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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.169 by root, Wed Jul 9 10:36:22 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 { $_[0]->recv });
22		31
23	=head1 INTRODUCTION/TUTORIAL	32	=head1 INTRODUCTION/TUTORIAL
24		33
25	This manpage is mainly a reference manual. If you are interested	34	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	35	in a tutorial or some gentle introduction, have a look at the
…		…
128	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
131	is in control).	140	is in control).
132		141
		142	Note that B<callbacks must not permanently change global variables>
		143	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		144	callbacks must not C<die> >>. The former is good programming practise in
		145	Perl and the latter stems from the fact that exception handling differs
		146	widely between event loops.
		147
133	To disable the watcher you have to destroy it (e.g. by setting the	148	To disable the watcher you have to destroy it (e.g. by setting the
134	variable you store it in to C<undef> or otherwise deleting all references	149	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	150	to it).
136		151
137	All watchers are created by calling a method on the C<AnyEvent> class.	152	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
153	=head2 I/O WATCHERS	168	=head2 I/O WATCHERS
154		169
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	170	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	171	with the following mandatory key-value pairs as arguments:
157		172
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	173	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
159	(AnyEvent might or might not keep a reference to this file handle). C<poll>	174	for events (AnyEvent might or might not keep a reference to this file
		175	handle). Note that only file handles pointing to things for which
		176	non-blocking operation makes sense are allowed. This includes sockets,
		177	most character devices, pipes, fifos and so on, but not for example files
		178	or block devices.
		179
160	must be a string that is either C<r> or C<w>, which creates a watcher	180	C<poll> must be a string that is either C<r> or C<w>, which creates a
161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the	181	watcher waiting for "r"eadable or "w"ritable events, respectively.
		182
162	callback to invoke each time the file handle becomes ready.	183	C<cb> is the callback to invoke each time the file handle becomes ready.
163		184
164	Although the callback might get passed parameters, their value and	185	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	186	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	187	callbacks cannot use arguments passed to I/O watcher callbacks.
167		188
…		…
299	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
300	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
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	322	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	323	account.
303		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
304	=back	340	=back
305		341
306	=head2 SIGNAL WATCHERS	342	=head2 SIGNAL WATCHERS
307		343
308	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
…		…
331	=head2 CHILD PROCESS WATCHERS	367	=head2 CHILD PROCESS WATCHERS
332		368
333	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.
334		370
335	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
336	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
337	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
338	signal handler for C<SIGCHLD>. The callback will be called with the pid	374	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	375
340	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).
341		384
342	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
343	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
344	have exited already (and no SIGCHLD will be sent anymore).	387	have exited already (and no SIGCHLD will be sent anymore).
345		388
…		…
381	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
382	because they represent a condition that must become true.	425	because they represent a condition that must become true.
383		426
384	Condition variables can be created by calling the C<< AnyEvent->condvar	427	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	428	>> method, usually without arguments. The only argument pair allowed is
		429
386	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
387	becomes true.	431	becomes true, with the condition variable as the first argument (but not
		432	the results).
388		433
389	After creation, the condition variable is "false" until it becomes "true"	434	After creation, the condition variable is "false" until it becomes "true"
390	by calling the C<send> method (or calling the condition variable as if it	435	by calling the C<send> method (or calling the condition variable as if it
391	were a callback, read about the caveats in the description for the C<<	436	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	437	->send >> method).
…		…
448		493
449	my $done = AnyEvent->condvar;	494	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	495	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	496	$done->recv;
452		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
453	=head3 METHODS FOR PRODUCERS	515	=head3 METHODS FOR PRODUCERS
454		516
455	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
456	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
457	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
…		…
590	=item $bool = $cv->ready	652	=item $bool = $cv->ready
591		653
592	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
593	C<croak> have been called.	655	C<croak> have been called.
594		656
595	=item $cb = $cv->cb ([new callback])	657	=item $cb = $cv->cb ($cb->($cv))
596		658
597	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
598	replaces it before doing so.	660	replaces it before doing so.
599		661
600	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
…		…
790	=item L<AnyEvent::IGS>	852	=item L<AnyEvent::IGS>
791		853
792	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
793	L<App::IGS>).	855	L<App::IGS>).
794		856
795	=item L<Net::IRC3>	857	=item L<AnyEvent::IRC>
796		858
797	AnyEvent based IRC client module family.	859	AnyEvent based IRC client module family (replacing the older Net::IRC3).
