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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.230 by root, Wed Jul 8 05:55:17 2009 UTC vs.
Revision 1.249 by root, Mon Jul 20 06:00:42 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"
…		…
530	after => 1,	561	after => 1,
531	cb => sub { $result_ready->send },	562	cb => sub { $result_ready->send },
532	);	563	);
533		564
534	# this "blocks" (while handling events) till the callback	565	# this "blocks" (while handling events) till the callback
535	# calls send	566	# calls -<send
536	$result_ready->recv;	567	$result_ready->recv;
537		568
538	Example: wait for a timer, but take advantage of the fact that	569	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	570	variables are also callable directly.
540		571
541	my $done = AnyEvent->condvar;	572	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	573	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	574	$done->recv;
544		575
…		…
550		581
551	...	582	...
552		583
553	my @info = $couchdb->info->recv;	584	my @info = $couchdb->info->recv;
554		585
555	And this is how you would just ste a callback to be called whenever the	586	And this is how you would just set a callback to be called whenever the
556	results are available:	587	results are available:
557		588
558	$couchdb->info->cb (sub {	589	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	590	my @info = $_[0]->recv;
560	});	591	});
…		…
578	immediately from within send.	609	immediately from within send.
579		610
580	Any arguments passed to the C<send> call will be returned by all	611	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	612	future C<< ->recv >> calls.
582		613
583	Condition variables are overloaded so one can call them directly	614	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	615	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	616	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		617
592	=item $cv->croak ($error)	618	=item $cv->croak ($error)
593		619
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	620	Similar to send, but causes all call's to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	621	C<Carp::croak> with the given error message/object/scalar.
596		622
597	This can be used to signal any errors to the condition variable	623	This can be used to signal any errors to the condition variable
598	user/consumer.	624	user/consumer. Doing it this way instead of calling C<croak> directly
		625	delays the error detetcion, but has the overwhelmign advantage that it
		626	diagnoses the error at the place where the result is expected, and not
		627	deep in some event clalback without connection to the actual code causing
		628	the problem.
599		629
600	=item $cv->begin ([group callback])	630	=item $cv->begin ([group callback])
601		631
602	=item $cv->end	632	=item $cv->end
603		633
…		…
699	function will call C<croak>.	729	function will call C<croak>.
700		730
701	In list context, all parameters passed to C<send> will be returned,	731	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	732	in scalar context only the first one will be returned.
703		733
		734	Note that doing a blocking wait in a callback is not supported by any
		735	event loop, that is, recursive invocation of a blocking C<< ->recv
		736	>> is not allowed, and the C<recv> call will C<croak> if such a
		737	condition is detected. This condition can be slightly loosened by using
		738	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		739	any thread that doesn't run the event loop itself.
		740
704	Not all event models support a blocking wait - some die in that case	741	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	742	(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	743	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	744	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	745	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	746	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	747	while still supporting blocking waits if the caller so desires).
711		748
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	749	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	750	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	751	time). This will work even when the event loop does not support blocking
726	waits otherwise.	752	waits otherwise.
727		753
…		…
740	variable itself. Calling C<recv> inside the callback or at any later time	766	variable itself. Calling C<recv> inside the callback or at any later time
741	is guaranteed not to block.	767	is guaranteed not to block.
742		768
743	=back	769	=back
744		770
		771	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		772
		773	The available backend classes are (every class has its own manpage):
		774
		775	=over 4
		776
		777	=item Backends that are autoprobed when no other event loop can be found.
		778
		779	EV is the preferred backend when no other event loop seems to be in
		780	use. If EV is not installed, then AnyEvent will try Event, and, failing
		781	that, will fall back to its own pure-perl implementation, which is
		782	available everywhere as it comes with AnyEvent itself.
		783
		784	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		785	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		786	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		787
		788	=item Backends that are transparently being picked up when they are used.
		789
		790	These will be used when they are currently loaded when the first watcher
		791	is created, in which case it is assumed that the application is using
		792	them. This means that AnyEvent will automatically pick the right backend
		793	when the main program loads an event module before anything starts to
		794	create watchers. Nothing special needs to be done by the main program.
		795
		796	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		797	AnyEvent::Impl::Tk based on Tk, very broken.
		798	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		799	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		800
		801	=item Backends with special needs.
