[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.200 by root, Wed Apr 1 14:02:27 2009 UTC vs.
Revision 1.243 by root, Fri Jul 17 23:12:20 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
168	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
169		177
170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
171	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
172		180
173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	181	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	182	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	183	handle). Note that only file handles pointing to things for which
176	non-blocking operation makes sense are allowed. This includes sockets,	184	non-blocking operation makes sense are allowed. This includes sockets,
177	most character devices, pipes, fifos and so on, but not for example files	185	most character devices, pipes, fifos and so on, but not for example files
178	or block devices.	186	or block devices.
…		…
320	In either case, if you care (and in most cases, you don't), then you	328	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	329	can get whatever behaviour you want with any event loop, by taking the
322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
323	account.	331	account.
324		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
325	=back	348	=back
326		349
327	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
328		351
329	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
338	invocation, and callback invocation will be synchronous. Synchronous means	361	invocation, and callback invocation will be synchronous. Synchronous means
339	that it might take a while until the signal gets handled by the process,	362	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.	363	but it is guaranteed not to interrupt any other callbacks.
341		364
342	The main advantage of using these watchers is that you can share a signal	365	The main advantage of using these watchers is that you can share a signal
343	between multiple watchers.	366	between multiple watchers, and AnyEvent will ensure that signals will not
		367	interrupt your program at bad times.
344		368
345	This watcher might use C<%SIG>, so programs overwriting those signals	369	This watcher might use C<%SIG> (depending on the event loop used),
346	directly will likely not work correctly.	370	so programs overwriting those signals directly will likely not work
		371	correctly.
		372
		373	Also note that many event loops (e.g. Glib, Tk, Qt, IO::Async) do not
		374	support attaching callbacks to signals, which is a pity, as you cannot do
		375	race-free signal handling in perl. AnyEvent will try to do it's best, but
		376	in some cases, signals will be delayed. The maximum time a signal might
		377	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		378	seconds). This variable can be changed only before the first signal
		379	watcher is created, and should be left alone otherwise. Higher values
		380	will cause fewer spurious wake-ups, which is better for power and CPU
		381	saving. All these problems can be avoided by installing the optional
		382	L<Async::Interrupt> module.
347		383
348	Example: exit on SIGINT	384	Example: exit on SIGINT
349		385
350	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	386	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
351		387
…		…
369		405
370	There is a slight catch to child watchers, however: you usually start them	406	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	407	I<after> the child process was created, and this means the process could
372	have exited already (and no SIGCHLD will be sent anymore).	408	have exited already (and no SIGCHLD will be sent anymore).
373		409
374	Not all event models handle this correctly (POE doesn't), but even for	410	Not all event models handle this correctly (neither POE nor IO::Async do,
		411	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	412	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).	413	the process exits (i.e. before you fork in the first place). AnyEvent's
		414	pure perl event loop handles all cases correctly regardless of when you
		415	start the watcher.
377		416
378	This means you cannot create a child watcher as the very first thing in an	417	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	418	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>).	419	watcher before you C<fork> the child (alternatively, you can call
		420	C<AnyEvent::detect>).
		421
		422	As most event loops do not support waiting for child events, they will be
		423	emulated by AnyEvent in most cases, in which the latency and race problems
		424	mentioned in the description of signal watchers apply.
381		425
382	Example: fork a process and wait for it	426	Example: fork a process and wait for it
383		427
384	my $done = AnyEvent->condvar;	428	my $done = AnyEvent->condvar;
385		429
…		…
395	);	439	);
396		440
397	# do something else, then wait for process exit	441	# do something else, then wait for process exit
398	$done->recv;	442	$done->recv;
399		443
		444	=head2 IDLE WATCHERS
		445
		446	Sometimes there is a need to do something, but it is not so important
		447	to do it instantly, but only when there is nothing better to do. This
		448	"nothing better to do" is usually defined to be "no other events need
		449	attention by the event loop".
		450
		451	Idle watchers ideally get invoked when the event loop has nothing
		452	better to do, just before it would block the process to wait for new
		453	events. Instead of blocking, the idle watcher is invoked.
		454
		455	Most event loops unfortunately do not really support idle watchers (only
		456	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		457	will simply call the callback "from time to time".
		458
		459	Example: read lines from STDIN, but only process them when the
		460	program is otherwise idle:
		461
		462	my @lines; # read data
		463	my $idle_w;
		464	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		465	push @lines, scalar <STDIN>;
		466
		467	# start an idle watcher, if not already done
		468	$idle_w \|\|= AnyEvent->idle (cb => sub {
		469	# handle only one line, when there are lines left
		470	if (my $line = shift @lines) {
		471	print "handled when idle: $line";
		472	} else {
		473	# otherwise disable the idle watcher again
		474	undef $idle_w;
		475	}
		476	});
		477	});
		478
400	=head2 CONDITION VARIABLES	479	=head2 CONDITION VARIABLES
401		480
402	If you are familiar with some event loops you will know that all of them	481	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	482	require you to run some blocking "loop", "run" or similar function that
404	will actively watch for new events and call your callbacks.	483	will actively watch for new events and call your callbacks.
405		484
406	AnyEvent is different, it expects somebody else to run the event loop and	485	AnyEvent is slightly different: it expects somebody else to run the event
407	will only block when necessary (usually when told by the user).	486	loop and will only block when necessary (usually when told by the user).
408		487
409	The instrument to do that is called a "condition variable", so called	488	The instrument to do that is called a "condition variable", so called
410	because they represent a condition that must become true.	489	because they represent a condition that must become true.
411		490
		491	Now is probably a good time to look at the examples further below.
		492
412	Condition variables can be created by calling the C<< AnyEvent->condvar	493	Condition variables can be created by calling the C<< AnyEvent->condvar
413	>> method, usually without arguments. The only argument pair allowed is	494	>> 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	495	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	496	becomes true, with the condition variable as the first argument (but not
417	the results).	497	the results).
418		498
419	After creation, the condition variable is "false" until it becomes "true"	499	After creation, the condition variable is "false" until it becomes "true"
…		…
468	after => 1,	548	after => 1,
469	cb => sub { $result_ready->send },	549	cb => sub { $result_ready->send },
470	);	550	);
471		551
472	# this "blocks" (while handling events) till the callback	552	# this "blocks" (while handling events) till the callback
473	# calls send	553	# calls -<send
474	$result_ready->recv;	554	$result_ready->recv;
475		555
476	Example: wait for a timer, but take advantage of the fact that	556	Example: wait for a timer, but take advantage of the fact that condition
477	condition variables are also code references.	557	variables are also callable directly.
