. But how would AnyEvent compare when used without the extra
		2410	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2411
		2412	The benchmark itself creates an echo-server, and then, for 500 times,
		2413	connects to the echo server, sends a line, waits for the reply, and then
		2414	creates the next connection. This is a rather bad benchmark, as it doesn't
		2415	test the efficiency of the framework or much non-blocking I/O, but it is a
		2416	benchmark nevertheless.
		2417
		2418	name runtime
		2419	Lambda/select 0.330 sec
		2420	+ optimized 0.122 sec
		2421	Lambda/AnyEvent 0.327 sec
		2422	+ optimized 0.138 sec
		2423	Raw sockets/select 0.077 sec
		2424	POE/select, components 0.662 sec
		2425	POE/select, raw sockets 0.226 sec
		2426	POE/select, optimized 0.404 sec
		2427
		2428	AnyEvent/select/nb 0.085 sec
		2429	AnyEvent/EV/nb 0.068 sec
		2430	+state machine 0.134 sec
		2431
		2432	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2433	benchmarks actually make blocking connects and use 100% blocking I/O,
		2434	defeating the purpose of an event-based solution. All of the newly
		2435	written AnyEvent benchmarks use 100% non-blocking connects (using
		2436	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2437	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2438	generally require a lot more bookkeeping and event handling than blocking
		2439	connects (which involve a single syscall only).
		2440
		2441	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2442	offers similar expressive power as POE and IO::Lambda, using conventional
		2443	Perl syntax. This means that both the echo server and the client are 100%
		2444	non-blocking, further placing it at a disadvantage.
		2445
		2446	As you can see, the AnyEvent + EV combination even beats the
		2447	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2448	backend easily beats IO::Lambda and POE.
		2449
		2450	And even the 100% non-blocking version written using the high-level (and
		2451	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2452	higher level ("unoptimised") abstractions by a large margin, even though
		2453	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2454
		2455	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2456	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2457	part of the IO::Lambda distribution and were used without any changes.
		2458
1806		2459
1807	=head1 SIGNALS	2460	=head1 SIGNALS
1808		2461
1809	AnyEvent currently installs handlers for these signals:	2462	AnyEvent currently installs handlers for these signals:
1810		2463
…		…
1813	=item SIGCHLD	2466	=item SIGCHLD
1814		2467
1815	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2468	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1816	emulation for event loops that do not support them natively. Also, some	2469	emulation for event loops that do not support them natively. Also, some
1817	event loops install a similar handler.	2470	event loops install a similar handler.
		2471
		2472	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2473	AnyEvent will reset it to default, to avoid losing child exit statuses.
1818		2474
1819	=item SIGPIPE	2475	=item SIGPIPE
1820		2476
1821	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2477	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1822	when AnyEvent gets loaded.	2478	when AnyEvent gets loaded.
…		…
1834		2490
1835	=back	2491	=back
1836		2492
1837	=cut	2493	=cut
1838		2494
		2495	undef $SIG{CHLD}
		2496	if $SIG{CHLD} eq 'IGNORE';
		2497
1839	$SIG{PIPE} = sub { }	2498	$SIG{PIPE} = sub { }
1840	unless defined $SIG{PIPE};	2499	unless defined $SIG{PIPE};
1841		2500
		2501	=head1 RECOMMENDED/OPTIONAL MODULES
		2502
		2503	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2504	it's built-in modules) are required to use it.
		2505
		2506	That does not mean that AnyEvent won't take advantage of some additional
		2507	modules if they are installed.
		2508
		2509	This section explains which additional modules will be used, and how they
		2510	affect AnyEvent's operation.
		2511
		2512	=over 4
		2513
		2514	=item L<Async::Interrupt>
		2515
		2516	This slightly arcane module is used to implement fast signal handling: To
		2517	my knowledge, there is no way to do completely race-free and quick
		2518	signal handling in pure perl. To ensure that signals still get
		2519	delivered, AnyEvent will start an interval timer to wake up perl (and
		2520	catch the signals) with some delay (default is 10 seconds, look for
		2521	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2522
		2523	If this module is available, then it will be used to implement signal
		2524	catching, which means that signals will not be delayed, and the event loop
		2525	will not be interrupted regularly, which is more efficient (and good for
		2526	battery life on laptops).
		2527
		2528	This affects not just the pure-perl event loop, but also other event loops
		2529	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2530
		2531	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2532	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2533	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2534	does nothing for those backends.
