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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC vs.
Revision 1.224 by root, Fri Jul 3 21:44:14 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.
…		…
518		599
519	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
520		601
521	=item $cv->end	602	=item $cv->end
522		603
523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
524
525	These two methods can be used to combine many transactions/events into	604	These two methods can be used to combine many transactions/events into
526	one. For example, a function that pings many hosts in parallel might want	605	one. For example, a function that pings many hosts in parallel might want
527	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
528		607
529	Every call to C<< ->begin >> will increment a counter, and every call to	608	Every call to C<< ->begin >> will increment a counter, and every call to
530	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
531	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
532	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
533	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
534		613
535	Let's clarify this with the ping example:	614	You can think of C<< $cv->send >> giving you an OR condition (one call
		615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
536		645
537	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
538		647
539	my %result;	648	my %result;
540	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
560	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
561	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
562	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
563	doesn't execute once).	672	doesn't execute once).
564		673
565	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
566	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
567	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
568	C<begin> and for each subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
569		679
570	=back	680	=back
571		681
572	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
573		683
…		…
653	AnyEvent::Impl::Tk based on Tk, very bad choice.	763	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	AnyEvent::Impl::POE based on POE, not generic enough for full support.	766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
657		767
		768	# warning, support for IO::Async is only partial, as it is too broken
		769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		771
658	There is no support for WxWidgets, as WxWidgets has no support for	772	There is no support for WxWidgets, as WxWidgets has no support for
659	watching file handles. However, you can use WxWidgets through the	773	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	774	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	775	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	776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
818	=item L<AnyEvent::IGS>	932	=item L<AnyEvent::IGS>
819		933
820	A non-blocking interface to the Internet Go Server protocol (used by	934	A non-blocking interface to the Internet Go Server protocol (used by
821	L<App::IGS>).	935	L<App::IGS>).
822		936
823	=item L<Net::IRC3>	937	=item L<AnyEvent::IRC>
824		938
825	AnyEvent based IRC client module family.	939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
826		940
827	=item L<Net::XMPP2>	941	=item L<Net::XMPP2>
828		942
829	AnyEvent based XMPP (Jabber protocol) module family.	943	AnyEvent based XMPP (Jabber protocol) module family.
830		944
…		…
850	=cut	964	=cut
851		965
852	package AnyEvent;	966	package AnyEvent;
853		967
854	no warnings;	968	no warnings;
855	use strict;	969	use strict qw(vars subs);
856		970
857	use Carp;	971	use Carp;
858		972
859	our $VERSION = 4.233;	973	our $VERSION = 4.452;
860	our $MODEL;	974	our $MODEL;
861		975
862	our $AUTOLOAD;	976	our $AUTOLOAD;
863	our @ISA;	977	our @ISA;
864		978
865	our @REGISTRY;	979	our @REGISTRY;
866		980
867	our $WIN32;	981	our $WIN32;
868		982
869	BEGIN {	983	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		986
		987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		988	if ${^TAINT};
872	}	989	}
873		990
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
875		992
876	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	993	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	1014	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	1015	[Prima:: => AnyEvent::Impl::POE::],
		1016	# IO::Async is just too broken - we would need workaorunds for its
		1017	# byzantine signal and broken child handling, among others.
		1018	# IO::Async is rather hard to detect, as it doesn't have any
		1019	# obvious default class.
		1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	1023	);
900		1024
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1025	our %method = map +($_ => 1),
		1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		1027
903	our @post_detect;	1028	our @post_detect;
904		1029
905	sub post_detect(&) {	1030	sub post_detect(&) {
906	my ($cb) = @_;	1031	my ($cb) = @_;
…		…
911	1	1036	1
912	} else {	1037	} else {
913	push @post_detect, $cb;	1038	push @post_detect, $cb;
914		1039
915	defined wantarray	1040	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1041	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1042	: ()
918	}	1043	}
919	}	1044	}
920		1045
921	sub AnyEvent::Util::PostDetect::DESTROY {	1046	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1048	}
924		1049
925	sub detect() {	1050	sub detect() {
926	unless ($MODEL) {	1051	unless ($MODEL) {
…		…
963	last;	1088	last;
964	}	1089	}
965	}	1090	}
966		1091
967	$MODEL	1092	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1094	}
970	}	1095	}
971		1096
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1098
…		…
994	}	1119	}
995		1120
996	# utility function to dup a filehandle. this is used by many backends	1121	# utility function to dup a filehandle. this is used by many backends
997	# to support binding more than one watcher per filehandle (they usually	1122	# 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).	1123	# allow only one watcher per fd, so we dup it to get a different one).