478		558
479	my $done = AnyEvent->condvar;	559	my $done = AnyEvent->condvar;
480	my $delay = AnyEvent->timer (after => 5, cb => $done);	560	my $delay = AnyEvent->timer (after => 5, cb => $done);
481	$done->recv;	561	$done->recv;
482		562
…		…
488		568
489	...	569	...
490		570
491	my @info = $couchdb->info->recv;	571	my @info = $couchdb->info->recv;
492		572
493	And this is how you would just ste a callback to be called whenever the	573	And this is how you would just set a callback to be called whenever the
494	results are available:	574	results are available:
495		575
496	$couchdb->info->cb (sub {	576	$couchdb->info->cb (sub {
497	my @info = $_[0]->recv;	577	my @info = $_[0]->recv;
498	});	578	});
…		…
516	immediately from within send.	596	immediately from within send.
517		597
518	Any arguments passed to the C<send> call will be returned by all	598	Any arguments passed to the C<send> call will be returned by all
519	future C<< ->recv >> calls.	599	future C<< ->recv >> calls.
520		600
521	Condition variables are overloaded so one can call them directly	601	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	602	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	603	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		604
530	=item $cv->croak ($error)	605	=item $cv->croak ($error)
531		606
532	Similar to send, but causes all call's to C<< ->recv >> to invoke	607	Similar to send, but causes all call's to C<< ->recv >> to invoke
533	C<Carp::croak> with the given error message/object/scalar.	608	C<Carp::croak> with the given error message/object/scalar.
534		609
535	This can be used to signal any errors to the condition variable	610	This can be used to signal any errors to the condition variable
536	user/consumer.	611	user/consumer. Doing it this way instead of calling C<croak> directly
		612	delays the error detetcion, but has the overwhelmign advantage that it
		613	diagnoses the error at the place where the result is expected, and not
		614	deep in some event clalback without connection to the actual code causing
		615	the problem.
537		616
538	=item $cv->begin ([group callback])	617	=item $cv->begin ([group callback])
539		618
540	=item $cv->end	619	=item $cv->end
541
542	These two methods are EXPERIMENTAL and MIGHT CHANGE.
543		620
544	These two methods can be used to combine many transactions/events into	621	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	622	one. For example, a function that pings many hosts in parallel might want
546	to use a condition variable for the whole process.	623	to use a condition variable for the whole process.
547		624
…		…
549	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	626	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	627	>>, the (last) callback passed to C<begin> will be executed. That callback
551	is I<supposed> to call C<< ->send >>, but that is not required. If no	628	is I<supposed> to call C<< ->send >>, but that is not required. If no
552	callback was set, C<send> will be called without any arguments.	629	callback was set, C<send> will be called without any arguments.
553		630
554	Let's clarify this with the ping example:	631	You can think of C<< $cv->send >> giving you an OR condition (one call
		632	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		633	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		634
		635	Let's start with a simple example: you have two I/O watchers (for example,
		636	STDOUT and STDERR for a program), and you want to wait for both streams to
		637	close before activating a condvar:
		638
		639	my $cv = AnyEvent->condvar;
		640
		641	$cv->begin; # first watcher
		642	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		643	defined sysread $fh1, my $buf, 4096
		644	or $cv->end;
		645	});
		646
		647	$cv->begin; # second watcher
		648	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		649	defined sysread $fh2, my $buf, 4096
		650	or $cv->end;
		651	});
		652
		653	$cv->recv;
		654
		655	This works because for every event source (EOF on file handle), there is
		656	one call to C<begin>, so the condvar waits for all calls to C<end> before
		657	sending.
		658
		659	The ping example mentioned above is slightly more complicated, as the
		660	there are results to be passwd back, and the number of tasks that are
		661	begung can potentially be zero:
555		662
556	my $cv = AnyEvent->condvar;	663	my $cv = AnyEvent->condvar;
557		664
558	my %result;	665	my %result;
559	$cv->begin (sub { $cv->send (\%result) });	666	$cv->begin (sub { $cv->send (\%result) });
…		…
579	loop, which serves two important purposes: first, it sets the callback	686	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	687	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	688	C<send> is called even when C<no> hosts are being pinged (the loop
582	doesn't execute once).	689	doesn't execute once).
583		690
584	This is the general pattern when you "fan out" into multiple subrequests:	691	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>	692	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	693	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>.	694	subrequest you start, call C<begin> and for each subrequest you finish,
		695	call C<end>.
588		696
589	=back	697	=back
590		698
591	=head3 METHODS FOR CONSUMERS	699	=head3 METHODS FOR CONSUMERS
592		700
…		…
608	function will call C<croak>.	716	function will call C<croak>.
609		717
610	In list context, all parameters passed to C<send> will be returned,	718	In list context, all parameters passed to C<send> will be returned,
611	in scalar context only the first one will be returned.	719	in scalar context only the first one will be returned.
612		720
		721	Note that doing a blocking wait in a callback is not supported by any
		722	event loop, that is, recursive invocation of a blocking C<< ->recv
		723	>> is not allowed, and the C<recv> call will C<croak> if such a
		724	condition is detected. This condition can be slightly loosened by using
		725	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		726	any thread that doesn't run the event loop itself.
		727
613	Not all event models support a blocking wait - some die in that case	728	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	729	(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	730	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	731	caller decide whether the call will block or not (for example, by coupling
617	condition variables with some kind of request results and supporting	732	condition variables with some kind of request results and supporting
618	callbacks so the caller knows that getting the result will not block,	733	callbacks so the caller knows that getting the result will not block,
619	while still supporting blocking waits if the caller so desires).	734	while still supporting blocking waits if the caller so desires).
620		735
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	736	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	737	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	738	time). This will work even when the event loop does not support blocking
635	waits otherwise.	739	waits otherwise.
636		740
…		…
649	variable itself. Calling C<recv> inside the callback or at any later time	753	variable itself. Calling C<recv> inside the callback or at any later time
650	is guaranteed not to block.	754	is guaranteed not to block.
651		755
652	=back	756	=back
653		757
		758	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		759
		760	The available backend classes are (every class has its own manpage):
		761
		762	=over 4
		763
		764	=item Backends that are autoprobed when no other event loop can be found.
		765
		766	EV is the preferred backend when no other event loop seems to be in
		767	use. If EV is not installed, then AnyEvent will try Event, and, failing
		768	that, will fall back to its own pure-perl implementation, which is
		769	available everywhere as it comes with AnyEvent itself.
		770
		771	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		772	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		773	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		774
		775	=item Backends that are transparently being picked up when they are used.
		776
		777	These will be used when they are currently loaded when the first watcher
		778	is created, in which case it is assumed that the application is using
		779	them. This means that AnyEvent will automatically pick the right backend
		780	when the main program loads an event module before anything starts to
		781	create watchers. Nothing special needs to be done by the main program.
