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Revision 1.200 by root, Wed Apr 1 14:02:27 2009 UTC vs.
Revision 1.323 by root, Thu May 20 21:22:20 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, 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	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
		15	# file handle or descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		17
		18	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		21
16	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		24
		25	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	26	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		27
		28	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	29	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	30	my ($pid, $status) = @_;
23	...	31	...
24	});	32	});
		33
		34	# called when event loop idle (if applicable)
		35	my $w = AnyEvent->idle (cb => sub { ... });
25		36
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	37	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	38	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	39	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	40	# use a condvar in callback mode:
…		…
32	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
33		44
34	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
35	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
36	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	There is a mailinglist for discussing all things AnyEvent, and an IRC
		52	channel, too.
		53
		54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
37		56
38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
39		58
40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
41	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
165	my variables are only visible after the statement in which they are	184	my variables are only visible after the statement in which they are
166	declared.	185	declared.
167		186
168	=head2 I/O WATCHERS	187	=head2 I/O WATCHERS
169		188
		189	$w = AnyEvent->io (
		190	fh => <filehandle_or_fileno>,
		191	poll => <"r" or "w">,
		192	cb => <callback>,
		193	);
		194
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	195	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	196	with the following mandatory key-value pairs as arguments:
172		197
173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	198	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
174	for events (AnyEvent might or might not keep a reference to this file	199	for events (AnyEvent might or might not keep a reference to this file
175	handle). Note that only file handles pointing to things for which	200	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	201	non-blocking operation makes sense are allowed. This includes sockets,
177	most character devices, pipes, fifos and so on, but not for example files	202	most character devices, pipes, fifos and so on, but not for example files
178	or block devices.	203	or block devices.
…		…
203	undef $w;	228	undef $w;
204	});	229	});
205		230
206	=head2 TIME WATCHERS	231	=head2 TIME WATCHERS
207		232
		233	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		234
		235	$w = AnyEvent->timer (
		236	after => <fractional_seconds>,
		237	interval => <fractional_seconds>,
		238	cb => <callback>,
		239	);
		240
208	You can create a time watcher by calling the C<< AnyEvent->timer >>	241	You can create a time watcher by calling the C<< AnyEvent->timer >>
209	method with the following mandatory arguments:	242	method with the following mandatory arguments:
210		243
211	C<after> specifies after how many seconds (fractional values are	244	C<after> specifies after how many seconds (fractional values are
212	supported) the callback should be invoked. C<cb> is the callback to invoke	245	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
320	In either case, if you care (and in most cases, you don't), then you	353	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	354	can get whatever behaviour you want with any event loop, by taking the
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	355	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	356	account.
324		357
		358	=item AnyEvent->now_update
		359
		360	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		361	the current time for each loop iteration (see the discussion of L<<
		362	AnyEvent->now >>, above).
		363
		364	When a callback runs for a long time (or when the process sleeps), then
		365	this "current" time will differ substantially from the real time, which
		366	might affect timers and time-outs.
		367
		368	When this is the case, you can call this method, which will update the
		369	event loop's idea of "current time".
		370
		371	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		372	when mod_perl executes the script, then the event loop will have the wrong
		373	idea about the "current time" (being potentially far in the past, when the
		374	script ran the last time). In that case you should arrange a call to C<<
		375	AnyEvent->now_update >> each time the web server process wakes up again
		376	(e.g. at the start of your script, or in a handler).
		377
		378	Note that updating the time I<might> cause some events to be handled.
		379
325	=back	380	=back
326		381
327	=head2 SIGNAL WATCHERS	382	=head2 SIGNAL WATCHERS
		383
		384	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
328		385
329	You can watch for signals using a signal watcher, C<signal> is the signal	386	You can watch for signals using a signal watcher, C<signal> is the signal
330	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	387	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
331	callback to be invoked whenever a signal occurs.	388	callback to be invoked whenever a signal occurs.
332		389
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	395	invocation, and callback invocation will be synchronous. Synchronous means
339	that it might take a while until the signal gets handled by the process,	396	that it might take a while until the signal gets handled by the process,
340	but it is guaranteed not to interrupt any other callbacks.	397	but it is guaranteed not to interrupt any other callbacks.
341		398
342	The main advantage of using these watchers is that you can share a signal	399	The main advantage of using these watchers is that you can share a signal
343	between multiple watchers.	400	between multiple watchers, and AnyEvent will ensure that signals will not
		401	interrupt your program at bad times.
344		402
345	This watcher might use C<%SIG>, so programs overwriting those signals	403	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	404	so programs overwriting those signals directly will likely not work
		405	correctly.
347		406
348	Example: exit on SIGINT	407	Example: exit on SIGINT
349		408
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	409	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351		410
		411	=head3 Restart Behaviour
		412
		413	While restart behaviour is up to the event loop implementation, most will
		414	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		415	pure perl implementation).
		416
		417	=head3 Safe/Unsafe Signals
		418
		419	Perl signals can be either "safe" (synchronous to opcode handling) or
		420	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		421	latter might corrupt your memory.
		422
		423	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		424	i.e. they will not interrupt your running perl program but will only be
		425	called as part of the normal event handling (just like timer, I/O etc.
		426	callbacks, too).
		427
		428	=head3 Signal Races, Delays and Workarounds
		429
		430	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		431	callbacks to signals in a generic way, which is a pity, as you cannot
		432	do race-free signal handling in perl, requiring C libraries for
		433	this. AnyEvent will try to do it's best, which means in some cases,
		434	signals will be delayed. The maximum time a signal might be delayed is
		435	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		436	variable can be changed only before the first signal watcher is created,
		437	and should be left alone otherwise. This variable determines how often
		438	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		439	will cause fewer spurious wake-ups, which is better for power and CPU
		440	saving.
		441
		442	All these problems can be avoided by installing the optional
		443	L<Async::Interrupt> module, which works with most event loops. It will not
		444	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		445	(and not with L<POE> currently, as POE does it's own workaround with
		446	one-second latency). For those, you just have to suffer the delays.
		447
352	=head2 CHILD PROCESS WATCHERS	448	=head2 CHILD PROCESS WATCHERS
353		449
		450	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		451
354	You can also watch on a child process exit and catch its exit status.	452	You can also watch on a child process exit and catch its exit status.
355		453
356	The child process is specified by the C<pid> argument (if set to C<0>, it	454	The child process is specified by the C<pid> argument (one some backends,
357	watches for any child process exit). The watcher will triggered only when	455	using C<0> watches for any child process exit, on others this will
358	the child process has finished and an exit status is available, not on	456	croak). The watcher will be triggered only when the child process has
359	any trace events (stopped/continued).	457	finished and an exit status is available, not on any trace events
		458	(stopped/continued).
360		459
361	The callback will be called with the pid and exit status (as returned by	460	The callback will be called with the pid and exit status (as returned by
362	waitpid), so unlike other watcher types, you I<can> rely on child watcher	461	waitpid), so unlike other watcher types, you I<can> rely on child watcher
363	callback arguments.	462	callback arguments.
364		463
…		…
369		468
370	There is a slight catch to child watchers, however: you usually start them	469	There is a slight catch to child watchers, however: you usually start them
371	I<after> the child process was created, and this means the process could	470	I<after> the child process was created, and this means the process could
372	have exited already (and no SIGCHLD will be sent anymore).	471	have exited already (and no SIGCHLD will be sent anymore).
373		472
374	Not all event models handle this correctly (POE doesn't), but even for	473	Not all event models handle this correctly (neither POE nor IO::Async do,
		474	see their AnyEvent::Impl manpages for details), but even for event models
375	event models that I<do> handle this correctly, they usually need to be	475	that I<do> handle this correctly, they usually need to be loaded before
376	loaded before the process exits (i.e. before you fork in the first place).	476	the process exits (i.e. before you fork in the first place). AnyEvent's
		477	pure perl event loop handles all cases correctly regardless of when you
		478	start the watcher.
377		479
378	This means you cannot create a child watcher as the very first thing in an	480	This means you cannot create a child watcher as the very first
379	AnyEvent program, you I<have> to create at least one watcher before you	481	thing in an AnyEvent program, you I<have> to create at least one
380	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	482	watcher before you C<fork> the child (alternatively, you can call
		483	C<AnyEvent::detect>).
		484
		485	As most event loops do not support waiting for child events, they will be
		486	emulated by AnyEvent in most cases, in which the latency and race problems
		487	mentioned in the description of signal watchers apply.
381		488
382	Example: fork a process and wait for it	489	Example: fork a process and wait for it
383		490
384	my $done = AnyEvent->condvar;	491	my $done = AnyEvent->condvar;
385		492
…		…
395	);	502	);
396		503
397	# do something else, then wait for process exit	504	# do something else, then wait for process exit
398	$done->recv;	505	$done->recv;
399		506
		507	=head2 IDLE WATCHERS
		508
		509	$w = AnyEvent->idle (cb => <callback>);
		510
		511	Repeatedly invoke the callback after the process becomes idle, until
		512	either the watcher is destroyed or new events have been detected.
		513
		514	Idle watchers are useful when there is a need to do something, but it
		515	is not so important (or wise) to do it instantly. The callback will be
		516	invoked only when there is "nothing better to do", which is usually
		517	defined as "all outstanding events have been handled and no new events
		518	have been detected". That means that idle watchers ideally get invoked
		519	when the event loop has just polled for new events but none have been
		520	detected. Instead of blocking to wait for more events, the idle watchers
		521	will be invoked.
