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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC vs.
Revision 1.199 by root, Fri Mar 27 10:49:50 2009 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
…		…
127	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
128	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
129	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
130	is in control).	140	is in control).
131		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		144	callbacks must not C<die> >>. The former is good programming practise in
		145	Perl and the latter stems from the fact that exception handling differs
		146	widely between event loops.
		147
132	To disable the watcher you have to destroy it (e.g. by setting the	148	To disable the watcher you have to destroy it (e.g. by setting the
133	variable you store it in to C<undef> or otherwise deleting all references	149	variable you store it in to C<undef> or otherwise deleting all references
134	to it).	150	to it).
135		151
136	All watchers are created by calling a method on the C<AnyEvent> class.	152	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
152	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
153		169
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
156		172
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		174	for events (AnyEvent might or might not keep a reference to this file
		175	handle). Note that only file handles pointing to things for which
		176	non-blocking operation makes sense are allowed. This includes sockets,
		177	most character devices, pipes, fifos and so on, but not for example files
		178	or block devices.
		179
158	for events. C<poll> must be a string that is either C<r> or C<w>,	180	C<poll> must be a string that is either C<r> or C<w>, which creates a
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	181	watcher waiting for "r"eadable or "w"ritable events, respectively.
		182
160	respectively. C<cb> is the callback to invoke each time the file handle	183	C<cb> is the callback to invoke each time the file handle becomes ready.
161	becomes ready.
162		184
163	Although the callback might get passed parameters, their value and	185	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	186	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	187	callbacks cannot use arguments passed to I/O watcher callbacks.
166		188
…		…
303	=back	325	=back
304		326
305	=head2 SIGNAL WATCHERS	327	=head2 SIGNAL WATCHERS
306		328
307	You can watch for signals using a signal watcher, C<signal> is the signal	329	You can watch for signals using a signal watcher, C<signal> is the signal
308	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	330	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
309	be invoked whenever a signal occurs.	331	callback to be invoked whenever a signal occurs.
310		332
311	Although the callback might get passed parameters, their value and	333	Although the callback might get passed parameters, their value and
312	presence is undefined and you cannot rely on them. Portable AnyEvent	334	presence is undefined and you cannot rely on them. Portable AnyEvent
313	callbacks cannot use arguments passed to signal watcher callbacks.	335	callbacks cannot use arguments passed to signal watcher callbacks.
314		336
…		…
330	=head2 CHILD PROCESS WATCHERS	352	=head2 CHILD PROCESS WATCHERS
331		353
332	You can also watch on a child process exit and catch its exit status.	354	You can also watch on a child process exit and catch its exit status.
333		355
334	The child process is specified by the C<pid> argument (if set to C<0>, it	356	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	357	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	358	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	359	any trace events (stopped/continued).
338	and exit status (as returned by waitpid), so unlike other watcher types,	360
339	you I<can> rely on child watcher callback arguments.	361	The callback will be called with the pid and exit status (as returned by
		362	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		363	callback arguments.
		364
		365	This watcher type works by installing a signal handler for C<SIGCHLD>,
		366	and since it cannot be shared, nothing else should use SIGCHLD or reap
		367	random child processes (waiting for specific child processes, e.g. inside
		368	C<system>, is just fine).
340		369
341	There is a slight catch to child watchers, however: you usually start them	370	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	371	I<after> the child process was created, and this means the process could
343	have exited already (and no SIGCHLD will be sent anymore).	372	have exited already (and no SIGCHLD will be sent anymore).
344		373
…		…
380	The instrument to do that is called a "condition variable", so called	409	The instrument to do that is called a "condition variable", so called
381	because they represent a condition that must become true.	410	because they represent a condition that must become true.
382		411
383	Condition variables can be created by calling the C<< AnyEvent->condvar	412	Condition variables can be created by calling the C<< AnyEvent->condvar
384	>> method, usually without arguments. The only argument pair allowed is	413	>> method, usually without arguments. The only argument pair allowed is
		414
385	C<cb>, which specifies a callback to be called when the condition variable	415	C<cb>, which specifies a callback to be called when the condition variable
386	becomes true.	416	becomes true, with the condition variable as the first argument (but not
		417	the results).