		802
		803	Qt requires the Qt::Application to be instantiated first, but will
		804	otherwise be picked up automatically. As long as the main program
		805	instantiates the application before any AnyEvent watchers are created,
		806	everything should just work.
		807
		808	AnyEvent::Impl::Qt based on Qt.
		809
		810	Support for IO::Async can only be partial, as it is too broken and
		811	architecturally limited to even support the AnyEvent API. It also
		812	is the only event loop that needs the loop to be set explicitly, so
		813	it can only be used by a main program knowing about AnyEvent. See
		814	L<AnyEvent::Impl::Async> for the gory details.
		815
		816	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		817
		818	=item Event loops that are indirectly supported via other backends.
		819
		820	Some event loops can be supported via other modules:
		821
		822	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		823
		824	B<WxWidgets> has no support for watching file handles. However, you can
		825	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		826	polls 20 times per second, which was considered to be too horrible to even
		827	consider for AnyEvent.
		828
		829	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		830	backend, so it can be supported through POE.
		831
		832	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		833	load L<POE> when detecting them, in the hope that POE will pick them up,
		834	in which case everything will be automatic.
		835
		836	=back
		837
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	838	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		839
		840	These are not normally required to use AnyEvent, but can be useful to
		841	write AnyEvent extension modules.
		842
747	=over 4	843	=over 4
748		844
749	=item $AnyEvent::MODEL	845	=item $AnyEvent::MODEL
750		846
751	Contains C<undef> until the first watcher is being created. Then it	847	Contains C<undef> until the first watcher is being created, before the
		848	backend has been autodetected.
		849
752	contains the event model that is being used, which is the name of the	850	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	851	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	852	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>).	853	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		854	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		855
782	=item AnyEvent::detect	856	=item AnyEvent::detect
783		857
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	858	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	859	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	860	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	861	runtime, and not e.g. while initialising of your module.
		862
		863	If you need to do some initialisation before AnyEvent watchers are
		864	created, use C<post_detect>.
788		865
789	=item $guard = AnyEvent::post_detect { BLOCK }	866	=item $guard = AnyEvent::post_detect { BLOCK }
790		867
791	Arranges for the code block to be executed as soon as the event model is	868	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	869	autodetected (or immediately if this has already happened).
		870
		871	The block will be executed I<after> the actual backend has been detected
		872	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		873	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		874	other initialisations - see the sources of L<AnyEvent::Strict> or
		875	L<AnyEvent::AIO> to see how this is used.
		876
		877	The most common usage is to create some global watchers, without forcing
		878	event module detection too early, for example, L<AnyEvent::AIO> creates
		879	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		880	avoid autodetecting the event module at load time.
793		881
794	If called in scalar or list context, then it creates and returns an object	882	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	883	that automatically removes the callback again when it is destroyed. See
796	L<Coro::BDB> for a case where this is useful.	884	L<Coro::BDB> for a case where this is useful.
797		885
…		…
800	If there are any code references in this array (you can C<push> to it	888	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	889	before or after loading AnyEvent), then they will called directly after
802	the event loop has been chosen.	890	the event loop has been chosen.
803		891
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	892	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	893	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	894	array will be ignored.
807		895
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	896	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		897	it,as it takes care of these details.
		898
		899	This variable is mainly useful for modules that can do something useful
		900	when AnyEvent is used and thus want to know when it is initialised, but do
		901	not need to even load it by default. This array provides the means to hook
		902	into AnyEvent passively, without loading it.
