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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.231 by root, Wed Jul 8 13:46:46 2009 UTC vs.
Revision 1.253 by root, Tue Jul 21 06:00:47 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - events independent of event loop implementation
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
6	event loops.	6	event loops.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
40	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
41		41
42	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	44	L<AnyEvent::Intro> manpage.
		45
		46	=head1 SUPPORT
		47
		48	There is a mailinglist for discussing all things AnyEvent, and an IRC
		49	channel, too.
		50
		51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		52	Respository>, at L<http://anyevent.schmorp.de>, for more info.
45		53
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		55
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	57	nowadays. So what is different about AnyEvent?
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	369	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	370	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	371	but it is guaranteed not to interrupt any other callbacks.
364		372
365	The main advantage of using these watchers is that you can share a signal	373	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	374	between multiple watchers, and AnyEvent will ensure that signals will not
		375	interrupt your program at bad times.
367		376
368	This watcher might use C<%SIG>, so programs overwriting those signals	377	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	378	so programs overwriting those signals directly will likely not work
		379	correctly.
370		380
371	Example: exit on SIGINT	381	Example: exit on SIGINT
372		382
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		384
		385	=head3 Signal Races, Delays and Workarounds
		386
		387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		388	callbacks to signals in a generic way, which is a pity, as you cannot do
		389	race-free signal handling in perl. AnyEvent will try to do it's best, but
		390	in some cases, signals will be delayed. The maximum time a signal might
		391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10
		392	seconds). This variable can be changed only before the first signal
		393	watcher is created, and should be left alone otherwise. Higher values
		394	will cause fewer spurious wake-ups, which is better for power and CPU
		395	saving. All these problems can be avoided by installing the optional
		396	L<Async::Interrupt> module. This will not work with inherently broken
		397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>
		398	currently, as POE does it's own workaround with one-second latency). With
		399	those, you just have to suffer the delays.
374		400
375	=head2 CHILD PROCESS WATCHERS	401	=head2 CHILD PROCESS WATCHERS
376		402
377	You can also watch on a child process exit and catch its exit status.	403	You can also watch on a child process exit and catch its exit status.
378		404
…		…
403		429
404	This means you cannot create a child watcher as the very first	430	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	431	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	432	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	433	C<AnyEvent::detect>).
		434
		435	As most event loops do not support waiting for child events, they will be
		436	emulated by AnyEvent in most cases, in which the latency and race problems
		437	mentioned in the description of signal watchers apply.
408		438
409	Example: fork a process and wait for it	439	Example: fork a process and wait for it
410		440
411	my $done = AnyEvent->condvar;	441	my $done = AnyEvent->condvar;
412		442
…		…
463		493
464	If you are familiar with some event loops you will know that all of them	494	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	495	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	496	will actively watch for new events and call your callbacks.
467		497
468	AnyEvent is different, it expects somebody else to run the event loop and	498	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	499	loop and will only block when necessary (usually when told by the user).
470		500
471	The instrument to do that is called a "condition variable", so called	501	The instrument to do that is called a "condition variable", so called
472	because they represent a condition that must become true.	502	because they represent a condition that must become true.
473		503
		504	Now is probably a good time to look at the examples further below.
		505
474	Condition variables can be created by calling the C<< AnyEvent->condvar	506	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	507	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	508	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	509	becomes true, with the condition variable as the first argument (but not
479	the results).	510	the results).
480		511
481	After creation, the condition variable is "false" until it becomes "true"	512	After creation, the condition variable is "false" until it becomes "true"
…		…
486	Condition variables are similar to callbacks, except that you can	517	Condition variables are similar to callbacks, except that you can
487	optionally wait for them. They can also be called merge points - points	518	optionally wait for them. They can also be called merge points - points
488	in time where multiple outstanding events have been processed. And yet	519	in time where multiple outstanding events have been processed. And yet
489	another way to call them is transactions - each condition variable can be	520	another way to call them is transactions - each condition variable can be
490	used to represent a transaction, which finishes at some point and delivers	521	used to represent a transaction, which finishes at some point and delivers
491	a result.	522	a result. And yet some people know them as "futures" - a promise to
		523	compute/deliver something that you can wait for.