387		418
388	After creation, the condition variable is "false" until it becomes "true"	419	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	420	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<<	421	were a callback, read about the caveats in the description for the C<<
391	->send >> method).	422	->send >> method).
…		…
447		478
448	my $done = AnyEvent->condvar;	479	my $done = AnyEvent->condvar;
449	my $delay = AnyEvent->timer (after => 5, cb => $done);	480	my $delay = AnyEvent->timer (after => 5, cb => $done);
450	$done->recv;	481	$done->recv;
451		482
		483	Example: Imagine an API that returns a condvar and doesn't support
		484	callbacks. This is how you make a synchronous call, for example from
		485	the main program:
		486
		487	use AnyEvent::CouchDB;
		488
		489	...
		490
		491	my @info = $couchdb->info->recv;
		492
		493	And this is how you would just ste a callback to be called whenever the
		494	results are available:
		495
		496	$couchdb->info->cb (sub {
		497	my @info = $_[0]->recv;
		498	});
		499
452	=head3 METHODS FOR PRODUCERS	500	=head3 METHODS FOR PRODUCERS
453		501
454	These methods should only be used by the producing side, i.e. the	502	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	503	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	504	the producer side which creates the condvar in most cases, but it isn't
…		…
589	=item $bool = $cv->ready	637	=item $bool = $cv->ready
590		638
591	Returns true when the condition is "true", i.e. whether C<send> or	639	Returns true when the condition is "true", i.e. whether C<send> or
592	C<croak> have been called.	640	C<croak> have been called.
593		641
594	=item $cb = $cv->cb ([new callback])	642	=item $cb = $cv->cb ($cb->($cv))
595		643
596	This is a mutator function that returns the callback set and optionally	644	This is a mutator function that returns the callback set and optionally
597	replaces it before doing so.	645	replaces it before doing so.
598		646
599	The callback will be called when the condition becomes "true", i.e. when	647	The callback will be called when the condition becomes "true", i.e. when
…		…
789	=item L<AnyEvent::IGS>	837	=item L<AnyEvent::IGS>
790		838
791	A non-blocking interface to the Internet Go Server protocol (used by	839	A non-blocking interface to the Internet Go Server protocol (used by
792	L<App::IGS>).	840	L<App::IGS>).
793		841
794	=item L<Net::IRC3>	842	=item L<AnyEvent::IRC>
795		843
796	AnyEvent based IRC client module family.	844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
797		845
798	=item L<Net::XMPP2>	846	=item L<Net::XMPP2>
799		847
800	AnyEvent based XMPP (Jabber protocol) module family.	848	AnyEvent based XMPP (Jabber protocol) module family.
801		849
…		…
821	=cut	869	=cut
822		870
823	package AnyEvent;	871	package AnyEvent;
824		872
825	no warnings;	873	no warnings;
826	use strict;	874	use strict qw(vars subs);
827		875
828	use Carp;	876	use Carp;
829		877
830	our $VERSION = 4.2;	878	our $VERSION = 4.35;
831	our $MODEL;	879	our $MODEL;
832		880
833	our $AUTOLOAD;	881	our $AUTOLOAD;
834	our @ISA;	882	our @ISA;
835		883
…		…
938	$MODEL	986	$MODEL
939	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	987	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
940	}	988	}
941	}	989	}
942		990
		991	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		992
943	unshift @ISA, $MODEL;	993	unshift @ISA, $MODEL;
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	994
		995	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
945		996
946	(shift @post_detect)->() while @post_detect;	997	(shift @post_detect)->() while @post_detect;
947	}	998	}
948		999
949	$MODEL	1000	$MODEL
…		…
959		1010
960	my $class = shift;	1011	my $class = shift;
961	$class->$func (@_);	1012	$class->$func (@_);
962	}	1013	}
963		1014
		1015	# utility function to dup a filehandle. this is used by many backends
		1016	# to support binding more than one watcher per filehandle (they usually
		1017	# allow only one watcher per fd, so we dup it to get a different one).
