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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.167 by root, Tue Jul 8 23:44:51 2008 UTC vs.
Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
12	...
13	});
14		12
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
16	...	23	...
17	});	24	});
18		25
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	27	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
		29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
22		31
23	=head1 INTRODUCTION/TUTORIAL	32	=head1 INTRODUCTION/TUTORIAL
24		33
25	This manpage is mainly a reference manual. If you are interested	34	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	35	in a tutorial or some gentle introduction, have a look at the
…		…
33		42
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
36		45
37	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
38	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
39	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
40	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
41	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
43		53
44	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
45	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
47	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
48	model you use.	58	model you use.
49		59
50	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
51	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
52	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
53	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
54	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
55	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
56		66
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60	your module uses one of those, every user of your module has to use it,	70	your module uses one of those, every user of your module has to use it,
61	too. But if your module uses AnyEvent, it works transparently with all	71	too. But if your module uses AnyEvent, it works transparently with all
62	event models it supports (including stuff like POE and IO::Async, as long	72	event models it supports (including stuff like IO::Async, as long as those
63	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
64	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
65		75
66	In addition to being free of having to use I<the one and only true event	76	In addition to being free of having to use I<the one and only true event
67	model>, AnyEvent also is free of bloat and policy: with POE or similar	77	model>, AnyEvent also is free of bloat and policy: with POE or similar
68	modules, you get an enormous amount of code and strict rules you have to	78	modules, you get an enormous amount of code and strict rules you have to
69	follow. AnyEvent, on the other hand, is lean and up to the point, by only	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
380	The instrument to do that is called a "condition variable", so called	390	The instrument to do that is called a "condition variable", so called
381	because they represent a condition that must become true.	391	because they represent a condition that must become true.
382		392
383	Condition variables can be created by calling the C<< AnyEvent->condvar	393	Condition variables can be created by calling the C<< AnyEvent->condvar
384	>> method, usually without arguments. The only argument pair allowed is	394	>> method, usually without arguments. The only argument pair allowed is
		395
385	C<cb>, which specifies a callback to be called when the condition variable	396	C<cb>, which specifies a callback to be called when the condition variable
386	becomes true.	397	becomes true, with the condition variable as the first argument (but not
		398	the results).
387		399
388	After creation, the condition variable is "false" until it becomes "true"	400	After creation, the condition variable is "false" until it becomes "true"
389	by calling the C<send> method (or calling the condition variable as if it	401	by calling the C<send> method (or calling the condition variable as if it
390	were a callback, read about the caveats in the description for the C<<	402	were a callback, read about the caveats in the description for the C<<
391	->send >> method).	403	->send >> method).
…		…
447		459
448	my $done = AnyEvent->condvar;	460	my $done = AnyEvent->condvar;
449	my $delay = AnyEvent->timer (after => 5, cb => $done);	461	my $delay = AnyEvent->timer (after => 5, cb => $done);
450	$done->recv;	462	$done->recv;
451		463
		464	Example: Imagine an API that returns a condvar and doesn't support
		465	callbacks. This is how you make a synchronous call, for example from
		466	the main program:
		467
		468	use AnyEvent::CouchDB;
		469
		470	...
		471
		472	my @info = $couchdb->info->recv;
		473
		474	And this is how you would just ste a callback to be called whenever the
		475	results are available:
		476
		477	$couchdb->info->cb (sub {
		478	my @info = $_[0]->recv;
		479	});
		480
452	=head3 METHODS FOR PRODUCERS	481	=head3 METHODS FOR PRODUCERS
453		482
454	These methods should only be used by the producing side, i.e. the	483	These methods should only be used by the producing side, i.e. the
455	code/module that eventually sends the signal. Note that it is also	484	code/module that eventually sends the signal. Note that it is also
456	the producer side which creates the condvar in most cases, but it isn't	485	the producer side which creates the condvar in most cases, but it isn't
…		…
589	=item $bool = $cv->ready	618	=item $bool = $cv->ready
590		619
591	Returns true when the condition is "true", i.e. whether C<send> or	620	Returns true when the condition is "true", i.e. whether C<send> or
592	C<croak> have been called.	621	C<croak> have been called.
593		622
594	=item $cb = $cv->cb ([new callback])	623	=item $cb = $cv->cb ($cb->($cv))
595		624
596	This is a mutator function that returns the callback set and optionally	625	This is a mutator function that returns the callback set and optionally
597	replaces it before doing so.	626	replaces it before doing so.