999	sub _dupfh($$$$) {	1124	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1125	my ($poll, $fh, $r, $w) = @_;
1001
1002	require Fcntl;
1003		1126
1004	# cygwin requires the fh mode to be matching, unix doesn't	1127	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006	: $poll eq "w" ? ($w, ">")	1129	: $poll eq "w" ? ($w, ">")
1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";	1130	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008		1131
1009	open my $fh2, "$mode&" . fileno $fh	1132	open my $fh2, "$mode&" . fileno $fh
1010	or die "cannot dup() filehandle: $!";	1133	or die "cannot dup() filehandle: $!,";
1011		1134
1012	# we assume CLOEXEC is already set by perl in all important cases	1135	# we assume CLOEXEC is already set by perl in all important cases
1013		1136
1014	($fh2, $rw)	1137	($fh2, $rw)
1015	}	1138	}
1016		1139
1017	package AnyEvent::Base;	1140	package AnyEvent::Base;
1018		1141
1019	# default implementation for now and time	1142	# default implementations for many methods
1020		1143
1021	BEGIN {	1144	BEGIN {
1022	if (eval "use Time::HiRes (); time (); 1") {	1145	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1023	*_time = \&Time::HiRes::time;	1146	*_time = \&Time::HiRes::time;
1024	# if (eval "use POSIX (); (POSIX::times())...	1147	# if (eval "use POSIX (); (POSIX::times())...
1025	} else {	1148	} else {
1026	*_time = \&CORE::time; # epic fail	1149	*_time = sub { time }; # epic fail
1027	}	1150	}
1028	}	1151	}
1029		1152
1030	sub time { _time }	1153	sub time { _time }
1031	sub now { _time }	1154	sub now { _time }
		1155	sub now_update { }
1032		1156
1033	# default implementation for ->condvar	1157	# default implementation for ->condvar
1034		1158
1035	sub condvar {	1159	sub condvar {
1036	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1160	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1037	}	1161	}
1038		1162
1039	# default implementation for ->signal	1163	# default implementation for ->signal
1040		1164
1041	our %SIG_CB;	1165	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1166
		1167	sub _signal_exec {
		1168	sysread $SIGPIPE_R, my $dummy, 4;
		1169
		1170	while (%SIG_EV) {
		1171	for (keys %SIG_EV) {
		1172	delete $SIG_EV{$_};
		1173	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1174	}
		1175	}
		1176	}
1042		1177
1043	sub signal {	1178	sub signal {
1044	my (undef, %arg) = @_;	1179	my (undef, %arg) = @_;
1045		1180
		1181	unless ($SIGPIPE_R) {
		1182	require Fcntl;
		1183
		1184	if (AnyEvent::WIN32) {
		1185	require AnyEvent::Util;
		1186
		1187	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1188	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1189	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1190	} else {
		1191	pipe $SIGPIPE_R, $SIGPIPE_W;
		1192	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1193	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1194
		1195	# not strictly required, as $^F is normally 2, but let's make sure...
		1196	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1197	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1198	}
		1199
		1200	$SIGPIPE_R
		1201	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1202
		1203	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1204	}
		1205
1046	my $signal = uc $arg{signal}	1206	my $signal = uc $arg{signal}
1047	or Carp::croak "required option 'signal' is missing";	1207	or Carp::croak "required option 'signal' is missing";
1048		1208
1049	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1209	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1050	$SIG{$signal} \|\|= sub {	1210	$SIG{$signal} \|\|= sub {
1051	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1211	local $!;
		1212	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1213	undef $SIG_EV{$signal};
1052	};	1214	};
1053		1215
1054	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1216	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1055	}	1217	}
1056		1218
1057	sub AnyEvent::Base::Signal::DESTROY {	1219	sub AnyEvent::Base::signal::DESTROY {
1058	my ($signal, $cb) = @{$_[0]};	1220	my ($signal, $cb) = @{$_[0]};
1059		1221
1060	delete $SIG_CB{$signal}{$cb};	1222	delete $SIG_CB{$signal}{$cb};
1061		1223
		1224	# delete doesn't work with older perls - they then
		1225	# print weird messages, or just unconditionally exit
		1226	# instead of getting the default action.
