[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 1.190 by root, Wed Nov 5 02:21:27 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
…		…
330	=head2 CHILD PROCESS WATCHERS	340	=head2 CHILD PROCESS WATCHERS
331		341
332	You can also watch on a child process exit and catch its exit status.	342	You can also watch on a child process exit and catch its exit status.
333		343
334	The child process is specified by the C<pid> argument (if set to C<0>, it	344	The child process is specified by the C<pid> argument (if set to C<0>, it
335	watches for any child process exit). The watcher will trigger as often	345	watches for any child process exit). The watcher will triggered only when
336	as status change for the child are received. This works by installing a	346	the child process has finished and an exit status is available, not on
337	signal handler for C<SIGCHLD>. The callback will be called with the pid	347	any trace events (stopped/continued).
338	and exit status (as returned by waitpid), so unlike other watcher types,	348
339	you I<can> rely on child watcher callback arguments.	349	The callback will be called with the pid and exit status (as returned by
		350	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		351	callback arguments.
		352
		353	This watcher type works by installing a signal handler for C<SIGCHLD>,
		354	and since it cannot be shared, nothing else should use SIGCHLD or reap
		355	random child processes (waiting for specific child processes, e.g. inside
		356	C<system>, is just fine).
340		357
341	There is a slight catch to child watchers, however: you usually start them	358	There is a slight catch to child watchers, however: you usually start them
342	I<after> the child process was created, and this means the process could	359	I<after> the child process was created, and this means the process could
343	have exited already (and no SIGCHLD will be sent anymore).	360	have exited already (and no SIGCHLD will be sent anymore).
344		361
…		…
380	The instrument to do that is called a "condition variable", so called	397	The instrument to do that is called a "condition variable", so called
381	because they represent a condition that must become true.	398	because they represent a condition that must become true.
382		399
383	Condition variables can be created by calling the C<< AnyEvent->condvar	400	Condition variables can be created by calling the C<< AnyEvent->condvar
384	>> method, usually without arguments. The only argument pair allowed is	401	>> method, usually without arguments. The only argument pair allowed is
		402
385	C<cb>, which specifies a callback to be called when the condition variable	403	C<cb>, which specifies a callback to be called when the condition variable
386	becomes true.	404	becomes true, with the condition variable as the first argument (but not
		405	the results).
387		406
388	After creation, the condition variable is "false" until it becomes "true"	407	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	408	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<<	409	were a callback, read about the caveats in the description for the C<<
391	->send >> method).	410	->send >> method).
…		…
447		466
448	my $done = AnyEvent->condvar;	467	my $done = AnyEvent->condvar;
449	my $delay = AnyEvent->timer (after => 5, cb => $done);	468	my $delay = AnyEvent->timer (after => 5, cb => $done);
450	$done->recv;	469	$done->recv;
451		470
		471	Example: Imagine an API that returns a condvar and doesn't support
		472	callbacks. This is how you make a synchronous call, for example from
		473	the main program:
		474
		475	use AnyEvent::CouchDB;
		476
		477	...
		478
		479	my @info = $couchdb->info->recv;
		480
		481	And this is how you would just ste a callback to be called whenever the
		482	results are available:
		483
		484	$couchdb->info->cb (sub {
		485	my @info = $_[0]->recv;
		486	});
		487
452	=head3 METHODS FOR PRODUCERS	488	=head3 METHODS FOR PRODUCERS
453		489
454	These methods should only be used by the producing side, i.e. the	490	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	491	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	492	the producer side which creates the condvar in most cases, but it isn't
…		…
589	=item $bool = $cv->ready	625	=item $bool = $cv->ready
590		626
591	Returns true when the condition is "true", i.e. whether C<send> or	627	Returns true when the condition is "true", i.e. whether C<send> or
592	C<croak> have been called.	628	C<croak> have been called.
593		629
594	=item $cb = $cv->cb ([new callback])	630	=item $cb = $cv->cb ($cb->($cv))
595		631
596	This is a mutator function that returns the callback set and optionally	632	This is a mutator function that returns the callback set and optionally
597	replaces it before doing so.	633	replaces it before doing so.
