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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs.
Revision 1.198 by root, Thu Mar 26 20:17:44 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.
…		…
152	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
153		169
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
156		172
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	173	C<fh> 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>,	174	(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,	175	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	176	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
161	becomes ready.	177	callback to invoke each time the file handle becomes ready.
162		178
163	Although the callback might get passed parameters, their value and	179	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	180	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	181	callbacks cannot use arguments passed to I/O watcher callbacks.
166		182
…		…
193	Although the callback might get passed parameters, their value and	209	Although the callback might get passed parameters, their value and
194	presence is undefined and you cannot rely on them. Portable AnyEvent	210	presence is undefined and you cannot rely on them. Portable AnyEvent
195	callbacks cannot use arguments passed to time watcher callbacks.	211	callbacks cannot use arguments passed to time watcher callbacks.
196		212
197	The callback will normally be invoked once only. If you specify another	213	The callback will normally be invoked once only. If you specify another
198	parameter, C<interval>, as a positive number, then the callback will be	214	parameter, C<interval>, as a strictly positive number (> 0), then the
199	invoked regularly at that interval (in fractional seconds) after the first	215	callback will be invoked regularly at that interval (in fractional
200	invocation.	216	seconds) after the first invocation. If C<interval> is specified with a
		217	false value, then it is treated as if it were missing.
201		218
202	The callback will be rescheduled before invoking the callback, but no	219	The callback will be rescheduled before invoking the callback, but no
203	attempt is done to avoid timer drift in most backends, so the interval is	220	attempt is done to avoid timer drift in most backends, so the interval is
204	only approximate.	221	only approximate.
205		222
…		…
302	=back	319	=back
303		320
304	=head2 SIGNAL WATCHERS	321	=head2 SIGNAL WATCHERS
305		322
306	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
307	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
308	be invoked whenever a signal occurs.	325	callback to be invoked whenever a signal occurs.
309		326
310	Although the callback might get passed parameters, their value and	327	Although the callback might get passed parameters, their value and
311	presence is undefined and you cannot rely on them. Portable AnyEvent	328	presence is undefined and you cannot rely on them. Portable AnyEvent
312	callbacks cannot use arguments passed to signal watcher callbacks.	329	callbacks cannot use arguments passed to signal watcher callbacks.
313		330
…		…
329	=head2 CHILD PROCESS WATCHERS	346	=head2 CHILD PROCESS WATCHERS
330		347
331	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.
332		349
333	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
334	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
335	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
336	signal handler for C<SIGCHLD>. The callback will be called with the pid	353	any trace events (stopped/continued).
337	and exit status (as returned by waitpid), so unlike other watcher types,	354
338	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).
339		363
340	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
341	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
342	have exited already (and no SIGCHLD will be sent anymore).	366	have exited already (and no SIGCHLD will be sent anymore).
343		367
…		…
379	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
380	because they represent a condition that must become true.	404	because they represent a condition that must become true.
381		405
382	Condition variables can be created by calling the C<< AnyEvent->condvar	406	Condition variables can be created by calling the C<< AnyEvent->condvar
383	>> method, usually without arguments. The only argument pair allowed is	407	>> method, usually without arguments. The only argument pair allowed is
		408
384	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
385	becomes true.	410	becomes true, with the condition variable as the first argument (but not
		411	the results).
386		412
387	After creation, the condition variable is "false" until it becomes "true"	413	After creation, the condition variable is "false" until it becomes "true"
388	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
389	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<<
390	->send >> method).	416	->send >> method).
…		…
446		472
447	my $done = AnyEvent->condvar;	473	my $done = AnyEvent->condvar;
448	my $delay = AnyEvent->timer (after => 5, cb => $done);	474	my $delay = AnyEvent->timer (after => 5, cb => $done);
449	$done->recv;	475	$done->recv;
450		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
451	=head3 METHODS FOR PRODUCERS	494	=head3 METHODS FOR PRODUCERS
452		495
453	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
454	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
455	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
…		…
588	=item $bool = $cv->ready	631	=item $bool = $cv->ready
589		632
590	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
591	C<croak> have been called.	634	C<croak> have been called.
592		635
593	=item $cb = $cv->cb ([new callback])	636	=item $cb = $cv->cb ($cb->($cv))
594		637
595	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
596	replaces it before doing so.	639	replaces it before doing so.
597		640
598	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
…		…
788	=item L<AnyEvent::IGS>	831	=item L<AnyEvent::IGS>
789		832
790	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
791	L<App::IGS>).	834	L<App::IGS>).
792		835
793	=item L<Net::IRC3>	836	=item L<AnyEvent::IRC>
794		837
795	AnyEvent based IRC client module family.	838	AnyEvent based IRC client module family (replacing the older Net::IRC3).
