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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs.
Revision 1.201 by root, Wed Apr 1 14:08:27 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 { $_[0]->recv });
22		31
23	=head1 INTRODUCTION/TUTORIAL	32	=head1 INTRODUCTION/TUTORIAL
24		33
25	This manpage is mainly a reference manual. If you are interested	34	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	35	in a tutorial or some gentle introduction, have a look at the
…		…
128	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
131	is in control).	140	is in control).
132		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> 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
133	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
134	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
135	to it).	150	to it).
136		151
137	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.
…		…
153	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
154		169
155	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
156	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
157		172
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	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
160	must be a string that is either C<r> or C<w>, which creates a watcher	180	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	181	watcher waiting for "r"eadable or "w"ritable events, respectively.
		182
162	callback to invoke each time the file handle becomes ready.	183	C<cb> is the callback to invoke each time the file handle becomes ready.
163		184
164	Although the callback might get passed parameters, their value and	185	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	186	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	187	callbacks cannot use arguments passed to I/O watcher callbacks.
167		188
…		…
331	=head2 CHILD PROCESS WATCHERS	352	=head2 CHILD PROCESS WATCHERS
332		353
333	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.
334		355
335	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
336	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
337	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
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	359	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	360
340	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).
341		369
342	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
343	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
344	have exited already (and no SIGCHLD will be sent anymore).	372	have exited already (and no SIGCHLD will be sent anymore).
345		373
…		…
381	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
382	because they represent a condition that must become true.	410	because they represent a condition that must become true.
383		411
384	Condition variables can be created by calling the C<< AnyEvent->condvar	412	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	413	>> method, usually without arguments. The only argument pair allowed is
		414
386	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
387	becomes true.	416	becomes true, with the condition variable as the first argument (but not
		417	the results).
388		418
389	After creation, the condition variable is "false" until it becomes "true"	419	After creation, the condition variable is "false" until it becomes "true"
390	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
391	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<<
392	->send >> method).	422	->send >> method).
…		…
448		478
449	my $done = AnyEvent->condvar;	479	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	480	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	481	$done->recv;
452		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
453	=head3 METHODS FOR PRODUCERS	500	=head3 METHODS FOR PRODUCERS
454		501
455	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
456	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
457	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
…		…
590	=item $bool = $cv->ready	637	=item $bool = $cv->ready
591		638
592	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
593	C<croak> have been called.	640	C<croak> have been called.
594		641
595	=item $cb = $cv->cb ([new callback])	642	=item $cb = $cv->cb ($cb->($cv))
596		643
597	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
598	replaces it before doing so.	645	replaces it before doing so.
599		646
600	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
…		…
790	=item L<AnyEvent::IGS>	837	=item L<AnyEvent::IGS>
791		838
792	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
793	L<App::IGS>).	840	L<App::IGS>).
794		841
795	=item L<Net::IRC3>	842	=item L<AnyEvent::IRC>
796		843
797	AnyEvent based IRC client module family.	844	AnyEvent based IRC client module family (replacing the older Net::IRC3).