598		634
599	The callback will be called when the condition becomes "true", i.e. when	635	The callback will be called when the condition becomes "true", i.e. when
…		…
789	=item L<AnyEvent::IGS>	825	=item L<AnyEvent::IGS>
790		826
791	A non-blocking interface to the Internet Go Server protocol (used by	827	A non-blocking interface to the Internet Go Server protocol (used by
792	L<App::IGS>).	828	L<App::IGS>).
793		829
794	=item L<Net::IRC3>	830	=item L<AnyEvent::IRC>
795		831
796	AnyEvent based IRC client module family.	832	AnyEvent based IRC client module family (replacing the older Net::IRC3).
797		833
798	=item L<Net::XMPP2>	834	=item L<Net::XMPP2>
799		835
800	AnyEvent based XMPP (Jabber protocol) module family.	836	AnyEvent based XMPP (Jabber protocol) module family.
801		837
…		…
821	=cut	857	=cut
822		858
823	package AnyEvent;	859	package AnyEvent;
824		860
825	no warnings;	861	no warnings;
826	use strict;	862	use strict qw(vars subs);
827		863
828	use Carp;	864	use Carp;
829		865
830	our $VERSION = 4.2;	866	our $VERSION = 4.32;
831	our $MODEL;	867	our $MODEL;
832		868
833	our $AUTOLOAD;	869	our $AUTOLOAD;
834	our @ISA;	870	our @ISA;
835		871
…		…
940	}	976	}
941	}	977	}
942		978
943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
944		980
945	if ($ENV{PERL_ANYEVENT_STRICT}) {
946	unshift @AnyEvent::Base::Strict::ISA, $MODEL;
947	unshift @ISA, AnyEvent::Base::Strict::
948	} else {
949	unshift @ISA, $MODEL;	981	unshift @ISA, $MODEL;
950	}	982
		983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
951		984
952	(shift @post_detect)->() while @post_detect;	985	(shift @post_detect)->() while @post_detect;
953	}	986	}
954		987
955	$MODEL	988	$MODEL
…		…
965		998
966	my $class = shift;	999	my $class = shift;
967	$class->$func (@_);	1000	$class->$func (@_);
968	}	1001	}
969		1002
		1003	# utility function to dup a filehandle. this is used by many backends
		1004	# to support binding more than one watcher per filehandle (they usually
		1005	# allow only one watcher per fd, so we dup it to get a different one).
		1006	sub _dupfh($$$$) {
		1007	my ($poll, $fh, $r, $w) = @_;
		1008
		1009	require Fcntl;
		1010
		1011	# cygwin requires the fh mode to be matching, unix doesn't
		1012	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1013	: $poll eq "w" ? ($w, ">")
		1014	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1015
		1016	open my $fh2, "$mode&" . fileno $fh
		1017	or die "cannot dup() filehandle: $!";
		1018
		1019	# we assume CLOEXEC is already set by perl in all important cases
		1020
		1021	($fh2, $rw)
		1022	}
		1023
970	package AnyEvent::Base;	1024	package AnyEvent::Base;
971		1025
972	# default implementation for now and time	1026	# default implementation for now and time
973		1027
974	use Time::HiRes ();	1028	BEGIN {
		1029	if (eval "use Time::HiRes (); time (); 1") {
		1030	*_time = \&Time::HiRes::time;
		1031	# if (eval "use POSIX (); (POSIX::times())...
		1032	} else {
		1033	*_time = sub { time }; # epic fail
		1034	}
		1035	}
975		1036
976	sub time { Time::HiRes::time }	1037	sub time { _time }
977	sub now { Time::HiRes::time }	1038	sub now { _time }
978		1039
979	# default implementation for ->condvar	1040	# default implementation for ->condvar
980		1041
981	sub condvar {	1042	sub condvar {
982	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
1121		1182
1122	# undocumented/compatibility with pre-3.4	1183	# undocumented/compatibility with pre-3.4
1123	*broadcast = \&send;	1184	*broadcast = \&send;
1124	*wait = \&_wait;	1185	*wait = \&_wait;
1125		1186
1126	package AnyEvent::Base::Strict;	1187	=head1 ERROR AND EXCEPTION HANDLING
1127		1188
1128	use Carp qw(croak);	1189	In general, AnyEvent does not do any error handling - it relies on the
		1190	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1191	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1192	checking of all AnyEvent methods, however, which is highly useful during
		1193	development.