		522
		523	Unfortunately, most event loops do not really support idle watchers (only
		524	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		525	will simply call the callback "from time to time".
		526
		527	Example: read lines from STDIN, but only process them when the
		528	program is otherwise idle:
		529
		530	my @lines; # read data
		531	my $idle_w;
		532	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		533	push @lines, scalar <STDIN>;
		534
		535	# start an idle watcher, if not already done
		536	$idle_w ||= AnyEvent->idle (cb => sub {
		537	# handle only one line, when there are lines left
		538	if (my $line = shift @lines) {
		539	print "handled when idle: $line";
		540	} else {
		541	# otherwise disable the idle watcher again
		542	undef $idle_w;
		543	}
		544	});
		545	});
		546
400	=head2 CONDITION VARIABLES	547	=head2 CONDITION VARIABLES
		548
		549	$cv = AnyEvent->condvar;
		550
		551	$cv->send (<list>);
		552	my @res = $cv->recv;
401		553
402	If you are familiar with some event loops you will know that all of them	554	If you are familiar with some event loops you will know that all of them
403	require you to run some blocking "loop", "run" or similar function that	555	require you to run some blocking "loop", "run" or similar function that
404	will actively watch for new events and call your callbacks.	556	will actively watch for new events and call your callbacks.
405		557
406	AnyEvent is different, it expects somebody else to run the event loop and	558	AnyEvent is slightly different: it expects somebody else to run the event
407	will only block when necessary (usually when told by the user).	559	loop and will only block when necessary (usually when told by the user).
408		560
409	The instrument to do that is called a "condition variable", so called	561	The instrument to do that is called a "condition variable", so called
410	because they represent a condition that must become true.	562	because they represent a condition that must become true.
411		563
		564	Now is probably a good time to look at the examples further below.
		565
412	Condition variables can be created by calling the C<< AnyEvent->condvar	566	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	567	>> 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	568	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	569	becomes true, with the condition variable as the first argument (but not
417	the results).	570	the results).
418		571
419	After creation, the condition variable is "false" until it becomes "true"	572	After creation, the condition variable is "false" until it becomes "true"
…		…
424	Condition variables are similar to callbacks, except that you can	577	Condition variables are similar to callbacks, except that you can
425	optionally wait for them. They can also be called merge points - points	578	optionally wait for them. They can also be called merge points - points
426	in time where multiple outstanding events have been processed. And yet	579	in time where multiple outstanding events have been processed. And yet
427	another way to call them is transactions - each condition variable can be	580	another way to call them is transactions - each condition variable can be
428	used to represent a transaction, which finishes at some point and delivers	581	used to represent a transaction, which finishes at some point and delivers
429	a result.	582	a result. And yet some people know them as "futures" - a promise to
		583	compute/deliver something that you can wait for.
430		584
431	Condition variables are very useful to signal that something has finished,	585	Condition variables are very useful to signal that something has finished,
432	for example, if you write a module that does asynchronous http requests,	586	for example, if you write a module that does asynchronous http requests,
433	then a condition variable would be the ideal candidate to signal the	587	then a condition variable would be the ideal candidate to signal the
434	availability of results. The user can either act when the callback is	588	availability of results. The user can either act when the callback is
…		…
455	eventually calls C<< -> send >>, and the "consumer side", which waits	609	eventually calls C<< -> send >>, and the "consumer side", which waits
456	for the send to occur.	610	for the send to occur.
457		611
458	Example: wait for a timer.	612	Example: wait for a timer.
459		613
460	# wait till the result is ready	614	# condition: "wait till the timer is fired"
461	my $result_ready = AnyEvent->condvar;	615	my $timer_fired = AnyEvent->condvar;
462		616
463	# do something such as adding a timer	617	# create the timer - we could wait for, say
464	# or socket watcher the calls $result_ready->send	618	# a handle becomign ready, or even an
465	# when the "result" is ready.	619	# AnyEvent::HTTP request to finish, but
466	# in this case, we simply use a timer:	620	# in this case, we simply use a timer:
467	my $w = AnyEvent->timer (	621	my $w = AnyEvent->timer (
468	after => 1,	622	after => 1,
469	cb => sub { $result_ready->send },	623	cb => sub { $timer_fired->send },
470	);	624	);
471		625
472	# this "blocks" (while handling events) till the callback	626	# this "blocks" (while handling events) till the callback
473	# calls send	627	# calls ->send
474	$result_ready->recv;	628	$timer_fired->recv;
475		629
476	Example: wait for a timer, but take advantage of the fact that	630	Example: wait for a timer, but take advantage of the fact that condition
477	condition variables are also code references.	631	variables are also callable directly.
478		632
479	my $done = AnyEvent->condvar;	633	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	634	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	635	$done->recv;
482		636
…		…
488		642
489	...	643	...
490		644
491	my @info = $couchdb->info->recv;	645	my @info = $couchdb->info->recv;
492		646
493	And this is how you would just ste a callback to be called whenever the	647	And this is how you would just set a callback to be called whenever the
494	results are available:	648	results are available:
495		649
496	$couchdb->info->cb (sub {	650	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	651	my @info = $_[0]->recv;
498	});	652	});
…		…
516	immediately from within send.	670	immediately from within send.
517		671
518	Any arguments passed to the C<send> call will be returned by all	672	Any arguments passed to the C<send> call will be returned by all
519	future C<< ->recv >> calls.	673	future C<< ->recv >> calls.
520		674
521	Condition variables are overloaded so one can call them directly	675	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	676	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	677	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		678
530	=item $cv->croak ($error)	679	=item $cv->croak ($error)
531		680
532	Similar to send, but causes all call's to C<< ->recv >> to invoke	681	Similar to send, but causes all call's to C<< ->recv >> to invoke
533	C<Carp::croak> with the given error message/object/scalar.	682	C<Carp::croak> with the given error message/object/scalar.
534		683
535	This can be used to signal any errors to the condition variable	684	This can be used to signal any errors to the condition variable
536	user/consumer.	685	user/consumer. Doing it this way instead of calling C<croak> directly
		686	delays the error detetcion, but has the overwhelmign advantage that it
		687	diagnoses the error at the place where the result is expected, and not
		688	deep in some event clalback without connection to the actual code causing
		689	the problem.
537		690
538	=item $cv->begin ([group callback])	691	=item $cv->begin ([group callback])
539		692
540	=item $cv->end	693	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		694
544	These two methods can be used to combine many transactions/events into	695	These two methods can be used to combine many transactions/events into
545	one. For example, a function that pings many hosts in parallel might want	696	one. For example, a function that pings many hosts in parallel might want
546	to use a condition variable for the whole process.	697	to use a condition variable for the whole process.
547		698
548	Every call to C<< ->begin >> will increment a counter, and every call to	699	Every call to C<< ->begin >> will increment a counter, and every call to
549	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	700	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
550	>>, the (last) callback passed to C<begin> will be executed. That callback	701	>>, the (last) callback passed to C<begin> will be executed, passing the
551	is I<supposed> to call C<< ->send >>, but that is not required. If no	702	condvar as first argument. That callback is I<supposed> to call C<< ->send
552	callback was set, C<send> will be called without any arguments.	703	>>, but that is not required. If no group callback was set, C<send> will
		704	be called without any arguments.
553		705
554	Let's clarify this with the ping example:	706	You can think of C<< $cv->send >> giving you an OR condition (one call
		707	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		708	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		709
		710	Let's start with a simple example: you have two I/O watchers (for example,
		711	STDOUT and STDERR for a program), and you want to wait for both streams to
		712	close before activating a condvar:
555		713
556	my $cv = AnyEvent->condvar;	714	my $cv = AnyEvent->condvar;
557		715
		716	$cv->begin; # first watcher
		717	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		718	defined sysread $fh1, my $buf, 4096
		719	or $cv->end;
		720	});
		721
		722	$cv->begin; # second watcher
		723	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		724	defined sysread $fh2, my $buf, 4096
		725	or $cv->end;
		726	});
		727
		728	$cv->recv;
		729
		730	This works because for every event source (EOF on file handle), there is
		731	one call to C<begin>, so the condvar waits for all calls to C<end> before
		732	sending.
		733
		734	The ping example mentioned above is slightly more complicated, as the
		735	there are results to be passwd back, and the number of tasks that are
		736	begung can potentially be zero:
		737
		738	my $cv = AnyEvent->condvar;
		739
558	my %result;	740	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	741	$cv->begin (sub { shift->send (\%result) });
560		742
561	for my $host (@list_of_hosts) {	743	for my $host (@list_of_hosts) {
562	$cv->begin;	744	$cv->begin;
563	ping_host_then_call_callback $host, sub {	745	ping_host_then_call_callback $host, sub {
564	$result{$host} = ...;	746	$result{$host} = ...;
…		…
579	loop, which serves two important purposes: first, it sets the callback	761	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	762	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	763	C<send> is called even when C<no> hosts are being pinged (the loop
582	doesn't execute once).	764	doesn't execute once).
583		765
584	This is the general pattern when you "fan out" into multiple subrequests:	766	This is the general pattern when you "fan out" into multiple (but
585	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	767	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
586	is called at least once, and then, for each subrequest you start, call	768	the callback and ensure C<end> is called at least once, and then, for each
587	C<begin> and for each subrequest you finish, call C<end>.	769	subrequest you start, call C<begin> and for each subrequest you finish,
		770	call C<end>.
