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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.176 by root, Wed Aug 20 12:37:21 2008 UTC vs.
Revision 1.221 by root, Fri Jun 26 06:33:17 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 { ... });
12		14
		15	# one-shot or repeating timers
13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
15		18
16	print AnyEvent->now; # prints current event loop time	19	print AnyEvent->now; # prints current event loop time
17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
18		21
		22	# POSIX signal
19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });	23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
20		24
		25	# child process exit
21	my $w = AnyEvent->child (pid => $pid, cb => sub {	26	my $w = AnyEvent->child (pid => $pid, cb => sub {
22	my ($pid, $status) = @_;	27	my ($pid, $status) = @_;
23	...	28	...
24	});	29	});
		30
		31	# called when event loop idle (if applicable)
		32	my $w = AnyEvent->idle (cb => sub { ... });
25		33
26	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
27	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
28	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
29	# use a condvar in callback mode:	37	# use a condvar in callback mode:
137	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
138	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
139	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
140	is in control).	148	is in control).
141		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> 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
142	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
143	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
144	to it).	158	to it).
145		159
146	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.
…		…
162	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
163		177
164	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
165	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
166		180
167	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
168	(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
169	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
170	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
171	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.
172		192
173	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
174	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
175	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
176		196
…		…
308	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
309	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
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	331	account.
312		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
313	=back	348	=back
314		349
315	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
316		351
317	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
…		…
340	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
341		376
342	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.
343		378
344	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
345	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
346	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
347	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
348	and exit status (as returned by waitpid), so unlike other watcher types,	383
349	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).
350		392
351	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
352	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
353	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
354		396
355	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
356	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
357	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.
358		403
359	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
360	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
361	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>).
362		408
363	Example: fork a process and wait for it	409	Example: fork a process and wait for it
364		410
365	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
366		412
…		…
376	);	422	);
377		423
378	# do something else, then wait for process exit	424	# do something else, then wait for process exit
379	$done->recv;	425	$done->recv;
380		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
381	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
382		463
383	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
384	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
385	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
…		…
653	AnyEvent::Impl::Tk based on Tk, very bad choice.	734	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	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).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	736	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	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.
657		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
658	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
659	watching file handles. However, you can use WxWidgets through the	744	watching file handles. However, you can use WxWidgets through the
660	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
661	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
662	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
…		…
818	=item L<AnyEvent::IGS>	903	=item L<AnyEvent::IGS>
819		904
820	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
821	L<App::IGS>).	906	L<App::IGS>).
822		907
823	=item L<Net::IRC3>	908	=item L<AnyEvent::IRC>
824		909
825	AnyEvent based IRC client module family.	910	AnyEvent based IRC client module family (replacing the older Net::IRC3).
826		911
827	=item L<Net::XMPP2>	912	=item L<Net::XMPP2>
828		913
829	AnyEvent based XMPP (Jabber protocol) module family.	914	AnyEvent based XMPP (Jabber protocol) module family.
830		915
…		…
850	=cut	935	=cut
851		936
852	package AnyEvent;	937	package AnyEvent;
853		938
854	no warnings;	939	no warnings;
855	use strict;	940	use strict qw(vars subs);
856		941
857	use Carp;	942	use Carp;
858		943
859	our $VERSION = 4.231;	944	our $VERSION = 4.42;
860	our $MODEL;	945	our $MODEL;
861		946
862	our $AUTOLOAD;	947	our $AUTOLOAD;
863	our @ISA;	948	our @ISA;
864		949
865	our @REGISTRY;	950	our @REGISTRY;
866		951
867	our $WIN32;	952	our $WIN32;
868		953
869	BEGIN {	954	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	955	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	956	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		957
		958	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		959	if ${^TAINT};
872	}	960	}
873		961
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	962	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
875		963
876	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	964	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	982	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	983	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	984	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	985	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	986	[Prima:: => AnyEvent::Impl::POE::],
		987	# IO::Async is just too broken - we would need workaorunds for its
		988	# byzantine signal and broken child handling, among others.
		989	# IO::Async is rather hard to detect, as it doesn't have any
		990	# obvious default class.