492		524
493	Condition variables are very useful to signal that something has finished,	525	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	526	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	527	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	528	availability of results. The user can either act when the callback is
…		…
530	after => 1,	562	after => 1,
531	cb => sub { $result_ready->send },	563	cb => sub { $result_ready->send },
532	);	564	);
533		565
534	# this "blocks" (while handling events) till the callback	566	# this "blocks" (while handling events) till the callback
535	# calls send	567	# calls -<send
536	$result_ready->recv;	568	$result_ready->recv;
537		569
538	Example: wait for a timer, but take advantage of the fact that	570	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	571	variables are also callable directly.
540		572
541	my $done = AnyEvent->condvar;	573	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	574	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	575	$done->recv;
544		576
…		…
550		582
551	...	583	...
552		584
553	my @info = $couchdb->info->recv;	585	my @info = $couchdb->info->recv;
554		586
555	And this is how you would just ste a callback to be called whenever the	587	And this is how you would just set a callback to be called whenever the
556	results are available:	588	results are available:
557		589
558	$couchdb->info->cb (sub {	590	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	591	my @info = $_[0]->recv;
560	});	592	});
…		…
578	immediately from within send.	610	immediately from within send.
579		611
580	Any arguments passed to the C<send> call will be returned by all	612	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	613	future C<< ->recv >> calls.
582		614
583	Condition variables are overloaded so one can call them directly	615	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	616	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	617	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		618
592	=item $cv->croak ($error)	619	=item $cv->croak ($error)
593		620
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	621	Similar to send, but causes all call's to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	622	C<Carp::croak> with the given error message/object/scalar.
596		623
597	This can be used to signal any errors to the condition variable	624	This can be used to signal any errors to the condition variable
598	user/consumer.	625	user/consumer. Doing it this way instead of calling C<croak> directly
		626	delays the error detetcion, but has the overwhelmign advantage that it
		627	diagnoses the error at the place where the result is expected, and not
		628	deep in some event clalback without connection to the actual code causing
		629	the problem.
599		630
600	=item $cv->begin ([group callback])	631	=item $cv->begin ([group callback])
601		632
602	=item $cv->end	633	=item $cv->end
603		634
…		…
699	function will call C<croak>.	730	function will call C<croak>.
700		731
701	In list context, all parameters passed to C<send> will be returned,	732	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	733	in scalar context only the first one will be returned.
703		734
		735	Note that doing a blocking wait in a callback is not supported by any
		736	event loop, that is, recursive invocation of a blocking C<< ->recv
		737	>> is not allowed, and the C<recv> call will C<croak> if such a
		738	condition is detected. This condition can be slightly loosened by using
		739	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		740	any thread that doesn't run the event loop itself.
		741
704	Not all event models support a blocking wait - some die in that case	742	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	743	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	744	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	745	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	746	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	747	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	748	while still supporting blocking waits if the caller so desires).
711		749
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	750	You can ensure that C<< -recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	751	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	752	time). This will work even when the event loop does not support blocking
726	waits otherwise.	753	waits otherwise.
727		754
…		…
740	variable itself. Calling C<recv> inside the callback or at any later time	767	variable itself. Calling C<recv> inside the callback or at any later time
741	is guaranteed not to block.	768	is guaranteed not to block.
742		769
743	=back	770	=back
744		771
		772	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		773
		774	The available backend classes are (every class has its own manpage):
		775
		776	=over 4
		777
		778	=item Backends that are autoprobed when no other event loop can be found.
		779
		780	EV is the preferred backend when no other event loop seems to be in
		781	use. If EV is not installed, then AnyEvent will try Event, and, failing
		782	that, will fall back to its own pure-perl implementation, which is
		783	available everywhere as it comes with AnyEvent itself.
		784
		785	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		786	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		787	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		788
		789	=item Backends that are transparently being picked up when they are used.
		790
		791	These will be used when they are currently loaded when the first watcher
		792	is created, in which case it is assumed that the application is using
		793	them. This means that AnyEvent will automatically pick the right backend
		794	when the main program loads an event module before anything starts to
		795	create watchers. Nothing special needs to be done by the main program.
		796
		797	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		798	AnyEvent::Impl::Tk based on Tk, very broken.
		799	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		800	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		801
		802	=item Backends with special needs.
		803
		804	Qt requires the Qt::Application to be instantiated first, but will
		805	otherwise be picked up automatically. As long as the main program
		806	instantiates the application before any AnyEvent watchers are created,
		807	everything should just work.
