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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.177 by root, Thu Aug 21 18:45:16 2008 UTC vs.
Revision 1.228 by root, Wed Jul 8 01:11:12 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, see below) to
168	(AnyEvent might or might not keep a reference to this file handle). C<poll>	182	watch for events (AnyEvent might or might not keep a reference to this
		183	file 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
…		…
189	chomp (my $input = <STDIN>);	209	chomp (my $input = <STDIN>);
190	warn "read: $input\n";	210	warn "read: $input\n";
191	undef $w;	211	undef $w;
192	});	212	});
193		213
		214	=head3 GETTING A FILE HANDLE FROM A FILE DESCRIPTOR
		215
		216	It is not uncommon to only have a file descriptor, while AnyEvent requires
		217	a Perl file handle.
		218
		219	There are basically two methods to convert a file descriptor into a file handle. If you own
		220	the file descriptor, you can open it with C<&=>, as in:
		221
		222	open my $fh, "<&=$fileno" or die "xxx: §!";
		223
		224	This will "own" the file descriptor, meaning that when C<$fh> is
		225	destroyed, it will automatically close the C<$fileno>. Also, note that
		226	the open mode (read, write, read/write) must correspond with how the
		227	underlying file descriptor was opened.
		228
		229	In many cases, taking over the file descriptor is now what you want, in
		230	which case the only alternative is to dup the file descriptor:
		231
		232	open my $fh, "<&$fileno" or die "xxx: $!";
		233
		234	This has the advantage of not closing the file descriptor and the
		235	disadvantage of making a slow copy.
		236
194	=head2 TIME WATCHERS	237	=head2 TIME WATCHERS
195		238
196	You can create a time watcher by calling the C<< AnyEvent->timer >>	239	You can create a time watcher by calling the C<< AnyEvent->timer >>
197	method with the following mandatory arguments:	240	method with the following mandatory arguments:
198		241
…		…
308	In either case, if you care (and in most cases, you don't), then you	351	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	352	can get whatever behaviour you want with any event loop, by taking the
310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	353	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
311	account.	354	account.
312		355
		356	=item AnyEvent->now_update
		357
		358	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		359	the current time for each loop iteration (see the discussion of L<<
		360	AnyEvent->now >>, above).
		361
		362	When a callback runs for a long time (or when the process sleeps), then
		363	this "current" time will differ substantially from the real time, which
		364	might affect timers and time-outs.
		365
		366	When this is the case, you can call this method, which will update the
		367	event loop's idea of "current time".
		368
		369	Note that updating the time I<might> cause some events to be handled.
		370
313	=back	371	=back
314		372
315	=head2 SIGNAL WATCHERS	373	=head2 SIGNAL WATCHERS
316		374
317	You can watch for signals using a signal watcher, C<signal> is the signal	375	You can watch for signals using a signal watcher, C<signal> is the signal
…		…
340	=head2 CHILD PROCESS WATCHERS	398	=head2 CHILD PROCESS WATCHERS
341		399
342	You can also watch on a child process exit and catch its exit status.	400	You can also watch on a child process exit and catch its exit status.
343		401
344	The child process is specified by the C<pid> argument (if set to C<0>, it	402	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	403	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	404	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	405	any trace events (stopped/continued).
348	and exit status (as returned by waitpid), so unlike other watcher types,	406
349	you I<can> rely on child watcher callback arguments.	407	The callback will be called with the pid and exit status (as returned by
		408	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		409	callback arguments.
		410
		411	This watcher type works by installing a signal handler for C<SIGCHLD>,
		412	and since it cannot be shared, nothing else should use SIGCHLD or reap
		413	random child processes (waiting for specific child processes, e.g. inside
		414	C<system>, is just fine).
350		415
351	There is a slight catch to child watchers, however: you usually start them	416	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	417	I<after> the child process was created, and this means the process could
353	have exited already (and no SIGCHLD will be sent anymore).	418	have exited already (and no SIGCHLD will be sent anymore).
354		419
355	Not all event models handle this correctly (POE doesn't), but even for	420	Not all event models handle this correctly (neither POE nor IO::Async do,
		421	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	422	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).	423	the process exits (i.e. before you fork in the first place). AnyEvent's
		424	pure perl event loop handles all cases correctly regardless of when you
		425	start the watcher.