		991	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		992	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		993	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	994	);
900		995
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	996	our %method = map +($_ => 1),
		997	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		998
903	our @post_detect;	999	our @post_detect;
904		1000
905	sub post_detect(&) {	1001	sub post_detect(&) {
906	my ($cb) = @_;	1002	my ($cb) = @_;
…		…
911	1	1007	1
912	} else {	1008	} else {
913	push @post_detect, $cb;	1009	push @post_detect, $cb;
914		1010
915	defined wantarray	1011	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1012	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1013	: ()
918	}	1014	}
919	}	1015	}
920		1016
921	sub AnyEvent::Util::PostDetect::DESTROY {	1017	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1018	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1019	}
924		1020
925	sub detect() {	1021	sub detect() {
926	unless ($MODEL) {	1022	unless ($MODEL) {
…		…
963	last;	1059	last;
964	}	1060	}
965	}	1061	}
966		1062
967	$MODEL	1063	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1064	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1065	}
970	}	1066	}
971		1067
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1068	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1069
…		…
994	}	1090	}
995		1091
996	# 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
997	# to support binding more than one watcher per filehandle (they usually	1093	# to support binding more than one watcher per filehandle (they usually
998	# 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).
999	sub _dupfh($$$$) {	1095	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1096	my ($poll, $fh, $r, $w) = @_;
1001
1002	require Fcntl;
1003		1097
1004	# cygwin requires the fh mode to be matching, unix doesn't	1098	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1099	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006	: $poll eq "w" ? ($w, ">")	1100	: $poll eq "w" ? ($w, ">")
1007	: 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'";
1008		1102
1009	open my $fh2, "$mode&" . fileno $fh	1103	open my $fh2, "$mode&" . fileno $fh
1010	or die "cannot dup() filehandle: $!";	1104	or die "cannot dup() filehandle: $!,";
1011		1105
1012	# 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
1013		1107
1014	($fh2, $rw)	1108	($fh2, $rw)
1015	}	1109	}
1016		1110
1017	package AnyEvent::Base;	1111	package AnyEvent::Base;
1018		1112
1019	# default implementation for now and time	1113	# default implementations for many methods
1020		1114
1021	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	}
1022		1123
1023	sub time { Time::HiRes::time }	1124	sub time { _time }
1024	sub now { Time::HiRes::time }	1125	sub now { _time }
		1126	sub now_update { }
1025		1127
1026	# default implementation for ->condvar	1128	# default implementation for ->condvar
1027		1129
1028	sub condvar {	1130	sub condvar {
1029	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1131	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1030	}	1132	}
1031		1133
1032	# default implementation for ->signal	1134	# default implementation for ->signal
1033		1135
1034	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	}
1035		1148
1036	sub signal {	1149	sub signal {
1037	my (undef, %arg) = @_;	1150	my (undef, %arg) = @_;
1038		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
1039	my $signal = uc $arg{signal}	1177	my $signal = uc $arg{signal}
1040	or Carp::croak "required option 'signal' is missing";	1178	or Carp::croak "required option 'signal' is missing";
1041		1179
1042	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1180	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1043	$SIG{$signal} \|\|= sub {	1181	$SIG{$signal} \|\|= sub {
1044	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1182	local $!;
		1183	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1184	undef $SIG_EV{$signal};
1045	};	1185	};
1046		1186
1047	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1187	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1048	}	1188	}
1049		1189
1050	sub AnyEvent::Base::Signal::DESTROY {	1190	sub AnyEvent::Base::signal::DESTROY {
1051	my ($signal, $cb) = @{$_[0]};	1191	my ($signal, $cb) = @{$_[0]};
1052		1192
1053	delete $SIG_CB{$signal}{$cb};	1193	delete $SIG_CB{$signal}{$cb};
1054		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.
1055	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1198	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1056	}	1199	}
1057		1200
1058	# default implementation for ->child	1201	# default implementation for ->child
1059		1202
1060	our %PID_CB;	1203	our %PID_CB;
1061	our $CHLD_W;	1204	our $CHLD_W;
1062	our $CHLD_DELAY_W;	1205	our $CHLD_DELAY_W;
1063	our $PID_IDLE;
1064	our $WNOHANG;	1206	our $WNOHANG;
1065		1207
1066	sub _child_wait {	1208	sub _sigchld {
1067	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1209	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1068	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1210	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1069	(values %{ $PID_CB{0} \|\| {} });	1211	(values %{ $PID_CB{0} \|\| {} });
1070	}	1212	}
1071
1072	undef $PID_IDLE;
1073	}
1074
1075	sub _sigchld {
1076	# make sure we deliver these changes "synchronous" with the event loop.