588		771
589	=back	772	=back
590		773
591	=head3 METHODS FOR CONSUMERS	774	=head3 METHODS FOR CONSUMERS
592		775
…		…
608	function will call C<croak>.	791	function will call C<croak>.
609		792
610	In list context, all parameters passed to C<send> will be returned,	793	In list context, all parameters passed to C<send> will be returned,
611	in scalar context only the first one will be returned.	794	in scalar context only the first one will be returned.
612		795
		796	Note that doing a blocking wait in a callback is not supported by any
		797	event loop, that is, recursive invocation of a blocking C<< ->recv
		798	>> is not allowed, and the C<recv> call will C<croak> if such a
		799	condition is detected. This condition can be slightly loosened by using
		800	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		801	any thread that doesn't run the event loop itself.
		802
613	Not all event models support a blocking wait - some die in that case	803	Not all event models support a blocking wait - some die in that case
614	(programs might want to do that to stay interactive), so I<if you are	804	(programs might want to do that to stay interactive), so I<if you are
615	using this from a module, never require a blocking wait>, but let the	805	using this from a module, never require a blocking wait>. Instead, let the
616	caller decide whether the call will block or not (for example, by coupling	806	caller decide whether the call will block or not (for example, by coupling
617	condition variables with some kind of request results and supporting	807	condition variables with some kind of request results and supporting
618	callbacks so the caller knows that getting the result will not block,	808	callbacks so the caller knows that getting the result will not block,
619	while still supporting blocking waits if the caller so desires).	809	while still supporting blocking waits if the caller so desires).
620		810
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	811	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	812	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	813	time). This will work even when the event loop does not support blocking
635	waits otherwise.	814	waits otherwise.
636		815
…		…
642	=item $cb = $cv->cb ($cb->($cv))	821	=item $cb = $cv->cb ($cb->($cv))
643		822
644	This is a mutator function that returns the callback set and optionally	823	This is a mutator function that returns the callback set and optionally
645	replaces it before doing so.	824	replaces it before doing so.
646		825
647	The callback will be called when the condition becomes "true", i.e. when	826	The callback will be called when the condition becomes (or already was)
648	C<send> or C<croak> are called, with the only argument being the condition	827	"true", i.e. when C<send> or C<croak> are called (or were called), with
649	variable itself. Calling C<recv> inside the callback or at any later time	828	the only argument being the condition variable itself. Calling C<recv>
650	is guaranteed not to block.	829	inside the callback or at any later time is guaranteed not to block.
651		830
652	=back	831	=back
653		832
		833	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		834
		835	The available backend classes are (every class has its own manpage):
		836
		837	=over 4
		838
		839	=item Backends that are autoprobed when no other event loop can be found.
		840
		841	EV is the preferred backend when no other event loop seems to be in
		842	use. If EV is not installed, then AnyEvent will fall back to its own
		843	pure-perl implementation, which is available everywhere as it comes with
		844	AnyEvent itself.
		845
		846	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		847	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		848
		849	=item Backends that are transparently being picked up when they are used.
		850
		851	These will be used when they are currently loaded when the first watcher
		852	is created, in which case it is assumed that the application is using
		853	them. This means that AnyEvent will automatically pick the right backend
		854	when the main program loads an event module before anything starts to
		855	create watchers. Nothing special needs to be done by the main program.
		856
		857	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		858	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		859	AnyEvent::Impl::Tk based on Tk, very broken.
		860	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		861	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		862	AnyEvent::Impl::Irssi used when running within irssi.
		863
		864	=item Backends with special needs.
		865
		866	Qt requires the Qt::Application to be instantiated first, but will
		867	otherwise be picked up automatically. As long as the main program
		868	instantiates the application before any AnyEvent watchers are created,
		869	everything should just work.
		870
		871	AnyEvent::Impl::Qt based on Qt.
		872
		873	Support for IO::Async can only be partial, as it is too broken and
		874	architecturally limited to even support the AnyEvent API. It also
		875	is the only event loop that needs the loop to be set explicitly, so
		876	it can only be used by a main program knowing about AnyEvent. See
		877	L<AnyEvent::Impl::Async> for the gory details.
		878
		879	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		880
		881	=item Event loops that are indirectly supported via other backends.
		882
		883	Some event loops can be supported via other modules:
		884
		885	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		886
		887	B<WxWidgets> has no support for watching file handles. However, you can
		888	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		889	polls 20 times per second, which was considered to be too horrible to even
		890	consider for AnyEvent.
		891
		892	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		893	backend, so it can be supported through POE.
		894
		895	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		896	load L<POE> when detecting them, in the hope that POE will pick them up,
		897	in which case everything will be automatic.
		898
		899	=back
		900
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	901	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		902
		903	These are not normally required to use AnyEvent, but can be useful to
		904	write AnyEvent extension modules.
		905
656	=over 4	906	=over 4
657		907
658	=item $AnyEvent::MODEL	908	=item $AnyEvent::MODEL
659		909
660	Contains C<undef> until the first watcher is being created. Then it	910	Contains C<undef> until the first watcher is being created, before the
		911	backend has been autodetected.
		912
661	contains the event model that is being used, which is the name of the	913	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	914	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	915	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	916	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		917	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		918
687	=item AnyEvent::detect	919	=item AnyEvent::detect
688		920
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	921	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	if necessary. You should only call this function right before you would	922	if necessary. You should only call this function right before you would
691	have created an AnyEvent watcher anyway, that is, as late as possible at	923	have created an AnyEvent watcher anyway, that is, as late as possible at
692	runtime.	924	runtime, and not e.g. while initialising of your module.
		925
		926	If you need to do some initialisation before AnyEvent watchers are
		927	created, use C<post_detect>.
693		928
694	=item $guard = AnyEvent::post_detect { BLOCK }	929	=item $guard = AnyEvent::post_detect { BLOCK }
695		930
696	Arranges for the code block to be executed as soon as the event model is	931	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	932	autodetected (or immediately if this has already happened).
698		933
		934	The block will be executed I<after> the actual backend has been detected
		935	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		936	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		937	other initialisations - see the sources of L<AnyEvent::Strict> or
		938	L<AnyEvent::AIO> to see how this is used.
		939
		940	The most common usage is to create some global watchers, without forcing
		941	event module detection too early, for example, L<AnyEvent::AIO> creates
		942	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		943	avoid autodetecting the event module at load time.
		944
699	If called in scalar or list context, then it creates and returns an object	945	If called in scalar or list context, then it creates and returns an object
700	that automatically removes the callback again when it is destroyed. See	946	that automatically removes the callback again when it is destroyed (or
		947	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
701	L<Coro::BDB> for a case where this is useful.	948	a case where this is useful.
		949
		950	Example: Create a watcher for the IO::AIO module and store it in
		951	C<$WATCHER>. Only do so after the event loop is initialised, though.
		952
		953	our WATCHER;
		954
		955	my $guard = AnyEvent::post_detect {
		956	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		957	};
		958
		959	# the ||= is important in case post_detect immediately runs the block,
		960	# as to not clobber the newly-created watcher. assigning both watcher and
		961	# post_detect guard to the same variable has the advantage of users being
		962	# able to just C<undef $WATCHER> if the watcher causes them grief.
		963
		964	$WATCHER ||= $guard;
702		965
703	=item @AnyEvent::post_detect	966	=item @AnyEvent::post_detect
704		967
705	If there are any code references in this array (you can C<push> to it	968	If there are any code references in this array (you can C<push> to it
706	before or after loading AnyEvent), then they will called directly after	969	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	970	the event loop has been chosen.
708		971
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	972	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	if it contains a true value then the event loop has already been detected,	973	if it is defined then the event loop has already been detected, and the
711	and the array will be ignored.	974	array will be ignored.
712		975
713	Best use C<AnyEvent::post_detect { BLOCK }> instead.	976	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		977	it, as it takes care of these details.
		978
		979	This variable is mainly useful for modules that can do something useful
		980	when AnyEvent is used and thus want to know when it is initialised, but do
		981	not need to even load it by default. This array provides the means to hook
		982	into AnyEvent passively, without loading it.
		983
		984	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		985	together, you could put this into Coro (this is the actual code used by
		986	Coro to accomplish this):
		987
		988	if (defined $AnyEvent::MODEL) {
		989	# AnyEvent already initialised, so load Coro::AnyEvent
		990	require Coro::AnyEvent;
		991	} else {
		992	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		993	# as soon as it is
		994	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		995	}
714		996
715	=back	997	=back
716		998
717	=head1 WHAT TO DO IN A MODULE	999	=head1 WHAT TO DO IN A MODULE
718		1000
…		…
773		1055
774		1056
775	=head1 OTHER MODULES	1057	=head1 OTHER MODULES
776		1058
777	The following is a non-exhaustive list of additional modules that use	1059	The following is a non-exhaustive list of additional modules that use
778	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1060	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
779	in the same program. Some of the modules come with AnyEvent, some are	1061	modules and other event loops in the same program. Some of the modules
780	available via CPAN.	1062	come with AnyEvent, most are available via CPAN.
