[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 1.219 by root, Thu Jun 25 11:16:08 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
22		39
23	=head1 INTRODUCTION/TUTORIAL	40	=head1 INTRODUCTION/TUTORIAL
24		41
25	This manpage is mainly a reference manual. If you are interested	42	This manpage is mainly a reference manual. If you are interested
26	in a tutorial or some gentle introduction, have a look at the	43	in a tutorial or some gentle introduction, have a look at the
128	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
129	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
130	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
131	is in control).	148	is in control).
132		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
133	To disable the watcher you have to destroy it (e.g. by setting the	156	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	157	variable you store it in to C<undef> or otherwise deleting all references
135	to it).	158	to it).
136		159
137	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
153	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
154		177
155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
156	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
157		180
158	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events	181	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>	182	for events (AnyEvent might or might not keep a reference to this file
		183	handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
160	must be a string that is either C<r> or C<w>, which creates a watcher	188	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	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
162	callback to invoke each time the file handle becomes ready.	191	C<cb> is the callback to invoke each time the file handle becomes ready.
163		192
164	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
165	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
166	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
167		196
…		…
299	In either case, if you care (and in most cases, you don't), then you	328	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	329	can get whatever behaviour you want with any event loop, by taking the
301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
302	account.	331	account.
303		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
304	=back	348	=back
305		349
306	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
307		351
308	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
331	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
332		376
333	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
334		378
335	The child process is specified by the C<pid> argument (if set to C<0>, it	379	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	380	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	381	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	382	any trace events (stopped/continued).
339	and exit status (as returned by waitpid), so unlike other watcher types,	383
340	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
341		392
342	There is a slight catch to child watchers, however: you usually start them	393	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	394	I<after> the child process was created, and this means the process could
344	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
345		396
346	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
347	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
348	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
349		403
350	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
351	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
353		408
354	Example: fork a process and wait for it	409	Example: fork a process and wait for it
355		410
356	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
357		412
…		…
367	);	422	);
368		423
369	# do something else, then wait for process exit	424	# do something else, then wait for process exit
370	$done->recv;	425	$done->recv;
371		426
		427	=head2 IDLE WATCHERS
		428
		429	Sometimes there is a need to do something, but it is not so important
		430	to do it instantly, but only when there is nothing better to do. This
		431	"nothing better to do" is usually defined to be "no other events need
		432	attention by the event loop".
		433
		434	Idle watchers ideally get invoked when the event loop has nothing
		435	better to do, just before it would block the process to wait for new
		436	events. Instead of blocking, the idle watcher is invoked.
		437
		438	Most event loops unfortunately do not really support idle watchers (only
		439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		440	will simply call the callback "from time to time".
		441
		442	Example: read lines from STDIN, but only process them when the
		443	program is otherwise idle:
		444
		445	my @lines; # read data
		446	my $idle_w;
		447	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		448	push @lines, scalar <STDIN>;
		449
		450	# start an idle watcher, if not already done
		451	$idle_w \|\|= AnyEvent->idle (cb => sub {
		452	# handle only one line, when there are lines left
		453	if (my $line = shift @lines) {
		454	print "handled when idle: $line";
		455	} else {
		456	# otherwise disable the idle watcher again
		457	undef $idle_w;
		458	}
		459	});
		460	});
		461
372	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
373		463
374	If you are familiar with some event loops you will know that all of them	464	If you are familiar with some event loops you will know that all of them
375	require you to run some blocking "loop", "run" or similar function that	465	require you to run some blocking "loop", "run" or similar function that
376	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
…		…
381	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
382	because they represent a condition that must become true.	472	because they represent a condition that must become true.
383		473
384	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
385	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
		476
386	C<cb>, which specifies a callback to be called when the condition variable	477	C<cb>, which specifies a callback to be called when the condition variable
387	becomes true.	478	becomes true, with the condition variable as the first argument (but not
		479	the results).
388		480
389	After creation, the condition variable is "false" until it becomes "true"	481	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	482	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<<	483	were a callback, read about the caveats in the description for the C<<
392	->send >> method).	484	->send >> method).