1129		1194
1130	# supply checks for argument validity for many functions	1195	As for exception handling (i.e. runtime errors and exceptions thrown while
		1196	executing a callback), this is not only highly event-loop specific, but
		1197	also not in any way wrapped by this module, as this is the job of the main
		1198	program.
1131		1199
1132	sub io {	1200	The pure perl event loop simply re-throws the exception (usually
1133	my $class = shift;	1201	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
1134	my %arg = @_;	1202	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1203	so on.
1135		1204
1136	ref $arg{cb}	1205	=head1 ENVIRONMENT VARIABLES
1137	or croak "AnyEvent->io called with illegal cb argument '$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		1206
1151	$class->SUPER::io (@_)	1207	The following environment variables are used by this module or its
1152	}	1208	submodules:
1153		1209
1154	sub timer {	1210	=over 4
1155	my $class = shift;
1156	my %arg = @_;
1157		1211
1158	ref $arg{cb}	1212	=item C<PERL_ANYEVENT_VERBOSE>
1159	or croak "AnyEvent->timer called with illegal cb argument '$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		1213
1173	$class->SUPER::timer (@_)	1214	By default, AnyEvent will be completely silent except in fatal
1174	}	1215	conditions. You can set this environment variable to make AnyEvent more
		1216	talkative.
1175		1217
1176	sub signal {	1218	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1177	my $class = shift;	1219	conditions, such as not being able to load the event model specified by
1178	my %arg = @_;	1220	C<PERL_ANYEVENT_MODEL>.
1179		1221
1180	ref $arg{cb}	1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1181	or croak "AnyEvent->signal called with illegal cb argument '$arg{cb}'";	1223	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		1224
1191	$class->SUPER::signal (@_)	1225	=item C<PERL_ANYEVENT_STRICT>
1192	}
1193		1226
1194	sub child {	1227	AnyEvent does not do much argument checking by default, as thorough
1195	my $class = shift;	1228	argument checking is very costly. Setting this variable to a true value
1196	my %arg = @_;	1229	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1230	check the arguments passed to most method calls. If it finds any problems
		1231	it will croak.
1197		1232
1198	ref $arg{cb}	1233	In other words, enables "strict" mode.
1199	or croak "AnyEvent->signal called with illegal cb argument '$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		1234
1209	$class->SUPER::child (@_)	1235	Unlike C<use strict>, it is definitely recommended ot keep it off in
1210	}	1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1237	developing programs can be very useful, however.
1211		1238
1212	sub condvar {	1239	=item C<PERL_ANYEVENT_MODEL>
1213	my $class = shift;
1214	my %arg = @_;
1215		1240
1216	!exists $arg{cb} or ref $arg{cb}	1241	This can be used to specify the event model to be used by AnyEvent, before
1217	or croak "AnyEvent->condvar called with illegal cb argument '$arg{cb}'";	1242	auto detection and -probing kicks in. It must be a string consisting
1218	delete $arg{cb};	1243	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1219		1244	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	1245	used as event model. If it fails to load AnyEvent will proceed with
1221	if keys %arg;	1246	auto detection and -probing.
1222		1247
1223	$class->SUPER::condvar (@_)	1248	This functionality might change in future versions.
1224	}
1225		1249
1226	sub time {	1250	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1227	my $class = shift;	1251	could start your program like this:
1228		1252
1229	@_	1253	PERL_ANYEVENT_MODEL=Perl perl ...
1230	and croak "AnyEvent->time wrongly called with paramaters";
1231		1254
1232	$class->SUPER::time (@_)	1255	=item C<PERL_ANYEVENT_PROTOCOLS>
1233	}
1234		1256
1235	sub now {	1257	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1236	my $class = shift;	1258	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1259	of auto probing).
1237		1260
1238	@_	1261	Must be set to a comma-separated list of protocols or address families,
1239	and croak "AnyEvent->now wrongly called with paramaters";	1262	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1263	used, and preference will be given to protocols mentioned earlier in the
		1264	list.