798		845
799	=item L<Net::XMPP2>	846	=item L<Net::XMPP2>
800		847
801	AnyEvent based XMPP (Jabber protocol) module family.	848	AnyEvent based XMPP (Jabber protocol) module family.
802		849
…		…
822	=cut	869	=cut
823		870
824	package AnyEvent;	871	package AnyEvent;
825		872
826	no warnings;	873	no warnings;
827	use strict;	874	use strict qw(vars subs);
828		875
829	use Carp;	876	use Carp;
830		877
831	our $VERSION = 4.2;	878	our $VERSION = 4.35;
832	our $MODEL;	879	our $MODEL;
833		880
834	our $AUTOLOAD;	881	our $AUTOLOAD;
835	our @ISA;	882	our @ISA;
836		883
…		…
963		1010
964	my $class = shift;	1011	my $class = shift;
965	$class->$func (@_);	1012	$class->$func (@_);
966	}	1013	}
967		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
968	package AnyEvent::Base;	1034	package AnyEvent::Base;
969		1035
970	# default implementation for now and time	1036	# default implementation for now and time
971		1037
972	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	}
973		1046
974	sub time { Time::HiRes::time }	1047	sub time { _time }
975	sub now { Time::HiRes::time }	1048	sub now { _time }
976		1049
977	# default implementation for ->condvar	1050	# default implementation for ->condvar
978		1051
979	sub condvar {	1052	sub condvar {
980	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1053	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
981	}	1054	}
982		1055
983	# default implementation for ->signal	1056	# default implementation for ->signal
984		1057
985	our %SIG_CB;	1058	our ($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	}
986		1070
987	sub signal {	1071	sub signal {
988	my (undef, %arg) = @_;	1072	my (undef, %arg) = @_;
989		1073
		1074	unless ($SIGPIPE_R) {
		1075	require Fcntl;
		1076
		1077	if (AnyEvent::WIN32) {
		1078	require AnyEvent::Util;
		1079
		1080	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1081	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1082	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1083	} else {
		1084	pipe $SIGPIPE_R, $SIGPIPE_W;
		1085	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1086	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1087	}
		1088
		1089	$SIGPIPE_R
		1090	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1091
		1092	# not strictly required, as $^F is normally 2, but let's make sure...
		1093	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1094	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1095
		1096	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1097	}
		1098
990	my $signal = uc $arg{signal}	1099	my $signal = uc $arg{signal}
991	or Carp::croak "required option 'signal' is missing";	1100	or Carp::croak "required option 'signal' is missing";
992		1101
993	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1102	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
994	$SIG{$signal} \|\|= sub {	1103	$SIG{$signal} \|\|= sub {
995	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1104	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1105	undef $SIG_EV{$signal};
996	};	1106	};
997		1107
998	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1108	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
999	}	1109	}
1000		1110
…		…
1119		1229
1120	# undocumented/compatibility with pre-3.4	1230	# undocumented/compatibility with pre-3.4
1121	*broadcast = \&send;	1231	*broadcast = \&send;
1122	*wait = \&_wait;	1232	*wait = \&_wait;
1123		1233
		1234	=head1 ERROR AND EXCEPTION HANDLING
		1235
		1236	In general, AnyEvent does not do any error handling - it relies on the
		1237	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1238	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1239	checking of all AnyEvent methods, however, which is highly useful during
		1240	development.
		1241
		1242	As for exception handling (i.e. runtime errors and exceptions thrown while
		1243	executing a callback), this is not only highly event-loop specific, but
		1244	also not in any way wrapped by this module, as this is the job of the main
		1245	program.
		1246
		1247	The pure perl event loop simply re-throws the exception (usually
		1248	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1249	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1250	so on.
		1251
		1252	=head1 ENVIRONMENT VARIABLES
		1253
		1254	The following environment variables are used by this module or its
		1255	submodules:
		1256
		1257	=over 4
		1258
		1259	=item C<PERL_ANYEVENT_VERBOSE>
		1260
		1261	By default, AnyEvent will be completely silent except in fatal
		1262	conditions. You can set this environment variable to make AnyEvent more
		1263	talkative.
		1264
		1265	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1266	conditions, such as not being able to load the event model specified by
		1267	C<PERL_ANYEVENT_MODEL>.
		1268
		1269	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1270	model it chooses.
		1271
		1272	=item C<PERL_ANYEVENT_STRICT>
		1273
		1274	AnyEvent does not do much argument checking by default, as thorough
		1275	argument checking is very costly. Setting this variable to a true value
		1276	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1277	check the arguments passed to most method calls. If it finds any problems
		1278	it will croak.
		1279
		1280	In other words, enables "strict" mode.
		1281
		1282	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1283	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1284	developing programs can be very useful, however.
		1285
		1286	=item C<PERL_ANYEVENT_MODEL>
		1287
		1288	This can be used to specify the event model to be used by AnyEvent, before
		1289	auto detection and -probing kicks in. It must be a string consisting
		1290	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1291	and the resulting module name is loaded and if the load was successful,
		1292	used as event model. If it fails to load AnyEvent will proceed with
		1293	auto detection and -probing.