358		426
359	This means you cannot create a child watcher as the very first thing in an	427	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	428	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>).	429	watcher before you C<fork> the child (alternatively, you can call
		430	C<AnyEvent::detect>).
362		431
363	Example: fork a process and wait for it	432	Example: fork a process and wait for it
364		433
365	my $done = AnyEvent->condvar;	434	my $done = AnyEvent->condvar;
366		435
…		…
376	);	445	);
377		446
378	# do something else, then wait for process exit	447	# do something else, then wait for process exit
379	$done->recv;	448	$done->recv;
380		449
		450	=head2 IDLE WATCHERS
		451
		452	Sometimes there is a need to do something, but it is not so important
		453	to do it instantly, but only when there is nothing better to do. This
		454	"nothing better to do" is usually defined to be "no other events need
		455	attention by the event loop".
		456
		457	Idle watchers ideally get invoked when the event loop has nothing
		458	better to do, just before it would block the process to wait for new
		459	events. Instead of blocking, the idle watcher is invoked.
		460
		461	Most event loops unfortunately do not really support idle watchers (only
		462	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		463	will simply call the callback "from time to time".
		464
		465	Example: read lines from STDIN, but only process them when the
		466	program is otherwise idle:
		467
		468	my @lines; # read data
		469	my $idle_w;
		470	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		471	push @lines, scalar <STDIN>;
		472
		473	# start an idle watcher, if not already done
		474	$idle_w \|\|= AnyEvent->idle (cb => sub {
		475	# handle only one line, when there are lines left
		476	if (my $line = shift @lines) {
		477	print "handled when idle: $line";
		478	} else {
		479	# otherwise disable the idle watcher again
		480	undef $idle_w;
		481	}
		482	});
		483	});
		484
381	=head2 CONDITION VARIABLES	485	=head2 CONDITION VARIABLES
382		486
383	If you are familiar with some event loops you will know that all of them	487	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	488	require you to run some blocking "loop", "run" or similar function that
385	will actively watch for new events and call your callbacks.	489	will actively watch for new events and call your callbacks.
…		…
518		622
519	=item $cv->begin ([group callback])	623	=item $cv->begin ([group callback])
520		624
521	=item $cv->end	625	=item $cv->end
522		626
523	These two methods are EXPERIMENTAL and MIGHT CHANGE.
524
525	These two methods can be used to combine many transactions/events into	627	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	628	one. For example, a function that pings many hosts in parallel might want
527	to use a condition variable for the whole process.	629	to use a condition variable for the whole process.
528		630
529	Every call to C<< ->begin >> will increment a counter, and every call to	631	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	632	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	633	>>, 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	634	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.	635	callback was set, C<send> will be called without any arguments.
534		636
535	Let's clarify this with the ping example:	637	You can think of C<< $cv->send >> giving you an OR condition (one call
		638	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		639	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		640
		641	Let's start with a simple example: you have two I/O watchers (for example,
		642	STDOUT and STDERR for a program), and you want to wait for both streams to
		643	close before activating a condvar:
		644
		645	my $cv = AnyEvent->condvar;
		646
		647	$cv->begin; # first watcher
		648	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		649	defined sysread $fh1, my $buf, 4096
		650	or $cv->end;
		651	});
		652
		653	$cv->begin; # second watcher
		654	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		655	defined sysread $fh2, my $buf, 4096
		656	or $cv->end;
		657	});
		658
		659	$cv->recv;
		660
		661	This works because for every event source (EOF on file handle), there is
		662	one call to C<begin>, so the condvar waits for all calls to C<end> before
		663	sending.
		664
		665	The ping example mentioned above is slightly more complicated, as the
		666	there are results to be passwd back, and the number of tasks that are
		667	begung can potentially be zero:
536		668
537	my $cv = AnyEvent->condvar;	669	my $cv = AnyEvent->condvar;
538		670
539	my %result;	671	my %result;
540	$cv->begin (sub { $cv->send (\%result) });	672	$cv->begin (sub { $cv->send (\%result) });
…		…
560	loop, which serves two important purposes: first, it sets the callback	692	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	693	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	694	C<send> is called even when C<no> hosts are being pinged (the loop
563	doesn't execute once).	695	doesn't execute once).
564		696
565	This is the general pattern when you "fan out" into multiple subrequests:	697	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>	698	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	699	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>.	700	subrequest you start, call C<begin> and for each subrequest you finish,
		701	call C<end>.
569		702
570	=back	703	=back
571		704
572	=head3 METHODS FOR CONSUMERS	705	=head3 METHODS FOR CONSUMERS
573		706
…		…
653	AnyEvent::Impl::Tk based on Tk, very bad choice.	786	AnyEvent::Impl::Tk based on Tk, very bad choice.
654	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	787	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
655	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	788	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
656	AnyEvent::Impl::POE based on POE, not generic enough for full support.	789	AnyEvent::Impl::POE based on POE, not generic enough for full support.