598		627
599	The callback will be called when the condition becomes "true", i.e. when	628	The callback will be called when the condition becomes "true", i.e. when
…		…
821	=cut	850	=cut
822		851
823	package AnyEvent;	852	package AnyEvent;
824		853
825	no warnings;	854	no warnings;
826	use strict;	855	use strict qw(vars subs);
827		856
828	use Carp;	857	use Carp;
829		858
830	our $VERSION = 4.2;	859	our $VERSION = 4.233;
831	our $MODEL;	860	our $MODEL;
832		861
833	our $AUTOLOAD;	862	our $AUTOLOAD;
834	our @ISA;	863	our @ISA;
835		864
…		…
940	}	969	}
941	}	970	}
942		971
943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
944		973
945	if ($ENV{PERL_ANYEVENT_STRICT}) {
946	unshift @AnyEvent::Base::Strict::ISA, $MODEL;
947	unshift @ISA, AnyEvent::Base::Strict::
948	} else {
949	unshift @ISA, $MODEL;	974	unshift @ISA, $MODEL;
950	}	975
		976	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
951		977
952	(shift @post_detect)->() while @post_detect;	978	(shift @post_detect)->() while @post_detect;
953	}	979	}
954		980
955	$MODEL	981	$MODEL
…		…
965		991
966	my $class = shift;	992	my $class = shift;
967	$class->$func (@_);	993	$class->$func (@_);
968	}	994	}
969		995
		996	# utility function to dup a filehandle. this is used by many backends
		997	# to support binding more than one watcher per filehandle (they usually
		998	# allow only one watcher per fd, so we dup it to get a different one).
		999	sub _dupfh($$$$) {
		1000	my ($poll, $fh, $r, $w) = @_;
		1001
		1002	require Fcntl;
		1003
		1004	# cygwin requires the fh mode to be matching, unix doesn't
		1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1006	: $poll eq "w" ? ($w, ">")
		1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1008
		1009	open my $fh2, "$mode&" . fileno $fh
		1010	or die "cannot dup() filehandle: $!";
		1011
		1012	# we assume CLOEXEC is already set by perl in all important cases
		1013
		1014	($fh2, $rw)
		1015	}
		1016
970	package AnyEvent::Base;	1017	package AnyEvent::Base;
971		1018
972	# default implementation for now and time	1019	# default implementation for now and time
973		1020
974	use Time::HiRes ();	1021	BEGIN {
		1022	if (eval "use Time::HiRes (); time (); 1") {
		1023	*_time = \&Time::HiRes::time;
		1024	# if (eval "use POSIX (); (POSIX::times())...
		1025	} else {
		1026	*_time = \&CORE::time; # epic fail
		1027	}
		1028	}
975		1029
976	sub time { Time::HiRes::time }	1030	sub time { _time }
977	sub now { Time::HiRes::time }	1031	sub now { _time }
978		1032
979	# default implementation for ->condvar	1033	# default implementation for ->condvar
980		1034
981	sub condvar {	1035	sub condvar {
982	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1036	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
1121		1175
1122	# undocumented/compatibility with pre-3.4	1176	# undocumented/compatibility with pre-3.4
1123	*broadcast = \&send;	1177	*broadcast = \&send;
1124	*wait = \&_wait;	1178	*wait = \&_wait;
1125		1179
1126	package AnyEvent::Base::Strict;	1180	=head1 ERROR AND EXCEPTION HANDLING
1127		1181
1128	use Carp qw(croak);	1182	In general, AnyEvent does not do any error handling - it relies on the
		1183	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1184	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1185	checking of all AnyEvent methods, however, which is highly useful during
		1186	development.
1129		1187
1130	# supply checks for argument validity for many functions	1188	As for exception handling (i.e. runtime errors and exceptions thrown while
		1189	executing a callback), this is not only highly event-loop specific, but
		1190	also not in any way wrapped by this module, as this is the job of the main
		1191	program.
1131		1192
1132	sub io {	1193	The pure perl event loop simply re-throws the exception (usually
1133	my $class = shift;	1194	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1134	my %arg = @_;	1195	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1196	so on.