809		903
810	=back	904	=back
811		905
812	=head1 WHAT TO DO IN A MODULE	906	=head1 WHAT TO DO IN A MODULE
813		907
…		…
960		1054
961	=cut	1055	=cut
962		1056
963	package AnyEvent;	1057	package AnyEvent;
964		1058
		1059	# basically a tuned-down version of common::sense
		1060	sub common_sense {
965	no warnings;	1061	# no warnings
		1062	${^WARNING_BITS} ^= ${^WARNING_BITS};
966	use strict qw(vars subs);	1063	# use strict vars subs
		1064	$^H \|= 0x00000600;
		1065	}
967		1066
		1067	BEGIN { AnyEvent::common_sense }
		1068
968	use Carp;	1069	use Carp ();
969		1070
970	our $VERSION = 4.8;	1071	our $VERSION = 4.85;
971	our $MODEL;	1072	our $MODEL;
972		1073
973	our $AUTOLOAD;	1074	our $AUTOLOAD;
974	our @ISA;	1075	our @ISA;
975		1076
976	our @REGISTRY;	1077	our @REGISTRY;
977		1078
978	our $WIN32;	1079	our $WIN32;
		1080
		1081	our $VERBOSE;
979		1082
980	BEGIN {	1083	BEGIN {
981	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1084	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
982	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1085	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
983		1086
984	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1087	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
985	if ${^TAINT};	1088	if ${^TAINT};
986	}
987		1089
988	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1090	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1091
		1092	}
		1093
		1094	our $MAX_SIGNAL_LATENCY = 10;
989		1095
990	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1096	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
991		1097
992	{	1098	{
993	my $idx;	1099	my $idx;
…		…
1001	[Event:: => AnyEvent::Impl::Event::],	1107	[Event:: => AnyEvent::Impl::Event::],
1002	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1108	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1003	# everything below here will not be autoprobed	1109	# everything below here will not be autoprobed
1004	# as the pureperl backend should work everywhere	1110	# as the pureperl backend should work everywhere
1005	# and is usually faster	1111	# and is usually faster
1006	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1007	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1112	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1008	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1113	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1114	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1009	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1115	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1010	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1116	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1011	[Wx:: => AnyEvent::Impl::POE::],	1117	[Wx:: => AnyEvent::Impl::POE::],
1012	[Prima:: => AnyEvent::Impl::POE::],	1118	[Prima:: => AnyEvent::Impl::POE::],
1013	# IO::Async is just too broken - we would need workaorunds for its	1119	# IO::Async is just too broken - we would need workarounds for its
1014	# byzantine signal and broken child handling, among others.	1120	# byzantine signal and broken child handling, among others.
1015	# IO::Async is rather hard to detect, as it doesn't have any	1121	# IO::Async is rather hard to detect, as it doesn't have any
1016	# obvious default class.	1122	# obvious default class.
1017	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1123	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1018	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1124	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
…		…
1044	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1150	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1045	}	1151	}
1046		1152
1047	sub detect() {	1153	sub detect() {
1048	unless ($MODEL) {	1154	unless ($MODEL) {
1049	no strict 'refs';
1050	local $SIG{__DIE__};	1155	local $SIG{__DIE__};
1051		1156
1052	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1157	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1053	my $model = "AnyEvent::Impl::$1";	1158	my $model = "AnyEvent::Impl::$1";
1054	if (eval "require $model") {	1159	if (eval "require $model") {
1055	$MODEL = $model;	1160	$MODEL = $model;
1056	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1161	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
1057	} else {	1162	} else {
1058	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1163	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1059	}	1164	}
1060	}	1165	}
1061		1166
1062	# check for already loaded models	1167	# check for already loaded models
1063	unless ($MODEL) {	1168	unless ($MODEL) {
1064	for (@REGISTRY, @models) {	1169	for (@REGISTRY, @models) {
1065	my ($package, $model) = @$_;	1170	my ($package, $model) = @$_;
1066	if (${"$package\::VERSION"} > 0) {	1171	if (${"$package\::VERSION"} > 0) {
1067	if (eval "require $model") {	1172	if (eval "require $model") {
1068	$MODEL = $model;	1173	$MODEL = $model;
1069	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1174	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1070	last;	1175	last;
1071	}	1176	}
1072	}	1177	}
1073	}	1178	}
1074		1179
…		…
1079	my ($package, $model) = @$_;	1184	my ($package, $model) = @$_;
1080	if (eval "require $package"	1185	if (eval "require $package"
1081	and ${"$package\::VERSION"} > 0	1186	and ${"$package\::VERSION"} > 0
1082	and eval "require $model") {	1187	and eval "require $model") {
1083	$MODEL = $model;	1188	$MODEL = $model;
1084	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;	1189	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1085	last;	1190	last;
1086	}	1191	}
1087	}	1192	}
1088		1193
1089	$MODEL	1194	$MODEL
…		…
1105		1210
1106	sub AUTOLOAD {	1211	sub AUTOLOAD {
1107	(my $func = $AUTOLOAD) =~ s/.*://;	1212	(my $func = $AUTOLOAD) =~ s/.*://;
1108		1213
1109	$method{$func}	1214	$method{$func}
1110	or croak "$func: not a valid method for AnyEvent objects";	1215	or Carp::croak "$func: not a valid method for AnyEvent objects";
1111		1216
1112	detect unless $MODEL;	1217	detect unless $MODEL;
1113		1218
1114	my $class = shift;	1219	my $class = shift;
1115	$class->$func (@_);	1220	$class->$func (@_);
…		…
1120	# allow only one watcher per fd, so we dup it to get a different one).	1225	# allow only one watcher per fd, so we dup it to get a different one).
