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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.166 by root, Tue Jul 8 23:10:20 2008 UTC vs.
Revision 1.197 by root, Thu Mar 26 15:51:44 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.
…		…
303	=back	319	=back
304		320
305	=head2 SIGNAL WATCHERS	321	=head2 SIGNAL WATCHERS
306		322
307	You can watch for signals using a signal watcher, C<signal> is the signal	323	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	324	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
309	be invoked whenever a signal occurs.	325	callback to be invoked whenever a signal occurs.
310		326
311	Although the callback might get passed parameters, their value and	327	Although the callback might get passed parameters, their value and
312	presence is undefined and you cannot rely on them. Portable AnyEvent	328	presence is undefined and you cannot rely on them. Portable AnyEvent
313	callbacks cannot use arguments passed to signal watcher callbacks.	329	callbacks cannot use arguments passed to signal watcher callbacks.
314		330
…		…
330	=head2 CHILD PROCESS WATCHERS	346	=head2 CHILD PROCESS WATCHERS
331		347
332	You can also watch on a child process exit and catch its exit status.	348	You can also watch on a child process exit and catch its exit status.
333		349
334	The child process is specified by the C<pid> argument (if set to C<0>, it	350	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	351	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	352	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	353	any trace events (stopped/continued).
338	and exit status (as returned by waitpid), so unlike other watcher types,	354
339	you I<can> rely on child watcher callback arguments.	355	The callback will be called with the pid and exit status (as returned by
		356	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		357	callback arguments.
		358
		359	This watcher type works by installing a signal handler for C<SIGCHLD>,
		360	and since it cannot be shared, nothing else should use SIGCHLD or reap
		361	random child processes (waiting for specific child processes, e.g. inside
		362	C<system>, is just fine).
340		363
341	There is a slight catch to child watchers, however: you usually start them	364	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	365	I<after> the child process was created, and this means the process could
343	have exited already (and no SIGCHLD will be sent anymore).	366	have exited already (and no SIGCHLD will be sent anymore).
344		367
…		…
380	The instrument to do that is called a "condition variable", so called	403	The instrument to do that is called a "condition variable", so called
381	because they represent a condition that must become true.	404	because they represent a condition that must become true.
382		405
383	Condition variables can be created by calling the C<< AnyEvent->condvar	406	Condition variables can be created by calling the C<< AnyEvent->condvar
384	>> method, usually without arguments. The only argument pair allowed is	407	>> method, usually without arguments. The only argument pair allowed is
		408
385	C<cb>, which specifies a callback to be called when the condition variable	409	C<cb>, which specifies a callback to be called when the condition variable
386	becomes true.	410	becomes true, with the condition variable as the first argument (but not
		411	the results).
387		412
388	After creation, the condition variable is "false" until it becomes "true"	413	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	414	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<<	415	were a callback, read about the caveats in the description for the C<<
391	->send >> method).	416	->send >> method).
…		…
447		472
448	my $done = AnyEvent->condvar;	473	my $done = AnyEvent->condvar;
449	my $delay = AnyEvent->timer (after => 5, cb => $done);	474	my $delay = AnyEvent->timer (after => 5, cb => $done);
450	$done->recv;	475	$done->recv;
451		476
		477	Example: Imagine an API that returns a condvar and doesn't support
		478	callbacks. This is how you make a synchronous call, for example from
		479	the main program:
		480
		481	use AnyEvent::CouchDB;
		482
		483	...
		484
		485	my @info = $couchdb->info->recv;
		486
		487	And this is how you would just ste a callback to be called whenever the
		488	results are available:
		489
		490	$couchdb->info->cb (sub {
		491	my @info = $_[0]->recv;
		492	});
		493
452	=head3 METHODS FOR PRODUCERS	494	=head3 METHODS FOR PRODUCERS
453		495
454	These methods should only be used by the producing side, i.e. the	496	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	497	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	498	the producer side which creates the condvar in most cases, but it isn't
…		…
589	=item $bool = $cv->ready	631	=item $bool = $cv->ready
590		632
591	Returns true when the condition is "true", i.e. whether C<send> or	633	Returns true when the condition is "true", i.e. whether C<send> or
592	C<croak> have been called.	634	C<croak> have been called.
593		635
594	=item $cb = $cv->cb ([new callback])	636	=item $cb = $cv->cb ($cb->($cv))
595		637
596	This is a mutator function that returns the callback set and optionally	638	This is a mutator function that returns the callback set and optionally
597	replaces it before doing so.	639	replaces it before doing so.