…		…
448		540
449	my $done = AnyEvent->condvar;	541	my $done = AnyEvent->condvar;
450	my $delay = AnyEvent->timer (after => 5, cb => $done);	542	my $delay = AnyEvent->timer (after => 5, cb => $done);
451	$done->recv;	543	$done->recv;
452		544
		545	Example: Imagine an API that returns a condvar and doesn't support
		546	callbacks. This is how you make a synchronous call, for example from
		547	the main program:
		548
		549	use AnyEvent::CouchDB;
		550
		551	...
		552
		553	my @info = $couchdb->info->recv;
		554
		555	And this is how you would just ste a callback to be called whenever the
		556	results are available:
		557
		558	$couchdb->info->cb (sub {
		559	my @info = $_[0]->recv;
		560	});
		561
453	=head3 METHODS FOR PRODUCERS	562	=head3 METHODS FOR PRODUCERS
454		563
455	These methods should only be used by the producing side, i.e. the	564	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	565	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	566	the producer side which creates the condvar in most cases, but it isn't
…		…
590	=item $bool = $cv->ready	699	=item $bool = $cv->ready
591		700
592	Returns true when the condition is "true", i.e. whether C<send> or	701	Returns true when the condition is "true", i.e. whether C<send> or
593	C<croak> have been called.	702	C<croak> have been called.
594		703
595	=item $cb = $cv->cb ([new callback])	704	=item $cb = $cv->cb ($cb->($cv))
596		705
597	This is a mutator function that returns the callback set and optionally	706	This is a mutator function that returns the callback set and optionally
598	replaces it before doing so.	707	replaces it before doing so.
599		708
600	The callback will be called when the condition becomes "true", i.e. when	709	The callback will be called when the condition becomes "true", i.e. when
…		…
625	AnyEvent::Impl::Tk based on Tk, very bad choice.	734	AnyEvent::Impl::Tk based on Tk, very bad choice.
626	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	735	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
627	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
628	AnyEvent::Impl::POE based on POE, not generic enough for full support.	737	AnyEvent::Impl::POE based on POE, not generic enough for full support.
629		738
		739	# warning, support for IO::Async is only partial, as it is too broken
		740	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		741	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		742
630	There is no support for WxWidgets, as WxWidgets has no support for	743	There is no support for WxWidgets, as WxWidgets has no support for
631	watching file handles. However, you can use WxWidgets through the	744	watching file handles. However, you can use WxWidgets through the
632	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	745	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
633	second, which was considered to be too horrible to even consider for	746	second, which was considered to be too horrible to even consider for
634	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using	747	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
790	=item L<AnyEvent::IGS>	903	=item L<AnyEvent::IGS>
791		904
792	A non-blocking interface to the Internet Go Server protocol (used by	905	A non-blocking interface to the Internet Go Server protocol (used by