1121	sub _dupfh($$;$$) {	1226	sub _dupfh($$;$$) {
1122	my ($poll, $fh, $r, $w) = @_;	1227	my ($poll, $fh, $r, $w) = @_;
1123		1228
1124	# cygwin requires the fh mode to be matching, unix doesn't	1229	# cygwin requires the fh mode to be matching, unix doesn't
1125	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1230	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1126		1231
1127	open my $fh2, "$mode&", $fh	1232	open my $fh2, $mode, $fh
1128	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1233	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1129		1234
1130	# we assume CLOEXEC is already set by perl in all important cases	1235	# we assume CLOEXEC is already set by perl in all important cases
1131		1236
1132	($fh2, $rw)	1237	($fh2, $rw)
…		…
1134		1239
1135	package AnyEvent::Base;	1240	package AnyEvent::Base;
1136		1241
1137	# default implementations for many methods	1242	# default implementations for many methods
1138		1243
1139	BEGIN {	1244	sub _time {
		1245	# probe for availability of Time::HiRes
1140	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1246	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1247	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1141	*_time = \&Time::HiRes::time;	1248	*_time = \&Time::HiRes::time;
1142	# if (eval "use POSIX (); (POSIX::times())...	1249	# if (eval "use POSIX (); (POSIX::times())...
1143	} else {	1250	} else {
		1251	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1144	*_time = sub { time }; # epic fail	1252	*_time = sub { time }; # epic fail
1145	}	1253	}
		1254
		1255	&_time
1146	}	1256	}
1147		1257
1148	sub time { _time }	1258	sub time { _time }
1149	sub now { _time }	1259	sub now { _time }
1150	sub now_update { }	1260	sub now_update { }
…		…
1155	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1265	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1156	}	1266	}
1157		1267
1158	# default implementation for ->signal	1268	# default implementation for ->signal
1159		1269
		1270	our $HAVE_ASYNC_INTERRUPT;
1160	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1271	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1272	our (%SIG_ASY, %SIG_ASY_W);
		1273	our ($SIG_COUNT, $SIG_TW);
1161		1274
1162	sub _signal_exec {	1275	sub _signal_exec {
		1276	$HAVE_ASYNC_INTERRUPT
		1277	? $SIGPIPE_R->drain
1163	sysread $SIGPIPE_R, my $dummy, 4;	1278	: sysread $SIGPIPE_R, my $dummy, 9;
1164		1279
1165	while (%SIG_EV) {	1280	while (%SIG_EV) {
1166	for (keys %SIG_EV) {	1281	for (keys %SIG_EV) {
1167	delete $SIG_EV{$_};	1282	delete $SIG_EV{$_};
1168	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1283	$_->() for values %{ $SIG_CB{$_} \|\| {} };
1169	}	1284	}
1170	}	1285	}
1171	}	1286	}
1172		1287
		1288	# install a dumym wakeupw atcher to reduce signal catching latency
		1289	sub _sig_add() {
		1290	unless ($SIG_COUNT++) {
		1291	# try to align timer on a full-second boundary, if possible
		1292	my $NOW = AnyEvent->now;
		1293
		1294	$SIG_TW = AnyEvent->timer (
		1295	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1296	interval => $MAX_SIGNAL_LATENCY,
		1297	cb => sub { }, # just for the PERL_ASYNC_CHECK
		1298	);
		1299	}
		1300	}
		1301
		1302	sub _sig_del {
		1303	undef $SIG_TW
		1304	unless --$SIG_COUNT;
		1305	}
		1306
		1307	sub _signal {
		1308	my (undef, %arg) = @_;
		1309
		1310	my $signal = uc $arg{signal}
		1311	or Carp::croak "required option 'signal' is missing";
		1312
		1313	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1314
		1315	if ($HAVE_ASYNC_INTERRUPT) {
		1316	# async::interrupt
		1317
		1318	$SIG_ASY{$signal} \|\|= do {
		1319	my $asy = new Async::Interrupt
		1320	cb => sub { undef $SIG_EV{$signal} },
		1321	signal => $signal,
		1322	pipe => [$SIGPIPE_R->filenos],
		1323	;
		1324	$asy->pipe_autodrain (0);
		1325
		1326	$asy
		1327	};
		1328
		1329	} else {
		1330	# pure perl
		1331
		1332	$SIG{$signal} \|\|= sub {
		1333	local $!;
		1334	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1335	undef $SIG_EV{$signal};
		1336	};
		1337
		1338	# can't do signal processing without introducing races in pure perl,
		1339	# so limit the signal latency.