598		640
599	The callback will be called when the condition becomes "true", i.e. when	641	The callback will be called when the condition becomes "true", i.e. when
…		…
789	=item L<AnyEvent::IGS>	831	=item L<AnyEvent::IGS>
790		832
791	A non-blocking interface to the Internet Go Server protocol (used by	833	A non-blocking interface to the Internet Go Server protocol (used by
792	L<App::IGS>).	834	L<App::IGS>).
793		835
794	=item L<Net::IRC3>	836	=item L<AnyEvent::IRC>
795		837
796	AnyEvent based IRC client module family.	838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
797		839
798	=item L<Net::XMPP2>	840	=item L<Net::XMPP2>
799		841
800	AnyEvent based XMPP (Jabber protocol) module family.	842	AnyEvent based XMPP (Jabber protocol) module family.
801		843
…		…
821	=cut	863	=cut
822		864
823	package AnyEvent;	865	package AnyEvent;
824		866
825	no warnings;	867	no warnings;
826	use strict;	868	use strict qw(vars subs);
827		869
828	use Carp;	870	use Carp;
829		871
830	our $VERSION = 4.2;	872	our $VERSION = 4.341;
831	our $MODEL;	873	our $MODEL;
832		874
833	our $AUTOLOAD;	875	our $AUTOLOAD;
834	our @ISA;	876	our @ISA;
835		877
…		…
938	$MODEL	980	$MODEL
939	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
940	}	982	}
941	}	983	}
942		984
		985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		986
943	unshift @ISA, $MODEL;	987	unshift @ISA, $MODEL;
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	988
		989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
945		990
946	(shift @post_detect)->() while @post_detect;	991	(shift @post_detect)->() while @post_detect;
947	}	992	}
948		993
949	$MODEL	994	$MODEL
…		…
959		1004
960	my $class = shift;	1005	my $class = shift;
961	$class->$func (@_);	1006	$class->$func (@_);
962	}	1007	}
963		1008
		1009	# utility function to dup a filehandle. this is used by many backends
		1010	# to support binding more than one watcher per filehandle (they usually
		1011	# allow only one watcher per fd, so we dup it to get a different one).
		1012	sub _dupfh($$$$) {
		1013	my ($poll, $fh, $r, $w) = @_;
		1014
		1015	# cygwin requires the fh mode to be matching, unix doesn't
		1016	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1017	: $poll eq "w" ? ($w, ">")
		1018	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1019
		1020	open my $fh2, "$mode&" . fileno $fh
		1021	or die "cannot dup() filehandle: $!";
		1022
		1023	# we assume CLOEXEC is already set by perl in all important cases
		1024
		1025	($fh2, $rw)
		1026	}
		1027
964	package AnyEvent::Base;	1028	package AnyEvent::Base;
965		1029
966	# default implementation for now and time	1030	# default implementation for now and time
967		1031
968	use Time::HiRes ();	1032	BEGIN {
		1033	if (eval "use Time::HiRes (); time (); 1") {
		1034	*_time = \&Time::HiRes::time;
		1035	# if (eval "use POSIX (); (POSIX::times())...