798		860
799	=item L<Net::XMPP2>	861	=item L<Net::XMPP2>
800		862
801	AnyEvent based XMPP (Jabber protocol) module family.	863	AnyEvent based XMPP (Jabber protocol) module family.
802		864
…		…
822	=cut	884	=cut
823		885
824	package AnyEvent;	886	package AnyEvent;
825		887
826	no warnings;	888	no warnings;
827	use strict;	889	use strict qw(vars subs);
828		890
829	use Carp;	891	use Carp;
830		892
831	our $VERSION = 4.2;	893	our $VERSION = 4.352;
832	our $MODEL;	894	our $MODEL;
833		895
834	our $AUTOLOAD;	896	our $AUTOLOAD;
835	our @ISA;	897	our @ISA;
836		898
…		…
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	930	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	931	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	932	[Prima:: => AnyEvent::Impl::POE::],
871	);	933	);
872		934
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	935	our %method = map +($_ => 1),
		936	qw(io timer time now now_update signal child condvar one_event DESTROY);
874		937
875	our @post_detect;	938	our @post_detect;
876		939
877	sub post_detect(&) {	940	sub post_detect(&) {
878	my ($cb) = @_;	941	my ($cb) = @_;
…		…
935	last;	998	last;
936	}	999	}
937	}	1000	}
938		1001
939	$MODEL	1002	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1003	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}	1004	}
942	}	1005	}
943		1006
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1007	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945		1008
…		…
969	# to support binding more than one watcher per filehandle (they usually	1032	# to support binding more than one watcher per filehandle (they usually
970	# allow only one watcher per fd, so we dup it to get a different one).	1033	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1034	sub _dupfh($$$$) {
972	my ($poll, $fh, $r, $w) = @_;	1035	my ($poll, $fh, $r, $w) = @_;
973		1036
974	require Fcntl;
975
976	# cygwin requires the fh mode to be matching, unix doesn't	1037	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1038	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
978	: $poll eq "w" ? ($w, ">")	1039	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";	1040	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1041
981	open my $fh2, "$mode&" . fileno $fh	1042	open my $fh2, "$mode&" . fileno $fh
982	or die "cannot dup() filehandle: $!";	1043	or die "cannot dup() filehandle: $!,";
983		1044
984	# we assume CLOEXEC is already set by perl in all important cases	1045	# we assume CLOEXEC is already set by perl in all important cases
985		1046
986	($fh2, $rw)	1047	($fh2, $rw)
987	}	1048	}
988		1049
989	package AnyEvent::Base;	1050	package AnyEvent::Base;
990		1051
991	# default implementation for now and time	1052	# default implementations for many methods
992		1053
993	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	}
994		1062
995	sub time { Time::HiRes::time }	1063	sub time { _time }
996	sub now { Time::HiRes::time }	1064	sub now { _time }
		1065	sub now_update { }
997		1066
998	# default implementation for ->condvar	1067	# default implementation for ->condvar
999		1068
1000	sub condvar {	1069	sub condvar {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1070	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
1002	}	1071	}
1003		1072
1004	# default implementation for ->signal	1073	# default implementation for ->signal
1005		1074
1006	our %SIG_CB;	1075	our ($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	}
1007		1087
1008	sub signal {	1088	sub signal {
1009	my (undef, %arg) = @_;	1089	my (undef, %arg) = @_;
1010		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
1011	my $signal = uc $arg{signal}	1116	my $signal = uc $arg{signal}
1012	or Carp::croak "required option 'signal' is missing";	1117	or Carp::croak "required option 'signal' is missing";
1013		1118
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1119	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1015	$SIG{$signal} \|\|= sub {	1120	$SIG{$signal} \|\|= sub {
1016	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1121	local $!;
		1122	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1123	undef $SIG_EV{$signal};
1017	};	1124	};
1018		1125
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1126	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"
1020	}	1127	}
1021		1128
…		…
1140		1247
1141	# undocumented/compatibility with pre-3.4	1248	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	1249	*broadcast = \&send;
1143	*wait = \&_wait;	1250	*wait = \&_wait;
1144		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
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1358	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		1359
1147	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
1148	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
1149	provide AnyEvent compatibility.	1362	provide AnyEvent compatibility.