		1340	_sig_add;
		1341	}
		1342
		1343	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1344	}
		1345
1173	sub signal {	1346	sub signal {
1174	my (undef, %arg) = @_;	1347	# probe for availability of Async::Interrupt
		1348	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
		1349	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1175		1350
1176	unless ($SIGPIPE_R) {	1351	$HAVE_ASYNC_INTERRUPT = 1;
		1352	$SIGPIPE_R = new Async::Interrupt::EventPipe;
		1353	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
		1354
		1355	} else {
		1356	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1357
1177	require Fcntl;	1358	require Fcntl;
1178		1359
1179	if (AnyEvent::WIN32) {	1360	if (AnyEvent::WIN32) {
1180	require AnyEvent::Util;	1361	require AnyEvent::Util;
1181		1362
…		…
1196	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1377	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1197		1378
1198	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1379	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1199	}	1380	}
1200		1381
1201	my $signal = uc $arg{signal}	1382	*signal = \&_signal;
1202	or Carp::croak "required option 'signal' is missing";	1383	&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, $arg{cb}], "AnyEvent::Base::signal"
1212	}	1384	}
1213		1385
1214	sub AnyEvent::Base::signal::DESTROY {	1386	sub AnyEvent::Base::signal::DESTROY {
1215	my ($signal, $cb) = @{$_[0]};	1387	my ($signal, $cb) = @{$_[0]};
1216		1388
		1389	_sig_del;
		1390
1217	delete $SIG_CB{$signal}{$cb};	1391	delete $SIG_CB{$signal}{$cb};
1218		1392
		1393	$HAVE_ASYNC_INTERRUPT
		1394	? delete $SIG_ASY{$signal}
1219	# delete doesn't work with older perls - they then	1395	: # delete doesn't work with older perls - they then
1220	# print weird messages, or just unconditionally exit	1396	# print weird messages, or just unconditionally exit
1221	# instead of getting the default action.	1397	# instead of getting the default action.
		1398	undef $SIG{$signal}
1222	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1399	unless keys %{ $SIG_CB{$signal} };
1223	}	1400	}
1224		1401
1225	# default implementation for ->child	1402	# default implementation for ->child
1226		1403
1227	our %PID_CB;	1404	our %PID_CB;
…		…
1229	our $CHLD_DELAY_W;	1406	our $CHLD_DELAY_W;
1230	our $WNOHANG;	1407	our $WNOHANG;
1231		1408
1232	sub _sigchld {	1409	sub _sigchld {
1233	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1410	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
		1411	$_->($pid, $?)