1062	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1227	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1063	}	1228	}
1064		1229
1065	# default implementation for ->child	1230	# default implementation for ->child
1066		1231
1067	our %PID_CB;	1232	our %PID_CB;
1068	our $CHLD_W;	1233	our $CHLD_W;
1069	our $CHLD_DELAY_W;	1234	our $CHLD_DELAY_W;
1070	our $PID_IDLE;
1071	our $WNOHANG;	1235	our $WNOHANG;
1072		1236
1073	sub _child_wait {	1237	sub _sigchld {
1074	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1238	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1075	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1239	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1076	(values %{ $PID_CB{0} \|\| {} });	1240	(values %{ $PID_CB{0} \|\| {} });
1077	}	1241	}
1078
1079	undef $PID_IDLE;
1080	}
1081
1082	sub _sigchld {
1083	# make sure we deliver these changes "synchronous" with the event loop.
1084	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
1085	undef $CHLD_DELAY_W;
1086	&_child_wait;
1087	});
1088	}	1242	}
1089		1243
1090	sub child {	1244	sub child {
1091	my (undef, %arg) = @_;	1245	my (undef, %arg) = @_;
1092		1246
1093	defined (my $pid = $arg{pid} + 0)	1247	defined (my $pid = $arg{pid} + 0)
1094	or Carp::croak "required option 'pid' is missing";	1248	or Carp::croak "required option 'pid' is missing";
1095		1249
1096	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1250	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1097		1251
1098	unless ($WNOHANG) {
1099	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1252	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1100	}
1101		1253
1102	unless ($CHLD_W) {	1254	unless ($CHLD_W) {
1103	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1255	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1104	# child could be a zombie already, so make at least one round	1256	# child could be a zombie already, so make at least one round
1105	&_sigchld;	1257	&_sigchld;
1106	}	1258	}
1107		1259
1108	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1260	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1109	}	1261	}
1110		1262
1111	sub AnyEvent::Base::Child::DESTROY {	1263	sub AnyEvent::Base::child::DESTROY {
1112	my ($pid, $cb) = @{$_[0]};	1264	my ($pid, $cb) = @{$_[0]};
1113		1265
1114	delete $PID_CB{$pid}{$cb};	1266	delete $PID_CB{$pid}{$cb};
1115	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1267	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1116		1268
1117	undef $CHLD_W unless keys %PID_CB;	1269	undef $CHLD_W unless keys %PID_CB;
		1270	}
		1271
		1272	# idle emulation is done by simply using a timer, regardless
		1273	# of whether the process is idle or not, and not letting
		1274	# the callback use more than 50% of the time.
		1275	sub idle {
		1276	my (undef, %arg) = @_;
		1277
		1278	my ($cb, $w, $rcb) = $arg{cb};
		1279
		1280	$rcb = sub {
		1281	if ($cb) {
		1282	$w = _time;
		1283	&$cb;
		1284	$w = _time - $w;
		1285
		1286	# never use more then 50% of the time for the idle watcher,
		1287	# within some limits
		1288	$w = 0.0001 if $w < 0.0001;
		1289	$w = 5 if $w > 5;
		1290
		1291	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1292	} else {
		1293	# clean up...