781		1063
782	=over 4	1064	=over 4
783		1065
784	=item L<AnyEvent::Util>	1066	=item L<AnyEvent::Util>
785		1067
…		…
794		1076
795	=item L<AnyEvent::Handle>	1077	=item L<AnyEvent::Handle>
796		1078
797	Provide read and write buffers, manages watchers for reads and writes,	1079	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	1080	supports raw and formatted I/O, I/O queued and fully transparent and
799	non-blocking SSL/TLS.	1081	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		1082
801	=item L<AnyEvent::DNS>	1083	=item L<AnyEvent::DNS>
802		1084
803	Provides rich asynchronous DNS resolver capabilities.	1085	Provides rich asynchronous DNS resolver capabilities.
804		1086
		1087	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1088
		1089	Implement event-based interfaces to the protocols of the same name (for
		1090	the curious, IGS is the International Go Server and FCP is the Freenet
		1091	Client Protocol).
		1092
		1093	=item L<AnyEvent::Handle::UDP>
		1094
		1095	Here be danger!
		1096
		1097	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1098	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1099	it's use of a stream-based API with a protocol that isn't streamable, that
		1100	the only way to improve it is to delete it.
		1101
		1102	It features data corruption (but typically only under load) and general
		1103	confusion. On top, the author is not only clueless about UDP but also
		1104	fact-resistant - some gems of his understanding: "connect doesn't work
		1105	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1106	packets", "I don't need to implement proper error checking as UDP doesn't
		1107	support error checking" and so on - he doesn't even understand what's
		1108	wrong with his module when it is explained to him.
		1109
805	=item L<AnyEvent::HTTP>	1110	=item L<AnyEvent::DBI>
806		1111
807	A simple-to-use HTTP library that is capable of making a lot of concurrent	1112	Executes L<DBI> requests asynchronously in a proxy process for you,
808	HTTP requests.	1113	notifying you in an event-bnased way when the operation is finished.
		1114
		1115	=item L<AnyEvent::AIO>
		1116
		1117	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1118	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1119	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1120	file I/O, and much more.
809		1121
810	=item L<AnyEvent::HTTPD>	1122	=item L<AnyEvent::HTTPD>
811		1123
812	Provides a simple web application server framework.	1124	A simple embedded webserver.
813		1125
814	=item L<AnyEvent::FastPing>	1126	=item L<AnyEvent::FastPing>
815		1127
816	The fastest ping in the west.	1128	The fastest ping in the west.
817		1129
818	=item L<AnyEvent::DBI>
819
820	Executes L<DBI> requests asynchronously in a proxy process.
821
822	=item L<AnyEvent::AIO>
823
824	Truly asynchronous I/O, should be in the toolbox of every event
825	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
826	together.
827
828	=item L<AnyEvent::BDB>
829
830	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
831	L<BDB> and AnyEvent together.
832
833	=item L<AnyEvent::GPSD>
834
835	A non-blocking interface to gpsd, a daemon delivering GPS information.
836
837	=item L<AnyEvent::IGS>
838
839	A non-blocking interface to the Internet Go Server protocol (used by
840	L<App::IGS>).
841
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>
851
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.
854
855	=item L<Event::ExecFlow>
856
857	High level API for event-based execution flow control.
858
859	=item L<Coro>	1130	=item L<Coro>
860		1131
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1132	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1133
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1134	=back
868		1135
869	=cut	1136	=cut
870		1137
871	package AnyEvent;	1138	package AnyEvent;
872		1139
873	no warnings;	1140	# basically a tuned-down version of common::sense
874	use strict qw(vars subs);	1141	sub common_sense {
		1142	# from common:.sense 1.0
		1143	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
		1144	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1145	$^H |= 0x00000600;
		1146	}
875		1147
		1148	BEGIN { AnyEvent::common_sense }
		1149
876	use Carp;	1150	use Carp ();
877		1151
878	our $VERSION = 4.35;	1152	our $VERSION = '5.261';
879	our $MODEL;	1153	our $MODEL;
880		1154
881	our $AUTOLOAD;	1155	our $AUTOLOAD;
882	our @ISA;	1156	our @ISA;
883		1157
884	our @REGISTRY;	1158	our @REGISTRY;
885		1159
886	our $WIN32;	1160	our $VERBOSE;
887		1161
888	BEGIN {	1162	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1163	require "AnyEvent/constants.pl";
890	eval "sub WIN32(){ $win32 }";
891	}
892		1164
		1165	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
		1166
		1167	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1168	if ${^TAINT};
		1169
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1170	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1171
		1172	}
		1173
		1174	our $MAX_SIGNAL_LATENCY = 10;
894		1175
895	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1176	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
896		1177
897	{	1178	{
898	my $idx;	1179	my $idx;
…		…
900	for reverse split /\s*,\s*/,	1181	for reverse split /\s*,\s*/,
901	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1182	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
902	}	1183	}
903		1184
904	my @models = (	1185	my @models = (
905	[EV:: => AnyEvent::Impl::EV::],	1186	[EV:: => AnyEvent::Impl::EV:: , 1],
906	[Event:: => AnyEvent::Impl::Event::],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1187	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
908	# everything below here will not be autoprobed	1188	# everything below here will not (normally) be autoprobed
909	# as the pureperl backend should work everywhere	1189	# as the pureperl backend should work everywhere
910	# and is usually faster	1190	# and is usually faster
		1191	[Event:: => AnyEvent::Impl::Event::, 1],
		1192	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1193	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1194	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1195	[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	1196	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1197	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1198	[Wx:: => AnyEvent::Impl::POE::],
917	[Prima:: => AnyEvent::Impl::POE::],	1199	[Prima:: => AnyEvent::Impl::POE::],
		1200	# IO::Async is just too broken - we would need workarounds for its
		1201	# byzantine signal and broken child handling, among others.
		1202	# IO::Async is rather hard to detect, as it doesn't have any
		1203	# obvious default class.
		1204	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1205	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1206	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1207	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
918	);	1208	);
919		1209
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1210	our %method = map +($_ => 1),
		1211	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1212
922	our @post_detect;	1213	our @post_detect;
923		1214
924	sub post_detect(&) {	1215	sub post_detect(&) {
925	my ($cb) = @_;	1216	my ($cb) = @_;
926		1217
927	if ($MODEL) {
928	$cb->();
929
930	1
931	} else {
932	push @post_detect, $cb;	1218	push @post_detect, $cb;
933		1219
934	defined wantarray	1220	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1221	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1222	: ()
		1223	}
		1224
		1225	sub AnyEvent::Util::postdetect::DESTROY {
		1226	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1227	}
		1228
		1229	sub detect() {
		1230	# free some memory
		1231	*detect = sub () { $MODEL };
		1232
		1233	local $!; # for good measure
		1234	local $SIG{__DIE__};
		1235
		1236	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1237	my $model = "AnyEvent::Impl::$1";
		1238	if (eval "require $model") {
		1239	$MODEL = $model;
		1240	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1241	} else {
		1242	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1243	}
937	}	1244	}
938	}
939		1245
940	sub AnyEvent::Util::PostDetect::DESTROY {	1246	# check for already loaded models
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}
943
944	sub detect() {
945	unless ($MODEL) {	1247	unless ($MODEL) {
946	no strict 'refs';	1248	for (@REGISTRY, @models) {
947	local $SIG{__DIE__};	1249	my ($package, $model) = @$_;
948		1250	if (${"$package\::VERSION"} > 0) {
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1251	if (eval "require $model") {
952	$MODEL = $model;	1252	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1253	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
954	} else {	1254	last;
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1255	}
956	}	1256	}
957	}	1257	}
958		1258
959	# check for already loaded models
960	unless ($MODEL) {	1259	unless ($MODEL) {
		1260	# try to autoload a model
961	for (@REGISTRY, @models) {	1261	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1262	my ($package, $model, $autoload) = @$_;
		1263	if (
		1264	$autoload
		1265	and eval "require $package"
963	if (${"$package\::VERSION"} > 0) {	1266	and ${"$package\::VERSION"} > 0
964	if (eval "require $model") {	1267	and eval "require $model"
		1268	) {
965	$MODEL = $model;	1269	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1270	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1271	last;
968	}
969	}	1272	}
970	}	1273	}
971		1274
972	unless ($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	1275	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1276	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}
989	}	1277	}
990
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992
993	unshift @ISA, $MODEL;
994
995	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
996
997	(shift @post_detect)->() while @post_detect;
998	}	1278	}
		1279
		1280	@models = (); # free probe data
		1281
		1282	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1283	unshift @ISA, $MODEL;
		1284
		1285	# now nuke some methods that are overriden by the backend.
		1286	# SUPER is not allowed.