793	L<App::IGS>).	906	L<App::IGS>).
794		907
795	=item L<Net::IRC3>	908	=item L<AnyEvent::IRC>
796		909
797	AnyEvent based IRC client module family.	910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
798		911
799	=item L<Net::XMPP2>	912	=item L<Net::XMPP2>
800		913
801	AnyEvent based XMPP (Jabber protocol) module family.	914	AnyEvent based XMPP (Jabber protocol) module family.
802		915
…		…
822	=cut	935	=cut
823		936
824	package AnyEvent;	937	package AnyEvent;
825		938
826	no warnings;	939	no warnings;
827	use strict;	940	use strict qw(vars subs);
828		941
829	use Carp;	942	use Carp;
830		943
831	our $VERSION = 4.2;	944	our $VERSION = 4.412;
832	our $MODEL;	945	our $MODEL;
833		946
834	our $AUTOLOAD;	947	our $AUTOLOAD;
835	our @ISA;	948	our @ISA;
836		949
837	our @REGISTRY;	950	our @REGISTRY;
838		951
839	our $WIN32;	952	our $WIN32;
840		953
841	BEGIN {	954	BEGIN {
842	my $win32 = ! ! ($^O =~ /mswin32/i);	955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
843	eval "sub WIN32(){ $win32 }";	956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		957
		958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		959	if ${^TAINT};
844	}	960	}
845		961
846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
847		963
848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	964	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
869	[Wx:: => AnyEvent::Impl::POE::],	985	[Wx:: => AnyEvent::Impl::POE::],
870	[Prima:: => AnyEvent::Impl::POE::],	986	[Prima:: => AnyEvent::Impl::POE::],
		987	# IO::Async is just too broken - we would need workaorunds for its
		988	# byzantine signal and broken child handling, among others.
		989	# IO::Async is rather hard to detect, as it doesn't have any
		990	# obvious default class.
		991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
871	);	994	);
872		995
873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	996	our %method = map +($_ => 1),
		997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
874		998
875	our @post_detect;	999	our @post_detect;
876		1000
877	sub post_detect(&) {	1001	sub post_detect(&) {
878	my ($cb) = @_;	1002	my ($cb) = @_;
…		…
883	1	1007	1
884	} else {	1008	} else {
885	push @post_detect, $cb;	1009	push @post_detect, $cb;
886		1010
887	defined wantarray	1011	defined wantarray
888	? bless \$cb, "AnyEvent::Util::PostDetect"	1012	? bless \$cb, "AnyEvent::Util::postdetect"
889	: ()	1013	: ()
890	}	1014	}
891	}	1015	}
892		1016
893	sub AnyEvent::Util::PostDetect::DESTROY {	1017	sub AnyEvent::Util::postdetect::DESTROY {
894	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;
895	}	1019	}
896		1020
897	sub detect() {	1021	sub detect() {
898	unless ($MODEL) {	1022	unless ($MODEL) {
…		…
935	last;	1059	last;
936	}	1060	}
937	}	1061	}
938		1062
939	$MODEL	1063	$MODEL
940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1064	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
941	}	1065	}
942	}	1066	}
943		1067
944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1068	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
945		1069
…		…
966	}	1090	}
967		1091
968	# utility function to dup a filehandle. this is used by many backends	1092	# utility function to dup a filehandle. this is used by many backends
969	# to support binding more than one watcher per filehandle (they usually	1093	# 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).	1094	# allow only one watcher per fd, so we dup it to get a different one).
971	sub _dupfh($$$$) {	1095	sub _dupfh($$;$$) {
972	my ($poll, $fh, $r, $w) = @_;	1096	my ($poll, $fh, $r, $w) = @_;
973
974	require Fcntl;
975		1097
976	# cygwin requires the fh mode to be matching, unix doesn't	1098	# cygwin requires the fh mode to be matching, unix doesn't
977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
978	: $poll eq "w" ? ($w, ">")	1100	: $poll eq "w" ? ($w, ">")
979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";	1101	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
980		1102
981	open my $fh2, "$mode&" . fileno $fh	1103	open my $fh2, "$mode&" . fileno $fh
982	or die "cannot dup() filehandle: $!";	1104	or die "cannot dup() filehandle: $!,";
983		1105
984	# we assume CLOEXEC is already set by perl in all important cases	1106	# we assume CLOEXEC is already set by perl in all important cases
985		1107
986	($fh2, $rw)	1108	($fh2, $rw)
987	}	1109	}
988		1110
989	package AnyEvent::Base;	1111	package AnyEvent::Base;
990		1112
991	# default implementation for now and time	1113	# default implementations for many methods
992		1114
993	use Time::HiRes ();	1115	BEGIN {
		1116	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1117	*_time = \&Time::HiRes::time;
		1118	# if (eval "use POSIX (); (POSIX::times())...