		808
		809	AnyEvent::Impl::Qt based on Qt.
		810
		811	Support for IO::Async can only be partial, as it is too broken and
		812	architecturally limited to even support the AnyEvent API. It also
		813	is the only event loop that needs the loop to be set explicitly, so
		814	it can only be used by a main program knowing about AnyEvent. See
		815	L<AnyEvent::Impl::Async> for the gory details.
		816
		817	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		818
		819	=item Event loops that are indirectly supported via other backends.
		820
		821	Some event loops can be supported via other modules:
		822
		823	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		824
		825	B<WxWidgets> has no support for watching file handles. However, you can
		826	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		827	polls 20 times per second, which was considered to be too horrible to even
		828	consider for AnyEvent.
		829
		830	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		831	backend, so it can be supported through POE.
		832
		833	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		834	load L<POE> when detecting them, in the hope that POE will pick them up,
		835	in which case everything will be automatic.
		836
		837	=back
		838
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	839	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		840
		841	These are not normally required to use AnyEvent, but can be useful to
		842	write AnyEvent extension modules.
		843
747	=over 4	844	=over 4
748		845
749	=item $AnyEvent::MODEL	846	=item $AnyEvent::MODEL
750		847
751	Contains C<undef> until the first watcher is being created. Then it	848	Contains C<undef> until the first watcher is being created, before the
		849	backend has been autodetected.
		850
752	contains the event model that is being used, which is the name of the	851	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	852	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	853	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	854	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		855	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		856
782	=item AnyEvent::detect	857	=item AnyEvent::detect
783		858
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	859	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	860	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	861	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	862	runtime, and not e.g. while initialising of your module.
		863
		864	If you need to do some initialisation before AnyEvent watchers are
		865	created, use C<post_detect>.
788		866
789	=item $guard = AnyEvent::post_detect { BLOCK }	867	=item $guard = AnyEvent::post_detect { BLOCK }
790		868
791	Arranges for the code block to be executed as soon as the event model is	869	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	870	autodetected (or immediately if this has already happened).
793		871
		872	The block will be executed I<after> the actual backend has been detected
		873	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		874	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		875	other initialisations - see the sources of L<AnyEvent::Strict> or
		876	L<AnyEvent::AIO> to see how this is used.
		877
		878	The most common usage is to create some global watchers, without forcing
		879	event module detection too early, for example, L<AnyEvent::AIO> creates
		880	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		881	avoid autodetecting the event module at load time.
		882
794	If called in scalar or list context, then it creates and returns an object	883	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	884	that automatically removes the callback again when it is destroyed (or
		885	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	886	a case where this is useful.
		887
		888	Example: Create a watcher for the IO::AIO module and store it in
		889	C<$WATCHER>. Only do so after the event loop is initialised, though.
		890
		891	our WATCHER;
		892
		893	my $guard = AnyEvent::post_detect {
		894	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		895	};
		896
		897	# the \|\|= is important in case post_detect immediately runs the block,
		898	# as to not clobber the newly-created watcher. assigning both watcher and
		899	# post_detect guard to the same variable has the advantage of users being
		900	# able to just C<undef $WATCHER> if the watcher causes them grief.
		901
		902	$WATCHER \|\|= $guard;
797		903
798	=item @AnyEvent::post_detect	904	=item @AnyEvent::post_detect
799		905
800	If there are any code references in this array (you can C<push> to it	906	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	907	before or after loading AnyEvent), then they will called directly after
802	the event loop has been chosen.	908	the event loop has been chosen.
803		909
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	910	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	911	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	912	array will be ignored.
807		913
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	914	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		915	it,as it takes care of these details.
		916
		917	This variable is mainly useful for modules that can do something useful
		918	when AnyEvent is used and thus want to know when it is initialised, but do
		919	not need to even load it by default. This array provides the means to hook
		920	into AnyEvent passively, without loading it.