		1018	sub _dupfh($$$$) {
		1019	my ($poll, $fh, $r, $w) = @_;
		1020
		1021	# cygwin requires the fh mode to be matching, unix doesn't
		1022	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1023	: $poll eq "w" ? ($w, ">")
		1024	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1025
		1026	open my $fh2, "$mode&" . fileno $fh
		1027	or die "cannot dup() filehandle: $!";
		1028
		1029	# we assume CLOEXEC is already set by perl in all important cases
		1030
		1031	($fh2, $rw)
		1032	}
		1033
964	package AnyEvent::Base;	1034	package AnyEvent::Base;
965		1035
966	# default implementation for now and time	1036	# default implementation for now and time
967		1037
968	use Time::HiRes ();	1038	BEGIN {
		1039	if (eval "use Time::HiRes (); time (); 1") {
		1040	*_time = \&Time::HiRes::time;
		1041	# if (eval "use POSIX (); (POSIX::times())...
		1042	} else {
		1043	*_time = sub { time }; # epic fail
		1044	}
		1045	}
969		1046
970	sub time { Time::HiRes::time }	1047	sub time { _time }
971	sub now { Time::HiRes::time }	1048	sub now { _time }
972		1049
973	# default implementation for ->condvar	1050	# default implementation for ->condvar
974		1051
975	sub condvar {	1052	sub condvar {
976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
977	}	1054	}
978		1055
979	# default implementation for ->signal	1056	# default implementation for ->signal
980		1057
981	our %SIG_CB;	1058	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1059
		1060	sub _signal_exec {
		1061	sysread $SIGPIPE_R, my $dummy, 4;
		1062
		1063	while (%SIG_EV) {
		1064	for (keys %SIG_EV) {
		1065	delete $SIG_EV{$_};
		1066	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1067	}
		1068	}
		1069	}
982		1070
983	sub signal {	1071	sub signal {
984	my (undef, %arg) = @_;	1072	my (undef, %arg) = @_;
985		1073
		1074	unless ($SIGPIPE_R) {
		1075	if (AnyEvent::WIN32) {
		1076	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1077	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1078	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1079	} else {
		1080	pipe $SIGPIPE_R, $SIGPIPE_W;
		1081	require Fcntl;
		1082	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1083	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1084	}
		1085
		1086	$SIGPIPE_R
		1087	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1088
		1089	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1090	}
		1091
986	my $signal = uc $arg{signal}	1092	my $signal = uc $arg{signal}
987	or Carp::croak "required option 'signal' is missing";	1093	or Carp::croak "required option 'signal' is missing";
988		1094
989	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1095	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
990	$SIG{$signal} \|\|= sub {	1096	$SIG{$signal} \|\|= sub {
991	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1097	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1098	undef $SIG_EV{$signal};
992	};	1099	};
993		1100
994	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1101	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
995	}	1102	}
996		1103
…		…
1115		1222
1116	# undocumented/compatibility with pre-3.4	1223	# undocumented/compatibility with pre-3.4
1117	*broadcast = \&send;	1224	*broadcast = \&send;
1118	*wait = \&_wait;	1225	*wait = \&_wait;
1119		1226
		1227	=head1 ERROR AND EXCEPTION HANDLING
		1228
		1229	In general, AnyEvent does not do any error handling - it relies on the
		1230	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1231	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1232	checking of all AnyEvent methods, however, which is highly useful during
		1233	development.
		1234
		1235	As for exception handling (i.e. runtime errors and exceptions thrown while
		1236	executing a callback), this is not only highly event-loop specific, but
		1237	also not in any way wrapped by this module, as this is the job of the main
		1238	program.
		1239
		1240	The pure perl event loop simply re-throws the exception (usually
		1241	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1242	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1243	so on.
		1244
		1245	=head1 ENVIRONMENT VARIABLES
		1246
		1247	The following environment variables are used by this module or its
		1248	submodules:
		1249
		1250	=over 4
		1251
		1252	=item C<PERL_ANYEVENT_VERBOSE>
		1253
		1254	By default, AnyEvent will be completely silent except in fatal
		1255	conditions. You can set this environment variable to make AnyEvent more
		1256	talkative.
		1257
		1258	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1259	conditions, such as not being able to load the event model specified by
		1260	C<PERL_ANYEVENT_MODEL>.
		1261
		1262	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1263	model it chooses.
		1264
		1265	=item C<PERL_ANYEVENT_STRICT>
		1266
		1267	AnyEvent does not do much argument checking by default, as thorough
		1268	argument checking is very costly. Setting this variable to a true value
		1269	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1270	check the arguments passed to most method calls. If it finds any problems
		1271	it will croak.