1234	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1412	for values %{ $PID_CB{$pid} \|\| {} },
1235	(values %{ $PID_CB{0} \|\| {} });	1413	values %{ $PID_CB{0} \|\| {} };
1236	}	1414	}
1237	}	1415	}
1238		1416
1239	sub child {	1417	sub child {
1240	my (undef, %arg) = @_;	1418	my (undef, %arg) = @_;
…		…
1242	defined (my $pid = $arg{pid} + 0)	1420	defined (my $pid = $arg{pid} + 0)
1243	or Carp::croak "required option 'pid' is missing";	1421	or Carp::croak "required option 'pid' is missing";
1244		1422
1245	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1423	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1246		1424
		1425	# WNOHANG is almost cetrainly 1 everywhere
		1426	$WNOHANG \|\|= $^O =~ /^(?:openbsd\|netbsd\|linux\|freebsd\|cygwin\|MSWin32)$/
		1427	? 1
1247	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1428	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1248		1429
1249	unless ($CHLD_W) {	1430	unless ($CHLD_W) {
1250	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1431	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1251	# child could be a zombie already, so make at least one round	1432	# child could be a zombie already, so make at least one round
1252	&_sigchld;	1433	&_sigchld;
…		…
1304		1485
1305	our @ISA = AnyEvent::CondVar::Base::;	1486	our @ISA = AnyEvent::CondVar::Base::;
1306		1487
1307	package AnyEvent::CondVar::Base;	1488	package AnyEvent::CondVar::Base;
1308		1489
1309	use overload	1490	#use overload
1310	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1491	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1311	fallback => 1;	1492	# fallback => 1;
		1493
		1494	# save 300+ kilobytes by dirtily hardcoding overloading
		1495	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1496	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1497	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1498	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1499
		1500	our $WAITING;
1312		1501
1313	sub _send {	1502	sub _send {
1314	# nop	1503	# nop
1315	}	1504	}
1316		1505
…		…
1329	sub ready {	1518	sub ready {
1330	$_[0]{_ae_sent}	1519	$_[0]{_ae_sent}
1331	}	1520	}
1332		1521
1333	sub _wait {	1522	sub _wait {
		1523	$WAITING
		1524	and !$_[0]{_ae_sent}
		1525	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1526
		1527	local $WAITING = 1;
1334	AnyEvent->one_event while !$_[0]{_ae_sent};	1528	AnyEvent->one_event while !$_[0]{_ae_sent};
1335	}	1529	}
1336		1530
1337	sub recv {	1531	sub recv {
1338	$_[0]->_wait;	1532	$_[0]->_wait;
…		…
1400	C<PERL_ANYEVENT_MODEL>.	1594	C<PERL_ANYEVENT_MODEL>.
1401		1595
1402	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1596	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1403	model it chooses.	1597	model it chooses.
1404		1598
		1599	When set to C<8> or higher, then AnyEvent will report extra information on
		1600	which optional modules it loads and how it implements certain features.
		1601
1405	=item C<PERL_ANYEVENT_STRICT>	1602	=item C<PERL_ANYEVENT_STRICT>
1406		1603
1407	AnyEvent does not do much argument checking by default, as thorough	1604	AnyEvent does not do much argument checking by default, as thorough
1408	argument checking is very costly. Setting this variable to a true value	1605	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	1606	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,	1607	check the arguments passed to most method calls. If it finds any problems,
1411	it will croak.	1608	it will croak.
1412		1609
1413	In other words, enables "strict" mode.	1610	In other words, enables "strict" mode.
1414		1611
1415	Unlike C<use strict>, it is definitely recommended to keep it off in	1612	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	1613	>>, it is definitely recommended to keep it off in production. Keeping
1417	developing programs can be very useful, however.	1614	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1615	can be very useful, however.
1418		1616
1419	=item C<PERL_ANYEVENT_MODEL>	1617	=item C<PERL_ANYEVENT_MODEL>
1420		1618
1421	This can be used to specify the event model to be used by AnyEvent, before	1619	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	1620	auto detection and -probing kicks in. It must be a string consisting
…		…
1484		1682
1485	When neither C<ca_file> nor C<ca_path> was specified during	1683	When neither C<ca_file> nor C<ca_path> was specified during
1486	L<AnyEvent::TLS> context creation, and either of these environment	1684	L<AnyEvent::TLS> context creation, and either of these environment
1487	variables exist, they will be used to specify CA certificate locations	1685	variables exist, they will be used to specify CA certificate locations
1488	instead of a system-dependent default.	1686	instead of a system-dependent default.
		1687
		1688	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1689
		1690	When these are set to C<1>, then the respective modules are not
		1691	loaded. Mostly good for testing AnyEvent itself.
1489		1692
1490	=back	1693	=back
1491		1694
1492	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1695	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1493		1696
…		…
2032		2235
2033	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2236	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	2237	emulation for event loops that do not support them natively. Also, some
2035	event loops install a similar handler.	2238	event loops install a similar handler.
