[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 1.206 by root, Mon Apr 20 14:34:18 2009 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
12	...
13	});
14		12
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
16	...	23	...
17	});	24	});
18		25
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	27	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
		29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
22		31
23	=head1 INTRODUCTION/TUTORIAL	32	=head1 INTRODUCTION/TUTORIAL
24		33
25	This manpage is mainly a reference manual. If you are interested	34	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	35	in a tutorial or some gentle introduction, have a look at the
…		…
33		42
34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
35	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
36		45
37	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
38	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
39	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
40	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
41	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
42	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
43		53
44	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
45	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
46	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
47	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
48	model you use.	58	model you use.
49		59
50	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
51	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
52	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
53	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
54	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
55	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
56		66
57	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
58	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
59	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
60	your module uses one of those, every user of your module has to use it,	70	your module uses one of those, every user of your module has to use it,
61	too. But if your module uses AnyEvent, it works transparently with all	71	too. But if your module uses AnyEvent, it works transparently with all
62	event models it supports (including stuff like POE and IO::Async, as long	72	event models it supports (including stuff like IO::Async, as long as those
63	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
64	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
65		75
66	In addition to being free of having to use I<the one and only true event	76	In addition to being free of having to use I<the one and only true event
67	model>, AnyEvent also is free of bloat and policy: with POE or similar	77	model>, AnyEvent also is free of bloat and policy: with POE or similar
68	modules, you get an enormous amount of code and strict rules you have to	78	modules, you get an enormous amount of code and strict rules you have to
69	follow. AnyEvent, on the other hand, is lean and up to the point, by only	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
…		…
127	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
128	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
129	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
130	is in control).	140	is in control).
131		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		144	callbacks must not C<die> >>. The former is good programming practise in
		145	Perl and the latter stems from the fact that exception handling differs
		146	widely between event loops.
		147
132	To disable the watcher you have to destroy it (e.g. by setting the	148	To disable the watcher you have to destroy it (e.g. by setting the
133	variable you store it in to C<undef> or otherwise deleting all references	149	variable you store it in to C<undef> or otherwise deleting all references
134	to it).	150	to it).
135		151
136	All watchers are created by calling a method on the C<AnyEvent> class.	152	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
152	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
153		169
154	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
155	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
156		172
157	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		174	for events (AnyEvent might or might not keep a reference to this file
		175	handle). Note that only file handles pointing to things for which
		176	non-blocking operation makes sense are allowed. This includes sockets,
		177	most character devices, pipes, fifos and so on, but not for example files
		178	or block devices.
		179
158	for events. C<poll> must be a string that is either C<r> or C<w>,	180	C<poll> must be a string that is either C<r> or C<w>, which creates a
159	which creates a watcher waiting for "r"eadable or "w"ritable events,	181	watcher waiting for "r"eadable or "w"ritable events, respectively.
		182
160	respectively. C<cb> is the callback to invoke each time the file handle	183	C<cb> is the callback to invoke each time the file handle becomes ready.
161	becomes ready.
162		184
163	Although the callback might get passed parameters, their value and	185	Although the callback might get passed parameters, their value and
164	presence is undefined and you cannot rely on them. Portable AnyEvent	186	presence is undefined and you cannot rely on them. Portable AnyEvent
165	callbacks cannot use arguments passed to I/O watcher callbacks.	187	callbacks cannot use arguments passed to I/O watcher callbacks.
166		188
…		…
298	In either case, if you care (and in most cases, you don't), then you	320	In either case, if you care (and in most cases, you don't), then you
299	can get whatever behaviour you want with any event loop, by taking the	321	can get whatever behaviour you want with any event loop, by taking the
300	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
301	account.	323	account.
302		324
		325	=item AnyEvent->now_update
		326
		327	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		328	the current time for each loop iteration (see the discussion of L<<
		329	AnyEvent->now >>, above).
		330
		331	When a callback runs for a long time (or when the process sleeps), then
		332	this "current" time will differ substantially from the real time, which
		333	might affect timers and time-outs.
		334
		335	When this is the case, you can call this method, which will update the
		336	event loop's idea of "current time".
		337
		338	Note that updating the time I<might> cause some events to be handled.
		339
303	=back	340	=back
304		341
305	=head2 SIGNAL WATCHERS	342	=head2 SIGNAL WATCHERS
306		343
307	You can watch for signals using a signal watcher, C<signal> is the signal	344	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	345	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
309	be invoked whenever a signal occurs.	346	callback to be invoked whenever a signal occurs.