1077	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1078	undef $CHLD_DELAY_W;
1079	&_child_wait;
1080	});
1081	}	1213	}
1082		1214
1083	sub child {	1215	sub child {
1084	my (undef, %arg) = @_;	1216	my (undef, %arg) = @_;
1085		1217
1086	defined (my $pid = $arg{pid} + 0)	1218	defined (my $pid = $arg{pid} + 0)
1087	or Carp::croak "required option 'pid' is missing";	1219	or Carp::croak "required option 'pid' is missing";
1088		1220
1089	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1221	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1090		1222
1091	unless ($WNOHANG) {
1092	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1223	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1093	}
1094		1224
1095	unless ($CHLD_W) {	1225	unless ($CHLD_W) {
1096	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1226	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1097	# 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
1098	&_sigchld;	1228	&_sigchld;
1099	}	1229	}
1100		1230
1101	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1231	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1102	}	1232	}
1103		1233
1104	sub AnyEvent::Base::Child::DESTROY {	1234	sub AnyEvent::Base::child::DESTROY {
1105	my ($pid, $cb) = @{$_[0]};	1235	my ($pid, $cb) = @{$_[0]};
1106		1236
1107	delete $PID_CB{$pid}{$cb};	1237	delete $PID_CB{$pid}{$cb};
1108	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1238	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1109		1239
1110	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]};
1111	}	1277	}
1112		1278
1113	package AnyEvent::CondVar;	1279	package AnyEvent::CondVar;
1114		1280
1115	our @ISA = AnyEvent::CondVar::Base::;	1281	our @ISA = AnyEvent::CondVar::Base::;
…		…
1167	}	1333	}
1168		1334
1169	# undocumented/compatibility with pre-3.4	1335	# undocumented/compatibility with pre-3.4
1170	*broadcast = \&send;	1336	*broadcast = \&send;
1171	*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
1172		1448
1173	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1449	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1174		1450
1175	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
1176	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
…		…
1210		1486
1211	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
1212	condition variables: code blocking while waiting for a condition will	1488	condition variables: code blocking while waiting for a condition will
1213	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
1214	not be done in an interactive application, so it makes sense.	1490	not be done in an interactive application, so it makes sense.
1215
1216	=head1 ENVIRONMENT VARIABLES
1217
1218	The following environment variables are used by this module:
1219
1220	=over 4
1221
1222	=item C<PERL_ANYEVENT_VERBOSE>
1223
1224	By default, AnyEvent will be completely silent except in fatal
1225	conditions. You can set this environment variable to make AnyEvent more
1226	talkative.
1227
1228	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1229	conditions, such as not being able to load the event model specified by
1230	C<PERL_ANYEVENT_MODEL>.
1231
1232	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1233	model it chooses.
1234
1235	=item C<PERL_ANYEVENT_STRICT>
1236
1237	AnyEvent does not do much argument checking by default, as thorough
1238	argument checking is very costly. Setting this variable to a true value
1239	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1240	check the arguments passed to most method calls. If it finds any problems
1241	it will croak.
1242
1243	In other words, enables "strict" mode.
1244
1245	Unlike C<use strict> it is definitely recommended ot keep it off in
1246	production.
1247
1248	=item C<PERL_ANYEVENT_MODEL>
1249
1250	This can be used to specify the event model to be used by AnyEvent, before
1251	auto detection and -probing kicks in. It must be a string consisting
1252	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1253	and the resulting module name is loaded and if the load was successful,
1254	used as event model. If it fails to load AnyEvent will proceed with
1255	auto detection and -probing.
1256
1257	This functionality might change in future versions.
1258
1259	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1260	could start your program like this:
1261
1262	PERL_ANYEVENT_MODEL=Perl perl ...
1263
1264	=item C<PERL_ANYEVENT_PROTOCOLS>
1265
1266	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1267	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1268	of auto probing).
1269
1270	Must be set to a comma-separated list of protocols or address families,
1271	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1272	used, and preference will be given to protocols mentioned earlier in the
1273	list.
1274
1275	This variable can effectively be used for denial-of-service attacks
1276	against local programs (e.g. when setuid), although the impact is likely
1277	small, as the program has to handle connection errors already-
1278
1279	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1280	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1281	- only support IPv4, never try to resolve or contact IPv6
1282	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1283	IPv6, but prefer IPv6 over IPv4.
1284
1285	=item C<PERL_ANYEVENT_EDNS0>
1286
1287	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1288	for DNS. This extension is generally useful to reduce DNS traffic, but
1289	some (broken) firewalls drop such DNS packets, which is why it is off by
1290	default.
1291
1292	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1293	EDNS0 in its DNS requests.
1294
1295	=item C<PERL_ANYEVENT_MAX_FORKS>
1296
1297	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1298	will create in parallel.
1299
1300	=back
1301		1491
1302	=head1 EXAMPLE PROGRAM	1492	=head1 EXAMPLE PROGRAM
1303		1493
1304	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
1305	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
…		…
1499	watcher.	1689	watcher.