		1294	undef $w;
		1295	undef $rcb;
		1296	}
		1297	};
		1298
		1299	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1300
		1301	bless \\$cb, "AnyEvent::Base::idle"
		1302	}
		1303
		1304	sub AnyEvent::Base::idle::DESTROY {
		1305	undef $${$_[0]};
1118	}	1306	}
1119		1307
1120	package AnyEvent::CondVar;	1308	package AnyEvent::CondVar;
1121		1309
1122	our @ISA = AnyEvent::CondVar::Base::;	1310	our @ISA = AnyEvent::CondVar::Base::;
…		…
1174	}	1362	}
1175		1363
1176	# undocumented/compatibility with pre-3.4	1364	# undocumented/compatibility with pre-3.4
1177	*broadcast = \&send;	1365	*broadcast = \&send;
1178	*wait = \&_wait;	1366	*wait = \&_wait;
		1367
		1368	=head1 ERROR AND EXCEPTION HANDLING
		1369
		1370	In general, AnyEvent does not do any error handling - it relies on the
		1371	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1372	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1373	checking of all AnyEvent methods, however, which is highly useful during
		1374	development.
		1375
		1376	As for exception handling (i.e. runtime errors and exceptions thrown while
		1377	executing a callback), this is not only highly event-loop specific, but
		1378	also not in any way wrapped by this module, as this is the job of the main
		1379	program.
		1380
		1381	The pure perl event loop simply re-throws the exception (usually
		1382	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1383	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1384	so on.
		1385
		1386	=head1 ENVIRONMENT VARIABLES
		1387
		1388	The following environment variables are used by this module or its
		1389	submodules.
		1390
		1391	Note that AnyEvent will remove I<all> environment variables starting with
		1392	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1393	enabled.
		1394
		1395	=over 4
		1396
		1397	=item C<PERL_ANYEVENT_VERBOSE>
		1398
		1399	By default, AnyEvent will be completely silent except in fatal
		1400	conditions. You can set this environment variable to make AnyEvent more
		1401	talkative.
		1402
		1403	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1404	conditions, such as not being able to load the event model specified by
		1405	C<PERL_ANYEVENT_MODEL>.
		1406
		1407	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1408	model it chooses.
		1409
		1410	=item C<PERL_ANYEVENT_STRICT>
		1411
		1412	AnyEvent does not do much argument checking by default, as thorough
		1413	argument checking is very costly. Setting this variable to a true value
		1414	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1415	check the arguments passed to most method calls. If it finds any problems,
		1416	it will croak.
		1417
		1418	In other words, enables "strict" mode.
		1419
		1420	Unlike C<use strict>, it is definitely recommended to keep it off in
		1421	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1422	developing programs can be very useful, however.
		1423
		1424	=item C<PERL_ANYEVENT_MODEL>
		1425
		1426	This can be used to specify the event model to be used by AnyEvent, before
		1427	auto detection and -probing kicks in. It must be a string consisting
		1428	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1429	and the resulting module name is loaded and if the load was successful,
		1430	used as event model. If it fails to load AnyEvent will proceed with
		1431	auto detection and -probing.
		1432
		1433	This functionality might change in future versions.
		1434
		1435	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1436	could start your program like this:
		1437
		1438	PERL_ANYEVENT_MODEL=Perl perl ...
		1439
		1440	=item C<PERL_ANYEVENT_PROTOCOLS>
		1441
		1442	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1443	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1444	of auto probing).
		1445
		1446	Must be set to a comma-separated list of protocols or address families,
		1447	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1448	used, and preference will be given to protocols mentioned earlier in the
		1449	list.
		1450
		1451	This variable can effectively be used for denial-of-service attacks
		1452	against local programs (e.g. when setuid), although the impact is likely
		1453	small, as the program has to handle conenction and other failures anyways.
		1454
		1455	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1456	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1457	- only support IPv4, never try to resolve or contact IPv6
		1458	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1459	IPv6, but prefer IPv6 over IPv4.
		1460
		1461	=item C<PERL_ANYEVENT_EDNS0>
		1462
		1463	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1464	for DNS. This extension is generally useful to reduce DNS traffic, but
		1465	some (broken) firewalls drop such DNS packets, which is why it is off by
		1466	default.
		1467
		1468	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1469	EDNS0 in its DNS requests.
		1470
		1471	=item C<PERL_ANYEVENT_MAX_FORKS>
		1472
		1473	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1474	will create in parallel.