		782
		783	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		784	AnyEvent::Impl::Tk based on Tk, very broken.
		785	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		786	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		787
		788	=item Backends with special needs.
		789
		790	Qt requires the Qt::Application to be instantiated first, but will
		791	otherwise be picked up automatically. As long as the main program
		792	instantiates the application before any AnyEvent watchers are created,
		793	everything should just work.
		794
		795	AnyEvent::Impl::Qt based on Qt.
		796
		797	Support for IO::Async can only be partial, as it is too broken and
		798	architecturally limited to even support the AnyEvent API. It also
		799	is the only event loop that needs the loop to be set explicitly, so
		800	it can only be used by a main program knowing about AnyEvent. See
		801	L<AnyEvent::Impl::Async> for the gory details.
		802
		803	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		804
		805	=item Event loops that are indirectly supported via other backends.
		806
		807	Some event loops can be supported via other modules:
		808
		809	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		810
		811	B<WxWidgets> has no support for watching file handles. However, you can
		812	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		813	polls 20 times per second, which was considered to be too horrible to even
		814	consider for AnyEvent.
		815
		816	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		817	backend, so it can be supported through POE.
		818
		819	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		820	load L<POE> when detecting them, in the hope that POE will pick them up,
		821	in which case everything will be automatic.
		822
		823	=back
		824
654	=head1 GLOBAL VARIABLES AND FUNCTIONS	825	=head1 GLOBAL VARIABLES AND FUNCTIONS
655		826
		827	These are not normally required to use AnyEvent, but can be useful to
		828	write AnyEvent extension modules.
		829
656	=over 4	830	=over 4
657		831
658	=item $AnyEvent::MODEL	832	=item $AnyEvent::MODEL
659		833
660	Contains C<undef> until the first watcher is being created. Then it	834	Contains C<undef> until the first watcher is being created, before the
		835	backend has been autodetected.
		836
661	contains the event model that is being used, which is the name of the	837	Afterwards it contains the event model that is being used, which is the
662	Perl class implementing the model. This class is usually one of the	838	name of the Perl class implementing the model. This class is usually one
663	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	839	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
664	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	840	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
665		841	will be C<urxvt::anyevent>).
666	The known classes so far are:
667
668	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
669	AnyEvent::Impl::Event based on Event, second best choice.
670	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
671	AnyEvent::Impl::Glib based on Glib, third-best choice.
672	AnyEvent::Impl::Tk based on Tk, very bad choice.
673	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
674	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
675	AnyEvent::Impl::POE based on POE, not generic enough for full support.
676
677	There is no support for WxWidgets, as WxWidgets has no support for
678	watching file handles. However, you can use WxWidgets through the
679	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
680	second, which was considered to be too horrible to even consider for
681	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
682	it's adaptor.
683
684	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
685	autodetecting them.
686		842
687	=item AnyEvent::detect	843	=item AnyEvent::detect
688		844
689	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	845	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
690	if necessary. You should only call this function right before you would	846	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	847	have created an AnyEvent watcher anyway, that is, as late as possible at
692	runtime.	848	runtime, and not e.g. while initialising of your module.
		849
		850	If you need to do some initialisation before AnyEvent watchers are
		851	created, use C<post_detect>.
693		852
694	=item $guard = AnyEvent::post_detect { BLOCK }	853	=item $guard = AnyEvent::post_detect { BLOCK }
695		854
696	Arranges for the code block to be executed as soon as the event model is	855	Arranges for the code block to be executed as soon as the event model is
697	autodetected (or immediately if this has already happened).	856	autodetected (or immediately if this has already happened).
		857
		858	The block will be executed I<after> the actual backend has been detected
		859	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		860	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		861	other initialisations - see the sources of L<AnyEvent::Strict> or
		862	L<AnyEvent::AIO> to see how this is used.
		863
		864	The most common usage is to create some global watchers, without forcing
		865	event module detection too early, for example, L<AnyEvent::AIO> creates
		866	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		867	avoid autodetecting the event module at load time.
698		868
699	If called in scalar or list context, then it creates and returns an object	869	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	870	that automatically removes the callback again when it is destroyed. See
701	L<Coro::BDB> for a case where this is useful.	871	L<Coro::BDB> for a case where this is useful.
702		872
…		…
705	If there are any code references in this array (you can C<push> to it	875	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	876	before or after loading AnyEvent), then they will called directly after
707	the event loop has been chosen.	877	the event loop has been chosen.
708		878
709	You should check C<$AnyEvent::MODEL> before adding to this array, though:	879	You should check C<$AnyEvent::MODEL> before adding to this array, though:
710	if it contains a true value then the event loop has already been detected,	880	if it is defined then the event loop has already been detected, and the
711	and the array will be ignored.	881	array will be ignored.
712		882
713	Best use C<AnyEvent::post_detect { BLOCK }> instead.	883	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		884	it,as it takes care of these details.
		885
		886	This variable is mainly useful for modules that can do something useful
		887	when AnyEvent is used and thus want to know when it is initialised, but do
		888	not need to even load it by default. This array provides the means to hook
		889	into AnyEvent passively, without loading it.
714		890
715	=back	891	=back
716		892
717	=head1 WHAT TO DO IN A MODULE	893	=head1 WHAT TO DO IN A MODULE
718		894
…		…
773		949
774		950
775	=head1 OTHER MODULES	951	=head1 OTHER MODULES
776		952
777	The following is a non-exhaustive list of additional modules that use	953	The following is a non-exhaustive list of additional modules that use
778	AnyEvent and can therefore be mixed easily with other AnyEvent modules	954	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	955	modules and other event loops in the same program. Some of the modules
780	available via CPAN.	956	come with AnyEvent, most are available via CPAN.
781		957
782	=over 4	958	=over 4
783		959
784	=item L<AnyEvent::Util>	960	=item L<AnyEvent::Util>
785		961
…		…
794		970
795	=item L<AnyEvent::Handle>	971	=item L<AnyEvent::Handle>
796		972
797	Provide read and write buffers, manages watchers for reads and writes,	973	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	974	supports raw and formatted I/O, I/O queued and fully transparent and
799	non-blocking SSL/TLS.	975	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
800		976
801	=item L<AnyEvent::DNS>	977	=item L<AnyEvent::DNS>
802		978
803	Provides rich asynchronous DNS resolver capabilities.	979	Provides rich asynchronous DNS resolver capabilities.
804		980
…		…
832		1008
833	=item L<AnyEvent::GPSD>	1009	=item L<AnyEvent::GPSD>
834		1010
835	A non-blocking interface to gpsd, a daemon delivering GPS information.	1011	A non-blocking interface to gpsd, a daemon delivering GPS information.