		1287	for (qw(time signal child idle)) {
		1288	undef &{"AnyEvent::Base::$_"}
		1289	if defined &{"$MODEL\::$_"};
		1290	}
		1291
		1292	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1293
		1294	(shift @post_detect)->() while @post_detect;
		1295
		1296	*post_detect = sub(&) {
		1297	shift->();
		1298
		1299	undef
		1300	};
999		1301
1000	$MODEL	1302	$MODEL
1001	}	1303	}
1002		1304
1003	sub AUTOLOAD {	1305	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1306	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1307
1006	$method{$func}	1308	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1309	or Carp::croak "$func: not a valid AnyEvent class method";
1008		1310
1009	detect unless $MODEL;	1311	detect;
1010		1312
1011	my $class = shift;	1313	my $class = shift;
1012	$class->$func (@_);	1314	$class->$func (@_);
1013	}	1315	}
1014		1316
1015	# utility function to dup a filehandle. this is used by many backends	1317	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1318	# 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).	1319	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1320	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1321	my ($poll, $fh, $r, $w) = @_;
1020		1322
1021	# cygwin requires the fh mode to be matching, unix doesn't	1323	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1324	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1023	: $poll eq "w" ? ($w, ">")
1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1025		1325
1026	open my $fh2, "$mode&" . fileno $fh	1326	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1327	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1328
1029	# we assume CLOEXEC is already set by perl in all important cases	1329	# we assume CLOEXEC is already set by perl in all important cases
1030		1330
1031	($fh2, $rw)	1331	($fh2, $rw)
1032	}	1332	}
1033		1333
		1334	=head1 SIMPLIFIED AE API
		1335
		1336	Starting with version 5.0, AnyEvent officially supports a second, much
		1337	simpler, API that is designed to reduce the calling, typing and memory
		1338	overhead by using function call syntax and a fixed number of parameters.
		1339
		1340	See the L<AE> manpage for details.
		1341
		1342	=cut
		1343
		1344	package AE;
		1345
		1346	our $VERSION = $AnyEvent::VERSION;
		1347
		1348	# fall back to the main API by default - backends and AnyEvent::Base
		1349	# implementations can overwrite these.
		1350
		1351	sub io($$$) {
		1352	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1353	}
		1354
		1355	sub timer($$$) {
		1356	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1357	}
		1358
		1359	sub signal($$) {
		1360	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1361	}
		1362
		1363	sub child($$) {
		1364	AnyEvent->child (pid => $_[0], cb => $_[1])
		1365	}
		1366
		1367	sub idle($) {
		1368	AnyEvent->idle (cb => $_[0])
		1369	}
		1370
		1371	sub cv(;&) {
		1372	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1373	}
		1374
		1375	sub now() {
		1376	AnyEvent->now
		1377	}
		1378
		1379	sub now_update() {
		1380	AnyEvent->now_update
		1381	}
		1382
		1383	sub time() {
		1384	AnyEvent->time
		1385	}
		1386
1034	package AnyEvent::Base;	1387	package AnyEvent::Base;
1035		1388
1036	# default implementation for now and time	1389	# default implementations for many methods
1037		1390
1038	BEGIN {	1391	sub time {
		1392	eval q{ # poor man's autoloading {}
		1393	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1394	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1395	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1396	*AE::time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1397	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1398	} else {
		1399	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1400	*AE::time = sub (){ time }; # epic fail
		1401	}
		1402
		1403	*time = sub { AE::time }; # different prototypes
		1404	};
		1405	die if $@;
		1406
		1407	&time
		1408	}
		1409
		1410	*now = \&time;
		1411
		1412	sub now_update { }
		1413
		1414	# default implementation for ->condvar
		1415
		1416	sub condvar {
		1417	eval q{ # poor man's autoloading {}
		1418	*condvar = sub {
		1419	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1420	};
		1421
		1422	*AE::cv = sub (;&) {
		1423	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1424	};
		1425	};
		1426	die if $@;
		1427
		1428	&condvar
		1429	}
		1430
		1431	# default implementation for ->signal
		1432
		1433	our $HAVE_ASYNC_INTERRUPT;
		1434
		1435	sub _have_async_interrupt() {
		1436	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1437	&& eval "use Async::Interrupt 1.02 (); 1")
		1438	unless defined $HAVE_ASYNC_INTERRUPT;
		1439
		1440	$HAVE_ASYNC_INTERRUPT
		1441	}
		1442
		1443	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1444	our (%SIG_ASY, %SIG_ASY_W);
		1445	our ($SIG_COUNT, $SIG_TW);
		1446
		1447	# install a dummy wakeup watcher to reduce signal catching latency
		1448	# used by Impls
		1449	sub _sig_add() {
		1450	unless ($SIG_COUNT++) {
		1451	# try to align timer on a full-second boundary, if possible
		1452	my $NOW = AE::now;
		1453
		1454	$SIG_TW = AE::timer
		1455	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1456	$MAX_SIGNAL_LATENCY,
		1457	sub { } # just for the PERL_ASYNC_CHECK
		1458	;
1044	}	1459	}
1045	}	1460	}
1046		1461
1047	sub time { _time }	1462	sub _sig_del {
1048	sub now { _time }	1463	undef $SIG_TW
1049		1464	unless --$SIG_COUNT;
1050	# default implementation for ->condvar
1051
1052	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1054	}	1465	}
1055		1466
1056	# default implementation for ->signal	1467	our $_sig_name_init; $_sig_name_init = sub {
		1468	eval q{ # poor man's autoloading {}
		1469	undef $_sig_name_init;
1057		1470
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1471	if (_have_async_interrupt) {
		1472	*sig2num = \&Async::Interrupt::sig2num;
		1473	*sig2name = \&Async::Interrupt::sig2name;
		1474	} else {
		1475	require Config;
1059		1476
1060	sub _signal_exec {	1477	my %signame2num;
1061	sysread $SIGPIPE_R, my $dummy, 4;	1478	@signame2num{ split ' ', $Config::Config{sig_name} }
		1479	= split ' ', $Config::Config{sig_num};
1062		1480
1063	while (%SIG_EV) {	1481	my @signum2name;
1064	for (keys %SIG_EV) {	1482	@signum2name[values %signame2num] = keys %signame2num;
1065	delete $SIG_EV{$_};	1483
1066	$_->() for values %{ $SIG_CB{$_} || {} };	1484	*sig2num = sub($) {
		1485	$_[0] > 0 ? shift : $signame2num{+shift}
		1486	};
		1487	*sig2name = sub ($) {
		1488	$_[0] > 0 ? $signum2name[+shift] : shift
		1489	};
1067	}	1490	}
1068	}	1491	};
1069	}	1492	die if $@;
		1493	};
		1494
		1495	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1496	sub sig2name($) { &$_sig_name_init; &sig2name }
1070		1497
1071	sub signal {	1498	sub signal {
1072	my (undef, %arg) = @_;	1499	eval q{ # poor man's autoloading {}
		1500	# probe for availability of Async::Interrupt
		1501	if (_have_async_interrupt) {
		1502	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1503
1074	unless ($SIGPIPE_R) {	1504	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1075	require Fcntl;	1505	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1076		1506
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 {	1507	} else {
		1508	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1509
		1510	if (AnyEvent::WIN32) {
		1511	require AnyEvent::Util;
		1512
		1513	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1514	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1515	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1516	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1517	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1518	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1519	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1520
		1521	# not strictly required, as $^F is normally 2, but let's make sure...
		1522	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1523	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1524	}
		1525
		1526	$SIGPIPE_R
		1527	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1528
		1529	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1087	}	1530	}
1088		1531
1089	$SIGPIPE_R	1532	*signal = $HAVE_ASYNC_INTERRUPT
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1533	? sub {
		1534	my (undef, %arg) = @_;
1091		1535
1092	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1536	# async::interrupt
1093	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094
1095	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1096	}
1097
1098	my $signal = uc $arg{signal}	1537	my $signal = sig2num $arg{signal};
1099	or Carp::croak "required option 'signal' is missing";
1100
1101	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1538	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1539
		1540	$SIG_ASY{$signal} ||= new Async::Interrupt
		1541	cb => sub { undef $SIG_EV{$signal} },
		1542	signal => $signal,
		1543	pipe => [$SIGPIPE_R->filenos],
		1544	pipe_autodrain => 0,
		1545	;
		1546
		1547	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1548	}
		1549	: sub {
		1550	my (undef, %arg) = @_;
		1551
		1552	# pure perl
		1553	my $signal = sig2name $arg{signal};
		1554	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1555
1102	$SIG{$signal} ||= sub {	1556	$SIG{$signal} ||= sub {
		1557	local $!;
1103	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1558	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1104	undef $SIG_EV{$signal};	1559	undef $SIG_EV{$signal};
		1560	};
		1561
		1562	# can't do signal processing without introducing races in pure perl,
		1563	# so limit the signal latency.
		1564	_sig_add;
		1565
		1566	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1567	}
		1568	;
		1569
		1570	*AnyEvent::Base::signal::DESTROY = sub {
		1571	my ($signal, $cb) = @{$_[0]};
		1572
		1573	_sig_del;
		1574
		1575	delete $SIG_CB{$signal}{$cb};
		1576
		1577	$HAVE_ASYNC_INTERRUPT
		1578	? delete $SIG_ASY{$signal}
		1579	: # delete doesn't work with older perls - they then
		1580	# print weird messages, or just unconditionally exit
		1581	# instead of getting the default action.