796		839
797	=item L<Net::XMPP2>	840	=item L<Net::XMPP2>
798		841
799	AnyEvent based XMPP (Jabber protocol) module family.	842	AnyEvent based XMPP (Jabber protocol) module family.
800		843
…		…
820	=cut	863	=cut
821		864
822	package AnyEvent;	865	package AnyEvent;
823		866
824	no warnings;	867	no warnings;
825	use strict;	868	use strict qw(vars subs);
826		869
827	use Carp;	870	use Carp;
828		871
829	our $VERSION = 4.2;	872	our $VERSION = 4.341;
830	our $MODEL;	873	our $MODEL;
831		874
832	our $AUTOLOAD;	875	our $AUTOLOAD;
833	our @ISA;	876	our @ISA;
834		877
…		…
937	$MODEL	980	$MODEL
938	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	981	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
939	}	982	}
940	}	983	}
941		984
		985	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		986
942	unshift @ISA, $MODEL;	987	unshift @ISA, $MODEL;
943	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	988
		989	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
944		990
945	(shift @post_detect)->() while @post_detect;	991	(shift @post_detect)->() while @post_detect;
946	}	992	}
947		993
948	$MODEL	994	$MODEL
…		…
958		1004
959	my $class = shift;	1005	my $class = shift;
960	$class->$func (@_);	1006	$class->$func (@_);
961	}	1007	}
962		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
963	package AnyEvent::Base;	1028	package AnyEvent::Base;
964		1029
965	# default implementation for now and time	1030	# default implementation for now and time
966		1031
967	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	}
968		1040
969	sub time { Time::HiRes::time }	1041	sub time { _time }
970	sub now { Time::HiRes::time }	1042	sub now { _time }
971		1043
972	# default implementation for ->condvar	1044	# default implementation for ->condvar
973		1045
974	sub condvar {	1046	sub condvar {
975	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1047	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
976	}	1048	}
977		1049
978	# default implementation for ->signal	1050	# default implementation for ->signal
979		1051
980	our %SIG_CB;	1052	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1053
		1054	sub _signal_exec {
		1055	sysread $SIGPIPE_R, my $dummy, 4;
		1056
		1057	while (%SIG_EV) {
		1058	for (keys %SIG_EV) {
		1059	delete $SIG_EV{$_};
		1060	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1061	}
		1062	}
		1063	}
981		1064
982	sub signal {	1065	sub signal {
983	my (undef, %arg) = @_;	1066	my (undef, %arg) = @_;
984		1067
		1068	unless ($SIGPIPE_R) {
		1069	if (AnyEvent::WIN32) {
		1070	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1071	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1072	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1073	} else {
		1074	pipe $SIGPIPE_R, $SIGPIPE_W;
		1075	require Fcntl;
		1076	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1077	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1078	}
		1079
		1080	$SIGPIPE_R
		1081	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1082
		1083	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1084	}
		1085
985	my $signal = uc $arg{signal}	1086	my $signal = uc $arg{signal}
986	or Carp::croak "required option 'signal' is missing";	1087	or Carp::croak "required option 'signal' is missing";
987		1088
988	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1089	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
989	$SIG{$signal} \|\|= sub {	1090	$SIG{$signal} \|\|= sub {
990	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1091	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1092	undef $SIG_EV{$signal};
991	};	1093	};
992		1094
993	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1095	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
994	}	1096	}
995		1097
…		…
1114		1216
1115	# undocumented/compatibility with pre-3.4	1217	# undocumented/compatibility with pre-3.4
1116	*broadcast = \&send;	1218	*broadcast = \&send;
1117	*wait = \&_wait;	1219	*wait = \&_wait;
1118		1220
		1221	=head1 ERROR AND EXCEPTION HANDLING
		1222
		1223	In general, AnyEvent does not do any error handling - it relies on the
		1224	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1225	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1226	checking of all AnyEvent methods, however, which is highly useful during
		1227	development.
		1228
		1229	As for exception handling (i.e. runtime errors and exceptions thrown while
		1230	executing a callback), this is not only highly event-loop specific, but
		1231	also not in any way wrapped by this module, as this is the job of the main
		1232	program.
		1233
		1234	The pure perl event loop simply re-throws the exception (usually
		1235	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1236	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1237	so on.