836		1012
		1013	=item L<AnyEvent::IRC>
		1014
		1015	AnyEvent based IRC client module family (replacing the older Net::IRC3).
		1016
		1017	=item L<AnyEvent::XMPP>
		1018
		1019	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1020	Net::XMPP2>.
		1021
837	=item L<AnyEvent::IGS>	1022	=item L<AnyEvent::IGS>
838		1023
839	A non-blocking interface to the Internet Go Server protocol (used by	1024	A non-blocking interface to the Internet Go Server protocol (used by
840	L<App::IGS>).	1025	L<App::IGS>).
841		1026
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>	1027	=item L<Net::FCP>
851		1028
852	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1029	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
853	of AnyEvent.	1030	of AnyEvent.
854		1031
…		…
858		1035
859	=item L<Coro>	1036	=item L<Coro>
860		1037
861	Has special support for AnyEvent via L<Coro::AnyEvent>.	1038	Has special support for AnyEvent via L<Coro::AnyEvent>.
862		1039
863	=item L<IO::Lambda>
864
865	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
866
867	=back	1040	=back
868		1041
869	=cut	1042	=cut
870		1043
871	package AnyEvent;	1044	package AnyEvent;
872		1045
		1046	# basically a tuned-down version of common::sense
		1047	sub common_sense {
873	no warnings;	1048	# no warnings
		1049	${^WARNING_BITS} ^= ${^WARNING_BITS};
874	use strict qw(vars subs);	1050	# use strict vars subs
		1051	$^H \|= 0x00000600;
		1052	}
875		1053
		1054	BEGIN { AnyEvent::common_sense }
		1055
876	use Carp;	1056	use Carp ();
877		1057
878	our $VERSION = 4.35;	1058	our $VERSION = 4.83;
879	our $MODEL;	1059	our $MODEL;
880		1060
881	our $AUTOLOAD;	1061	our $AUTOLOAD;
882	our @ISA;	1062	our @ISA;
883		1063
884	our @REGISTRY;	1064	our @REGISTRY;
885		1065
886	our $WIN32;	1066	our $WIN32;
887		1067
		1068	our $VERBOSE;
		1069
888	BEGIN {	1070	BEGIN {
889	my $win32 = ! ! ($^O =~ /mswin32/i);	1071	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
890	eval "sub WIN32(){ $win32 }";	1072	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
891	}
892		1073
		1074	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1075	if ${^TAINT};
		1076
893	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1077	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1078
		1079	}
		1080
		1081	our $MAX_SIGNAL_LATENCY = 10;
894		1082
895	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1083	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
896		1084
897	{	1085	{
898	my $idx;	1086	my $idx;
…		…
906	[Event:: => AnyEvent::Impl::Event::],	1094	[Event:: => AnyEvent::Impl::Event::],
907	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1095	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
908	# everything below here will not be autoprobed	1096	# everything below here will not be autoprobed
909	# as the pureperl backend should work everywhere	1097	# as the pureperl backend should work everywhere
910	# and is usually faster	1098	# and is usually faster
911	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
912	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1099	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
913	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1100	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1101	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
914	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1102	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
915	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1103	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
916	[Wx:: => AnyEvent::Impl::POE::],	1104	[Wx:: => AnyEvent::Impl::POE::],
917	[Prima:: => AnyEvent::Impl::POE::],	1105	[Prima:: => AnyEvent::Impl::POE::],
		1106	# IO::Async is just too broken - we would need workarounds for its
		1107	# byzantine signal and broken child handling, among others.
		1108	# IO::Async is rather hard to detect, as it doesn't have any
		1109	# obvious default class.
		1110	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1111	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1112	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
918	);	1113	);
919		1114
920	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1115	our %method = map +($_ => 1),
		1116	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
921		1117
922	our @post_detect;	1118	our @post_detect;
923		1119
924	sub post_detect(&) {	1120	sub post_detect(&) {
925	my ($cb) = @_;	1121	my ($cb) = @_;
…		…
930	1	1126	1
931	} else {	1127	} else {
932	push @post_detect, $cb;	1128	push @post_detect, $cb;
933		1129
934	defined wantarray	1130	defined wantarray
935	? bless \$cb, "AnyEvent::Util::PostDetect"	1131	? bless \$cb, "AnyEvent::Util::postdetect"
936	: ()	1132	: ()
937	}	1133	}
938	}	1134	}
939		1135
940	sub AnyEvent::Util::PostDetect::DESTROY {	1136	sub AnyEvent::Util::postdetect::DESTROY {
941	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1137	@post_detect = grep $_ != ${$_[0]}, @post_detect;
942	}	1138	}
943		1139
944	sub detect() {	1140	sub detect() {
945	unless ($MODEL) {	1141	unless ($MODEL) {
946	no strict 'refs';
947	local $SIG{__DIE__};	1142	local $SIG{__DIE__};
948		1143
949	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1144	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
950	my $model = "AnyEvent::Impl::$1";	1145	my $model = "AnyEvent::Impl::$1";
951	if (eval "require $model") {	1146	if (eval "require $model") {
952	$MODEL = $model;	1147	$MODEL = $model;
953	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1148	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
954	} else {	1149	} else {
955	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1150	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
956	}	1151	}
957	}	1152	}
958		1153
959	# check for already loaded models	1154	# check for already loaded models
960	unless ($MODEL) {	1155	unless ($MODEL) {
961	for (@REGISTRY, @models) {	1156	for (@REGISTRY, @models) {
962	my ($package, $model) = @$_;	1157	my ($package, $model) = @$_;
963	if (${"$package\::VERSION"} > 0) {	1158	if (${"$package\::VERSION"} > 0) {
964	if (eval "require $model") {	1159	if (eval "require $model") {
965	$MODEL = $model;	1160	$MODEL = $model;
966	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1161	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
967	last;	1162	last;
968	}	1163	}
969	}	1164	}
970	}	1165	}
971		1166
…		…
976	my ($package, $model) = @$_;	1171	my ($package, $model) = @$_;
977	if (eval "require $package"	1172	if (eval "require $package"
978	and ${"$package\::VERSION"} > 0	1173	and ${"$package\::VERSION"} > 0
979	and eval "require $model") {	1174	and eval "require $model") {
980	$MODEL = $model;	1175	$MODEL = $model;
981	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1176	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
982	last;	1177	last;
983	}	1178	}
984	}	1179	}
985		1180
986	$MODEL	1181	$MODEL
987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1182	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
988	}	1183	}
989	}	1184	}
990		1185
991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1186	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
992		1187
…		…
1002		1197
1003	sub AUTOLOAD {	1198	sub AUTOLOAD {
1004	(my $func = $AUTOLOAD) =~ s/.*://;	1199	(my $func = $AUTOLOAD) =~ s/.*://;
1005		1200
1006	$method{$func}	1201	$method{$func}
1007	or croak "$func: not a valid method for AnyEvent objects";	1202	or Carp::croak "$func: not a valid method for AnyEvent objects";
1008		1203
1009	detect unless $MODEL;	1204	detect unless $MODEL;
1010		1205
1011	my $class = shift;	1206	my $class = shift;
1012	$class->$func (@_);	1207	$class->$func (@_);
1013	}	1208	}
1014		1209
1015	# utility function to dup a filehandle. this is used by many backends	1210	# utility function to dup a filehandle. this is used by many backends
1016	# to support binding more than one watcher per filehandle (they usually	1211	# 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).	1212	# allow only one watcher per fd, so we dup it to get a different one).