		1582	undef $SIG{$signal}
		1583	unless keys %{ $SIG_CB{$signal} };
		1584	};
		1585
		1586	*_signal_exec = sub {
		1587	$HAVE_ASYNC_INTERRUPT
		1588	? $SIGPIPE_R->drain
		1589	: sysread $SIGPIPE_R, (my $dummy), 9;
		1590
		1591	while (%SIG_EV) {
		1592	for (keys %SIG_EV) {
		1593	delete $SIG_EV{$_};
		1594	$_->() for values %{ $SIG_CB{$_} || {} };
		1595	}
		1596	}
		1597	};
1105	};	1598	};
		1599	die if $@;
1106		1600
1107	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1601	&signal
1108	}
1109
1110	sub AnyEvent::Base::Signal::DESTROY {
1111	my ($signal, $cb) = @{$_[0]};
1112
1113	delete $SIG_CB{$signal}{$cb};
1114
1115	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1116	}	1602	}
1117		1603
1118	# default implementation for ->child	1604	# default implementation for ->child
1119		1605
1120	our %PID_CB;	1606	our %PID_CB;
1121	our $CHLD_W;	1607	our $CHLD_W;
1122	our $CHLD_DELAY_W;	1608	our $CHLD_DELAY_W;
1123	our $PID_IDLE;
1124	our $WNOHANG;	1609	our $WNOHANG;
1125		1610
1126	sub _child_wait {	1611	# used by many Impl's
1127	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1612	sub _emit_childstatus($$) {
		1613	my (undef, $rpid, $rstatus) = @_;
		1614
		1615	$_->($rpid, $rstatus)
1128	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1616	for values %{ $PID_CB{$rpid} || {} },
1129	(values %{ $PID_CB{0} || {} });	1617	values %{ $PID_CB{0} || {} };
1130	}
1131
1132	undef $PID_IDLE;
1133	}
1134
1135	sub _sigchld {
1136	# make sure we deliver these changes "synchronous" with the event loop.
1137	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
1138	undef $CHLD_DELAY_W;
1139	&_child_wait;
1140	});
1141	}	1618	}
1142		1619
1143	sub child {	1620	sub child {
		1621	eval q{ # poor man's autoloading {}
		1622	*_sigchld = sub {
		1623	my $pid;
		1624
		1625	AnyEvent->_emit_childstatus ($pid, $?)
		1626	while ($pid = waitpid -1, $WNOHANG) > 0;
		1627	};
		1628
		1629	*child = sub {
1144	my (undef, %arg) = @_;	1630	my (undef, %arg) = @_;
1145		1631
1146	defined (my $pid = $arg{pid} + 0)	1632	defined (my $pid = $arg{pid} + 0)
1147	or Carp::croak "required option 'pid' is missing";	1633	or Carp::croak "required option 'pid' is missing";
1148		1634
1149	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1635	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1150		1636
1151	unless ($WNOHANG) {	1637	# WNOHANG is almost cetrainly 1 everywhere
		1638	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1639	? 1
1152	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1640	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1153	}
1154		1641
1155	unless ($CHLD_W) {	1642	unless ($CHLD_W) {
1156	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1643	$CHLD_W = AE::signal CHLD => \&_sigchld;
1157	# child could be a zombie already, so make at least one round	1644	# child could be a zombie already, so make at least one round
1158	&_sigchld;	1645	&_sigchld;
1159	}	1646	}
1160		1647
1161	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1648	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1162	}	1649	};
1163		1650
1164	sub AnyEvent::Base::Child::DESTROY {	1651	*AnyEvent::Base::child::DESTROY = sub {
1165	my ($pid, $cb) = @{$_[0]};	1652	my ($pid, $cb) = @{$_[0]};
1166		1653
1167	delete $PID_CB{$pid}{$cb};	1654	delete $PID_CB{$pid}{$cb};
1168	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1655	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1169		1656
1170	undef $CHLD_W unless keys %PID_CB;	1657	undef $CHLD_W unless keys %PID_CB;
		1658	};
		1659	};
		1660	die if $@;
		1661
		1662	&child
		1663	}
		1664
		1665	# idle emulation is done by simply using a timer, regardless
		1666	# of whether the process is idle or not, and not letting
		1667	# the callback use more than 50% of the time.
		1668	sub idle {
		1669	eval q{ # poor man's autoloading {}
		1670	*idle = sub {
		1671	my (undef, %arg) = @_;
		1672
		1673	my ($cb, $w, $rcb) = $arg{cb};
		1674
		1675	$rcb = sub {
		1676	if ($cb) {
		1677	$w = _time;
		1678	&$cb;
		1679	$w = _time - $w;
		1680
		1681	# never use more then 50% of the time for the idle watcher,
		1682	# within some limits
		1683	$w = 0.0001 if $w < 0.0001;
		1684	$w = 5 if $w > 5;
		1685
		1686	$w = AE::timer $w, 0, $rcb;
		1687	} else {
		1688	# clean up...
		1689	undef $w;
		1690	undef $rcb;
		1691	}
		1692	};
		1693
		1694	$w = AE::timer 0.05, 0, $rcb;
		1695
		1696	bless \\$cb, "AnyEvent::Base::idle"
		1697	};
		1698
		1699	*AnyEvent::Base::idle::DESTROY = sub {
		1700	undef $${$_[0]};
		1701	};
		1702	};
		1703	die if $@;
		1704
		1705	&idle
1171	}	1706	}
1172		1707
1173	package AnyEvent::CondVar;	1708	package AnyEvent::CondVar;
1174		1709
1175	our @ISA = AnyEvent::CondVar::Base::;	1710	our @ISA = AnyEvent::CondVar::Base::;
1176		1711
1177	package AnyEvent::CondVar::Base;	1712	package AnyEvent::CondVar::Base;
1178		1713
1179	use overload	1714	#use overload
1180	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1715	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1181	fallback => 1;	1716	# fallback => 1;
		1717
		1718	# save 300+ kilobytes by dirtily hardcoding overloading
		1719	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1720	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1721	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1722	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1723
		1724	our $WAITING;
1182		1725
1183	sub _send {	1726	sub _send {
1184	# nop	1727	# nop
1185	}	1728	}
1186		1729
…		…
1199	sub ready {	1742	sub ready {
1200	$_[0]{_ae_sent}	1743	$_[0]{_ae_sent}
1201	}	1744	}
1202		1745
1203	sub _wait {	1746	sub _wait {
		1747	$WAITING
		1748	and !$_[0]{_ae_sent}
		1749	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1750
		1751	local $WAITING = 1;
1204	AnyEvent->one_event while !$_[0]{_ae_sent};	1752	AnyEvent->one_event while !$_[0]{_ae_sent};
1205	}	1753	}
1206		1754
1207	sub recv {	1755	sub recv {
1208	$_[0]->_wait;	1756	$_[0]->_wait;
…		…
1210	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1758	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1211	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1759	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1212	}	1760	}
1213		1761
1214	sub cb {	1762	sub cb {
1215	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1763	my $cv = shift;
		1764
		1765	@_
		1766	and $cv->{_ae_cb} = shift
		1767	and $cv->{_ae_sent}
		1768	and (delete $cv->{_ae_cb})->($cv);
		1769
1216	$_[0]{_ae_cb}	1770	$cv->{_ae_cb}
1217	}	1771	}
1218		1772
1219	sub begin {	1773	sub begin {
1220	++$_[0]{_ae_counter};	1774	++$_[0]{_ae_counter};
1221	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1775	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1249	so on.	1803	so on.
1250		1804
1251	=head1 ENVIRONMENT VARIABLES	1805	=head1 ENVIRONMENT VARIABLES
1252		1806
1253	The following environment variables are used by this module or its	1807	The following environment variables are used by this module or its
1254	submodules:	1808	submodules.
		1809
		1810	Note that AnyEvent will remove I<all> environment variables starting with
		1811	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1812	enabled.
1255		1813
1256	=over 4	1814	=over 4
1257		1815
1258	=item C<PERL_ANYEVENT_VERBOSE>	1816	=item C<PERL_ANYEVENT_VERBOSE>
1259		1817
…		…
1266	C<PERL_ANYEVENT_MODEL>.	1824	C<PERL_ANYEVENT_MODEL>.
1267		1825
1268	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1826	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1269	model it chooses.	1827	model it chooses.
1270		1828
		1829	When set to C<8> or higher, then AnyEvent will report extra information on
		1830	which optional modules it loads and how it implements certain features.
		1831
1271	=item C<PERL_ANYEVENT_STRICT>	1832	=item C<PERL_ANYEVENT_STRICT>
1272		1833
1273	AnyEvent does not do much argument checking by default, as thorough	1834	AnyEvent does not do much argument checking by default, as thorough
1274	argument checking is very costly. Setting this variable to a true value	1835	argument checking is very costly. Setting this variable to a true value
1275	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1836	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1276	check the arguments passed to most method calls. If it finds any problems	1837	check the arguments passed to most method calls. If it finds any problems,
1277	it will croak.	1838	it will croak.
1278		1839
1279	In other words, enables "strict" mode.	1840	In other words, enables "strict" mode.
1280		1841
1281	Unlike C<use strict>, it is definitely recommended ot keep it off in	1842	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1282	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1843	>>, it is definitely recommended to keep it off in production. Keeping
1283	developing programs can be very useful, however.	1844	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1845	can be very useful, however.
1284		1846
1285	=item C<PERL_ANYEVENT_MODEL>	1847	=item C<PERL_ANYEVENT_MODEL>
1286		1848
1287	This can be used to specify the event model to be used by AnyEvent, before	1849	This can be used to specify the event model to be used by AnyEvent, before
1288	auto detection and -probing kicks in. It must be a string consisting	1850	auto detection and -probing kicks in. It must be a string consisting
…		…
1331		1893
1332	=item C<PERL_ANYEVENT_MAX_FORKS>	1894	=item C<PERL_ANYEVENT_MAX_FORKS>
1333		1895
1334	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1896	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1335	will create in parallel.	1897	will create in parallel.