1240		1265
1241	$class->SUPER::now (@_)	1266	This variable can effectively be used for denial-of-service attacks
1242	}	1267	against local programs (e.g. when setuid), although the impact is likely
		1268	small, as the program has to handle connection errors already-
		1269
		1270	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1271	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1272	- only support IPv4, never try to resolve or contact IPv6
		1273	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1274	IPv6, but prefer IPv6 over IPv4.
		1275
		1276	=item C<PERL_ANYEVENT_EDNS0>
		1277
		1278	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1279	for DNS. This extension is generally useful to reduce DNS traffic, but
		1280	some (broken) firewalls drop such DNS packets, which is why it is off by
		1281	default.
		1282
		1283	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1284	EDNS0 in its DNS requests.
		1285
		1286	=item C<PERL_ANYEVENT_MAX_FORKS>
		1287
		1288	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1289	will create in parallel.
		1290
		1291	=back
1243		1292
1244	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1245		1294
1246	This is an advanced topic that you do not normally need to use AnyEvent in	1295	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	1296	a module. This section is only of use to event loop authors who want to
…		…
1281		1330
1282	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1331	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1283	condition variables: code blocking while waiting for a condition will	1332	condition variables: code blocking while waiting for a condition will
1284	C<die>. This still works with most modules/usages, and blocking calls must	1333	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.	1334	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		1335
1369	=head1 EXAMPLE PROGRAM	1336	=head1 EXAMPLE PROGRAM
1370		1337
1371	The following program uses an I/O watcher to read data from STDIN, a timer	1338	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	1339	to display a message once per second, and a condition variable to quit the
…		…
1566	watcher.	1533	watcher.
1567		1534
1568	=head3 Results	1535	=head3 Results
1569		1536
1570	name watchers bytes create invoke destroy comment	1537	name watchers bytes create invoke destroy comment
1571	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1538	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1572	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1539	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1573	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1540	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1574	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1541	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1575	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1542	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1576	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1543	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1577	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1544	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1578	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1545	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1579	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1546	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1580	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1547	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1581		1548
1582	=head3 Discussion	1549	=head3 Discussion
1583		1550
1584	The benchmark does I<not> measure scalability of the event loop very	1551	The benchmark does I<not> measure scalability of the event loop very
1585	well. For example, a select-based event loop (such as the pure perl one)	1552	well. For example, a select-based event loop (such as the pure perl one)
…		…
1787	watchers, as the management overhead dominates.	1754	watchers, as the management overhead dominates.
1788		1755
1789	=back	1756	=back
1790		1757
1791		1758
		1759	=head1 SIGNALS
		1760
		1761	AnyEvent currently installs handlers for these signals:
		1762
		1763	=over 4
		1764
		1765	=item SIGCHLD
		1766
		1767	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1768	emulation for event loops that do not support them natively. Also, some
		1769	event loops install a similar handler.
		1770
		1771	=item SIGPIPE
		1772
		1773	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1774	when AnyEvent gets loaded.
		1775
		1776	The rationale for this is that AnyEvent users usually do not really depend
		1777	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1778	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1779	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1780	some random socket.
		1781
		1782	The rationale for installing a no-op handler as opposed to ignoring it is
		1783	that this way, the handler will be restored to defaults on exec.
		1784
		1785	Feel free to install your own handler, or reset it to defaults.
		1786
		1787	=back
		1788
		1789	=cut
		1790
		1791	$SIG{PIPE} = sub { }
		1792	unless defined $SIG{PIPE};
		1793
		1794
1792	=head1 FORK	1795	=head1 FORK
1793		1796
1794	Most event libraries are not fork-safe. The ones who are usually are	1797	Most event libraries are not fork-safe. The ones who are usually are
1795	because they rely on inefficient but fork-safe C<select> or C<poll>	1798	because they rely on inefficient but fork-safe C<select> or C<poll>
1796	calls. Only L<EV> is fully fork-aware.	1799	calls. Only L<EV> is fully fork-aware.

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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 1.190 by root, Wed Nov 5 02:21:27 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 1.190 by root, Wed Nov 5 02:21:27 2008 UTC