		1119	} else {
		1120	*_time = sub { time }; # epic fail
		1121	}
		1122	}
994		1123
995	sub time { Time::HiRes::time }	1124	sub time { _time }
996	sub now { Time::HiRes::time }	1125	sub now { _time }
		1126	sub now_update { }
997		1127
998	# default implementation for ->condvar	1128	# default implementation for ->condvar
999		1129
1000	sub condvar {	1130	sub condvar {
1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1002	}	1132	}
1003		1133
1004	# default implementation for ->signal	1134	# default implementation for ->signal
1005		1135
1006	our %SIG_CB;	1136	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1137
		1138	sub _signal_exec {
		1139	sysread $SIGPIPE_R, my $dummy, 4;
		1140
		1141	while (%SIG_EV) {
		1142	for (keys %SIG_EV) {
		1143	delete $SIG_EV{$_};
		1144	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1145	}
		1146	}
		1147	}
1007		1148
1008	sub signal {	1149	sub signal {
1009	my (undef, %arg) = @_;	1150	my (undef, %arg) = @_;
1010		1151
		1152	unless ($SIGPIPE_R) {
		1153	require Fcntl;
		1154
		1155	if (AnyEvent::WIN32) {
		1156	require AnyEvent::Util;
		1157
		1158	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1159	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1160	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1161	} else {
		1162	pipe $SIGPIPE_R, $SIGPIPE_W;
		1163	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1164	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1165
		1166	# not strictly required, as $^F is normally 2, but let's make sure...
		1167	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1168	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1169	}
		1170
		1171	$SIGPIPE_R
		1172	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1173
		1174	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1175	}
		1176
1011	my $signal = uc $arg{signal}	1177	my $signal = uc $arg{signal}
1012	or Carp::croak "required option 'signal' is missing";	1178	or Carp::croak "required option 'signal' is missing";
1013		1179
1014	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1015	$SIG{$signal} \|\|= sub {	1181	$SIG{$signal} \|\|= sub {
1016	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1182	local $!;
		1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1184	undef $SIG_EV{$signal};
1017	};	1185	};
1018		1186
1019	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1020	}	1188	}
1021		1189
1022	sub AnyEvent::Base::Signal::DESTROY {	1190	sub AnyEvent::Base::signal::DESTROY {
1023	my ($signal, $cb) = @{$_[0]};	1191	my ($signal, $cb) = @{$_[0]};
1024		1192
1025	delete $SIG_CB{$signal}{$cb};	1193	delete $SIG_CB{$signal}{$cb};
1026		1194
		1195	# delete doesn't work with older perls - they then
		1196	# print weird messages, or just unconditionally exit
		1197	# instead of getting the default action.
1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1028	}	1199	}
1029		1200
1030	# default implementation for ->child	1201	# default implementation for ->child
1031		1202
1032	our %PID_CB;	1203	our %PID_CB;
1033	our $CHLD_W;	1204	our $CHLD_W;
1034	our $CHLD_DELAY_W;	1205	our $CHLD_DELAY_W;
1035	our $PID_IDLE;
1036	our $WNOHANG;	1206	our $WNOHANG;
1037		1207
1038	sub _child_wait {	1208	sub _sigchld {
1039	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1040	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1041	(values %{ $PID_CB{0} \|\| {} });	1211	(values %{ $PID_CB{0} \|\| {} });
1042	}	1212	}
1043
1044	undef $PID_IDLE;
1045	}
1046
1047	sub _sigchld {
1048	# make sure we deliver these changes "synchronous" with the event loop.