809		921
810	=back	922	=back
811		923
812	=head1 WHAT TO DO IN A MODULE	924	=head1 WHAT TO DO IN A MODULE
813		925
…		…
960		1072
961	=cut	1073	=cut
962		1074
963	package AnyEvent;	1075	package AnyEvent;
964		1076
		1077	# basically a tuned-down version of common::sense
		1078	sub common_sense {
965	no warnings;	1079	# no warnings
		1080	${^WARNING_BITS} ^= ${^WARNING_BITS};
966	use strict qw(vars subs);	1081	# use strict vars subs
		1082	$^H \|= 0x00000600;
		1083	}
967		1084
		1085	BEGIN { AnyEvent::common_sense }
		1086
968	use Carp;	1087	use Carp ();
969		1088
970	our $VERSION = 4.801;	1089	our $VERSION = 4.86;
971	our $MODEL;	1090	our $MODEL;
972		1091
973	our $AUTOLOAD;	1092	our $AUTOLOAD;
974	our @ISA;	1093	our @ISA;
975		1094
976	our @REGISTRY;	1095	our @REGISTRY;
977		1096
978	our $WIN32;	1097	our $WIN32;
		1098
		1099	our $VERBOSE;
979		1100
980	BEGIN {	1101	BEGIN {
981	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1102	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
982	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1103	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
983		1104
984	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1105	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
985	if ${^TAINT};	1106	if ${^TAINT};
986	}
987		1107
988	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1108	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1109
		1110	}
		1111
		1112	our $MAX_SIGNAL_LATENCY = 10;
989		1113
990	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1114	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
991		1115
992	{	1116	{
993	my $idx;	1117	my $idx;
…		…
1001	[Event:: => AnyEvent::Impl::Event::],	1125	[Event:: => AnyEvent::Impl::Event::],
1002	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1126	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1003	# everything below here will not be autoprobed	1127	# everything below here will not be autoprobed
1004	# as the pureperl backend should work everywhere	1128	# as the pureperl backend should work everywhere
1005	# and is usually faster	1129	# and is usually faster
1006	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1007	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1130	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1008	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1131	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1132	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1009	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1133	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1010	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1134	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1011	[Wx:: => AnyEvent::Impl::POE::],	1135	[Wx:: => AnyEvent::Impl::POE::],
1012	[Prima:: => AnyEvent::Impl::POE::],	1136	[Prima:: => AnyEvent::Impl::POE::],
1013	# IO::Async is just too broken - we would need workaorunds for its	1137	# IO::Async is just too broken - we would need workarounds for its
1014	# byzantine signal and broken child handling, among others.	1138	# byzantine signal and broken child handling, among others.
1015	# IO::Async is rather hard to detect, as it doesn't have any	1139	# IO::Async is rather hard to detect, as it doesn't have any
1016	# obvious default class.	1140	# obvious default class.
1017	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1141	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1018	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1142	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
…		…
1028	my ($cb) = @_;	1152	my ($cb) = @_;
1029		1153
1030	if ($MODEL) {	1154	if ($MODEL) {
1031	$cb->();	1155	$cb->();
1032		1156
1033	1	1157	undef
1034	} else {	1158	} else {
1035	push @post_detect, $cb;	1159	push @post_detect, $cb;
1036		1160
1037	defined wantarray	1161	defined wantarray
1038	? bless \$cb, "AnyEvent::Util::postdetect"	1162	? bless \$cb, "AnyEvent::Util::postdetect"
…		…
1044	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1168	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1045	}	1169	}
1046		1170
1047	sub detect() {	1171	sub detect() {
1048	unless ($MODEL) {	1172	unless ($MODEL) {
1049	no strict 'refs';
1050	local $SIG{__DIE__};	1173	local $SIG{__DIE__};
1051		1174
1052	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1175	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1053	my $model = "AnyEvent::Impl::$1";	1176	my $model = "AnyEvent::Impl::$1";
1054	if (eval "require $model") {	1177	if (eval "require $model") {
1055	$MODEL = $model;	1178	$MODEL = $model;
1056	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1179	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1057	} else {	1180	} else {
1058	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1181	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1059	}	1182	}
1060	}	1183	}
1061		1184
1062	# check for already loaded models	1185	# check for already loaded models
1063	unless ($MODEL) {	1186	unless ($MODEL) {
1064	for (@REGISTRY, @models) {	1187	for (@REGISTRY, @models) {
1065	my ($package, $model) = @$_;	1188	my ($package, $model) = @$_;
1066	if (${"$package\::VERSION"} > 0) {	1189	if (${"$package\::VERSION"} > 0) {
1067	if (eval "require $model") {	1190	if (eval "require $model") {
1068	$MODEL = $model;	1191	$MODEL = $model;
1069	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1192	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1070	last;	1193	last;
1071	}	1194	}
1072	}	1195	}
1073	}	1196	}
1074		1197
…		…
1079	my ($package, $model) = @$_;	1202	my ($package, $model) = @$_;
1080	if (eval "require $package"	1203	if (eval "require $package"
1081	and ${"$package\::VERSION"} > 0	1204	and ${"$package\::VERSION"} > 0
1082	and eval "require $model") {	1205	and eval "require $model") {
1083	$MODEL = $model;	1206	$MODEL = $model;
1084	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1207	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1085	last;	1208	last;
1086	}	1209	}
1087	}	1210	}
1088		1211
1089	$MODEL	1212	$MODEL
…		…
1105		1228
1106	sub AUTOLOAD {	1229	sub AUTOLOAD {
1107	(my $func = $AUTOLOAD) =~ s/.*://;	1230	(my $func = $AUTOLOAD) =~ s/.*://;
1108		1231
1109	$method{$func}	1232	$method{$func}
1110	or croak "$func: not a valid method for AnyEvent objects";	1233	or Carp::croak "$func: not a valid method for AnyEvent objects";
1111		1234
1112	detect unless $MODEL;	1235	detect unless $MODEL;
1113		1236
1114	my $class = shift;	1237	my $class = shift;
1115	$class->$func (@_);	1238	$class->$func (@_);
…		…
1120	# allow only one watcher per fd, so we dup it to get a different one).	1243	# allow only one watcher per fd, so we dup it to get a different one).