		1475
		1476	=back
1179		1477
1180	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1478	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1181		1479
1182	This is an advanced topic that you do not normally need to use AnyEvent in	1480	This is an advanced topic that you do not normally need to use AnyEvent in
1183	a module. This section is only of use to event loop authors who want to	1481	a module. This section is only of use to event loop authors who want to
…		…
1217		1515
1218	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1516	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1219	condition variables: code blocking while waiting for a condition will	1517	condition variables: code blocking while waiting for a condition will
1220	C<die>. This still works with most modules/usages, and blocking calls must	1518	C<die>. This still works with most modules/usages, and blocking calls must
1221	not be done in an interactive application, so it makes sense.	1519	not be done in an interactive application, so it makes sense.
1222
1223	=head1 ENVIRONMENT VARIABLES
1224
1225	The following environment variables are used by this module:
1226
1227	=over 4
1228
1229	=item C<PERL_ANYEVENT_VERBOSE>
1230
1231	By default, AnyEvent will be completely silent except in fatal
1232	conditions. You can set this environment variable to make AnyEvent more
1233	talkative.
1234
1235	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1236	conditions, such as not being able to load the event model specified by
1237	C<PERL_ANYEVENT_MODEL>.
1238
1239	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1240	model it chooses.
1241
1242	=item C<PERL_ANYEVENT_STRICT>
1243
1244	AnyEvent does not do much argument checking by default, as thorough
1245	argument checking is very costly. Setting this variable to a true value
1246	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1247	check the arguments passed to most method calls. If it finds any problems
1248	it will croak.
1249
1250	In other words, enables "strict" mode.
1251
1252	Unlike C<use strict> it is definitely recommended ot keep it off in
1253	production.
1254
1255	=item C<PERL_ANYEVENT_MODEL>
1256
1257	This can be used to specify the event model to be used by AnyEvent, before
1258	auto detection and -probing kicks in. It must be a string consisting
1259	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1260	and the resulting module name is loaded and if the load was successful,
1261	used as event model. If it fails to load AnyEvent will proceed with
1262	auto detection and -probing.
1263
1264	This functionality might change in future versions.
1265
1266	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1267	could start your program like this:
1268
1269	PERL_ANYEVENT_MODEL=Perl perl ...
1270
1271	=item C<PERL_ANYEVENT_PROTOCOLS>
1272
1273	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1274	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1275	of auto probing).
1276
1277	Must be set to a comma-separated list of protocols or address families,
1278	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1279	used, and preference will be given to protocols mentioned earlier in the
1280	list.
1281
1282	This variable can effectively be used for denial-of-service attacks
1283	against local programs (e.g. when setuid), although the impact is likely
1284	small, as the program has to handle connection errors already-
1285
1286	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1287	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1288	- only support IPv4, never try to resolve or contact IPv6
1289	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1290	IPv6, but prefer IPv6 over IPv4.
1291
1292	=item C<PERL_ANYEVENT_EDNS0>
1293
1294	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1295	for DNS. This extension is generally useful to reduce DNS traffic, but
1296	some (broken) firewalls drop such DNS packets, which is why it is off by
1297	default.
1298
1299	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1300	EDNS0 in its DNS requests.
1301
1302	=item C<PERL_ANYEVENT_MAX_FORKS>
1303
1304	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1305	will create in parallel.
1306
1307	=back
1308		1520
1309	=head1 EXAMPLE PROGRAM	1521	=head1 EXAMPLE PROGRAM
1310		1522
1311	The following program uses an I/O watcher to read data from STDIN, a timer	1523	The following program uses an I/O watcher to read data from STDIN, a timer
1312	to display a message once per second, and a condition variable to quit the	1524	to display a message once per second, and a condition variable to quit the
…		…
1506	watcher.	1718	watcher.
1507		1719
1508	=head3 Results	1720	=head3 Results
1509		1721
1510	name watchers bytes create invoke destroy comment	1722	name watchers bytes create invoke destroy comment
1511	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1723	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1512	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1724	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1513	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1725	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1514	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1726	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1515	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1727	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1516	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1728	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1729	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1730	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1517	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1731	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1518	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1732	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1519	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1733	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1520	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1734	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1521		1735
1522	=head3 Discussion	1736	=head3 Discussion
1523		1737
1524	The benchmark does I<not> measure scalability of the event loop very	1738	The benchmark does I<not> measure scalability of the event loop very
1525	well. For example, a select-based event loop (such as the pure perl one)	1739	well. For example, a select-based event loop (such as the pure perl one)
…		…
1550	performance becomes really bad with lots of file descriptors (and few of	1764	performance becomes really bad with lots of file descriptors (and few of
1551	them active), of course, but this was not subject of this benchmark.	1765	them active), of course, but this was not subject of this benchmark.