…		…
1182		1395
1183	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
1184	condition variables: code blocking while waiting for a condition will	1397	condition variables: code blocking while waiting for a condition will
1185	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
1186	not be done in an interactive application, so it makes sense.	1399	not be done in an interactive application, so it makes sense.
1187
1188	=head1 ENVIRONMENT VARIABLES
1189
1190	The following environment variables are used by this module:
1191
1192	=over 4
1193
1194	=item C<PERL_ANYEVENT_VERBOSE>
1195
1196	By default, AnyEvent will be completely silent except in fatal
1197	conditions. You can set this environment variable to make AnyEvent more
1198	talkative.
1199
1200	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1201	conditions, such as not being able to load the event model specified by
1202	C<PERL_ANYEVENT_MODEL>.
1203
1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1205	model it chooses.
1206
1207	=item C<PERL_ANYEVENT_STRICT>
1208
1209	AnyEvent does not do much argument checking by default, as thorough
1210	argument checking is very costly. Setting this variable to a true value
1211	will cause AnyEvent to thoroughly check the arguments passed to most
1212	method calls and croaks if it finds any problems. In other words, enables
1213	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
1214	it off in production.
1215
1216	=item C<PERL_ANYEVENT_MODEL>
1217
1218	This can be used to specify the event model to be used by AnyEvent, before
1219	auto detection and -probing kicks in. It must be a string consisting
1220	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1221	and the resulting module name is loaded and if the load was successful,
1222	used as event model. If it fails to load AnyEvent will proceed with
1223	auto detection and -probing.
1224
1225	This functionality might change in future versions.
1226
1227	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1228	could start your program like this:
1229
1230	PERL_ANYEVENT_MODEL=Perl perl ...
1231
1232	=item C<PERL_ANYEVENT_PROTOCOLS>
1233
1234	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1235	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1236	of auto probing).
1237
1238	Must be set to a comma-separated list of protocols or address families,
1239	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1240	used, and preference will be given to protocols mentioned earlier in the
1241	list.
1242
1243	This variable can effectively be used for denial-of-service attacks
1244	against local programs (e.g. when setuid), although the impact is likely
1245	small, as the program has to handle connection errors already-
1246
1247	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1248	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1249	- only support IPv4, never try to resolve or contact IPv6
1250	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1251	IPv6, but prefer IPv6 over IPv4.
1252
1253	=item C<PERL_ANYEVENT_EDNS0>
1254
1255	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1256	for DNS. This extension is generally useful to reduce DNS traffic, but
1257	some (broken) firewalls drop such DNS packets, which is why it is off by
1258	default.
1259
1260	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1261	EDNS0 in its DNS requests.
1262
1263	=item C<PERL_ANYEVENT_MAX_FORKS>
1264
1265	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1266	will create in parallel.
1267
1268	=back
1269		1400
1270	=head1 EXAMPLE PROGRAM	1401	=head1 EXAMPLE PROGRAM
1271		1402
1272	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
1273	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
…		…
1467	watcher.	1598	watcher.
1468		1599
1469	=head3 Results	1600	=head3 Results
1470		1601
1471	name watchers bytes create invoke destroy comment	1602	name watchers bytes create invoke destroy comment
1472	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
1473	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
1474	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
1475	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
1476	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
1477	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
1478	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
1479	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
1480	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
1481	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
1482		1613
1483	=head3 Discussion	1614	=head3 Discussion
1484		1615
1485	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
1486	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)
…		…
1688	watchers, as the management overhead dominates.	1819	watchers, as the management overhead dominates.
1689		1820
1690	=back	1821	=back
1691		1822
1692		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
1693	=head1 FORK	1860	=head1 FORK
1694		1861
1695	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
1696	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>
1697	calls. Only L<EV> is fully fork-aware.	1864	calls. Only L<EV> is fully fork-aware.
…		…
1725	=head1 BUGS	1892	=head1 BUGS
1726		1893
1727	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
1728	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
1729	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
1730	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
1731	pronounced).	1898	pronounced).
1732		1899
1733		1900
1734	=head1 SEE ALSO	1901	=head1 SEE ALSO
1735		1902

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC vs. Revision 1.206 by root, Mon Apr 20 14:34:18 2009 UTC

Diff Legend

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC vs.
Revision 1.206 by root, Mon Apr 20 14:34:18 2009 UTC