1018	sub _dupfh($$$$) {	1213	sub _dupfh($$;$$) {
1019	my ($poll, $fh, $r, $w) = @_;	1214	my ($poll, $fh, $r, $w) = @_;
1020		1215
1021	# cygwin requires the fh mode to be matching, unix doesn't	1216	# cygwin requires the fh mode to be matching, unix doesn't
1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1217	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		1218
1026	open my $fh2, "$mode&" . fileno $fh	1219	open my $fh2, $mode, $fh
1027	or die "cannot dup() filehandle: $!";	1220	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1028		1221
1029	# we assume CLOEXEC is already set by perl in all important cases	1222	# we assume CLOEXEC is already set by perl in all important cases
1030		1223
1031	($fh2, $rw)	1224	($fh2, $rw)
1032	}	1225	}
1033		1226
1034	package AnyEvent::Base;	1227	package AnyEvent::Base;
1035		1228
1036	# default implementation for now and time	1229	# default implementations for many methods
1037		1230
1038	BEGIN {	1231	sub _time {
		1232	# probe for availability of Time::HiRes
1039	if (eval "use Time::HiRes (); time (); 1") {	1233	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1234	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1040	*_time = \&Time::HiRes::time;	1235	*_time = \&Time::HiRes::time;
1041	# if (eval "use POSIX (); (POSIX::times())...	1236	# if (eval "use POSIX (); (POSIX::times())...
1042	} else {	1237	} else {
		1238	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1043	*_time = sub { time }; # epic fail	1239	*_time = sub { time }; # epic fail
1044	}	1240	}
		1241
		1242	&_time
1045	}	1243	}
1046		1244
1047	sub time { _time }	1245	sub time { _time }
1048	sub now { _time }	1246	sub now { _time }
		1247	sub now_update { }
1049		1248
1050	# default implementation for ->condvar	1249	# default implementation for ->condvar
1051		1250
1052	sub condvar {	1251	sub condvar {
1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1252	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1054	}	1253	}
1055		1254
1056	# default implementation for ->signal	1255	# default implementation for ->signal
1057		1256
		1257	our $HAVE_ASYNC_INTERRUPT;
1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1258	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1259	our (%SIG_ASY, %SIG_ASY_W);
		1260	our ($SIG_COUNT, $SIG_TW);
1059		1261
1060	sub _signal_exec {	1262	sub _signal_exec {
		1263	$HAVE_ASYNC_INTERRUPT
		1264	? $SIGPIPE_R->drain
1061	sysread $SIGPIPE_R, my $dummy, 4;	1265	: sysread $SIGPIPE_R, my $dummy, 9;
1062		1266
1063	while (%SIG_EV) {	1267	while (%SIG_EV) {
1064	for (keys %SIG_EV) {	1268	for (keys %SIG_EV) {
1065	delete $SIG_EV{$_};	1269	delete $SIG_EV{$_};
1066	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1270	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1067	}	1271	}
1068	}	1272	}
1069	}	1273	}
1070		1274
		1275	sub _signal {
		1276	my (undef, %arg) = @_;
		1277
		1278	my $signal = uc $arg{signal}
		1279	or Carp::croak "required option 'signal' is missing";
		1280
		1281	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1282
		1283	if ($HAVE_ASYNC_INTERRUPT) {
		1284	# async::interrupt
		1285
		1286	$SIG_ASY{$signal} \|\|= do {
		1287	my $asy = new Async::Interrupt
		1288	cb => sub { undef $SIG_EV{$signal} },
		1289	signal => $signal,
		1290	pipe => [$SIGPIPE_R->filenos],
		1291	;
		1292	$asy->pipe_autodrain (0);
		1293
		1294	$asy
		1295	};
		1296
		1297	} else {
		1298	# pure perl
		1299
		1300	$SIG{$signal} \|\|= sub {
		1301	local $!;
		1302	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1303	undef $SIG_EV{$signal};
		1304	};
		1305
		1306	# can't do signal processing without introducing races in pure perl,
		1307	# so limit the signal latency.
		1308	++$SIG_COUNT;
		1309	$SIG_TW \|\|= AnyEvent->timer (
		1310	after => $MAX_SIGNAL_LATENCY,
		1311	interval => $MAX_SIGNAL_LATENCY,
		1312	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1313	);
		1314	}
		1315
		1316	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1317	}
		1318
1071	sub signal {	1319	sub signal {
1072	my (undef, %arg) = @_;	1320	# probe for availability of Async::Interrupt
		1321	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1322	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1073		1323
1074	unless ($SIGPIPE_R) {	1324	$HAVE_ASYNC_INTERRUPT = 1;
		1325	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1326	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1327
		1328	} else {
		1329	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1330
1075	require Fcntl;	1331	require Fcntl;
1076		1332
1077	if (AnyEvent::WIN32) {	1333	if (AnyEvent::WIN32) {
1078	require AnyEvent::Util;	1334	require AnyEvent::Util;
1079		1335
…		…
1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case	1338	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1083	} else {	1339	} else {
1084	pipe $SIGPIPE_R, $SIGPIPE_W;	1340	pipe $SIGPIPE_R, $SIGPIPE_W;
1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1341	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1342	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1343
		1344	# not strictly required, as $^F is normally 2, but let's make sure...