		1272
		1273	In other words, enables "strict" mode.
		1274
		1275	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1276	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1277	developing programs can be very useful, however.
		1278
		1279	=item C<PERL_ANYEVENT_MODEL>
		1280
		1281	This can be used to specify the event model to be used by AnyEvent, before
		1282	auto detection and -probing kicks in. It must be a string consisting
		1283	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1284	and the resulting module name is loaded and if the load was successful,
		1285	used as event model. If it fails to load AnyEvent will proceed with
		1286	auto detection and -probing.
		1287
		1288	This functionality might change in future versions.
		1289
		1290	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1291	could start your program like this:
		1292
		1293	PERL_ANYEVENT_MODEL=Perl perl ...
		1294
		1295	=item C<PERL_ANYEVENT_PROTOCOLS>
		1296
		1297	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1298	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1299	of auto probing).
		1300
		1301	Must be set to a comma-separated list of protocols or address families,
		1302	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1303	used, and preference will be given to protocols mentioned earlier in the
		1304	list.
		1305
		1306	This variable can effectively be used for denial-of-service attacks
		1307	against local programs (e.g. when setuid), although the impact is likely
		1308	small, as the program has to handle conenction and other failures anyways.
		1309
		1310	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1311	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1312	- only support IPv4, never try to resolve or contact IPv6
		1313	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1314	IPv6, but prefer IPv6 over IPv4.
		1315
		1316	=item C<PERL_ANYEVENT_EDNS0>
		1317
		1318	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1319	for DNS. This extension is generally useful to reduce DNS traffic, but
		1320	some (broken) firewalls drop such DNS packets, which is why it is off by
		1321	default.
		1322
		1323	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1324	EDNS0 in its DNS requests.
		1325
		1326	=item C<PERL_ANYEVENT_MAX_FORKS>
		1327
		1328	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1329	will create in parallel.
		1330
		1331	=back
		1332
1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1333	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1121		1334
1122	This is an advanced topic that you do not normally need to use AnyEvent in	1335	This is an advanced topic that you do not normally need to use AnyEvent in
1123	a module. This section is only of use to event loop authors who want to	1336	a module. This section is only of use to event loop authors who want to
1124	provide AnyEvent compatibility.	1337	provide AnyEvent compatibility.
…		…
1157		1370
1158	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1371	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1159	condition variables: code blocking while waiting for a condition will	1372	condition variables: code blocking while waiting for a condition will
1160	C<die>. This still works with most modules/usages, and blocking calls must	1373	C<die>. This still works with most modules/usages, and blocking calls must
1161	not be done in an interactive application, so it makes sense.	1374	not be done in an interactive application, so it makes sense.
1162
1163	=head1 ENVIRONMENT VARIABLES
1164
1165	The following environment variables are used by this module:
1166
1167	=over 4
1168
1169	=item C<PERL_ANYEVENT_VERBOSE>
1170
1171	By default, AnyEvent will be completely silent except in fatal
1172	conditions. You can set this environment variable to make AnyEvent more
1173	talkative.
1174
1175	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1176	conditions, such as not being able to load the event model specified by
1177	C<PERL_ANYEVENT_MODEL>.
1178
1179	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1180	model it chooses.
1181
1182	=item C<PERL_ANYEVENT_MODEL>
1183
1184	This can be used to specify the event model to be used by AnyEvent, before
1185	auto detection and -probing kicks in. It must be a string consisting
1186	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1187	and the resulting module name is loaded and if the load was successful,
1188	used as event model. If it fails to load AnyEvent will proceed with
1189	auto detection and -probing.
1190
1191	This functionality might change in future versions.
1192
1193	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1194	could start your program like this:
1195
1196	PERL_ANYEVENT_MODEL=Perl perl ...
1197
1198	=item C<PERL_ANYEVENT_PROTOCOLS>
1199
1200	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1201	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1202	of auto probing).
1203
1204	Must be set to a comma-separated list of protocols or address families,
1205	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1206	used, and preference will be given to protocols mentioned earlier in the
1207	list.
1208
1209	This variable can effectively be used for denial-of-service attacks
1210	against local programs (e.g. when setuid), although the impact is likely
1211	small, as the program has to handle connection errors already-
1212
1213	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1214	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1215	- only support IPv4, never try to resolve or contact IPv6
1216	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1217	IPv6, but prefer IPv6 over IPv4.