310		347
311	Although the callback might get passed parameters, their value and	348	Although the callback might get passed parameters, their value and
312	presence is undefined and you cannot rely on them. Portable AnyEvent	349	presence is undefined and you cannot rely on them. Portable AnyEvent
313	callbacks cannot use arguments passed to signal watcher callbacks.	350	callbacks cannot use arguments passed to signal watcher callbacks.
314		351
…		…
330	=head2 CHILD PROCESS WATCHERS	367	=head2 CHILD PROCESS WATCHERS
331		368
332	You can also watch on a child process exit and catch its exit status.	369	You can also watch on a child process exit and catch its exit status.
333		370
334	The child process is specified by the C<pid> argument (if set to C<0>, it	371	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	372	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	373	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	374	any trace events (stopped/continued).
338	and exit status (as returned by waitpid), so unlike other watcher types,	375
339	you I<can> rely on child watcher callback arguments.	376	The callback will be called with the pid and exit status (as returned by
		377	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		378	callback arguments.
		379
		380	This watcher type works by installing a signal handler for C<SIGCHLD>,
		381	and since it cannot be shared, nothing else should use SIGCHLD or reap
		382	random child processes (waiting for specific child processes, e.g. inside
		383	C<system>, is just fine).
340		384
341	There is a slight catch to child watchers, however: you usually start them	385	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	386	I<after> the child process was created, and this means the process could
343	have exited already (and no SIGCHLD will be sent anymore).	387	have exited already (and no SIGCHLD will be sent anymore).
344		388
…		…
380	The instrument to do that is called a "condition variable", so called	424	The instrument to do that is called a "condition variable", so called
381	because they represent a condition that must become true.	425	because they represent a condition that must become true.
382		426
383	Condition variables can be created by calling the C<< AnyEvent->condvar	427	Condition variables can be created by calling the C<< AnyEvent->condvar
384	>> method, usually without arguments. The only argument pair allowed is	428	>> method, usually without arguments. The only argument pair allowed is
		429
385	C<cb>, which specifies a callback to be called when the condition variable	430	C<cb>, which specifies a callback to be called when the condition variable
386	becomes true.	431	becomes true, with the condition variable as the first argument (but not
		432	the results).
387		433
388	After creation, the condition variable is "false" until it becomes "true"	434	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	435	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<<	436	were a callback, read about the caveats in the description for the C<<
391	->send >> method).	437	->send >> method).
…		…
447		493
448	my $done = AnyEvent->condvar;	494	my $done = AnyEvent->condvar;
449	my $delay = AnyEvent->timer (after => 5, cb => $done);	495	my $delay = AnyEvent->timer (after => 5, cb => $done);
450	$done->recv;	496	$done->recv;
451		497
		498	Example: Imagine an API that returns a condvar and doesn't support
		499	callbacks. This is how you make a synchronous call, for example from
		500	the main program:
		501
		502	use AnyEvent::CouchDB;
		503
		504	...
		505
		506	my @info = $couchdb->info->recv;
		507
		508	And this is how you would just ste a callback to be called whenever the
		509	results are available:
		510
		511	$couchdb->info->cb (sub {
		512	my @info = $_[0]->recv;
		513	});
		514
452	=head3 METHODS FOR PRODUCERS	515	=head3 METHODS FOR PRODUCERS
453		516
454	These methods should only be used by the producing side, i.e. the	517	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	518	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	519	the producer side which creates the condvar in most cases, but it isn't
…		…
589	=item $bool = $cv->ready	652	=item $bool = $cv->ready
590		653
591	Returns true when the condition is "true", i.e. whether C<send> or	654	Returns true when the condition is "true", i.e. whether C<send> or
592	C<croak> have been called.	655	C<croak> have been called.
593		656
594	=item $cb = $cv->cb ([new callback])	657	=item $cb = $cv->cb ($cb->($cv))
595		658
596	This is a mutator function that returns the callback set and optionally	659	This is a mutator function that returns the callback set and optionally
597	replaces it before doing so.	660	replaces it before doing so.