1121	sub _dupfh($$;$$) {	1244	sub _dupfh($$;$$) {
1122	my ($poll, $fh, $r, $w) = @_;	1245	my ($poll, $fh, $r, $w) = @_;
1123		1246
1124	# cygwin requires the fh mode to be matching, unix doesn't	1247	# cygwin requires the fh mode to be matching, unix doesn't
1125	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1248	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1126		1249
1127	open my $fh2, "$mode&", $fh	1250	open my $fh2, $mode, $fh
1128	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1251	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1129		1252
1130	# we assume CLOEXEC is already set by perl in all important cases	1253	# we assume CLOEXEC is already set by perl in all important cases
1131		1254
1132	($fh2, $rw)	1255	($fh2, $rw)
…		…
1134		1257
1135	package AnyEvent::Base;	1258	package AnyEvent::Base;
1136		1259
1137	# default implementations for many methods	1260	# default implementations for many methods
1138		1261
1139	BEGIN {	1262	sub _time {
		1263	# probe for availability of Time::HiRes
1140	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1264	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1265	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1141	*_time = \&Time::HiRes::time;	1266	*_time = \&Time::HiRes::time;
1142	# if (eval "use POSIX (); (POSIX::times())...	1267	# if (eval "use POSIX (); (POSIX::times())...
1143	} else {	1268	} else {
		1269	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1144	*_time = sub { time }; # epic fail	1270	*_time = sub { time }; # epic fail
1145	}	1271	}
		1272
		1273	&_time
1146	}	1274	}
1147		1275
1148	sub time { _time }	1276	sub time { _time }
1149	sub now { _time }	1277	sub now { _time }
1150	sub now_update { }	1278	sub now_update { }
…		…
1155	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1283	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1156	}	1284	}
1157		1285
1158	# default implementation for ->signal	1286	# default implementation for ->signal
1159		1287
		1288	our $HAVE_ASYNC_INTERRUPT;
1160	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1289	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1290	our (%SIG_ASY, %SIG_ASY_W);
		1291	our ($SIG_COUNT, $SIG_TW);
1161		1292
1162	sub _signal_exec {	1293	sub _signal_exec {
		1294	$HAVE_ASYNC_INTERRUPT
		1295	? $SIGPIPE_R->drain
1163	sysread $SIGPIPE_R, my $dummy, 4;	1296	: sysread $SIGPIPE_R, my $dummy, 9;
1164		1297
1165	while (%SIG_EV) {	1298	while (%SIG_EV) {
1166	for (keys %SIG_EV) {	1299	for (keys %SIG_EV) {
1167	delete $SIG_EV{$_};	1300	delete $SIG_EV{$_};
1168	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1301	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1169	}	1302	}
1170	}	1303	}
1171	}	1304	}
1172		1305
		1306	# install a dumym wakeupw atcher to reduce signal catching latency
		1307	sub _sig_add() {
		1308	unless ($SIG_COUNT++) {
		1309	# try to align timer on a full-second boundary, if possible
		1310	my $NOW = AnyEvent->now;
		1311
		1312	$SIG_TW = AnyEvent->timer (
		1313	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1314	interval => $MAX_SIGNAL_LATENCY,
		1315	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1316	);
		1317	}
		1318	}
		1319
		1320	sub _sig_del {
		1321	undef $SIG_TW
		1322	unless --$SIG_COUNT;
		1323	}
		1324
		1325	sub _signal {
		1326	my (undef, %arg) = @_;
		1327
		1328	my $signal = uc $arg{signal}
		1329	or Carp::croak "required option 'signal' is missing";
		1330
		1331	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1332
		1333	if ($HAVE_ASYNC_INTERRUPT) {
		1334	# async::interrupt
		1335
		1336	$SIG_ASY{$signal} \|\|= do {
		1337	my $asy = new Async::Interrupt
		1338	cb => sub { undef $SIG_EV{$signal} },
		1339	signal => $signal,
		1340	pipe => [$SIGPIPE_R->filenos],
		1341	;
		1342	$asy->pipe_autodrain (0);
		1343
		1344	$asy
		1345	};
		1346
		1347	} else {
		1348	# pure perl
		1349
		1350	$SIG{$signal} \|\|= sub {
		1351	local $!;
		1352	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1353	undef $SIG_EV{$signal};
		1354	};
		1355
		1356	# can't do signal processing without introducing races in pure perl,
		1357	# so limit the signal latency.