1049	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1050	undef $CHLD_DELAY_W;
1051	&_child_wait;
1052	});
1053	}	1213	}
1054		1214
1055	sub child {	1215	sub child {
1056	my (undef, %arg) = @_;	1216	my (undef, %arg) = @_;
1057		1217
1058	defined (my $pid = $arg{pid} + 0)	1218	defined (my $pid = $arg{pid} + 0)
1059	or Carp::croak "required option 'pid' is missing";	1219	or Carp::croak "required option 'pid' is missing";
1060		1220
1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1062		1222
1063	unless ($WNOHANG) {
1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1223	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1065	}
1066		1224
1067	unless ($CHLD_W) {	1225	unless ($CHLD_W) {
1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1069	# child could be a zombie already, so make at least one round	1227	# child could be a zombie already, so make at least one round
1070	&_sigchld;	1228	&_sigchld;
1071	}	1229	}
1072		1230
1073	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1074	}	1232	}
1075		1233
1076	sub AnyEvent::Base::Child::DESTROY {	1234	sub AnyEvent::Base::child::DESTROY {
1077	my ($pid, $cb) = @{$_[0]};	1235	my ($pid, $cb) = @{$_[0]};
1078		1236
1079	delete $PID_CB{$pid}{$cb};	1237	delete $PID_CB{$pid}{$cb};
1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1238	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1081		1239
1082	undef $CHLD_W unless keys %PID_CB;	1240	undef $CHLD_W unless keys %PID_CB;
		1241	}
		1242
		1243	# idle emulation is done by simply using a timer, regardless
		1244	# of whether the process is idle or not, and not letting
		1245	# the callback use more than 50% of the time.
		1246	sub idle {
		1247	my (undef, %arg) = @_;
		1248
		1249	my ($cb, $w, $rcb) = $arg{cb};
		1250
		1251	$rcb = sub {
		1252	if ($cb) {
		1253	$w = _time;
		1254	&$cb;
		1255	$w = _time - $w;
		1256
		1257	# never use more then 50% of the time for the idle watcher,
		1258	# within some limits
		1259	$w = 0.0001 if $w < 0.0001;
		1260	$w = 5 if $w > 5;
		1261
		1262	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1263	} else {
		1264	# clean up...
		1265	undef $w;
		1266	undef $rcb;
		1267	}
		1268	};
		1269
		1270	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1271
		1272	bless \\$cb, "AnyEvent::Base::idle"
		1273	}
		1274
		1275	sub AnyEvent::Base::idle::DESTROY {
		1276	undef $${$_[0]};
1083	}	1277	}
1084		1278
1085	package AnyEvent::CondVar;	1279	package AnyEvent::CondVar;
1086		1280
1087	our @ISA = AnyEvent::CondVar::Base::;	1281	our @ISA = AnyEvent::CondVar::Base::;
…		…
1139	}	1333	}
1140		1334
1141	# undocumented/compatibility with pre-3.4	1335	# undocumented/compatibility with pre-3.4
1142	*broadcast = \&send;	1336	*broadcast = \&send;
1143	*wait = \&_wait;	1337	*wait = \&_wait;
		1338
		1339	=head1 ERROR AND EXCEPTION HANDLING
		1340
		1341	In general, AnyEvent does not do any error handling - it relies on the
		1342	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1343	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1344	checking of all AnyEvent methods, however, which is highly useful during
		1345	development.
		1346
		1347	As for exception handling (i.e. runtime errors and exceptions thrown while
		1348	executing a callback), this is not only highly event-loop specific, but
		1349	also not in any way wrapped by this module, as this is the job of the main
		1350	program.
		1351
		1352	The pure perl event loop simply re-throws the exception (usually
		1353	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1354	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1355	so on.
		1356
		1357	=head1 ENVIRONMENT VARIABLES
		1358
		1359	The following environment variables are used by this module or its
		1360	submodules.
		1361
		1362	Note that AnyEvent will remove I<all> environment variables starting with
		1363	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1364	enabled.
		1365
		1366	=over 4
		1367
		1368	=item C<PERL_ANYEVENT_VERBOSE>
		1369
		1370	By default, AnyEvent will be completely silent except in fatal
		1371	conditions. You can set this environment variable to make AnyEvent more
		1372	talkative.
		1373
		1374	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1375	conditions, such as not being able to load the event model specified by
		1376	C<PERL_ANYEVENT_MODEL>.
		1377
		1378	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1379	model it chooses.
		1380
		1381	=item C<PERL_ANYEVENT_STRICT>
		1382
		1383	AnyEvent does not do much argument checking by default, as thorough
		1384	argument checking is very costly. Setting this variable to a true value
		1385	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1386	check the arguments passed to most method calls. If it finds any problems,
		1387	it will croak.