598		661
599	The callback will be called when the condition becomes "true", i.e. when	662	The callback will be called when the condition becomes "true", i.e. when
…		…
789	=item L<AnyEvent::IGS>	852	=item L<AnyEvent::IGS>
790		853
791	A non-blocking interface to the Internet Go Server protocol (used by	854	A non-blocking interface to the Internet Go Server protocol (used by
792	L<App::IGS>).	855	L<App::IGS>).
793		856
794	=item L<Net::IRC3>	857	=item L<AnyEvent::IRC>
795		858
796	AnyEvent based IRC client module family.	859	AnyEvent based IRC client module family (replacing the older Net::IRC3).
797		860
798	=item L<Net::XMPP2>	861	=item L<Net::XMPP2>
799		862
800	AnyEvent based XMPP (Jabber protocol) module family.	863	AnyEvent based XMPP (Jabber protocol) module family.
801		864
…		…
821	=cut	884	=cut
822		885
823	package AnyEvent;	886	package AnyEvent;
824		887
825	no warnings;	888	no warnings;
826	use strict;	889	use strict qw(vars subs);
827		890
828	use Carp;	891	use Carp;
829		892
830	our $VERSION = 4.2;	893	our $VERSION = 4.352;
831	our $MODEL;	894	our $MODEL;
832		895
833	our $AUTOLOAD;	896	our $AUTOLOAD;
834	our @ISA;	897	our @ISA;
835		898
…		…
867	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	930	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
868	[Wx:: => AnyEvent::Impl::POE::],	931	[Wx:: => AnyEvent::Impl::POE::],
869	[Prima:: => AnyEvent::Impl::POE::],	932	[Prima:: => AnyEvent::Impl::POE::],
870	);	933	);
871		934
872	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	935	our %method = map +($_ => 1),
		936	qw(io timer time now now_update signal child condvar one_event DESTROY);
873		937
874	our @post_detect;	938	our @post_detect;
875		939
876	sub post_detect(&) {	940	sub post_detect(&) {
877	my ($cb) = @_;	941	my ($cb) = @_;
…		…
934	last;	998	last;
935	}	999	}
936	}	1000	}
937		1001
938	$MODEL	1002	$MODEL
939	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1003	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
940	}	1004	}
941	}	1005	}
942		1006
		1007	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1008
943	unshift @ISA, $MODEL;	1009	unshift @ISA, $MODEL;
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1010
		1011	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
945		1012
946	(shift @post_detect)->() while @post_detect;	1013	(shift @post_detect)->() while @post_detect;
947	}	1014	}
948		1015
949	$MODEL	1016	$MODEL
…		…
959		1026
960	my $class = shift;	1027	my $class = shift;
961	$class->$func (@_);	1028	$class->$func (@_);
962	}	1029	}
963		1030
		1031	# utility function to dup a filehandle. this is used by many backends
		1032	# to support binding more than one watcher per filehandle (they usually
		1033	# allow only one watcher per fd, so we dup it to get a different one).
		1034	sub _dupfh($$$$) {
		1035	my ($poll, $fh, $r, $w) = @_;
		1036
		1037	# cygwin requires the fh mode to be matching, unix doesn't
		1038	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1039	: $poll eq "w" ? ($w, ">")
		1040	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1041
		1042	open my $fh2, "$mode&" . fileno $fh
		1043	or die "cannot dup() filehandle: $!,";
		1044
		1045	# we assume CLOEXEC is already set by perl in all important cases
		1046
		1047	($fh2, $rw)
		1048	}
		1049
964	package AnyEvent::Base;	1050	package AnyEvent::Base;
965		1051
966	# default implementation for now and time	1052	# default implementations for many methods
967		1053
968	use Time::HiRes ();	1054	BEGIN {
		1055	if (eval "use Time::HiRes (); time (); 1") {
		1056	*_time = \&Time::HiRes::time;
		1057	# if (eval "use POSIX (); (POSIX::times())...
