[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 1.192 by root, Tue Jan 6 20:08:05 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
…		…
152	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
153		163
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
156		166
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
158	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
160	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
161	becomes ready.	171	callback to invoke each time the file handle becomes ready.
162		172
163	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
166		176
…		…
303	=back	313	=back
304		314
305	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
306		316
307	You can watch for signals using a signal watcher, C<signal> is the signal	317	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	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
309	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
310		320
311	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
312	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
313	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
314		324
…		…
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 = 4.331;
831	our $MODEL;	867	our $MODEL;
832		868
833	our $AUTOLOAD;	869	our $AUTOLOAD;
834	our @ISA;	870	our @ISA;
835		871
…		…
938	$MODEL	974	$MODEL
939	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	975	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
940	}	976	}
941	}	977	}
942		978
		979	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		980
943	unshift @ISA, $MODEL;	981	unshift @ISA, $MODEL;
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	982
		983	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
945		984
946	(shift @post_detect)->() while @post_detect;	985	(shift @post_detect)->() while @post_detect;
947	}	986	}
948		987
949	$MODEL	988	$MODEL
…		…
959		998
960	my $class = shift;	999	my $class = shift;
961	$class->$func (@_);	1000	$class->$func (@_);
962	}	1001	}
963		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
964	package AnyEvent::Base;	1024	package AnyEvent::Base;
965		1025
966	# default implementation for now and time	1026	# default implementation for now and time
967		1027
968	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	}
969		1036
970	sub time { Time::HiRes::time }	1037	sub time { _time }
971	sub now { Time::HiRes::time }	1038	sub now { _time }
972		1039
973	# default implementation for ->condvar	1040	# default implementation for ->condvar
974		1041
975	sub condvar {	1042	sub condvar {
976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1043	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
…		…
1115		1182
1116	# undocumented/compatibility with pre-3.4	1183	# undocumented/compatibility with pre-3.4
1117	*broadcast = \&send;	1184	*broadcast = \&send;
1118	*wait = \&_wait;	1185	*wait = \&_wait;
1119		1186
		1187	=head1 ERROR AND EXCEPTION HANDLING
		1188
		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.
		1194
		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.
		1199
		1200	The pure perl event loop simply re-throws the exception (usually
		1201	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1202	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1203	so on.
		1204
		1205	=head1 ENVIRONMENT VARIABLES
		1206
		1207	The following environment variables are used by this module or its
		1208	submodules:
		1209
		1210	=over 4
		1211
		1212	=item C<PERL_ANYEVENT_VERBOSE>
		1213
		1214	By default, AnyEvent will be completely silent except in fatal
		1215	conditions. You can set this environment variable to make AnyEvent more
		1216	talkative.
		1217
		1218	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1219	conditions, such as not being able to load the event model specified by
		1220	C<PERL_ANYEVENT_MODEL>.
		1221
		1222	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1223	model it chooses.
		1224
		1225	=item C<PERL_ANYEVENT_STRICT>
		1226
		1227	AnyEvent does not do much argument checking by default, as thorough
		1228	argument checking is very costly. Setting this variable to a true value
		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.
		1232
		1233	In other words, enables "strict" mode.
		1234
		1235	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1236	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1237	developing programs can be very useful, however.
		1238
		1239	=item C<PERL_ANYEVENT_MODEL>
		1240
		1241	This can be used to specify the event model to be used by AnyEvent, before
		1242	auto detection and -probing kicks in. It must be a string consisting
		1243	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1244	and the resulting module name is loaded and if the load was successful,
		1245	used as event model. If it fails to load AnyEvent will proceed with
		1246	auto detection and -probing.
		1247
		1248	This functionality might change in future versions.
		1249
		1250	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1251	could start your program like this:
		1252
		1253	PERL_ANYEVENT_MODEL=Perl perl ...
		1254
		1255	=item C<PERL_ANYEVENT_PROTOCOLS>
		1256
		1257	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1258	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1259	of auto probing).
		1260
		1261	Must be set to a comma-separated list of protocols or address families,
		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.
		1265
		1266	This variable can effectively be used for denial-of-service attacks
		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
		1292
1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1293	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1121		1294
1122	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
1123	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
1124	provide AnyEvent compatibility.	1297	provide AnyEvent compatibility.
…		…
1157		1330
1158	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
1159	condition variables: code blocking while waiting for a condition will	1332	condition variables: code blocking while waiting for a condition will
1160	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
1161	not be done in an interactive application, so it makes sense.	1334	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		1335
1236	=head1 EXAMPLE PROGRAM	1336	=head1 EXAMPLE PROGRAM
1237		1337
1238	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
1239	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
…		…
1433	watcher.	1533	watcher.
1434		1534
1435	=head3 Results	1535	=head3 Results
1436		1536
1437	name watchers bytes create invoke destroy comment	1537	name watchers bytes create invoke destroy comment
1438	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
1439	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
1440	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
1441	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
1442	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
1443	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
1444	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
1445	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
1446	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
1447	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
1448		1548
1449	=head3 Discussion	1549	=head3 Discussion
1450		1550
1451	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
1452	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)
…		…
1654	watchers, as the management overhead dominates.	1754	watchers, as the management overhead dominates.
1655		1755
1656	=back	1756	=back
1657		1757
1658		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
1659	=head1 FORK	1795	=head1 FORK
1660		1796
1661	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
1662	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>
1663	calls. Only L<EV> is fully fork-aware.	1799	calls. Only L<EV> is fully fork-aware.
…		…
1682		1818
1683	use AnyEvent;	1819	use AnyEvent;
1684		1820
1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1821	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	1822	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).	1823	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1824	$ENV{PERL_ANYEGENT_STRICT}.
1688		1825
1689		1826
1690	=head1 BUGS	1827	=head1 BUGS
1691		1828
1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1829	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard

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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 1.192 by root, Tue Jan 6 20:08:05 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 1.192 by root, Tue Jan 6 20:08:05 2009 UTC