		1345	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1346	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1087	}	1347	}
1088		1348
1089	$SIGPIPE_R	1349	$SIGPIPE_R
1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1350	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1091		1351
1092	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1093	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1094
1095	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1352	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1096	}	1353	}
1097		1354
1098	my $signal = uc $arg{signal}	1355	*signal = \&_signal;
1099	or Carp::croak "required option 'signal' is missing";	1356	&signal
1100
1101	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1102	$SIG{$signal} \|\|= sub {
1103	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1104	undef $SIG_EV{$signal};
1105	};
1106
1107	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1108	}	1357	}
1109		1358
1110	sub AnyEvent::Base::Signal::DESTROY {	1359	sub AnyEvent::Base::signal::DESTROY {
1111	my ($signal, $cb) = @{$_[0]};	1360	my ($signal, $cb) = @{$_[0]};
1112		1361
		1362	undef $SIG_TW
		1363	unless --$SIG_COUNT;
		1364
1113	delete $SIG_CB{$signal}{$cb};	1365	delete $SIG_CB{$signal}{$cb};
1114		1366
		1367	# delete doesn't work with older perls - they then
		1368	# print weird messages, or just unconditionally exit
		1369	# instead of getting the default action.
		1370	undef $SIG{$signal}
1115	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1371	unless keys %{ $SIG_CB{$signal} };
1116	}	1372	}
1117		1373
1118	# default implementation for ->child	1374	# default implementation for ->child
1119		1375
1120	our %PID_CB;	1376	our %PID_CB;
1121	our $CHLD_W;	1377	our $CHLD_W;
1122	our $CHLD_DELAY_W;	1378	our $CHLD_DELAY_W;
1123	our $PID_IDLE;
1124	our $WNOHANG;	1379	our $WNOHANG;
1125		1380
1126	sub _child_wait {	1381	sub _sigchld {
1127	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1382	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1383	$_->($pid, $?)
1128	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1384	for values %{ $PID_CB{$pid} \|\| {} },
1129	(values %{ $PID_CB{0} \|\| {} });	1385	values %{ $PID_CB{0} \|\| {} };
1130	}	1386	}
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	}	1387	}
1142		1388
1143	sub child {	1389	sub child {
1144	my (undef, %arg) = @_;	1390	my (undef, %arg) = @_;
1145		1391
1146	defined (my $pid = $arg{pid} + 0)	1392	defined (my $pid = $arg{pid} + 0)
1147	or Carp::croak "required option 'pid' is missing";	1393	or Carp::croak "required option 'pid' is missing";
1148		1394
1149	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1395	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1150		1396
1151	unless ($WNOHANG) {	1397	# WNOHANG is almost cetrainly 1 everywhere
		1398	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1399	? 1
1152	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1400	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1153	}
1154		1401
1155	unless ($CHLD_W) {	1402	unless ($CHLD_W) {
1156	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1403	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1157	# child could be a zombie already, so make at least one round	1404	# child could be a zombie already, so make at least one round
1158	&_sigchld;	1405	&_sigchld;
1159	}	1406	}
1160		1407
1161	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1408	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1162	}	1409	}
1163		1410
1164	sub AnyEvent::Base::Child::DESTROY {	1411	sub AnyEvent::Base::child::DESTROY {
1165	my ($pid, $cb) = @{$_[0]};	1412	my ($pid, $cb) = @{$_[0]};
1166		1413
1167	delete $PID_CB{$pid}{$cb};	1414	delete $PID_CB{$pid}{$cb};
1168	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1415	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1169		1416
1170	undef $CHLD_W unless keys %PID_CB;	1417	undef $CHLD_W unless keys %PID_CB;
1171	}	1418	}
1172		1419
		1420	# idle emulation is done by simply using a timer, regardless
		1421	# of whether the process is idle or not, and not letting
		1422	# the callback use more than 50% of the time.
		1423	sub idle {
		1424	my (undef, %arg) = @_;
		1425
		1426	my ($cb, $w, $rcb) = $arg{cb};
		1427
		1428	$rcb = sub {
		1429	if ($cb) {
		1430	$w = _time;
		1431	&$cb;
		1432	$w = _time - $w;
		1433
		1434	# never use more then 50% of the time for the idle watcher,
		1435	# within some limits
		1436	$w = 0.0001 if $w < 0.0001;
		1437	$w = 5 if $w > 5;
		1438
		1439	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1440	} else {
		1441	# clean up...
		1442	undef $w;
		1443	undef $rcb;
		1444	}
		1445	};
		1446
		1447	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1448
		1449	bless \\$cb, "AnyEvent::Base::idle"
		1450	}
		1451
		1452	sub AnyEvent::Base::idle::DESTROY {
		1453	undef $${$_[0]};
		1454	}
		1455
1173	package AnyEvent::CondVar;	1456	package AnyEvent::CondVar;
1174		1457
1175	our @ISA = AnyEvent::CondVar::Base::;	1458	our @ISA = AnyEvent::CondVar::Base::;
1176		1459
1177	package AnyEvent::CondVar::Base;	1460	package AnyEvent::CondVar::Base;
1178		1461
1179	use overload	1462	#use overload
1180	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1463	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1181	fallback => 1;	1464	# fallback => 1;
		1465
		1466	# save 300+ kilobytes by dirtily hardcoding overloading
		1467	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1468	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1469	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1470	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1471
		1472	our $WAITING;
1182		1473
1183	sub _send {	1474	sub _send {
1184	# nop	1475	# nop
1185	}	1476	}
1186		1477
…		…
1199	sub ready {	1490	sub ready {
1200	$_[0]{_ae_sent}	1491	$_[0]{_ae_sent}
1201	}	1492	}
1202		1493
1203	sub _wait {	1494	sub _wait {
		1495	$WAITING
		1496	and !$_[0]{_ae_sent}
		1497	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1498
		1499	local $WAITING = 1;
1204	AnyEvent->one_event while !$_[0]{_ae_sent};	1500	AnyEvent->one_event while !$_[0]{_ae_sent};
1205	}	1501	}
1206		1502
1207	sub recv {	1503	sub recv {
1208	$_[0]->_wait;	1504	$_[0]->_wait;
…		…
1249	so on.	1545	so on.
1250		1546
1251	=head1 ENVIRONMENT VARIABLES	1547	=head1 ENVIRONMENT VARIABLES
1252		1548
1253	The following environment variables are used by this module or its	1549	The following environment variables are used by this module or its
1254	submodules:	1550	submodules.
		1551
		1552	Note that AnyEvent will remove I<all> environment variables starting with
		1553	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1554	enabled.
1255		1555
1256	=over 4	1556	=over 4
1257		1557
1258	=item C<PERL_ANYEVENT_VERBOSE>	1558	=item C<PERL_ANYEVENT_VERBOSE>
1259		1559
…		…
1271	=item C<PERL_ANYEVENT_STRICT>	1571	=item C<PERL_ANYEVENT_STRICT>
1272		1572
1273	AnyEvent does not do much argument checking by default, as thorough	1573	AnyEvent does not do much argument checking by default, as thorough
1274	argument checking is very costly. Setting this variable to a true value	1574	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	1575	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	1576	check the arguments passed to most method calls. If it finds any problems,
1277	it will croak.	1577	it will croak.