		1058	} else {
		1059	*_time = sub { time }; # epic fail
		1060	}
		1061	}
969		1062
970	sub time { Time::HiRes::time }	1063	sub time { _time }
971	sub now { Time::HiRes::time }	1064	sub now { _time }
		1065	sub now_update { }
972		1066
973	# default implementation for ->condvar	1067	# default implementation for ->condvar
974		1068
975	sub condvar {	1069	sub condvar {
976	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1070	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
977	}	1071	}
978		1072
979	# default implementation for ->signal	1073	# default implementation for ->signal
980		1074
981	our %SIG_CB;	1075	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1076
		1077	sub _signal_exec {
		1078	sysread $SIGPIPE_R, my $dummy, 4;
		1079
		1080	while (%SIG_EV) {
		1081	for (keys %SIG_EV) {
		1082	delete $SIG_EV{$_};
		1083	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1084	}
		1085	}
		1086	}
982		1087
983	sub signal {	1088	sub signal {
984	my (undef, %arg) = @_;	1089	my (undef, %arg) = @_;
985		1090
		1091	unless ($SIGPIPE_R) {
		1092	require Fcntl;
		1093
		1094	if (AnyEvent::WIN32) {
		1095	require AnyEvent::Util;
		1096
		1097	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1098	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1099	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1100	} else {
		1101	pipe $SIGPIPE_R, $SIGPIPE_W;
		1102	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1103	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1104	}
		1105
		1106	$SIGPIPE_R
		1107	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1108
		1109	# not strictly required, as $^F is normally 2, but let's make sure...
		1110	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1111	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1112
		1113	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1114	}
		1115
986	my $signal = uc $arg{signal}	1116	my $signal = uc $arg{signal}
987	or Carp::croak "required option 'signal' is missing";	1117	or Carp::croak "required option 'signal' is missing";
988		1118
989	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1119	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
990	$SIG{$signal} \|\|= sub {	1120	$SIG{$signal} \|\|= sub {
991	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1121	local $!;
		1122	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1123	undef $SIG_EV{$signal};
992	};	1124	};
993		1125
994	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1126	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
995	}	1127	}
996		1128
…		…
1115		1247
1116	# undocumented/compatibility with pre-3.4	1248	# undocumented/compatibility with pre-3.4
1117	*broadcast = \&send;	1249	*broadcast = \&send;
1118	*wait = \&_wait;	1250	*wait = \&_wait;
1119		1251
		1252	=head1 ERROR AND EXCEPTION HANDLING
		1253
		1254	In general, AnyEvent does not do any error handling - it relies on the
		1255	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1256	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1257	checking of all AnyEvent methods, however, which is highly useful during
		1258	development.
		1259
		1260	As for exception handling (i.e. runtime errors and exceptions thrown while
		1261	executing a callback), this is not only highly event-loop specific, but
		1262	also not in any way wrapped by this module, as this is the job of the main
		1263	program.
		1264
		1265	The pure perl event loop simply re-throws the exception (usually
		1266	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1267	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1268	so on.
		1269
		1270	=head1 ENVIRONMENT VARIABLES
		1271
		1272	The following environment variables are used by this module or its
		1273	submodules:
		1274
		1275	=over 4
		1276
		1277	=item C<PERL_ANYEVENT_VERBOSE>
		1278
		1279	By default, AnyEvent will be completely silent except in fatal
		1280	conditions. You can set this environment variable to make AnyEvent more
		1281	talkative.
		1282
		1283	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1284	conditions, such as not being able to load the event model specified by
		1285	C<PERL_ANYEVENT_MODEL>.
		1286
		1287	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1288	model it chooses.
		1289
		1290	=item C<PERL_ANYEVENT_STRICT>
		1291
		1292	AnyEvent does not do much argument checking by default, as thorough
		1293	argument checking is very costly. Setting this variable to a true value
		1294	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1295	check the arguments passed to most method calls. If it finds any problems
		1296	it will croak.
		1297
		1298	In other words, enables "strict" mode.
		1299
		1300	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1301	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1302	developing programs can be very useful, however.
		1303
		1304	=item C<PERL_ANYEVENT_MODEL>
		1305
		1306	This can be used to specify the event model to be used by AnyEvent, before
		1307	auto detection and -probing kicks in. It must be a string consisting
		1308	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1309	and the resulting module name is loaded and if the load was successful,
		1310	used as event model. If it fails to load AnyEvent will proceed with
		1311	auto detection and -probing.
		1312
		1313	This functionality might change in future versions.
		1314
		1315	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1316	could start your program like this:
		1317
		1318	PERL_ANYEVENT_MODEL=Perl perl ...
		1319
		1320	=item C<PERL_ANYEVENT_PROTOCOLS>
		1321
		1322	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1323	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1324	of auto probing).
		1325
		1326	Must be set to a comma-separated list of protocols or address families,
		1327	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1328	used, and preference will be given to protocols mentioned earlier in the
		1329	list.