		2535
		2536	=item L<EV>
		2537
		2538	This module isn't really "optional", as it is simply one of the backend
		2539	event loops that AnyEvent can use. However, it is simply the best event
		2540	loop available in terms of features, speed and stability: It supports
		2541	the AnyEvent API optimally, implements all the watcher types in XS, does
		2542	automatic timer adjustments even when no monotonic clock is available,
		2543	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2544	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2545	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2546
		2547	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2548	then this module will do nothing for you.
		2549
		2550	=item L<Guard>
		2551
		2552	The guard module, when used, will be used to implement
		2553	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2554	lot less memory), but otherwise doesn't affect guard operation much. It is
		2555	purely used for performance.
		2556
		2557	=item L<JSON> and L<JSON::XS>
		2558
		2559	One of these modules is required when you want to read or write JSON data
		2560	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2561	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2562
		2563	=item L<Net::SSLeay>
		2564
		2565	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2566	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2567	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2568
		2569	=item L<Time::HiRes>
		2570
		2571	This module is part of perl since release 5.008. It will be used when the
		2572	chosen event library does not come with a timing source on it's own. The
		2573	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2574	try to use a monotonic clock for timing stability.
		2575
		2576	=back
		2577
1842		2578
1843	=head1 FORK	2579	=head1 FORK
1844		2580
1845	Most event libraries are not fork-safe. The ones who are usually are	2581	Most event libraries are not fork-safe. The ones who are usually are
1846	because they rely on inefficient but fork-safe C<select> or C<poll>	2582	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1847	calls. Only L<EV> is fully fork-aware.	2583	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2584	are usually badly thought-out hacks that are incompatible with fork in
		2585	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2586	continue event-processing in both parent and child (or both, if you know
		2587	what you are doing).
		2588
		2589	This means that, in general, you cannot fork and do event processing in
		2590	the child if the event library was initialised before the fork (which
		2591	usually happens when the first AnyEvent watcher is created, or the library
		2592	is loaded).
1848		2593
1849	If you have to fork, you must either do so I<before> creating your first	2594	If you have to fork, you must either do so I<before> creating your first
1850	watcher OR you must not use AnyEvent at all in the child.	2595	watcher OR you must not use AnyEvent at all in the child OR you must do
		2596	something completely out of the scope of AnyEvent.
		2597
		2598	The problem of doing event processing in the parent I<and> the child
		2599	is much more complicated: even for backends that I<are> fork-aware or
		2600	fork-safe, their behaviour is not usually what you want: fork clones all
		2601	watchers, that means all timers, I/O watchers etc. are active in both
		2602	parent and child, which is almost never what you want. USing C<exec>
		2603	to start worker children from some kind of manage rprocess is usually
		2604	preferred, because it is much easier and cleaner, at the expense of having
		2605	to have another binary.
1851		2606
1852		2607
1853	=head1 SECURITY CONSIDERATIONS	2608	=head1 SECURITY CONSIDERATIONS
1854		2609
1855	AnyEvent can be forced to load any event model via	2610	AnyEvent can be forced to load any event model via
…		…
1867	use AnyEvent;	2622	use AnyEvent;
1868		2623
1869	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2624	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1870	be used to probe what backend is used and gain other information (which is	2625	be used to probe what backend is used and gain other information (which is
1871	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2626	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1872	$ENV{PERL_ANYEGENT_STRICT}.	2627	$ENV{PERL_ANYEVENT_STRICT}.
		2628
		2629	Note that AnyEvent will remove I<all> environment variables starting with
		2630	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2631	enabled.
1873		2632
1874		2633
1875	=head1 BUGS	2634	=head1 BUGS
1876		2635
1877	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2636	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1889	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2648	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1890		2649
1891	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2650	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1892	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2651	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1893	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2652	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1894	L<AnyEvent::Impl::POE>.	2653	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1895		2654
1896	Non-blocking file handles, sockets, TCP clients and	2655	Non-blocking file handles, sockets, TCP clients and
1897	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2656	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1898		2657
1899	Asynchronous DNS: L<AnyEvent::DNS>.	2658	Asynchronous DNS: L<AnyEvent::DNS>.
1900		2659
1901	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2660	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2661	L<Coro::Event>,
1902		2662
1903	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2663	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2664	L<AnyEvent::HTTP>.
1904		2665
1905		2666
1906	=head1 AUTHOR	2667	=head1 AUTHOR
1907		2668
1908	Marc Lehmann <schmorp@schmorp.de>	2669	Marc Lehmann <schmorp@schmorp.de>

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