		1358	_sig_add;
		1359	}
		1360
		1361	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1362	}
		1363
1173	sub signal {	1364	sub signal {
1174	my (undef, %arg) = @_;	1365	# probe for availability of Async::Interrupt
		1366	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1367	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1175		1368
1176	unless ($SIGPIPE_R) {	1369	$HAVE_ASYNC_INTERRUPT = 1;
		1370	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1371	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1372
		1373	} else {
		1374	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1375
1177	require Fcntl;	1376	require Fcntl;
1178		1377
1179	if (AnyEvent::WIN32) {	1378	if (AnyEvent::WIN32) {
1180	require AnyEvent::Util;	1379	require AnyEvent::Util;
1181		1380
…		…
1196	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1395	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1197		1396
1198	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1397	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1199	}	1398	}
1200		1399
1201	my $signal = uc $arg{signal}	1400	*signal = \&_signal;
1202	or Carp::croak "required option 'signal' is missing";	1401	&signal
1203
1204	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1205	$SIG{$signal} \|\|= sub {
1206	local $!;
1207	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1208	undef $SIG_EV{$signal};
1209	};
1210
1211	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1212	}	1402	}
1213		1403
1214	sub AnyEvent::Base::signal::DESTROY {	1404	sub AnyEvent::Base::signal::DESTROY {
1215	my ($signal, $cb) = @{$_[0]};	1405	my ($signal, $cb) = @{$_[0]};
1216		1406
		1407	_sig_del;
		1408
1217	delete $SIG_CB{$signal}{$cb};	1409	delete $SIG_CB{$signal}{$cb};
1218		1410
		1411	$HAVE_ASYNC_INTERRUPT
		1412	? delete $SIG_ASY{$signal}
1219	# delete doesn't work with older perls - they then	1413	: # delete doesn't work with older perls - they then
1220	# print weird messages, or just unconditionally exit	1414	# print weird messages, or just unconditionally exit
1221	# instead of getting the default action.	1415	# instead of getting the default action.
		1416	undef $SIG{$signal}
1222	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1417	unless keys %{ $SIG_CB{$signal} };
1223	}	1418	}
1224		1419
1225	# default implementation for ->child	1420	# default implementation for ->child
1226		1421
1227	our %PID_CB;	1422	our %PID_CB;
…		…
1229	our $CHLD_DELAY_W;	1424	our $CHLD_DELAY_W;
1230	our $WNOHANG;	1425	our $WNOHANG;
1231		1426
1232	sub _sigchld {	1427	sub _sigchld {
1233	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1428	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1429	$_->($pid, $?)