		1330
		1331	This variable can effectively be used for denial-of-service attacks
		1332	against local programs (e.g. when setuid), although the impact is likely
		1333	small, as the program has to handle conenction and other failures anyways.
		1334
		1335	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1336	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1337	- only support IPv4, never try to resolve or contact IPv6
		1338	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1339	IPv6, but prefer IPv6 over IPv4.
		1340
		1341	=item C<PERL_ANYEVENT_EDNS0>
		1342
		1343	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1344	for DNS. This extension is generally useful to reduce DNS traffic, but
		1345	some (broken) firewalls drop such DNS packets, which is why it is off by
		1346	default.
		1347
		1348	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1349	EDNS0 in its DNS requests.
		1350
		1351	=item C<PERL_ANYEVENT_MAX_FORKS>
		1352
		1353	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1354	will create in parallel.
		1355
		1356	=back
		1357
1120	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1358	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1121		1359
1122	This is an advanced topic that you do not normally need to use AnyEvent in	1360	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	1361	a module. This section is only of use to event loop authors who want to
1124	provide AnyEvent compatibility.	1362	provide AnyEvent compatibility.
…		…
1157		1395
1158	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1396	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1159	condition variables: code blocking while waiting for a condition will	1397	condition variables: code blocking while waiting for a condition will
1160	C<die>. This still works with most modules/usages, and blocking calls must	1398	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.	1399	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		1400
1236	=head1 EXAMPLE PROGRAM	1401	=head1 EXAMPLE PROGRAM
1237		1402
1238	The following program uses an I/O watcher to read data from STDIN, a timer	1403	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	1404	to display a message once per second, and a condition variable to quit the
…		…
1433	watcher.	1598	watcher.
1434		1599
1435	=head3 Results	1600	=head3 Results
1436		1601
1437	name watchers bytes create invoke destroy comment	1602	name watchers bytes create invoke destroy comment
1438	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1603	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	1604	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	1605	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	1606	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	1607	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	1608	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	1609	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	1610	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	1611	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	1612	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1448		1613
1449	=head3 Discussion	1614	=head3 Discussion
1450		1615
1451	The benchmark does I<not> measure scalability of the event loop very	1616	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)	1617	well. For example, a select-based event loop (such as the pure perl one)
…		…
1654	watchers, as the management overhead dominates.	1819	watchers, as the management overhead dominates.
1655		1820
1656	=back	1821	=back
1657		1822
1658		1823
		1824	=head1 SIGNALS
		1825
		1826	AnyEvent currently installs handlers for these signals:
		1827
		1828	=over 4
		1829
		1830	=item SIGCHLD
		1831
		1832	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1833	emulation for event loops that do not support them natively. Also, some
		1834	event loops install a similar handler.
		1835
		1836	=item SIGPIPE
		1837
		1838	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1839	when AnyEvent gets loaded.
		1840
		1841	The rationale for this is that AnyEvent users usually do not really depend
		1842	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1843	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1844	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1845	some random socket.
		1846
		1847	The rationale for installing a no-op handler as opposed to ignoring it is
		1848	that this way, the handler will be restored to defaults on exec.
		1849
		1850	Feel free to install your own handler, or reset it to defaults.
		1851
		1852	=back
		1853
		1854	=cut
		1855
		1856	$SIG{PIPE} = sub { }
		1857	unless defined $SIG{PIPE};
		1858
		1859
1659	=head1 FORK	1860	=head1 FORK
1660		1861
1661	Most event libraries are not fork-safe. The ones who are usually are	1862	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>	1863	because they rely on inefficient but fork-safe C<select> or C<poll>
1663	calls. Only L<EV> is fully fork-aware.	1864	calls. Only L<EV> is fully fork-aware.
…		…
1682		1883
1683	use AnyEvent;	1884	use AnyEvent;
1684		1885
1685	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1886	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	1887	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).	1888	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1889	$ENV{PERL_ANYEGENT_STRICT}.
1688		1890
1689		1891
1690	=head1 BUGS	1892	=head1 BUGS
1691		1893
1692	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	1894	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	1895	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	1896	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	1897	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1696	pronounced).	1898	pronounced).
1697		1899
1698		1900
1699	=head1 SEE ALSO	1901	=head1 SEE ALSO
1700		1902

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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 1.206 by root, Mon Apr 20 14:34:18 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 1.206 by root, Mon Apr 20 14:34:18 2009 UTC