1135		1197
1136	ref $arg{cb}	1198	=head1 ENVIRONMENT VARIABLES
1137	or croak "AnyEvent->io called with illegal cb argument '$arg{cb}'";
1138	delete $arg{cb};
1139
1140	fileno $arg{fh}
1141	or croak "AnyEvent->io called with illegal fh argument '$arg{fh}'";
1142	delete $arg{fh};
1143
1144	$arg{poll} =~ /^[rw]$/
1145	or croak "AnyEvent->io called with illegal poll argument '$arg{poll}'";
1146	delete $arg{poll};
1147
1148	croak "AnyEvent->io called with unsupported parameter(s) " . join ", ", keys %arg
1149	if keys %arg;
1150		1199
1151	$class->SUPER::io (@_)	1200	The following environment variables are used by this module or its
1152	}	1201	submodules:
1153		1202
1154	sub timer {	1203	=over 4
1155	my $class = shift;
1156	my %arg = @_;
1157		1204
1158	ref $arg{cb}	1205	=item C<PERL_ANYEVENT_VERBOSE>
1159	or croak "AnyEvent->timer called with illegal cb argument '$arg{cb}'";
1160	delete $arg{cb};
1161
1162	exists $arg{after}
1163	or croak "AnyEvent->timer called without mandatory 'after' parameter";
1164	delete $arg{after};
1165
1166	$arg{interval} > 0 \|\| !$arg{interval}
1167	or croak "AnyEvent->timer called with illegal interval argument '$arg{interval}'";
1168	delete $arg{interval};
1169
1170	croak "AnyEvent->timer called with unsupported parameter(s) " . join ", ", keys %arg
1171	if keys %arg;
1172		1206
1173	$class->SUPER::timer (@_)	1207	By default, AnyEvent will be completely silent except in fatal
1174	}	1208	conditions. You can set this environment variable to make AnyEvent more
		1209	talkative.
1175		1210
1176	sub signal {	1211	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1177	my $class = shift;	1212	conditions, such as not being able to load the event model specified by
1178	my %arg = @_;	1213	C<PERL_ANYEVENT_MODEL>.
1179		1214
1180	ref $arg{cb}	1215	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1181	or croak "AnyEvent->signal called with illegal cb argument '$arg{cb}'";	1216	model it chooses.
1182	delete $arg{cb};
1183
1184	eval "require POSIX; defined &POSIX::SIG$arg{signal}"
1185	or croak "AnyEvent->signal called with illegal signal name '$arg{signal}'";
1186	delete $arg{signal};
1187
1188	croak "AnyEvent->signal called with unsupported parameter(s) " . join ", ", keys %arg
1189	if keys %arg;
1190		1217
1191	$class->SUPER::signal (@_)	1218	=item C<PERL_ANYEVENT_STRICT>
1192	}
1193		1219
1194	sub child {	1220	AnyEvent does not do much argument checking by default, as thorough
1195	my $class = shift;	1221	argument checking is very costly. Setting this variable to a true value
1196	my %arg = @_;	1222	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1223	check the arguments passed to most method calls. If it finds any problems
		1224	it will croak.
1197		1225
1198	ref $arg{cb}	1226	In other words, enables "strict" mode.
1199	or croak "AnyEvent->signal called with illegal cb argument '$arg{cb}'";
1200	delete $arg{cb};
1201
1202	$arg{pid} =~ /^-?\d+$/
1203	or croak "AnyEvent->signal called with illegal pid value '$arg{pid}'";
1204	delete $arg{pid};
1205
1206	croak "AnyEvent->signal called with unsupported parameter(s) " . join ", ", keys %arg
1207	if keys %arg;
1208		1227
1209	$class->SUPER::child (@_)	1228	Unlike C<use strict>, it is definitely recommended ot keep it off in
1210	}	1229	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1230	developing programs can be very useful, however.
1211		1231
1212	sub condvar {	1232	=item C<PERL_ANYEVENT_MODEL>
1213	my $class = shift;
1214	my %arg = @_;
1215		1233
1216	!exists $arg{cb} or ref $arg{cb}	1234	This can be used to specify the event model to be used by AnyEvent, before
1217	or croak "AnyEvent->condvar called with illegal cb argument '$arg{cb}'";	1235	auto detection and -probing kicks in. It must be a string consisting
1218	delete $arg{cb};	1236	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1219		1237	and the resulting module name is loaded and if the load was successful,
1220	croak "AnyEvent->condvar called with unsupported parameter(s) " . join ", ", keys %arg	1238	used as event model. If it fails to load AnyEvent will proceed with
1221	if keys %arg;	1239	auto detection and -probing.
1222		1240
1223	$class->SUPER::condvar (@_)	1241	This functionality might change in future versions.
1224	}
1225		1242
1226	sub time {	1243	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1227	my $class = shift;	1244	could start your program like this:
1228		1245
1229	@_	1246	PERL_ANYEVENT_MODEL=Perl perl ...
1230	and croak "AnyEvent->time wrongly called with paramaters";
1231		1247
1232	$class->SUPER::time (@_)	1248	=item C<PERL_ANYEVENT_PROTOCOLS>
1233	}
1234		1249
1235	sub now {	1250	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1236	my $class = shift;	1251	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1252	of auto probing).
1237		1253
1238	@_	1254	Must be set to a comma-separated list of protocols or address families,
1239	and croak "AnyEvent->now wrongly called with paramaters";	1255	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1256	used, and preference will be given to protocols mentioned earlier in the
		1257	list.