1234	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1430	for values %{ $PID_CB{$pid} \|\| {} },
1235	(values %{ $PID_CB{0} \|\| {} });	1431	values %{ $PID_CB{0} \|\| {} };
1236	}	1432	}
1237	}	1433	}
1238		1434
1239	sub child {	1435	sub child {
1240	my (undef, %arg) = @_;	1436	my (undef, %arg) = @_;
…		…
1242	defined (my $pid = $arg{pid} + 0)	1438	defined (my $pid = $arg{pid} + 0)
1243	or Carp::croak "required option 'pid' is missing";	1439	or Carp::croak "required option 'pid' is missing";
1244		1440
1245	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1441	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1246		1442
		1443	# WNOHANG is almost cetrainly 1 everywhere
		1444	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1445	? 1
1247	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1446	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1248		1447
1249	unless ($CHLD_W) {	1448	unless ($CHLD_W) {
1250	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1449	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1251	# child could be a zombie already, so make at least one round	1450	# child could be a zombie already, so make at least one round
1252	&_sigchld;	1451	&_sigchld;
…		…
1304		1503
1305	our @ISA = AnyEvent::CondVar::Base::;	1504	our @ISA = AnyEvent::CondVar::Base::;
1306		1505
1307	package AnyEvent::CondVar::Base;	1506	package AnyEvent::CondVar::Base;
1308		1507
1309	use overload	1508	#use overload
1310	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1509	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1311	fallback => 1;	1510	# fallback => 1;
		1511
		1512	# save 300+ kilobytes by dirtily hardcoding overloading
		1513	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1514	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1515	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1516	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1517
		1518	our $WAITING;
1312		1519
1313	sub _send {	1520	sub _send {
1314	# nop	1521	# nop
1315	}	1522	}
1316		1523
…		…
1329	sub ready {	1536	sub ready {
1330	$_[0]{_ae_sent}	1537	$_[0]{_ae_sent}
1331	}	1538	}
1332		1539
1333	sub _wait {	1540	sub _wait {
		1541	$WAITING
		1542	and !$_[0]{_ae_sent}
		1543	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1544
		1545	local $WAITING = 1;
1334	AnyEvent->one_event while !$_[0]{_ae_sent};	1546	AnyEvent->one_event while !$_[0]{_ae_sent};
1335	}	1547	}
1336		1548
1337	sub recv {	1549	sub recv {
1338	$_[0]->_wait;	1550	$_[0]->_wait;
…		…
1400	C<PERL_ANYEVENT_MODEL>.	1612	C<PERL_ANYEVENT_MODEL>.
1401		1613
1402	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1614	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1403	model it chooses.	1615	model it chooses.
1404		1616
		1617	When set to C<8> or higher, then AnyEvent will report extra information on
		1618	which optional modules it loads and how it implements certain features.
		1619
1405	=item C<PERL_ANYEVENT_STRICT>	1620	=item C<PERL_ANYEVENT_STRICT>
1406		1621
1407	AnyEvent does not do much argument checking by default, as thorough	1622	AnyEvent does not do much argument checking by default, as thorough
1408	argument checking is very costly. Setting this variable to a true value	1623	argument checking is very costly. Setting this variable to a true value
1409	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1624	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1410	check the arguments passed to most method calls. If it finds any problems,	1625	check the arguments passed to most method calls. If it finds any problems,
1411	it will croak.	1626	it will croak.
1412		1627
1413	In other words, enables "strict" mode.	1628	In other words, enables "strict" mode.
1414		1629
1415	Unlike C<use strict>, it is definitely recommended to keep it off in	1630	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>
1416	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1631	>>, it is definitely recommended to keep it off in production. Keeping
1417	developing programs can be very useful, however.	1632	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1633	can be very useful, however.
1418		1634
1419	=item C<PERL_ANYEVENT_MODEL>	1635	=item C<PERL_ANYEVENT_MODEL>
1420		1636
1421	This can be used to specify the event model to be used by AnyEvent, before	1637	This can be used to specify the event model to be used by AnyEvent, before
1422	auto detection and -probing kicks in. It must be a string consisting	1638	auto detection and -probing kicks in. It must be a string consisting
…		…
1484		1700
1485	When neither C<ca_file> nor C<ca_path> was specified during	1701	When neither C<ca_file> nor C<ca_path> was specified during
1486	L<AnyEvent::TLS> context creation, and either of these environment	1702	L<AnyEvent::TLS> context creation, and either of these environment
1487	variables exist, they will be used to specify CA certificate locations	1703	variables exist, they will be used to specify CA certificate locations
1488	instead of a system-dependent default.	1704	instead of a system-dependent default.
		1705
		1706	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1707
		1708	When these are set to C<1>, then the respective modules are not
		1709	loaded. Mostly good for testing AnyEvent itself.
1489		1710
1490	=back	1711	=back
1491		1712
1492	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1713	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1493		1714
…		…
2032		2253
2033	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2254	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2034	emulation for event loops that do not support them natively. Also, some	2255	emulation for event loops that do not support them natively. Also, some
2035	event loops install a similar handler.	2256	event loops install a similar handler.