		1898
		1899	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1900
		1901	The default value for the C<max_outstanding> parameter for the default DNS
		1902	resolver - this is the maximum number of parallel DNS requests that are
		1903	sent to the DNS server.
		1904
		1905	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1906
		1907	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1908	configuration) in the default resolver. When set to the empty string, no
		1909	default config will be used.
		1910
		1911	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1912
		1913	When neither C<ca_file> nor C<ca_path> was specified during
		1914	L<AnyEvent::TLS> context creation, and either of these environment
		1915	variables exist, they will be used to specify CA certificate locations
		1916	instead of a system-dependent default.
		1917
		1918	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1919
		1920	When these are set to C<1>, then the respective modules are not
		1921	loaded. Mostly good for testing AnyEvent itself.
1336		1922
1337	=back	1923	=back
1338		1924
1339	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1925	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1340		1926
…		…
1398	warn "read: $input\n"; # output what has been read	1984	warn "read: $input\n"; # output what has been read
1399	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1985	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1400	},	1986	},
1401	);	1987	);
1402		1988
1403	my $time_watcher; # can only be used once
1404
1405	sub new_timer {
1406	$timer = AnyEvent->timer (after => 1, cb => sub {	1989	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1407	warn "timeout\n"; # print 'timeout' about every second	1990	warn "timeout\n"; # print 'timeout' at most every second
1408	&new_timer; # and restart the time
1409	});	1991	});
1410	}
1411
1412	new_timer; # create first timer
1413		1992
1414	$cv->recv; # wait until user enters /^q/i	1993	$cv->recv; # wait until user enters /^q/i
1415		1994
1416	=head1 REAL-WORLD EXAMPLE	1995	=head1 REAL-WORLD EXAMPLE
1417		1996
…		…
1490		2069
1491	The actual code goes further and collects all errors (C<die>s, exceptions)	2070	The actual code goes further and collects all errors (C<die>s, exceptions)
1492	that occurred during request processing. The C<result> method detects	2071	that occurred during request processing. The C<result> method detects
1493	whether an exception as thrown (it is stored inside the $txn object)	2072	whether an exception as thrown (it is stored inside the $txn object)
1494	and just throws the exception, which means connection errors and other	2073	and just throws the exception, which means connection errors and other
1495	problems get reported tot he code that tries to use the result, not in a	2074	problems get reported to the code that tries to use the result, not in a
1496	random callback.	2075	random callback.
1497		2076
1498	All of this enables the following usage styles:	2077	All of this enables the following usage styles:
1499		2078
1500	1. Blocking:	2079	1. Blocking:
…		…
1548	through AnyEvent. The benchmark creates a lot of timers (with a zero	2127	through AnyEvent. The benchmark creates a lot of timers (with a zero
1549	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2128	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1550	which it is), lets them fire exactly once and destroys them again.	2129	which it is), lets them fire exactly once and destroys them again.
1551		2130
1552	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2131	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1553	distribution.	2132	distribution. It uses the L<AE> interface, which makes a real difference
		2133	for the EV and Perl backends only.
1554		2134
1555	=head3 Explanation of the columns	2135	=head3 Explanation of the columns
1556		2136
1557	I<watcher> is the number of event watchers created/destroyed. Since	2137	I<watcher> is the number of event watchers created/destroyed. Since
1558	different event models feature vastly different performances, each event	2138	different event models feature vastly different performances, each event
…		…
1579	watcher.	2159	watcher.
1580		2160
1581	=head3 Results	2161	=head3 Results
1582		2162
1583	name watchers bytes create invoke destroy comment	2163	name watchers bytes create invoke destroy comment
1584	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2164	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1585	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2165	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1586	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2166	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1587	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2167	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1588	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2168	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1589	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2169	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
		2170	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
		2171	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1590	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2172	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1591	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2173	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1592	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2174	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1593	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2175	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1594		2176
1595	=head3 Discussion	2177	=head3 Discussion
1596		2178
1597	The benchmark does I<not> measure scalability of the event loop very	2179	The benchmark does I<not> measure scalability of the event loop very
1598	well. For example, a select-based event loop (such as the pure perl one)	2180	well. For example, a select-based event loop (such as the pure perl one)
…		…
1610	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2192	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1611	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2193	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1612	cycles with POE.	2194	cycles with POE.
1613		2195
1614	C<EV> is the sole leader regarding speed and memory use, which are both	2196	C<EV> is the sole leader regarding speed and memory use, which are both
1615	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2197	maximal/minimal, respectively. When using the L<AE> API there is zero
		2198	overhead (when going through the AnyEvent API create is about 5-6 times
		2199	slower, with other times being equal, so still uses far less memory than
1616	far less memory than any other event loop and is still faster than Event	2200	any other event loop and is still faster than Event natively).
1617	natively.
1618		2201
1619	The pure perl implementation is hit in a few sweet spots (both the	2202	The pure perl implementation is hit in a few sweet spots (both the
1620	constant timeout and the use of a single fd hit optimisations in the perl	2203	constant timeout and the use of a single fd hit optimisations in the perl
1621	interpreter and the backend itself). Nevertheless this shows that it	2204	interpreter and the backend itself). Nevertheless this shows that it
1622	adds very little overhead in itself. Like any select-based backend its	2205	adds very little overhead in itself. Like any select-based backend its
1623	performance becomes really bad with lots of file descriptors (and few of	2206	performance becomes really bad with lots of file descriptors (and few of
1624	them active), of course, but this was not subject of this benchmark.	2207	them active), of course, but this was not subject of this benchmark.
1625		2208
1626	The C<Event> module has a relatively high setup and callback invocation	2209	The C<Event> module has a relatively high setup and callback invocation
1627	cost, but overall scores in on the third place.	2210	cost, but overall scores in on the third place.
		2211
		2212	C<IO::Async> performs admirably well, about on par with C<Event>, even
		2213	when using its pure perl backend.
1628		2214
1629	C<Glib>'s memory usage is quite a bit higher, but it features a	2215	C<Glib>'s memory usage is quite a bit higher, but it features a
1630	faster callback invocation and overall ends up in the same class as	2216	faster callback invocation and overall ends up in the same class as
1631	C<Event>. However, Glib scales extremely badly, doubling the number of	2217	C<Event>. However, Glib scales extremely badly, doubling the number of
1632	watchers increases the processing time by more than a factor of four,	2218	watchers increases the processing time by more than a factor of four,
…		…
1693	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2279	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1694	(1%) are active. This mirrors the activity of large servers with many	2280	(1%) are active. This mirrors the activity of large servers with many
1695	connections, most of which are idle at any one point in time.	2281	connections, most of which are idle at any one point in time.
1696		2282
1697	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2283	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1698	distribution.	2284	distribution. It uses the L<AE> interface, which makes a real difference
		2285	for the EV and Perl backends only.
1699		2286
1700	=head3 Explanation of the columns	2287	=head3 Explanation of the columns
1701		2288
1702	I<sockets> is the number of sockets, and twice the number of "servers" (as	2289	I<sockets> is the number of sockets, and twice the number of "servers" (as
1703	each server has a read and write socket end).	2290	each server has a read and write socket end).
…		…
1710	it to another server. This includes deleting the old timeout and creating	2297	it to another server. This includes deleting the old timeout and creating
1711	a new one that moves the timeout into the future.	2298	a new one that moves the timeout into the future.
1712		2299
1713	=head3 Results	2300	=head3 Results
1714		2301
1715	name sockets create request	2302	name sockets create request
1716	EV 20000 69.01 11.16	2303	EV 20000 62.66 7.99
1717	Perl 20000 73.32 35.87	2304	Perl 20000 68.32 32.64
1718	Event 20000 212.62 257.32	2305	IOAsync 20000 174.06 101.15 epoll
1719	Glib 20000 651.16 1896.30	2306	IOAsync 20000 174.67 610.84 poll
		2307	Event 20000 202.69 242.91
		2308	Glib 20000 557.01 1689.52
1720	POE 20000 349.67 12317.24 uses POE::Loop::Event	2309	POE 20000 341.54 12086.32 uses POE::Loop::Event
1721		2310
1722	=head3 Discussion	2311	=head3 Discussion
1723		2312
1724	This benchmark I<does> measure scalability and overall performance of the	2313	This benchmark I<does> measure scalability and overall performance of the
1725	particular event loop.	2314	particular event loop.
…		…
1727	EV is again fastest. Since it is using epoll on my system, the setup time	2316	EV is again fastest. Since it is using epoll on my system, the setup time
1728	is relatively high, though.	2317	is relatively high, though.
1729		2318
1730	Perl surprisingly comes second. It is much faster than the C-based event	2319	Perl surprisingly comes second. It is much faster than the C-based event
1731	loops Event and Glib.	2320	loops Event and Glib.
		2321
		2322	IO::Async performs very well when using its epoll backend, and still quite
		2323	good compared to Glib when using its pure perl backend.
1732		2324
1733	Event suffers from high setup time as well (look at its code and you will	2325	Event suffers from high setup time as well (look at its code and you will
1734	understand why). Callback invocation also has a high overhead compared to	2326	understand why). Callback invocation also has a high overhead compared to
1735	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2327	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1736	uses select or poll in basically all documented configurations.	2328	uses select or poll in basically all documented configurations.