1240		1258
1241	$class->SUPER::now (@_)	1259	This variable can effectively be used for denial-of-service attacks
1242	}	1260	against local programs (e.g. when setuid), although the impact is likely
		1261	small, as the program has to handle connection errors already-
		1262
		1263	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1264	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1265	- only support IPv4, never try to resolve or contact IPv6
		1266	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1267	IPv6, but prefer IPv6 over IPv4.
		1268
		1269	=item C<PERL_ANYEVENT_EDNS0>
		1270
		1271	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1272	for DNS. This extension is generally useful to reduce DNS traffic, but
		1273	some (broken) firewalls drop such DNS packets, which is why it is off by
		1274	default.
		1275
		1276	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1277	EDNS0 in its DNS requests.
		1278
		1279	=item C<PERL_ANYEVENT_MAX_FORKS>
		1280
		1281	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1282	will create in parallel.
		1283
		1284	=back
1243		1285
1244	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1286	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1245		1287
1246	This is an advanced topic that you do not normally need to use AnyEvent in	1288	This is an advanced topic that you do not normally need to use AnyEvent in
1247	a module. This section is only of use to event loop authors who want to	1289	a module. This section is only of use to event loop authors who want to
…		…
1281		1323
1282	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1324	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1283	condition variables: code blocking while waiting for a condition will	1325	condition variables: code blocking while waiting for a condition will
1284	C<die>. This still works with most modules/usages, and blocking calls must	1326	C<die>. This still works with most modules/usages, and blocking calls must
1285	not be done in an interactive application, so it makes sense.	1327	not be done in an interactive application, so it makes sense.
1286
1287	=head1 ENVIRONMENT VARIABLES
1288
1289	The following environment variables are used by this module:
1290
1291	=over 4
1292
1293	=item C<PERL_ANYEVENT_VERBOSE>
1294
1295	By default, AnyEvent will be completely silent except in fatal
1296	conditions. You can set this environment variable to make AnyEvent more
1297	talkative.
1298
1299	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1300	conditions, such as not being able to load the event model specified by
1301	C<PERL_ANYEVENT_MODEL>.
1302
1303	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1304	model it chooses.
1305
1306	=item C<PERL_ANYEVENT_STRICT>
1307
1308	AnyEvent does not do much argument checking by default, as thorough
1309	argument checking is very costly. Setting this variable to a true value
1310	will cause AnyEvent to thoroughly check the arguments passed to most
1311	method calls and croaks if it finds any problems. In other words, enables
1312	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
1313	it off in production.
1314
1315	=item C<PERL_ANYEVENT_MODEL>
1316
1317	This can be used to specify the event model to be used by AnyEvent, before
1318	auto detection and -probing kicks in. It must be a string consisting
1319	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1320	and the resulting module name is loaded and if the load was successful,
1321	used as event model. If it fails to load AnyEvent will proceed with
1322	auto detection and -probing.
1323
1324	This functionality might change in future versions.
1325
1326	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1327	could start your program like this:
1328
1329	PERL_ANYEVENT_MODEL=Perl perl ...
1330
1331	=item C<PERL_ANYEVENT_PROTOCOLS>
1332
1333	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1334	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1335	of auto probing).
1336
1337	Must be set to a comma-separated list of protocols or address families,
1338	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1339	used, and preference will be given to protocols mentioned earlier in the
1340	list.
1341
1342	This variable can effectively be used for denial-of-service attacks
1343	against local programs (e.g. when setuid), although the impact is likely
1344	small, as the program has to handle connection errors already-
1345
1346	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1347	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1348	- only support IPv4, never try to resolve or contact IPv6
1349	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1350	IPv6, but prefer IPv6 over IPv4.
1351
1352	=item C<PERL_ANYEVENT_EDNS0>
1353
1354	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1355	for DNS. This extension is generally useful to reduce DNS traffic, but
1356	some (broken) firewalls drop such DNS packets, which is why it is off by
1357	default.
1358
1359	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1360	EDNS0 in its DNS requests.
1361
1362	=item C<PERL_ANYEVENT_MAX_FORKS>
1363
1364	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1365	will create in parallel.
1366
1367	=back
1368		1328
1369	=head1 EXAMPLE PROGRAM	1329	=head1 EXAMPLE PROGRAM
1370		1330
1371	The following program uses an I/O watcher to read data from STDIN, a timer	1331	The following program uses an I/O watcher to read data from STDIN, a timer
1372	to display a message once per second, and a condition variable to quit the	1332	to display a message once per second, and a condition variable to quit the

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.167 by root, Tue Jul 8 23:44:51 2008 UTC vs. Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.167 by root, Tue Jul 8 23:44:51 2008 UTC vs.
Revision 1.180 by root, Sat Sep 6 07:00:45 2008 UTC