2036		2257
2037	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2258	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2038	reset it to default, to avoid losing child exit statuses.	2259	AnyEvent will reset it to default, to avoid losing child exit statuses.
2039		2260
2040	=item SIGPIPE	2261	=item SIGPIPE
2041		2262
2042	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2263	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2043	when AnyEvent gets loaded.	2264	when AnyEvent gets loaded.
…		…
2061	if $SIG{CHLD} eq 'IGNORE';	2282	if $SIG{CHLD} eq 'IGNORE';
2062		2283
2063	$SIG{PIPE} = sub { }	2284	$SIG{PIPE} = sub { }
2064	unless defined $SIG{PIPE};	2285	unless defined $SIG{PIPE};
2065		2286
		2287	=head1 RECOMMENDED/OPTIONAL MODULES
		2288
		2289	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2290	it's built-in modules) are required to use it.
		2291
		2292	That does not mean that AnyEvent won't take advantage of some additional
		2293	modules if they are installed.
		2294
		2295	This section epxlains which additional modules will be used, and how they
		2296	affect AnyEvent's operetion.
		2297
		2298	=over 4
		2299
		2300	=item L<Async::Interrupt>
		2301
		2302	This slightly arcane module is used to implement fast signal handling: To
		2303	my knowledge, there is no way to do completely race-free and quick
		2304	signal handling in pure perl. To ensure that signals still get
		2305	delivered, AnyEvent will start an interval timer to wake up perl (and
		2306	catch the signals) with some delay (default is 10 seconds, look for
		2307	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2308
		2309	If this module is available, then it will be used to implement signal
		2310	catching, which means that signals will not be delayed, and the event loop
		2311	will not be interrupted regularly, which is more efficient (And good for
		2312	battery life on laptops).
		2313
		2314	This affects not just the pure-perl event loop, but also other event loops
		2315	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2316
		2317	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2318	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2319	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2320	does nothing for those backends.
		2321
		2322	=item L<EV>
		2323
		2324	This module isn't really "optional", as it is simply one of the backend
		2325	event loops that AnyEvent can use. However, it is simply the best event
		2326	loop available in terms of features, speed and stability: It supports
		2327	the AnyEvent API optimally, implements all the watcher types in XS, does
		2328	automatic timer adjustments even when no monotonic clock is available,
		2329	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2330	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2331	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2332
		2333	=item L<Guard>
		2334
		2335	The guard module, when used, will be used to implement
		2336	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2337	lot less memory), but otherwise doesn't affect guard operation much. It is
		2338	purely used for performance.
		2339
		2340	=item L<JSON> and L<JSON::XS>
		2341
		2342	This module is required when you want to read or write JSON data via
		2343	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2344	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2345
		2346	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2347	installed.
		2348
		2349	=item L<Net::SSLeay>
		2350
		2351	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2352	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2353	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2354
		2355	=item L<Time::HiRes>
		2356
		2357	This module is part of perl since release 5.008. It will be used when the
		2358	chosen event library does not come with a timing source on it's own. The
		2359	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2360	try to use a monotonic clock for timing stability.
		2361
		2362	=back
		2363
		2364
2066	=head1 FORK	2365	=head1 FORK
2067		2366
2068	Most event libraries are not fork-safe. The ones who are usually are	2367	Most event libraries are not fork-safe. The ones who are usually are
2069	because they rely on inefficient but fork-safe C<select> or C<poll>	2368	because they rely on inefficient but fork-safe C<select> or C<poll>
2070	calls. Only L<EV> is fully fork-aware.	2369	calls. Only L<EV> is fully fork-aware.
2071		2370
2072	If you have to fork, you must either do so I<before> creating your first	2371	If you have to fork, you must either do so I<before> creating your first
2073	watcher OR you must not use AnyEvent at all in the child.	2372	watcher OR you must not use AnyEvent at all in the child OR you must do
		2373	something completely out of the scope of AnyEvent.
2074		2374
2075		2375
2076	=head1 SECURITY CONSIDERATIONS	2376	=head1 SECURITY CONSIDERATIONS
2077		2377
2078	AnyEvent can be forced to load any event model via	2378	AnyEvent can be forced to load any event model via

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.231 by root, Wed Jul 8 13:46:46 2009 UTC vs. Revision 1.253 by root, Tue Jul 21 06:00:47 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.231 by root, Wed Jul 8 13:46:46 2009 UTC vs.
Revision 1.253 by root, Tue Jul 21 06:00:47 2009 UTC