1278		1578
1279	In other words, enables "strict" mode.	1579	In other words, enables "strict" mode.
1280		1580
1281	Unlike C<use strict>, it is definitely recommended ot keep it off in	1581	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	1582	>>, it is definitely recommended to keep it off in production. Keeping
1283	developing programs can be very useful, however.	1583	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1584	can be very useful, however.
1284		1585
1285	=item C<PERL_ANYEVENT_MODEL>	1586	=item C<PERL_ANYEVENT_MODEL>
1286		1587
1287	This can be used to specify the event model to be used by AnyEvent, before	1588	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	1589	auto detection and -probing kicks in. It must be a string consisting
…		…
1331		1632
1332	=item C<PERL_ANYEVENT_MAX_FORKS>	1633	=item C<PERL_ANYEVENT_MAX_FORKS>
1333		1634
1334	The maximum number of child processes that C<AnyEvent::Util::fork_call>	1635	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1335	will create in parallel.	1636	will create in parallel.
		1637
		1638	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1639
		1640	The default value for the C<max_outstanding> parameter for the default DNS
		1641	resolver - this is the maximum number of parallel DNS requests that are
		1642	sent to the DNS server.
		1643
		1644	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1645
		1646	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1647	configuration) in the default resolver. When set to the empty string, no
		1648	default config will be used.
		1649
		1650	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1651
		1652	When neither C<ca_file> nor C<ca_path> was specified during
		1653	L<AnyEvent::TLS> context creation, and either of these environment
		1654	variables exist, they will be used to specify CA certificate locations
		1655	instead of a system-dependent default.
1336		1656
1337	=back	1657	=back
1338		1658
1339	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1659	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1340		1660
…		…
1585	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	1905	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1586	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	1906	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1587	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	1907	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1588	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	1908	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1589	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	1909	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1910	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1911	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1590	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	1912	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1591	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	1913	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1592	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	1914	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1593	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	1915	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1594		1916
…		…
1623	performance becomes really bad with lots of file descriptors (and few of	1945	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.	1946	them active), of course, but this was not subject of this benchmark.
1625		1947
1626	The C<Event> module has a relatively high setup and callback invocation	1948	The C<Event> module has a relatively high setup and callback invocation
1627	cost, but overall scores in on the third place.	1949	cost, but overall scores in on the third place.
		1950
		1951	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1952	when using its pure perl backend.
1628		1953
1629	C<Glib>'s memory usage is quite a bit higher, but it features a	1954	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	1955	faster callback invocation and overall ends up in the same class as
1631	C<Event>. However, Glib scales extremely badly, doubling the number of	1956	C<Event>. However, Glib scales extremely badly, doubling the number of
1632	watchers increases the processing time by more than a factor of four,	1957	watchers increases the processing time by more than a factor of four,
…		…
1710	it to another server. This includes deleting the old timeout and creating	2035	it to another server. This includes deleting the old timeout and creating
1711	a new one that moves the timeout into the future.	2036	a new one that moves the timeout into the future.
1712		2037
1713	=head3 Results	2038	=head3 Results
1714		2039
1715	name sockets create request	2040	name sockets create request
1716	EV 20000 69.01 11.16	2041	EV 20000 69.01 11.16
1717	Perl 20000 73.32 35.87	2042	Perl 20000 73.32 35.87
		2043	IOAsync 20000 157.00 98.14 epoll
		2044	IOAsync 20000 159.31 616.06 poll
1718	Event 20000 212.62 257.32	2045	Event 20000 212.62 257.32
1719	Glib 20000 651.16 1896.30	2046	Glib 20000 651.16 1896.30
1720	POE 20000 349.67 12317.24 uses POE::Loop::Event	2047	POE 20000 349.67 12317.24 uses POE::Loop::Event
1721		2048
1722	=head3 Discussion	2049	=head3 Discussion
1723		2050
1724	This benchmark I<does> measure scalability and overall performance of the	2051	This benchmark I<does> measure scalability and overall performance of the
1725	particular event loop.	2052	particular event loop.
…		…
1727	EV is again fastest. Since it is using epoll on my system, the setup time	2054	EV is again fastest. Since it is using epoll on my system, the setup time
1728	is relatively high, though.	2055	is relatively high, though.
1729		2056
1730	Perl surprisingly comes second. It is much faster than the C-based event	2057	Perl surprisingly comes second. It is much faster than the C-based event
1731	loops Event and Glib.	2058	loops Event and Glib.
		2059
		2060	IO::Async performs very well when using its epoll backend, and still quite
		2061	good compared to Glib when using its pure perl backend.
1732		2062
1733	Event suffers from high setup time as well (look at its code and you will	2063	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	2064	understand why). Callback invocation also has a high overhead compared to
1735	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	2065	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1736	uses select or poll in basically all documented configurations.	2066	uses select or poll in basically all documented configurations.
…		…
1799	=item * C-based event loops perform very well with small number of	2129	=item * C-based event loops perform very well with small number of
1800	watchers, as the management overhead dominates.	2130	watchers, as the management overhead dominates.
1801		2131
1802	=back	2132	=back
1803		2133
		2134	=head2 THE IO::Lambda BENCHMARK
		2135
		2136	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2137	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2138	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2139	shouldn't come as a surprise to anybody). As such, the benchmark is
		2140	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2141	very optimal. But how would AnyEvent compare when used without the extra
		2142	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2143
		2144	The benchmark itself creates an echo-server, and then, for 500 times,
		2145	connects to the echo server, sends a line, waits for the reply, and then
		2146	creates the next connection. This is a rather bad benchmark, as it doesn't
		2147	test the efficiency of the framework or much non-blocking I/O, but it is a
		2148	benchmark nevertheless.
		2149
		2150	name runtime
		2151	Lambda/select 0.330 sec
		2152	+ optimized 0.122 sec
		2153	Lambda/AnyEvent 0.327 sec
		2154	+ optimized 0.138 sec
		2155	Raw sockets/select 0.077 sec
		2156	POE/select, components 0.662 sec
		2157	POE/select, raw sockets 0.226 sec
		2158	POE/select, optimized 0.404 sec
		2159
		2160	AnyEvent/select/nb 0.085 sec
		2161	AnyEvent/EV/nb 0.068 sec
		2162	+state machine 0.134 sec
		2163
		2164	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2165	benchmarks actually make blocking connects and use 100% blocking I/O,
		2166	defeating the purpose of an event-based solution. All of the newly
		2167	written AnyEvent benchmarks use 100% non-blocking connects (using
		2168	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2169	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2170	generally require a lot more bookkeeping and event handling than blocking
		2171	connects (which involve a single syscall only).