		1238
		1239	=head1 ENVIRONMENT VARIABLES
		1240
		1241	The following environment variables are used by this module or its
		1242	submodules:
		1243
		1244	=over 4
		1245
		1246	=item C<PERL_ANYEVENT_VERBOSE>
		1247
		1248	By default, AnyEvent will be completely silent except in fatal
		1249	conditions. You can set this environment variable to make AnyEvent more
		1250	talkative.
		1251
		1252	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1253	conditions, such as not being able to load the event model specified by
		1254	C<PERL_ANYEVENT_MODEL>.
		1255
		1256	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1257	model it chooses.
		1258
		1259	=item C<PERL_ANYEVENT_STRICT>
		1260
		1261	AnyEvent does not do much argument checking by default, as thorough
		1262	argument checking is very costly. Setting this variable to a true value
		1263	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1264	check the arguments passed to most method calls. If it finds any problems
		1265	it will croak.
		1266
		1267	In other words, enables "strict" mode.
		1268
		1269	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1270	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1271	developing programs can be very useful, however.
		1272
		1273	=item C<PERL_ANYEVENT_MODEL>
		1274
		1275	This can be used to specify the event model to be used by AnyEvent, before
		1276	auto detection and -probing kicks in. It must be a string consisting
		1277	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1278	and the resulting module name is loaded and if the load was successful,
		1279	used as event model. If it fails to load AnyEvent will proceed with
		1280	auto detection and -probing.
		1281
		1282	This functionality might change in future versions.
		1283
		1284	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1285	could start your program like this:
		1286
		1287	PERL_ANYEVENT_MODEL=Perl perl ...
		1288
		1289	=item C<PERL_ANYEVENT_PROTOCOLS>
		1290
		1291	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1292	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1293	of auto probing).
		1294
		1295	Must be set to a comma-separated list of protocols or address families,
		1296	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1297	used, and preference will be given to protocols mentioned earlier in the
		1298	list.
		1299
		1300	This variable can effectively be used for denial-of-service attacks
		1301	against local programs (e.g. when setuid), although the impact is likely
		1302	small, as the program has to handle conenction and other failures anyways.
		1303
		1304	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1305	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1306	- only support IPv4, never try to resolve or contact IPv6
		1307	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1308	IPv6, but prefer IPv6 over IPv4.
		1309
		1310	=item C<PERL_ANYEVENT_EDNS0>
		1311
		1312	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1313	for DNS. This extension is generally useful to reduce DNS traffic, but
		1314	some (broken) firewalls drop such DNS packets, which is why it is off by
		1315	default.
		1316
		1317	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1318	EDNS0 in its DNS requests.
		1319
		1320	=item C<PERL_ANYEVENT_MAX_FORKS>
		1321
		1322	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1323	will create in parallel.
		1324
		1325	=back
		1326
1119	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1327	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1120		1328
1121	This is an advanced topic that you do not normally need to use AnyEvent in	1329	This is an advanced topic that you do not normally need to use AnyEvent in
1122	a module. This section is only of use to event loop authors who want to	1330	a module. This section is only of use to event loop authors who want to
1123	provide AnyEvent compatibility.	1331	provide AnyEvent compatibility.
…		…
1156		1364
1157	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1365	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1158	condition variables: code blocking while waiting for a condition will	1366	condition variables: code blocking while waiting for a condition will
1159	C<die>. This still works with most modules/usages, and blocking calls must	1367	C<die>. This still works with most modules/usages, and blocking calls must
1160	not be done in an interactive application, so it makes sense.	1368	not be done in an interactive application, so it makes sense.
1161
1162	=head1 ENVIRONMENT VARIABLES
1163
1164	The following environment variables are used by this module:
1165
1166	=over 4
1167
1168	=item C<PERL_ANYEVENT_VERBOSE>
1169
1170	By default, AnyEvent will be completely silent except in fatal
1171	conditions. You can set this environment variable to make AnyEvent more
1172	talkative.
1173
1174	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1175	conditions, such as not being able to load the event model specified by
1176	C<PERL_ANYEVENT_MODEL>.
1177
1178	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1179	model it chooses.
1180
1181	=item C<PERL_ANYEVENT_MODEL>
1182
1183	This can be used to specify the event model to be used by AnyEvent, before
1184	auto detection and -probing kicks in. It must be a string consisting
1185	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1186	and the resulting module name is loaded and if the load was successful,
1187	used as event model. If it fails to load AnyEvent will proceed with
1188	auto detection and -probing.
1189
1190	This functionality might change in future versions.
1191
1192	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1193	could start your program like this:
1194
1195	PERL_ANYEVENT_MODEL=Perl perl ...
1196
1197	=item C<PERL_ANYEVENT_PROTOCOLS>
1198
1199	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1200	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1201	of auto probing).