1500		1690
1501	=head3 Results	1691	=head3 Results
1502		1692
1503	name watchers bytes create invoke destroy comment	1693	name watchers bytes create invoke destroy comment
1504	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
1505	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
1506	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
1507	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
1508	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
1509	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
		1700	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1701	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1510	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1702	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1511	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1703	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1512	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1704	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1513	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1705	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1514		1706
1515	=head3 Discussion	1707	=head3 Discussion
1516		1708
1517	The benchmark does I<not> measure scalability of the event loop very	1709	The benchmark does I<not> measure scalability of the event loop very
1518	well. For example, a select-based event loop (such as the pure perl one)	1710	well. For example, a select-based event loop (such as the pure perl one)
…		…
1543	performance becomes really bad with lots of file descriptors (and few of	1735	performance becomes really bad with lots of file descriptors (and few of
1544	them active), of course, but this was not subject of this benchmark.	1736	them active), of course, but this was not subject of this benchmark.
1545		1737
1546	The C<Event> module has a relatively high setup and callback invocation	1738	The C<Event> module has a relatively high setup and callback invocation
1547	cost, but overall scores in on the third place.	1739	cost, but overall scores in on the third place.
		1740
		1741	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1742	when using its pure perl backend.
1548		1743
1549	C<Glib>'s memory usage is quite a bit higher, but it features a	1744	C<Glib>'s memory usage is quite a bit higher, but it features a
1550	faster callback invocation and overall ends up in the same class as	1745	faster callback invocation and overall ends up in the same class as
1551	C<Event>. However, Glib scales extremely badly, doubling the number of	1746	C<Event>. However, Glib scales extremely badly, doubling the number of
1552	watchers increases the processing time by more than a factor of four,	1747	watchers increases the processing time by more than a factor of four,
…		…
1630	it to another server. This includes deleting the old timeout and creating	1825	it to another server. This includes deleting the old timeout and creating
1631	a new one that moves the timeout into the future.	1826	a new one that moves the timeout into the future.
1632		1827
1633	=head3 Results	1828	=head3 Results
1634		1829
1635	name sockets create request	1830	name sockets create request
1636	EV 20000 69.01 11.16	1831	EV 20000 69.01 11.16
1637	Perl 20000 73.32 35.87	1832	Perl 20000 73.32 35.87
		1833	IOAsync 20000 157.00 98.14 epoll
		1834	IOAsync 20000 159.31 616.06 poll
1638	Event 20000 212.62 257.32	1835	Event 20000 212.62 257.32
1639	Glib 20000 651.16 1896.30	1836	Glib 20000 651.16 1896.30
1640	POE 20000 349.67 12317.24 uses POE::Loop::Event	1837	POE 20000 349.67 12317.24 uses POE::Loop::Event
1641		1838
1642	=head3 Discussion	1839	=head3 Discussion
1643		1840
1644	This benchmark I<does> measure scalability and overall performance of the	1841	This benchmark I<does> measure scalability and overall performance of the
1645	particular event loop.	1842	particular event loop.
…		…
1647	EV is again fastest. Since it is using epoll on my system, the setup time	1844	EV is again fastest. Since it is using epoll on my system, the setup time
1648	is relatively high, though.	1845	is relatively high, though.
1649		1846
1650	Perl surprisingly comes second. It is much faster than the C-based event	1847	Perl surprisingly comes second. It is much faster than the C-based event
1651	loops Event and Glib.	1848	loops Event and Glib.
		1849
		1850	IO::Async performs very well when using its epoll backend, and still quite
		1851	good compared to Glib when using its pure perl backend.
1652		1852
1653	Event suffers from high setup time as well (look at its code and you will	1853	Event suffers from high setup time as well (look at its code and you will
1654	understand why). Callback invocation also has a high overhead compared to	1854	understand why). Callback invocation also has a high overhead compared to
1655	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1855	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1656	uses select or poll in basically all documented configurations.	1856	uses select or poll in basically all documented configurations.
…		…
1719	=item * C-based event loops perform very well with small number of	1919	=item * C-based event loops perform very well with small number of
1720	watchers, as the management overhead dominates.	1920	watchers, as the management overhead dominates.