1218
1219	=item C<PERL_ANYEVENT_EDNS0>
1220
1221	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1222	for DNS. This extension is generally useful to reduce DNS traffic, but
1223	some (broken) firewalls drop such DNS packets, which is why it is off by
1224	default.
1225
1226	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1227	EDNS0 in its DNS requests.
1228
1229	=item C<PERL_ANYEVENT_MAX_FORKS>
1230
1231	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1232	will create in parallel.
1233
1234	=back
1235		1375
1236	=head1 EXAMPLE PROGRAM	1376	=head1 EXAMPLE PROGRAM
1237		1377
1238	The following program uses an I/O watcher to read data from STDIN, a timer	1378	The following program uses an I/O watcher to read data from STDIN, a timer
1239	to display a message once per second, and a condition variable to quit the	1379	to display a message once per second, and a condition variable to quit the
…		…
1433	watcher.	1573	watcher.
1434		1574
1435	=head3 Results	1575	=head3 Results
1436		1576
1437	name watchers bytes create invoke destroy comment	1577	name watchers bytes create invoke destroy comment
1438	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1578	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1439	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1579	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1440	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1580	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1441	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1581	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1442	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1582	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1443	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1583	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1444	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1584	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1445	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1585	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1446	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1586	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1447	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1587	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1448		1588
1449	=head3 Discussion	1589	=head3 Discussion
1450		1590
1451	The benchmark does I<not> measure scalability of the event loop very	1591	The benchmark does I<not> measure scalability of the event loop very
1452	well. For example, a select-based event loop (such as the pure perl one)	1592	well. For example, a select-based event loop (such as the pure perl one)
…		…
1654	watchers, as the management overhead dominates.	1794	watchers, as the management overhead dominates.
1655		1795
1656	=back	1796	=back
1657		1797
1658		1798
		1799	=head1 SIGNALS
		1800
		1801	AnyEvent currently installs handlers for these signals:
		1802
		1803	=over 4
		1804
		1805	=item SIGCHLD
		1806
		1807	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1808	emulation for event loops that do not support them natively. Also, some
		1809	event loops install a similar handler.
		1810
		1811	=item SIGPIPE
		1812
		1813	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1814	when AnyEvent gets loaded.
		1815
		1816	The rationale for this is that AnyEvent users usually do not really depend
		1817	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1818	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1819	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1820	some random socket.
		1821
		1822	The rationale for installing a no-op handler as opposed to ignoring it is
		1823	that this way, the handler will be restored to defaults on exec.
		1824
		1825	Feel free to install your own handler, or reset it to defaults.
		1826
		1827	=back
		1828
		1829	=cut
		1830
		1831	$SIG{PIPE} = sub { }
		1832	unless defined $SIG{PIPE};
		1833
		1834
1659	=head1 FORK	1835	=head1 FORK
1660		1836
1661	Most event libraries are not fork-safe. The ones who are usually are	1837	Most event libraries are not fork-safe. The ones who are usually are
1662	because they rely on inefficient but fork-safe C<select> or C<poll>	1838	because they rely on inefficient but fork-safe C<select> or C<poll>
1663	calls. Only L<EV> is fully fork-aware.	1839	calls. Only L<EV> is fully fork-aware.
…		…
1682		1858
1683	use AnyEvent;	1859	use AnyEvent;
1684		1860
1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1861	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1686	be used to probe what backend is used and gain other information (which is	1862	be used to probe what backend is used and gain other information (which is
1687	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1863	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1864	$ENV{PERL_ANYEGENT_STRICT}.
1688		1865
1689		1866
1690	=head1 BUGS	1867	=head1 BUGS
1691		1868
1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1869	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1693	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	1870	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1694	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	1871	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1695	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	1872	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1696	pronounced).	1873	pronounced).
1697		1874
1698		1875
1699	=head1 SEE ALSO	1876	=head1 SEE ALSO
1700		1877

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC vs. Revision 1.199 by root, Fri Mar 27 10:49:50 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.165 by root, Tue Jul 8 23:07:26 2008 UTC vs.
Revision 1.199 by root, Fri Mar 27 10:49:50 2009 UTC