		2172
		2173	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2174	offers similar expressive power as POE and IO::Lambda, using conventional
		2175	Perl syntax. This means that both the echo server and the client are 100%
		2176	non-blocking, further placing it at a disadvantage.
		2177
		2178	As you can see, the AnyEvent + EV combination even beats the
		2179	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2180	backend easily beats IO::Lambda and POE.
		2181
		2182	And even the 100% non-blocking version written using the high-level (and
		2183	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2184	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2185	in a non-blocking way.
		2186
		2187	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2188	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2189	part of the IO::lambda distribution and were used without any changes.
		2190
1804		2191
1805	=head1 SIGNALS	2192	=head1 SIGNALS
1806		2193
1807	AnyEvent currently installs handlers for these signals:	2194	AnyEvent currently installs handlers for these signals:
1808		2195
…		…
1811	=item SIGCHLD	2198	=item SIGCHLD
1812		2199
1813	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2200	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	2201	emulation for event loops that do not support them natively. Also, some
1815	event loops install a similar handler.	2202	event loops install a similar handler.
		2203
		2204	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2205	AnyEvent will reset it to default, to avoid losing child exit statuses.
1816		2206
1817	=item SIGPIPE	2207	=item SIGPIPE
1818		2208
1819	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2209	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
1820	when AnyEvent gets loaded.	2210	when AnyEvent gets loaded.
…		…
1832		2222
1833	=back	2223	=back
1834		2224
1835	=cut	2225	=cut
1836		2226
		2227	undef $SIG{CHLD}
		2228	if $SIG{CHLD} eq 'IGNORE';
		2229
1837	$SIG{PIPE} = sub { }	2230	$SIG{PIPE} = sub { }
1838	unless defined $SIG{PIPE};	2231	unless defined $SIG{PIPE};
		2232
		2233	=head1 RECOMMENDED/OPTIONAL MODULES
		2234
		2235	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2236	it's built-in modules) are required to use it.
		2237
		2238	That does not mean that AnyEvent won't take advantage of some additional
		2239	modules if they are installed.
		2240
		2241	This section epxlains which additional modules will be used, and how they
		2242	affect AnyEvent's operetion.
		2243
		2244	=over 4
		2245
		2246	=item L<Async::Interrupt>
		2247
		2248	This slightly arcane module is used to implement fast signal handling: To
		2249	my knowledge, there is no way to do completely race-free and quick
		2250	signal handling in pure perl. To ensure that signals still get
		2251	delivered, AnyEvent will start an interval timer to wake up perl (and
		2252	catch the signals) with soemd elay (default is 10 seconds, look for
		2253	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2254
		2255	If this module is available, then it will be used to implement signal
		2256	catching, which means that signals will not be delayed, and the event loop
		2257	will not be interrupted regularly, which is more efficient (And good for
		2258	battery life on laptops).
		2259
		2260	This affects not just the pure-perl event loop, but also other event loops
		2261	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2262
		2263	=item L<EV>
		2264
		2265	This module isn't really "optional", as it is simply one of the backend
		2266	event loops that AnyEvent can use. However, it is simply the best event
		2267	loop available in terms of features, speed and stability: It supports
		2268	the AnyEvent API optimally, implements all the watcher types in XS, does
		2269	automatic timer adjustments even when no monotonic clock is available,
		2270	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2271	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2272	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2273
		2274	=item L<Guard>
		2275
		2276	The guard module, when used, will be used to implement
		2277	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2278	lot less memory), but otherwise doesn't affect guard operation much. It is
		2279	purely used for performance.
		2280
		2281	=item L<JSON> and L<JSON::XS>
		2282
		2283	This module is required when you want to read or write JSON data via
		2284	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2285	advantage of the ulta-high-speed L<JSON::XS> module when it is installed.
		2286
		2287	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2288	installed.
		2289
		2290	=item L<Net::SSLeay>
		2291
		2292	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2293	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2294	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2295
		2296	=item L<Time::HiRes>
		2297
		2298	This module is part of perl since release 5.008. It will be used when the
		2299	chosen event library does not come with a timing source on it's own. The
		2300	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2301	try to use a monotonic clock for timing stability.
		2302
		2303	=back
1839		2304
1840		2305
1841	=head1 FORK	2306	=head1 FORK
1842		2307
1843	Most event libraries are not fork-safe. The ones who are usually are	2308	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>	2309	because they rely on inefficient but fork-safe C<select> or C<poll>
1845	calls. Only L<EV> is fully fork-aware.	2310	calls. Only L<EV> is fully fork-aware.
1846		2311
1847	If you have to fork, you must either do so I<before> creating your first	2312	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.	2313	watcher OR you must not use AnyEvent at all in the child OR you must do
		2314	something completely out of the scope of AnyEvent.
1849		2315
1850		2316
1851	=head1 SECURITY CONSIDERATIONS	2317	=head1 SECURITY CONSIDERATIONS
1852		2318
1853	AnyEvent can be forced to load any event model via	2319	AnyEvent can be forced to load any event model via
…		…
1865	use AnyEvent;	2331	use AnyEvent;
1866		2332
1867	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2333	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	2334	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	2335	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1870	$ENV{PERL_ANYEGENT_STRICT}.	2336	$ENV{PERL_ANYEVENT_STRICT}.
		2337
		2338	Note that AnyEvent will remove I<all> environment variables starting with
		2339	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2340	enabled.
1871		2341
1872		2342
1873	=head1 BUGS	2343	=head1 BUGS
1874		2344
1875	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2345	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>.	2357	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1888		2358
1889	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2359	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1890	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2360	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1891	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2361	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1892	L<AnyEvent::Impl::POE>.	2362	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1893		2363
1894	Non-blocking file handles, sockets, TCP clients and	2364	Non-blocking file handles, sockets, TCP clients and
1895	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2365	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1896		2366
1897	Asynchronous DNS: L<AnyEvent::DNS>.	2367	Asynchronous DNS: L<AnyEvent::DNS>.
1898		2368
1899	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2369	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2370	L<Coro::Event>,
1900		2371
1901	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2372	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2373	L<AnyEvent::HTTP>.
1902		2374
1903		2375
1904	=head1 AUTHOR	2376	=head1 AUTHOR
1905		2377
1906	Marc Lehmann <schmorp@schmorp.de>	2378	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.200 by root, Wed Apr 1 14:02:27 2009 UTC vs. Revision 1.243 by root, Fri Jul 17 23:12:20 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.200 by root, Wed Apr 1 14:02:27 2009 UTC vs.
Revision 1.243 by root, Fri Jul 17 23:12:20 2009 UTC