		1388
		1389	In other words, enables "strict" mode.
		1390
		1391	Unlike C<use strict>, it is definitely recommended to keep it off in
		1392	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1393	developing programs can be very useful, however.
		1394
		1395	=item C<PERL_ANYEVENT_MODEL>
		1396
		1397	This can be used to specify the event model to be used by AnyEvent, before
		1398	auto detection and -probing kicks in. It must be a string consisting
		1399	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1400	and the resulting module name is loaded and if the load was successful,
		1401	used as event model. If it fails to load AnyEvent will proceed with
		1402	auto detection and -probing.
		1403
		1404	This functionality might change in future versions.
		1405
		1406	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1407	could start your program like this:
		1408
		1409	PERL_ANYEVENT_MODEL=Perl perl ...
		1410
		1411	=item C<PERL_ANYEVENT_PROTOCOLS>
		1412
		1413	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1414	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1415	of auto probing).
		1416
		1417	Must be set to a comma-separated list of protocols or address families,
		1418	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1419	used, and preference will be given to protocols mentioned earlier in the
		1420	list.
		1421
		1422	This variable can effectively be used for denial-of-service attacks
		1423	against local programs (e.g. when setuid), although the impact is likely
		1424	small, as the program has to handle conenction and other failures anyways.
		1425
		1426	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1427	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1428	- only support IPv4, never try to resolve or contact IPv6
		1429	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1430	IPv6, but prefer IPv6 over IPv4.
		1431
		1432	=item C<PERL_ANYEVENT_EDNS0>
		1433
		1434	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1435	for DNS. This extension is generally useful to reduce DNS traffic, but
		1436	some (broken) firewalls drop such DNS packets, which is why it is off by
		1437	default.
		1438
		1439	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1440	EDNS0 in its DNS requests.
		1441
		1442	=item C<PERL_ANYEVENT_MAX_FORKS>
		1443
		1444	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1445	will create in parallel.
		1446
		1447	=back
1144		1448
1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1146		1450
1147	This is an advanced topic that you do not normally need to use AnyEvent in	1451	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	1452	a module. This section is only of use to event loop authors who want to
…		…
1182		1486
1183	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1487	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1184	condition variables: code blocking while waiting for a condition will	1488	condition variables: code blocking while waiting for a condition will
1185	C<die>. This still works with most modules/usages, and blocking calls must	1489	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.	1490	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		1491
1270	=head1 EXAMPLE PROGRAM	1492	=head1 EXAMPLE PROGRAM
1271		1493
1272	The following program uses an I/O watcher to read data from STDIN, a timer	1494	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	1495	to display a message once per second, and a condition variable to quit the
…		…
1467	watcher.	1689	watcher.
1468		1690
1469	=head3 Results	1691	=head3 Results
1470		1692
1471	name watchers bytes create invoke destroy comment	1693	name watchers bytes create invoke destroy comment
1472	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1694	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	1695	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	1696	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	1697	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	1698	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	1699	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	1700	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	1701	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	1702	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	1703	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1482		1704
1483	=head3 Discussion	1705	=head3 Discussion
1484		1706
1485	The benchmark does I<not> measure scalability of the event loop very	1707	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)	1708	well. For example, a select-based event loop (such as the pure perl one)
…		…
1687	=item * C-based event loops perform very well with small number of	1909	=item * C-based event loops perform very well with small number of
1688	watchers, as the management overhead dominates.	1910	watchers, as the management overhead dominates.
1689		1911
1690	=back	1912	=back
1691		1913
		1914	=head2 THE IO::Lambda BENCHMARK
		1915
		1916	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1917	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1918	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1919	shouldn't come as a surprise to anybody). As such, the benchmark is
		1920	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1921	very optimal. But how would AnyEvent compare when used without the extra
		1922	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1923
		1924	The benchmark itself creates an echo-server, and then, for 500 times,
		1925	connects to the echo server, sends a line, waits for the reply, and then
		1926	creates the next connection. This is a rather bad benchmark, as it doesn't
		1927	test the efficiency of the framework or much non-blocking I/O, but it is a
		1928	benchmark nevertheless.