		1036	} else {
		1037	*_time = sub { time }; # epic fail
		1038	}
		1039	}
969		1040
970	sub time { Time::HiRes::time }	1041	sub time { _time }
971	sub now { Time::HiRes::time }	1042	sub now { _time }
972		1043
973	# default implementation for ->condvar	1044	# default implementation for ->condvar
974		1045
975	sub condvar {	1046	sub condvar {
976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
977	}	1048	}
978		1049
979	# default implementation for ->signal	1050	# default implementation for ->signal
980		1051
981	our %SIG_CB;	1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1053
		1054	sub _signal_exec {
		1055	while (%SIG_EV) {
		1056	sysread $SIGPIPE_R, my $dummy, 4;
		1057	for (keys %SIG_EV) {
		1058	delete $SIG_EV{$_};
		1059	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1060	}
		1061	}
		1062	}
982		1063
983	sub signal {	1064	sub signal {
984	my (undef, %arg) = @_;	1065	my (undef, %arg) = @_;
985		1066
		1067	unless ($SIGPIPE_R) {
		1068	if (AnyEvent::WIN32) {
		1069	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1070	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1072	} else {
		1073	pipe $SIGPIPE_R, $SIGPIPE_W;
		1074	require Fcntl;
		1075	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1076	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1077	}
		1078
		1079	$SIGPIPE_R
		1080	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1081
		1082	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1083	}
		1084
986	my $signal = uc $arg{signal}	1085	my $signal = uc $arg{signal}
987	or Carp::croak "required option 'signal' is missing";	1086	or Carp::croak "required option 'signal' is missing";
988		1087
989	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1088	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
990	$SIG{$signal} \|\|= sub {	1089	$SIG{$signal} \|\|= sub {
991	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1090	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1091	undef $SIG_EV{$signal};
992	};	1092	};
993		1093
994	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1094	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
995	}	1095	}
996		1096
…		…
1115		1215
1116	# undocumented/compatibility with pre-3.4	1216	# undocumented/compatibility with pre-3.4
1117	*broadcast = \&send;	1217	*broadcast = \&send;
1118	*wait = \&_wait;	1218	*wait = \&_wait;
1119		1219
		1220	=head1 ERROR AND EXCEPTION HANDLING
		1221
		1222	In general, AnyEvent does not do any error handling - it relies on the
		1223	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1224	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1225	checking of all AnyEvent methods, however, which is highly useful during
		1226	development.
		1227
		1228	As for exception handling (i.e. runtime errors and exceptions thrown while
		1229	executing a callback), this is not only highly event-loop specific, but
		1230	also not in any way wrapped by this module, as this is the job of the main
		1231	program.
		1232
		1233	The pure perl event loop simply re-throws the exception (usually
		1234	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1235	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1236	so on.
		1237
		1238	=head1 ENVIRONMENT VARIABLES
		1239
		1240	The following environment variables are used by this module or its
		1241	submodules:
		1242
		1243	=over 4
		1244
		1245	=item C<PERL_ANYEVENT_VERBOSE>
		1246
		1247	By default, AnyEvent will be completely silent except in fatal
		1248	conditions. You can set this environment variable to make AnyEvent more
		1249	talkative.
		1250
		1251	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1252	conditions, such as not being able to load the event model specified by
		1253	C<PERL_ANYEVENT_MODEL>.
		1254
		1255	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1256	model it chooses.
		1257
		1258	=item C<PERL_ANYEVENT_STRICT>
		1259
		1260	AnyEvent does not do much argument checking by default, as thorough
		1261	argument checking is very costly. Setting this variable to a true value
		1262	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1263	check the arguments passed to most method calls. If it finds any problems
		1264	it will croak.
		1265
		1266	In other words, enables "strict" mode.
		1267
		1268	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1269	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1270	developing programs can be very useful, however.
		1271
		1272	=item C<PERL_ANYEVENT_MODEL>
		1273
		1274	This can be used to specify the event model to be used by AnyEvent, before
		1275	auto detection and -probing kicks in. It must be a string consisting
		1276	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1277	and the resulting module name is loaded and if the load was successful,
		1278	used as event model. If it fails to load AnyEvent will proceed with
		1279	auto detection and -probing.
		1280
		1281	This functionality might change in future versions.
		1282
		1283	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1284	could start your program like this:
		1285
		1286	PERL_ANYEVENT_MODEL=Perl perl ...
		1287
		1288	=item C<PERL_ANYEVENT_PROTOCOLS>
		1289
		1290	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1291	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1292	of auto probing).
		1293
		1294	Must be set to a comma-separated list of protocols or address families,
		1295	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1296	used, and preference will be given to protocols mentioned earlier in the
		1297	list.
		1298
		1299	This variable can effectively be used for denial-of-service attacks
		1300	against local programs (e.g. when setuid), although the impact is likely
		1301	small, as the program has to handle conenction and other failures anyways.
		1302
		1303	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1304	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1305	- only support IPv4, never try to resolve or contact IPv6
		1306	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1307	IPv6, but prefer IPv6 over IPv4.