1721		1921
1722	=back	1922	=back
1723		1923
		1924	=head2 THE IO::Lambda BENCHMARK
		1925
		1926	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1927	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1928	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1929	shouldn't come as a surprise to anybody). As such, the benchmark is
		1930	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1931	very optimal. But how would AnyEvent compare when used without the extra
		1932	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1933
		1934	The benchmark itself creates an echo-server, and then, for 500 times,
		1935	connects to the echo server, sends a line, waits for the reply, and then
		1936	creates the next connection. This is a rather bad benchmark, as it doesn't
		1937	test the efficiency of the framework or much non-blocking I/O, but it is a
		1938	benchmark nevertheless.
		1939
		1940	name runtime
		1941	Lambda/select 0.330 sec
		1942	+ optimized 0.122 sec
		1943	Lambda/AnyEvent 0.327 sec
		1944	+ optimized 0.138 sec
		1945	Raw sockets/select 0.077 sec
		1946	POE/select, components 0.662 sec
		1947	POE/select, raw sockets 0.226 sec
		1948	POE/select, optimized 0.404 sec
		1949
		1950	AnyEvent/select/nb 0.085 sec
		1951	AnyEvent/EV/nb 0.068 sec
		1952	+state machine 0.134 sec
		1953
		1954	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1955	benchmarks actually make blocking connects and use 100% blocking I/O,
		1956	defeating the purpose of an event-based solution. All of the newly
		1957	written AnyEvent benchmarks use 100% non-blocking connects (using
		1958	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1959	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		1960	generally require a lot more bookkeeping and event handling than blocking
		1961	connects (which involve a single syscall only).
		1962
		1963	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		1964	offers similar expressive power as POE and IO::Lambda, using conventional
		1965	Perl syntax. This means that both the echo server and the client are 100%
		1966	non-blocking, further placing it at a disadvantage.
		1967
		1968	As you can see, the AnyEvent + EV combination even beats the
		1969	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		1970	backend easily beats IO::Lambda and POE.
		1971
		1972	And even the 100% non-blocking version written using the high-level (and
		1973	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		1974	large margin, even though it does all of DNS, tcp-connect and socket I/O
		1975	in a non-blocking way.
		1976
		1977	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		1978	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		1979	part of the IO::lambda distribution and were used without any changes.
		1980
		1981
		1982	=head1 SIGNALS
		1983
		1984	AnyEvent currently installs handlers for these signals:
		1985
		1986	=over 4
		1987
		1988	=item SIGCHLD
		1989
		1990	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1991	emulation for event loops that do not support them natively. Also, some
		1992	event loops install a similar handler.
		1993
		1994	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		1995	reset it to default, to avoid losing child exit statuses.
		1996
		1997	=item SIGPIPE
		1998
		1999	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2000	when AnyEvent gets loaded.
		2001
		2002	The rationale for this is that AnyEvent users usually do not really depend
		2003	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2004	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2005	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2006	some random socket.
		2007
		2008	The rationale for installing a no-op handler as opposed to ignoring it is
		2009	that this way, the handler will be restored to defaults on exec.
		2010
		2011	Feel free to install your own handler, or reset it to defaults.
		2012
		2013	=back
		2014
		2015	=cut
		2016
		2017	undef $SIG{CHLD}
		2018	if $SIG{CHLD} eq 'IGNORE';
		2019
		2020	$SIG{PIPE} = sub { }
		2021	unless defined $SIG{PIPE};
1724		2022
1725	=head1 FORK	2023	=head1 FORK
1726		2024
1727	Most event libraries are not fork-safe. The ones who are usually are	2025	Most event libraries are not fork-safe. The ones who are usually are
1728	because they rely on inefficient but fork-safe C<select> or C<poll>	2026	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1749	use AnyEvent;	2047	use AnyEvent;
1750		2048
1751	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2049	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1752	be used to probe what backend is used and gain other information (which is	2050	be used to probe what backend is used and gain other information (which is
1753	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2051	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1754	$ENV{PERL_ANYEGENT_STRICT}.	2052	$ENV{PERL_ANYEVENT_STRICT}.
		2053
		2054	Note that AnyEvent will remove I<all> environment variables starting with
		2055	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2056	enabled.
1755		2057
1756		2058
1757	=head1 BUGS	2059	=head1 BUGS
1758		2060
1759	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2061	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1760	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2062	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1761	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2063	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1762	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2064	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1763	pronounced).	2065	pronounced).
1764		2066
1765		2067
1766	=head1 SEE ALSO	2068	=head1 SEE ALSO
1767		2069

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.176 by root, Wed Aug 20 12:37:21 2008 UTC vs. Revision 1.221 by root, Fri Jun 26 06:33:17 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.176 by root, Wed Aug 20 12:37:21 2008 UTC vs.
Revision 1.221 by root, Fri Jun 26 06:33:17 2009 UTC