2036		2239
2037	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2240	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2038	reset it to default, to avoid losing child exit statuses.	2241	AnyEvent will reset it to default, to avoid losing child exit statuses.
2039		2242
2040	=item SIGPIPE	2243	=item SIGPIPE
2041		2244
2042	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2245	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2043	when AnyEvent gets loaded.	2246	when AnyEvent gets loaded.
…		…
2061	if $SIG{CHLD} eq 'IGNORE';	2264	if $SIG{CHLD} eq 'IGNORE';
2062		2265
2063	$SIG{PIPE} = sub { }	2266	$SIG{PIPE} = sub { }
2064	unless defined $SIG{PIPE};	2267	unless defined $SIG{PIPE};
2065		2268
		2269	=head1 RECOMMENDED/OPTIONAL MODULES
		2270
		2271	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2272	it's built-in modules) are required to use it.
		2273
		2274	That does not mean that AnyEvent won't take advantage of some additional
		2275	modules if they are installed.
		2276
		2277	This section epxlains which additional modules will be used, and how they
		2278	affect AnyEvent's operetion.
		2279
		2280	=over 4
		2281
		2282	=item L<Async::Interrupt>
		2283
		2284	This slightly arcane module is used to implement fast signal handling: To
		2285	my knowledge, there is no way to do completely race-free and quick
		2286	signal handling in pure perl. To ensure that signals still get
		2287	delivered, AnyEvent will start an interval timer to wake up perl (and
		2288	catch the signals) with some delay (default is 10 seconds, look for
		2289	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2290
		2291	If this module is available, then it will be used to implement signal
		2292	catching, which means that signals will not be delayed, and the event loop
		2293	will not be interrupted regularly, which is more efficient (And good for
		2294	battery life on laptops).
		2295
		2296	This affects not just the pure-perl event loop, but also other event loops
		2297	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2298
		2299	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2300	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2301	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2302	does nothing for those backends.
		2303
		2304	=item L<EV>
		2305
		2306	This module isn't really "optional", as it is simply one of the backend
		2307	event loops that AnyEvent can use. However, it is simply the best event
		2308	loop available in terms of features, speed and stability: It supports
		2309	the AnyEvent API optimally, implements all the watcher types in XS, does
		2310	automatic timer adjustments even when no monotonic clock is available,
		2311	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2312	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2313	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2314
		2315	=item L<Guard>
		2316
		2317	The guard module, when used, will be used to implement
		2318	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2319	lot less memory), but otherwise doesn't affect guard operation much. It is
		2320	purely used for performance.
		2321
		2322	=item L<JSON> and L<JSON::XS>
		2323
		2324	This module is required when you want to read or write JSON data via
		2325	L<AnyEvent::Handle>. It is also written in pure-perl, but can take
		2326	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2327
		2328	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
		2329	installed.
		2330
		2331	=item L<Net::SSLeay>
		2332
		2333	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2334	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2335	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2336
		2337	=item L<Time::HiRes>
		2338
		2339	This module is part of perl since release 5.008. It will be used when the
		2340	chosen event library does not come with a timing source on it's own. The
		2341	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2342	try to use a monotonic clock for timing stability.
		2343
		2344	=back
		2345
		2346
2066	=head1 FORK	2347	=head1 FORK
2067		2348
2068	Most event libraries are not fork-safe. The ones who are usually are	2349	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>	2350	because they rely on inefficient but fork-safe C<select> or C<poll>
2070	calls. Only L<EV> is fully fork-aware.	2351	calls. Only L<EV> is fully fork-aware.
2071		2352
2072	If you have to fork, you must either do so I<before> creating your first	2353	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.	2354	watcher OR you must not use AnyEvent at all in the child OR you must do
		2355	something completely out of the scope of AnyEvent.
2074		2356
2075		2357
2076	=head1 SECURITY CONSIDERATIONS	2358	=head1 SECURITY CONSIDERATIONS
2077		2359
2078	AnyEvent can be forced to load any event model via	2360	AnyEvent can be forced to load any event model via

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.230 by root, Wed Jul 8 05:55:17 2009 UTC vs. Revision 1.249 by root, Mon Jul 20 06:00:42 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.230 by root, Wed Jul 8 05:55:17 2009 UTC vs.
Revision 1.249 by root, Mon Jul 20 06:00:42 2009 UTC