		1308
		1309	=item C<PERL_ANYEVENT_EDNS0>
		1310
		1311	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1312	for DNS. This extension is generally useful to reduce DNS traffic, but
		1313	some (broken) firewalls drop such DNS packets, which is why it is off by
		1314	default.
		1315
		1316	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1317	EDNS0 in its DNS requests.
		1318
		1319	=item C<PERL_ANYEVENT_MAX_FORKS>
		1320
		1321	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1322	will create in parallel.
		1323
		1324	=back
		1325
1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1326	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1121		1327
1122	This is an advanced topic that you do not normally need to use AnyEvent in	1328	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	1329	a module. This section is only of use to event loop authors who want to
1124	provide AnyEvent compatibility.	1330	provide AnyEvent compatibility.
…		…
1157		1363
1158	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1364	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1159	condition variables: code blocking while waiting for a condition will	1365	condition variables: code blocking while waiting for a condition will
1160	C<die>. This still works with most modules/usages, and blocking calls must	1366	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.	1367	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		1368
1236	=head1 EXAMPLE PROGRAM	1369	=head1 EXAMPLE PROGRAM
1237		1370
1238	The following program uses an I/O watcher to read data from STDIN, a timer	1371	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	1372	to display a message once per second, and a condition variable to quit the
…		…
1433	watcher.	1566	watcher.
1434		1567
1435	=head3 Results	1568	=head3 Results
1436		1569
1437	name watchers bytes create invoke destroy comment	1570	name watchers bytes create invoke destroy comment
1438	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1571	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	1572	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	1573	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	1574	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	1575	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	1576	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	1577	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	1578	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	1579	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	1580	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1448		1581
1449	=head3 Discussion	1582	=head3 Discussion
1450		1583
1451	The benchmark does I<not> measure scalability of the event loop very	1584	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)	1585	well. For example, a select-based event loop (such as the pure perl one)
…		…
1654	watchers, as the management overhead dominates.	1787	watchers, as the management overhead dominates.
1655		1788
1656	=back	1789	=back
1657		1790
1658		1791
		1792	=head1 SIGNALS
		1793
		1794	AnyEvent currently installs handlers for these signals:
		1795
		1796	=over 4
		1797
		1798	=item SIGCHLD
		1799
		1800	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1801	emulation for event loops that do not support them natively. Also, some
		1802	event loops install a similar handler.
		1803
		1804	=item SIGPIPE
		1805
		1806	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1807	when AnyEvent gets loaded.
		1808
		1809	The rationale for this is that AnyEvent users usually do not really depend
		1810	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1811	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1812	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1813	some random socket.
		1814
		1815	The rationale for installing a no-op handler as opposed to ignoring it is
		1816	that this way, the handler will be restored to defaults on exec.
		1817
		1818	Feel free to install your own handler, or reset it to defaults.
		1819
		1820	=back
		1821
		1822	=cut
		1823
		1824	$SIG{PIPE} = sub { }
		1825	unless defined $SIG{PIPE};
		1826
		1827
1659	=head1 FORK	1828	=head1 FORK
1660		1829
1661	Most event libraries are not fork-safe. The ones who are usually are	1830	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>	1831	because they rely on inefficient but fork-safe C<select> or C<poll>
1663	calls. Only L<EV> is fully fork-aware.	1832	calls. Only L<EV> is fully fork-aware.
…		…
1682		1851
1683	use AnyEvent;	1852	use AnyEvent;
1684		1853
1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1854	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	1855	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).	1856	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1857	$ENV{PERL_ANYEGENT_STRICT}.
1688		1858
1689		1859
1690	=head1 BUGS	1860	=head1 BUGS
1691		1861
1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1862	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	1863	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	1864	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	1865	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1696	pronounced).	1866	pronounced).
1697		1867
1698		1868
1699	=head1 SEE ALSO	1869	=head1 SEE ALSO
1700		1870

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.166 by root, Tue Jul 8 23:10:20 2008 UTC vs. Revision 1.197 by root, Thu Mar 26 15:51:44 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.166 by root, Tue Jul 8 23:10:20 2008 UTC vs.
Revision 1.197 by root, Thu Mar 26 15:51:44 2009 UTC