1552		1766
1553	The C<Event> module has a relatively high setup and callback invocation	1767	The C<Event> module has a relatively high setup and callback invocation
1554	cost, but overall scores in on the third place.	1768	cost, but overall scores in on the third place.
		1769
		1770	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1771	when using its pure perl backend.
1555		1772
1556	C<Glib>'s memory usage is quite a bit higher, but it features a	1773	C<Glib>'s memory usage is quite a bit higher, but it features a
1557	faster callback invocation and overall ends up in the same class as	1774	faster callback invocation and overall ends up in the same class as
1558	C<Event>. However, Glib scales extremely badly, doubling the number of	1775	C<Event>. However, Glib scales extremely badly, doubling the number of
1559	watchers increases the processing time by more than a factor of four,	1776	watchers increases the processing time by more than a factor of four,
…		…
1637	it to another server. This includes deleting the old timeout and creating	1854	it to another server. This includes deleting the old timeout and creating
1638	a new one that moves the timeout into the future.	1855	a new one that moves the timeout into the future.
1639		1856
1640	=head3 Results	1857	=head3 Results
1641		1858
1642	name sockets create request	1859	name sockets create request
1643	EV 20000 69.01 11.16	1860	EV 20000 69.01 11.16
1644	Perl 20000 73.32 35.87	1861	Perl 20000 73.32 35.87
		1862	IOAsync 20000 157.00 98.14 epoll
		1863	IOAsync 20000 159.31 616.06 poll
1645	Event 20000 212.62 257.32	1864	Event 20000 212.62 257.32
1646	Glib 20000 651.16 1896.30	1865	Glib 20000 651.16 1896.30
1647	POE 20000 349.67 12317.24 uses POE::Loop::Event	1866	POE 20000 349.67 12317.24 uses POE::Loop::Event
1648		1867
1649	=head3 Discussion	1868	=head3 Discussion
1650		1869
1651	This benchmark I<does> measure scalability and overall performance of the	1870	This benchmark I<does> measure scalability and overall performance of the
1652	particular event loop.	1871	particular event loop.
…		…
1654	EV is again fastest. Since it is using epoll on my system, the setup time	1873	EV is again fastest. Since it is using epoll on my system, the setup time
1655	is relatively high, though.	1874	is relatively high, though.
1656		1875
1657	Perl surprisingly comes second. It is much faster than the C-based event	1876	Perl surprisingly comes second. It is much faster than the C-based event
1658	loops Event and Glib.	1877	loops Event and Glib.
		1878
		1879	IO::Async performs very well when using its epoll backend, and still quite
		1880	good compared to Glib when using its pure perl backend.
1659		1881
1660	Event suffers from high setup time as well (look at its code and you will	1882	Event suffers from high setup time as well (look at its code and you will
1661	understand why). Callback invocation also has a high overhead compared to	1883	understand why). Callback invocation also has a high overhead compared to
1662	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1884	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1663	uses select or poll in basically all documented configurations.	1885	uses select or poll in basically all documented configurations.
…		…
1726	=item * C-based event loops perform very well with small number of	1948	=item * C-based event loops perform very well with small number of
1727	watchers, as the management overhead dominates.	1949	watchers, as the management overhead dominates.
1728		1950
1729	=back	1951	=back
1730		1952
		1953	=head2 THE IO::Lambda BENCHMARK
		1954
		1955	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1956	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1957	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		1958	shouldn't come as a surprise to anybody). As such, the benchmark is
		1959	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		1960	very optimal. But how would AnyEvent compare when used without the extra
		1961	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		1962
		1963	The benchmark itself creates an echo-server, and then, for 500 times,
		1964	connects to the echo server, sends a line, waits for the reply, and then
		1965	creates the next connection. This is a rather bad benchmark, as it doesn't
		1966	test the efficiency of the framework or much non-blocking I/O, but it is a
		1967	benchmark nevertheless.