		1294
		1295	This functionality might change in future versions.
		1296
		1297	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1298	could start your program like this:
		1299
		1300	PERL_ANYEVENT_MODEL=Perl perl ...
		1301
		1302	=item C<PERL_ANYEVENT_PROTOCOLS>
		1303
		1304	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1305	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1306	of auto probing).
		1307
		1308	Must be set to a comma-separated list of protocols or address families,
		1309	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1310	used, and preference will be given to protocols mentioned earlier in the
		1311	list.
		1312
		1313	This variable can effectively be used for denial-of-service attacks
		1314	against local programs (e.g. when setuid), although the impact is likely
		1315	small, as the program has to handle conenction and other failures anyways.
		1316
		1317	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1318	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1319	- only support IPv4, never try to resolve or contact IPv6
		1320	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1321	IPv6, but prefer IPv6 over IPv4.
		1322
		1323	=item C<PERL_ANYEVENT_EDNS0>
		1324
		1325	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1326	for DNS. This extension is generally useful to reduce DNS traffic, but
		1327	some (broken) firewalls drop such DNS packets, which is why it is off by
		1328	default.
		1329
		1330	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1331	EDNS0 in its DNS requests.
		1332
		1333	=item C<PERL_ANYEVENT_MAX_FORKS>
		1334
		1335	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1336	will create in parallel.
		1337
		1338	=back
		1339
1124	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1340	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1125		1341
1126	This is an advanced topic that you do not normally need to use AnyEvent in	1342	This is an advanced topic that you do not normally need to use AnyEvent in
1127	a module. This section is only of use to event loop authors who want to	1343	a module. This section is only of use to event loop authors who want to
1128	provide AnyEvent compatibility.	1344	provide AnyEvent compatibility.
…		…
1161		1377
1162	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1378	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1163	condition variables: code blocking while waiting for a condition will	1379	condition variables: code blocking while waiting for a condition will
1164	C<die>. This still works with most modules/usages, and blocking calls must	1380	C<die>. This still works with most modules/usages, and blocking calls must
1165	not be done in an interactive application, so it makes sense.	1381	not be done in an interactive application, so it makes sense.
1166
1167	=head1 ENVIRONMENT VARIABLES
1168
1169	The following environment variables are used by this module:
1170
1171	=over 4
1172
1173	=item C<PERL_ANYEVENT_VERBOSE>
1174
1175	By default, AnyEvent will be completely silent except in fatal
1176	conditions. You can set this environment variable to make AnyEvent more
1177	talkative.
1178
1179	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1180	conditions, such as not being able to load the event model specified by
1181	C<PERL_ANYEVENT_MODEL>.
1182
1183	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1184	model it chooses.
1185
1186	=item C<PERL_ANYEVENT_STRICT>
1187
1188	AnyEvent does not do much argument checking by default, as thorough
1189	argument checking is very costly. Setting this variable to a true value
1190	will cause AnyEvent to thoroughly check the arguments passed to most
1191	method calls and croaks if it finds any problems. In other words, enables
1192	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
1193	it off in production.
1194
1195	=item C<PERL_ANYEVENT_MODEL>
1196
1197	This can be used to specify the event model to be used by AnyEvent, before
1198	auto detection and -probing kicks in. It must be a string consisting
1199	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1200	and the resulting module name is loaded and if the load was successful,
1201	used as event model. If it fails to load AnyEvent will proceed with
1202	auto detection and -probing.
1203
1204	This functionality might change in future versions.
1205
1206	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1207	could start your program like this:
1208
1209	PERL_ANYEVENT_MODEL=Perl perl ...
1210
1211	=item C<PERL_ANYEVENT_PROTOCOLS>
1212
1213	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1214	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1215	of auto probing).
1216
1217	Must be set to a comma-separated list of protocols or address families,
1218	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1219	used, and preference will be given to protocols mentioned earlier in the
1220	list.