1202
1203	Must be set to a comma-separated list of protocols or address families,
1204	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1205	used, and preference will be given to protocols mentioned earlier in the
1206	list.
1207
1208	This variable can effectively be used for denial-of-service attacks
1209	against local programs (e.g. when setuid), although the impact is likely
1210	small, as the program has to handle connection errors already-
1211
1212	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1213	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1214	- only support IPv4, never try to resolve or contact IPv6
1215	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1216	IPv6, but prefer IPv6 over IPv4.
1217
1218	=item C<PERL_ANYEVENT_EDNS0>
1219
1220	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1221	for DNS. This extension is generally useful to reduce DNS traffic, but
1222	some (broken) firewalls drop such DNS packets, which is why it is off by
1223	default.
1224
1225	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1226	EDNS0 in its DNS requests.
1227
1228	=item C<PERL_ANYEVENT_MAX_FORKS>
1229
1230	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1231	will create in parallel.
1232
1233	=back
1234		1369
1235	=head1 EXAMPLE PROGRAM	1370	=head1 EXAMPLE PROGRAM
1236		1371
1237	The following program uses an I/O watcher to read data from STDIN, a timer	1372	The following program uses an I/O watcher to read data from STDIN, a timer
1238	to display a message once per second, and a condition variable to quit the	1373	to display a message once per second, and a condition variable to quit the
…		…
1432	watcher.	1567	watcher.
1433		1568
1434	=head3 Results	1569	=head3 Results
1435		1570
1436	name watchers bytes create invoke destroy comment	1571	name watchers bytes create invoke destroy comment
1437	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1572	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1438	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1573	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1439	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1574	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1440	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1575	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1441	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1576	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1442	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1577	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1443	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1578	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1444	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1579	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1445	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1580	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1446	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1581	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1447		1582
1448	=head3 Discussion	1583	=head3 Discussion
1449		1584
1450	The benchmark does I<not> measure scalability of the event loop very	1585	The benchmark does I<not> measure scalability of the event loop very
1451	well. For example, a select-based event loop (such as the pure perl one)	1586	well. For example, a select-based event loop (such as the pure perl one)
…		…
1653	watchers, as the management overhead dominates.	1788	watchers, as the management overhead dominates.
1654		1789
1655	=back	1790	=back
1656		1791
1657		1792
		1793	=head1 SIGNALS
		1794
		1795	AnyEvent currently installs handlers for these signals:
		1796
		1797	=over 4
		1798
		1799	=item SIGCHLD
		1800
		1801	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1802	emulation for event loops that do not support them natively. Also, some
		1803	event loops install a similar handler.
		1804
		1805	=item SIGPIPE
		1806
		1807	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1808	when AnyEvent gets loaded.
		1809
		1810	The rationale for this is that AnyEvent users usually do not really depend
		1811	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1812	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1813	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1814	some random socket.
		1815
		1816	The rationale for installing a no-op handler as opposed to ignoring it is
		1817	that this way, the handler will be restored to defaults on exec.
		1818
		1819	Feel free to install your own handler, or reset it to defaults.
		1820
		1821	=back
		1822
		1823	=cut
		1824
		1825	$SIG{PIPE} = sub { }
		1826	unless defined $SIG{PIPE};
		1827
		1828
1658	=head1 FORK	1829	=head1 FORK
1659		1830
1660	Most event libraries are not fork-safe. The ones who are usually are	1831	Most event libraries are not fork-safe. The ones who are usually are
1661	because they rely on inefficient but fork-safe C<select> or C<poll>	1832	because they rely on inefficient but fork-safe C<select> or C<poll>
1662	calls. Only L<EV> is fully fork-aware.	1833	calls. Only L<EV> is fully fork-aware.
…		…
1681		1852
1682	use AnyEvent;	1853	use AnyEvent;
1683		1854
1684	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1855	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1685	be used to probe what backend is used and gain other information (which is	1856	be used to probe what backend is used and gain other information (which is
1686	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1857	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1858	$ENV{PERL_ANYEGENT_STRICT}.
1687		1859
1688		1860
1689	=head1 BUGS	1861	=head1 BUGS
1690		1862
1691	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1863	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1692	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	1864	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1693	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	1865	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1694	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	1866	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1695	pronounced).	1867	pronounced).
1696		1868
1697		1869
1698	=head1 SEE ALSO	1870	=head1 SEE ALSO
1699		1871

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs. Revision 1.198 by root, Thu Mar 26 20:17:44 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.164 by root, Tue Jul 8 19:50:25 2008 UTC vs.
Revision 1.198 by root, Thu Mar 26 20:17:44 2009 UTC