		1968
		1969	name runtime
		1970	Lambda/select 0.330 sec
		1971	+ optimized 0.122 sec
		1972	Lambda/AnyEvent 0.327 sec
		1973	+ optimized 0.138 sec
		1974	Raw sockets/select 0.077 sec
		1975	POE/select, components 0.662 sec
		1976	POE/select, raw sockets 0.226 sec
		1977	POE/select, optimized 0.404 sec
		1978
		1979	AnyEvent/select/nb 0.085 sec
		1980	AnyEvent/EV/nb 0.068 sec
		1981	+state machine 0.134 sec
		1982
		1983	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1984	benchmarks actually make blocking connects and use 100% blocking I/O,
		1985	defeating the purpose of an event-based solution. All of the newly
		1986	written AnyEvent benchmarks use 100% non-blocking connects (using
		1987	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1988	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		1989	generally require a lot more bookkeeping and event handling than blocking
		1990	connects (which involve a single syscall only).
		1991
		1992	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		1993	offers similar expressive power as POE and IO::Lambda, using conventional
		1994	Perl syntax. This means that both the echo server and the client are 100%
		1995	non-blocking, further placing it at a disadvantage.
		1996
		1997	As you can see, the AnyEvent + EV combination even beats the
		1998	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		1999	backend easily beats IO::Lambda and POE.
		2000
		2001	And even the 100% non-blocking version written using the high-level (and
		2002	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2003	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2004	in a non-blocking way.
		2005
		2006	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2007	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2008	part of the IO::lambda distribution and were used without any changes.
		2009
		2010
		2011	=head1 SIGNALS
		2012
		2013	AnyEvent currently installs handlers for these signals:
		2014
		2015	=over 4
		2016
		2017	=item SIGCHLD
		2018
		2019	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2020	emulation for event loops that do not support them natively. Also, some
		2021	event loops install a similar handler.
		2022
		2023	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2024	reset it to default, to avoid losing child exit statuses.
		2025
		2026	=item SIGPIPE
		2027
		2028	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2029	when AnyEvent gets loaded.
		2030
		2031	The rationale for this is that AnyEvent users usually do not really depend
		2032	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2033	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2034	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2035	some random socket.
		2036
		2037	The rationale for installing a no-op handler as opposed to ignoring it is
		2038	that this way, the handler will be restored to defaults on exec.
		2039
		2040	Feel free to install your own handler, or reset it to defaults.
		2041
		2042	=back
		2043
		2044	=cut
		2045
		2046	undef $SIG{CHLD}
		2047	if $SIG{CHLD} eq 'IGNORE';
		2048
		2049	$SIG{PIPE} = sub { }
		2050	unless defined $SIG{PIPE};
1731		2051
1732	=head1 FORK	2052	=head1 FORK
1733		2053
1734	Most event libraries are not fork-safe. The ones who are usually are	2054	Most event libraries are not fork-safe. The ones who are usually are
1735	because they rely on inefficient but fork-safe C<select> or C<poll>	2055	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1756	use AnyEvent;	2076	use AnyEvent;
1757		2077
1758	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2078	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1759	be used to probe what backend is used and gain other information (which is	2079	be used to probe what backend is used and gain other information (which is
1760	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and	2080	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1761	$ENV{PERL_ANYEGENT_STRICT}.	2081	$ENV{PERL_ANYEVENT_STRICT}.
		2082
		2083	Note that AnyEvent will remove I<all> environment variables starting with
		2084	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2085	enabled.
1762		2086
1763		2087
1764	=head1 BUGS	2088	=head1 BUGS
1765		2089
1766	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2090	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
1767	to work around. If you suffer from memleaks, first upgrade to Perl 5.10	2091	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
1768	and check wether the leaks still show up. (Perl 5.10.0 has other annoying	2092	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
1769	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as	2093	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1770	pronounced).	2094	pronounced).
1771		2095
1772		2096
1773	=head1 SEE ALSO	2097	=head1 SEE ALSO
1774		2098

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC vs. Revision 1.224 by root, Fri Jul 3 21:44:14 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC vs.
Revision 1.224 by root, Fri Jul 3 21:44:14 2009 UTC