1221
1222	This variable can effectively be used for denial-of-service attacks
1223	against local programs (e.g. when setuid), although the impact is likely
1224	small, as the program has to handle connection errors already-
1225
1226	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1227	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1228	- only support IPv4, never try to resolve or contact IPv6
1229	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1230	IPv6, but prefer IPv6 over IPv4.
1231
1232	=item C<PERL_ANYEVENT_EDNS0>
1233
1234	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1235	for DNS. This extension is generally useful to reduce DNS traffic, but
1236	some (broken) firewalls drop such DNS packets, which is why it is off by
1237	default.
1238
1239	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1240	EDNS0 in its DNS requests.
1241
1242	=item C<PERL_ANYEVENT_MAX_FORKS>
1243
1244	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1245	will create in parallel.
1246
1247	=back
1248		1382
1249	=head1 EXAMPLE PROGRAM	1383	=head1 EXAMPLE PROGRAM
1250		1384
1251	The following program uses an I/O watcher to read data from STDIN, a timer	1385	The following program uses an I/O watcher to read data from STDIN, a timer
1252	to display a message once per second, and a condition variable to quit the	1386	to display a message once per second, and a condition variable to quit the
…		…
1446	watcher.	1580	watcher.
1447		1581
1448	=head3 Results	1582	=head3 Results
1449		1583
1450	name watchers bytes create invoke destroy comment	1584	name watchers bytes create invoke destroy comment
1451	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1585	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1452	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1586	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1453	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1587	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1454	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1588	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1455	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1589	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1456	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1590	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1457	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1591	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1458	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1592	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1459	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1593	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1460	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1594	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1461		1595
1462	=head3 Discussion	1596	=head3 Discussion
1463		1597
1464	The benchmark does I<not> measure scalability of the event loop very	1598	The benchmark does I<not> measure scalability of the event loop very
1465	well. For example, a select-based event loop (such as the pure perl one)	1599	well. For example, a select-based event loop (such as the pure perl one)
…		…
1667	watchers, as the management overhead dominates.	1801	watchers, as the management overhead dominates.
1668		1802
1669	=back	1803	=back
1670		1804
1671		1805
		1806	=head1 SIGNALS
		1807
		1808	AnyEvent currently installs handlers for these signals:
		1809
		1810	=over 4
		1811
		1812	=item SIGCHLD
		1813
		1814	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1815	emulation for event loops that do not support them natively. Also, some
		1816	event loops install a similar handler.
		1817
		1818	=item SIGPIPE
		1819
		1820	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1821	when AnyEvent gets loaded.
		1822
		1823	The rationale for this is that AnyEvent users usually do not really depend
		1824	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1825	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1826	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1827	some random socket.
		1828
		1829	The rationale for installing a no-op handler as opposed to ignoring it is
		1830	that this way, the handler will be restored to defaults on exec.
		1831
		1832	Feel free to install your own handler, or reset it to defaults.
		1833
		1834	=back
		1835
		1836	=cut
		1837
		1838	$SIG{PIPE} = sub { }
		1839	unless defined $SIG{PIPE};
		1840
		1841
1672	=head1 FORK	1842	=head1 FORK
1673		1843
1674	Most event libraries are not fork-safe. The ones who are usually are	1844	Most event libraries are not fork-safe. The ones who are usually are
1675	because they rely on inefficient but fork-safe C<select> or C<poll>	1845	because they rely on inefficient but fork-safe C<select> or C<poll>
1676	calls. Only L<EV> is fully fork-aware.	1846	calls. Only L<EV> is fully fork-aware.
…		…
1704	=head1 BUGS	1874	=head1 BUGS
1705		1875
1706	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1876	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1707	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	1877	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1708	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	1878	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1709	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	1879	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1710	pronounced).	1880	pronounced).
1711		1881
1712		1882
1713	=head1 SEE ALSO	1883	=head1 SEE ALSO
1714		1884

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs. Revision 1.201 by root, Wed Apr 1 14:08:27 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.168 by root, Tue Jul 8 23:53:37 2008 UTC vs.
Revision 1.201 by root, Wed Apr 1 14:08:27 2009 UTC