…		…
1799	=item * C-based event loops perform very well with small number of	2391	=item * C-based event loops perform very well with small number of
1800	watchers, as the management overhead dominates.	2392	watchers, as the management overhead dominates.
1801		2393
1802	=back	2394	=back
1803		2395
		2396	=head2 THE IO::Lambda BENCHMARK
		2397
		2398	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2399	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2400	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2401	shouldn't come as a surprise to anybody). As such, the benchmark is
		2402	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2403	very optimal. But how would AnyEvent compare when used without the extra
		2404	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2405
		2406	The benchmark itself creates an echo-server, and then, for 500 times,
		2407	connects to the echo server, sends a line, waits for the reply, and then
		2408	creates the next connection. This is a rather bad benchmark, as it doesn't
		2409	test the efficiency of the framework or much non-blocking I/O, but it is a
		2410	benchmark nevertheless.
		2411
		2412	name runtime
		2413	Lambda/select 0.330 sec
		2414	+ optimized 0.122 sec
		2415	Lambda/AnyEvent 0.327 sec
		2416	+ optimized 0.138 sec
		2417	Raw sockets/select 0.077 sec
		2418	POE/select, components 0.662 sec
		2419	POE/select, raw sockets 0.226 sec
		2420	POE/select, optimized 0.404 sec
		2421
		2422	AnyEvent/select/nb 0.085 sec
		2423	AnyEvent/EV/nb 0.068 sec
		2424	+state machine 0.134 sec
		2425
		2426	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2427	benchmarks actually make blocking connects and use 100% blocking I/O,
		2428	defeating the purpose of an event-based solution. All of the newly
		2429	written AnyEvent benchmarks use 100% non-blocking connects (using
		2430	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2431	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2432	generally require a lot more bookkeeping and event handling than blocking
		2433	connects (which involve a single syscall only).
		2434
		2435	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2436	offers similar expressive power as POE and IO::Lambda, using conventional
		2437	Perl syntax. This means that both the echo server and the client are 100%
		2438	non-blocking, further placing it at a disadvantage.
		2439
		2440	As you can see, the AnyEvent + EV combination even beats the
		2441	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2442	backend easily beats IO::Lambda and POE.
		2443
		2444	And even the 100% non-blocking version written using the high-level (and
		2445	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
		2446	higher level ("unoptimised") abstractions by a large margin, even though
		2447	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
		2448
		2449	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2450	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2451	part of the IO::Lambda distribution and were used without any changes.
		2452
1804		2453
1805	=head1 SIGNALS	2454	=head1 SIGNALS
1806		2455
1807	AnyEvent currently installs handlers for these signals:	2456	AnyEvent currently installs handlers for these signals:
1808		2457
…		…
1811	=item SIGCHLD	2460	=item SIGCHLD
1812		2461
1813	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2462	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
1814	emulation for event loops that do not support them natively. Also, some	2463	emulation for event loops that do not support them natively. Also, some
1815	event loops install a similar handler.	2464	event loops install a similar handler.
		2465
		2466	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2467	AnyEvent will reset it to default, to avoid losing child exit statuses.
1816		2468
1817	=item SIGPIPE	2469	=item SIGPIPE
1818		2470
1819	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2471	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1820	when AnyEvent gets loaded.	2472	when AnyEvent gets loaded.
…		…
1832		2484
1833	=back	2485	=back
1834		2486
1835	=cut	2487	=cut
1836		2488
		2489	undef $SIG{CHLD}
		2490	if $SIG{CHLD} eq 'IGNORE';
		2491
1837	$SIG{PIPE} = sub { }	2492	$SIG{PIPE} = sub { }
1838	unless defined $SIG{PIPE};	2493	unless defined $SIG{PIPE};
1839		2494
		2495	=head1 RECOMMENDED/OPTIONAL MODULES
		2496
		2497	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2498	it's built-in modules) are required to use it.
		2499
		2500	That does not mean that AnyEvent won't take advantage of some additional
		2501	modules if they are installed.
		2502
		2503	This section explains which additional modules will be used, and how they
		2504	affect AnyEvent's operation.
		2505
		2506	=over 4
		2507
		2508	=item L<Async::Interrupt>
		2509
		2510	This slightly arcane module is used to implement fast signal handling: To
		2511	my knowledge, there is no way to do completely race-free and quick
		2512	signal handling in pure perl. To ensure that signals still get
		2513	delivered, AnyEvent will start an interval timer to wake up perl (and
		2514	catch the signals) with some delay (default is 10 seconds, look for
		2515	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2516
		2517	If this module is available, then it will be used to implement signal
		2518	catching, which means that signals will not be delayed, and the event loop
		2519	will not be interrupted regularly, which is more efficient (and good for
		2520	battery life on laptops).
		2521
		2522	This affects not just the pure-perl event loop, but also other event loops
		2523	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2524
		2525	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2526	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2527	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2528	does nothing for those backends.
		2529
		2530	=item L<EV>
		2531
		2532	This module isn't really "optional", as it is simply one of the backend
		2533	event loops that AnyEvent can use. However, it is simply the best event
		2534	loop available in terms of features, speed and stability: It supports
		2535	the AnyEvent API optimally, implements all the watcher types in XS, does
		2536	automatic timer adjustments even when no monotonic clock is available,
		2537	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2538	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2539	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2540
		2541	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2542	then this module will do nothing for you.
		2543
		2544	=item L<Guard>
		2545
		2546	The guard module, when used, will be used to implement
		2547	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2548	lot less memory), but otherwise doesn't affect guard operation much. It is
		2549	purely used for performance.
		2550
		2551	=item L<JSON> and L<JSON::XS>
		2552
		2553	One of these modules is required when you want to read or write JSON data
		2554	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2555	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2556
		2557	=item L<Net::SSLeay>
		2558
		2559	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2560	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2561	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2562
		2563	=item L<Time::HiRes>
		2564
		2565	This module is part of perl since release 5.008. It will be used when the
		2566	chosen event library does not come with a timing source on it's own. The
		2567	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2568	try to use a monotonic clock for timing stability.
		2569
		2570	=back
		2571
1840		2572
1841	=head1 FORK	2573	=head1 FORK
1842		2574
1843	Most event libraries are not fork-safe. The ones who are usually are	2575	Most event libraries are not fork-safe. The ones who are usually are
1844	because they rely on inefficient but fork-safe C<select> or C<poll>	2576	because they rely on inefficient but fork-safe C<select> or C<poll> calls
1845	calls. Only L<EV> is fully fork-aware.	2577	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2578	are usually badly thought-out hacks that are incompatible with fork in
		2579	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2580	continue event-processing in both parent and child (or both, if you know
		2581	what you are doing).
		2582
		2583	This means that, in general, you cannot fork and do event processing in
		2584	the child if the event library was initialised before the fork (which
		2585	usually happens when the first AnyEvent watcher is created, or the library
		2586	is loaded).
1846		2587
1847	If you have to fork, you must either do so I<before> creating your first	2588	If you have to fork, you must either do so I<before> creating your first
1848	watcher OR you must not use AnyEvent at all in the child.	2589	watcher OR you must not use AnyEvent at all in the child OR you must do
		2590	something completely out of the scope of AnyEvent.
		2591
		2592	The problem of doing event processing in the parent I<and> the child
		2593	is much more complicated: even for backends that I<are> fork-aware or
		2594	fork-safe, their behaviour is not usually what you want: fork clones all
		2595	watchers, that means all timers, I/O watchers etc. are active in both
		2596	parent and child, which is almost never what you want. USing C<exec>
		2597	to start worker children from some kind of manage rprocess is usually
		2598	preferred, because it is much easier and cleaner, at the expense of having
		2599	to have another binary.
1849		2600
1850		2601
1851	=head1 SECURITY CONSIDERATIONS	2602	=head1 SECURITY CONSIDERATIONS
1852		2603
1853	AnyEvent can be forced to load any event model via	2604	AnyEvent can be forced to load any event model via
…		…
1865	use AnyEvent;	2616	use AnyEvent;
1866		2617
1867	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2618	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1868	be used to probe what backend is used and gain other information (which is	2619	be used to probe what backend is used and gain other information (which is
1869	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2620	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1870	$ENV{PERL_ANYEGENT_STRICT}.	2621	$ENV{PERL_ANYEVENT_STRICT}.
		2622
		2623	Note that AnyEvent will remove I<all> environment variables starting with
		2624	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2625	enabled.
1871		2626
1872		2627
1873	=head1 BUGS	2628	=head1 BUGS
1874		2629
1875	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2630	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
…		…
1887	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2642	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1888		2643
1889	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2644	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1890	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2645	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1891	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2646	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1892	L<AnyEvent::Impl::POE>.	2647	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
1893		2648
1894	Non-blocking file handles, sockets, TCP clients and	2649	Non-blocking file handles, sockets, TCP clients and
1895	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2650	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1896		2651
1897	Asynchronous DNS: L<AnyEvent::DNS>.	2652	Asynchronous DNS: L<AnyEvent::DNS>.
1898		2653
1899	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2654	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2655	L<Coro::Event>,
1900		2656
1901	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2657	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2658	L<AnyEvent::HTTP>.
1902		2659
1903		2660
1904	=head1 AUTHOR	2661	=head1 AUTHOR
1905		2662
1906	Marc Lehmann <schmorp@schmorp.de>	2663	Marc Lehmann <schmorp@schmorp.de>

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