		1929
		1930	name runtime
		1931	Lambda/select 0.330 sec
		1932	+ optimized 0.122 sec
		1933	Lambda/AnyEvent 0.327 sec
		1934	+ optimized 0.138 sec
		1935	Raw sockets/select 0.077 sec
		1936	POE/select, components 0.662 sec
		1937	POE/select, raw sockets 0.226 sec
		1938	POE/select, optimized 0.404 sec
		1939
		1940	AnyEvent/select/nb 0.085 sec
		1941	AnyEvent/EV/nb 0.068 sec
		1942	+state machine 0.134 sec
		1943
		1944	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1945	benchmarks actually make blocking connects and use 100% blocking I/O,
		1946	defeating the purpose of an event-based solution. All of the newly
		1947	written AnyEvent benchmarks use 100% non-blocking connects (using
		1948	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1949	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		1950	generally require a lot more bookkeeping and event handling than blocking
		1951	connects (which involve a single syscall only).
		1952
		1953	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		1954	offers similar expressive power as POE and IO::Lambda, using conventional
		1955	Perl syntax. This means that both the echo server and the client are 100%
		1956	non-blocking, further placing it at a disadvantage.
		1957
		1958	As you can see, the AnyEvent + EV combination even beats the
		1959	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		1960	backend easily beats IO::Lambda and POE.
		1961
		1962	And even the 100% non-blocking version written using the high-level (and
		1963	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		1964	large margin, even though it does all of DNS, tcp-connect and socket I/O
		1965	in a non-blocking way.
		1966
		1967	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		1968	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		1969	part of the IO::lambda distribution and were used without any changes.
		1970
		1971
		1972	=head1 SIGNALS
		1973
		1974	AnyEvent currently installs handlers for these signals:
		1975
		1976	=over 4
		1977
		1978	=item SIGCHLD
		1979
		1980	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1981	emulation for event loops that do not support them natively. Also, some
		1982	event loops install a similar handler.
		1983
		1984	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		1985	reset it to default, to avoid losing child exit statuses.
		1986
		1987	=item SIGPIPE
		1988
		1989	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1990	when AnyEvent gets loaded.
		1991
		1992	The rationale for this is that AnyEvent users usually do not really depend
		1993	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1994	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1995	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1996	some random socket.
		1997
		1998	The rationale for installing a no-op handler as opposed to ignoring it is
		1999	that this way, the handler will be restored to defaults on exec.
		2000
		2001	Feel free to install your own handler, or reset it to defaults.
		2002
		2003	=back
		2004
		2005	=cut
		2006
		2007	undef $SIG{CHLD}
		2008	if $SIG{CHLD} eq 'IGNORE';
		2009
		2010	$SIG{PIPE} = sub { }
		2011	unless defined $SIG{PIPE};
1692		2012
1693	=head1 FORK	2013	=head1 FORK
1694		2014
1695	Most event libraries are not fork-safe. The ones who are usually are	2015	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>	2016	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1717	use AnyEvent;	2037	use AnyEvent;
1718		2038
1719	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2039	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1720	be used to probe what backend is used and gain other information (which is	2040	be used to probe what backend is used and gain other information (which is
1721	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2041	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1722	$ENV{PERL_ANYEGENT_STRICT}.	2042	$ENV{PERL_ANYEVENT_STRICT}.
		2043
		2044	Note that AnyEvent will remove I<all> environment variables starting with
		2045	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2046	enabled.
1723		2047
1724		2048
1725	=head1 BUGS	2049	=head1 BUGS
1726		2050
1727	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2051	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	2052	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	2053	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	2054	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1731	pronounced).	2055	pronounced).
1732		2056
1733		2057
1734	=head1 SEE ALSO	2058	=head1 SEE ALSO
1735		2059

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC vs. Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC vs.
Revision 1.219 by root, Thu Jun 25 11:16:08 2009 UTC