657		790
		791	# warning, support for IO::Async is only partial, as it is too broken
		792	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		793	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		794
658	There is no support for WxWidgets, as WxWidgets has no support for	795	There is no support for WxWidgets, as WxWidgets has no support for
659	watching file handles. However, you can use WxWidgets through the	796	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	797	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	798	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	799	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
…		…
818	=item L<AnyEvent::IGS>	955	=item L<AnyEvent::IGS>
819		956
820	A non-blocking interface to the Internet Go Server protocol (used by	957	A non-blocking interface to the Internet Go Server protocol (used by
821	L<App::IGS>).	958	L<App::IGS>).
822		959
823	=item L<Net::IRC3>	960	=item L<AnyEvent::IRC>
824		961
825	AnyEvent based IRC client module family.	962	AnyEvent based IRC client module family (replacing the older Net::IRC3).
826		963
827	=item L<Net::XMPP2>	964	=item L<Net::XMPP2>
828		965
829	AnyEvent based XMPP (Jabber protocol) module family.	966	AnyEvent based XMPP (Jabber protocol) module family.
830		967
…		…
850	=cut	987	=cut
851		988
852	package AnyEvent;	989	package AnyEvent;
853		990
854	no warnings;	991	no warnings;
855	use strict;	992	use strict qw(vars subs);
856		993
857	use Carp;	994	use Carp;
858		995
859	our $VERSION = 4.232;	996	our $VERSION = 4.8;
860	our $MODEL;	997	our $MODEL;
861		998
862	our $AUTOLOAD;	999	our $AUTOLOAD;
863	our @ISA;	1000	our @ISA;
864		1001
865	our @REGISTRY;	1002	our @REGISTRY;
866		1003
867	our $WIN32;	1004	our $WIN32;
868		1005
869	BEGIN {	1006	BEGIN {
870	my $win32 = ! ! ($^O =~ /mswin32/i);	1007	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
871	eval "sub WIN32(){ $win32 }";	1008	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1009
		1010	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1011	if ${^TAINT};
872	}	1012	}
873		1013
874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1014	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
875		1015
876	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred	1016	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
…		…
894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1034	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1035	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1036	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
897	[Wx:: => AnyEvent::Impl::POE::],	1037	[Wx:: => AnyEvent::Impl::POE::],
898	[Prima:: => AnyEvent::Impl::POE::],	1038	[Prima:: => AnyEvent::Impl::POE::],
		1039	# IO::Async is just too broken - we would need workaorunds for its
		1040	# byzantine signal and broken child handling, among others.
		1041	# IO::Async is rather hard to detect, as it doesn't have any
		1042	# obvious default class.
		1043	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1044	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1045	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
899	);	1046	);
900		1047
901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1048	our %method = map +($_ => 1),
		1049	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
902		1050
903	our @post_detect;	1051	our @post_detect;
904		1052
905	sub post_detect(&) {	1053	sub post_detect(&) {
906	my ($cb) = @_;	1054	my ($cb) = @_;
…		…
911	1	1059	1
912	} else {	1060	} else {
913	push @post_detect, $cb;	1061	push @post_detect, $cb;
914		1062
915	defined wantarray	1063	defined wantarray
916	? bless \$cb, "AnyEvent::Util::PostDetect"	1064	? bless \$cb, "AnyEvent::Util::postdetect"
917	: ()	1065	: ()
918	}	1066	}
919	}	1067	}
920		1068
921	sub AnyEvent::Util::PostDetect::DESTROY {	1069	sub AnyEvent::Util::postdetect::DESTROY {
922	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1070	@post_detect = grep $_ != ${$_[0]}, @post_detect;
923	}	1071	}
924		1072
925	sub detect() {	1073	sub detect() {
926	unless ($MODEL) {	1074	unless ($MODEL) {
…		…
963	last;	1111	last;
964	}	1112	}
965	}	1113	}
966		1114
967	$MODEL	1115	$MODEL
968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1116	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
969	}	1117	}
970	}	1118	}
971		1119
972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1120	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
973		1121
…		…
994	}	1142	}
995		1143
996	# utility function to dup a filehandle. this is used by many backends	1144	# utility function to dup a filehandle. this is used by many backends
997	# to support binding more than one watcher per filehandle (they usually	1145	# 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).	1146	# allow only one watcher per fd, so we dup it to get a different one).
999	sub _dupfh($$$$) {	1147	sub _dupfh($$;$$) {
1000	my ($poll, $fh, $r, $w) = @_;	1148	my ($poll, $fh, $r, $w) = @_;
1001
1002	require Fcntl;
1003		1149
1004	# cygwin requires the fh mode to be matching, unix doesn't	1150	# cygwin requires the fh mode to be matching, unix doesn't
1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1151	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
1006	: $poll eq "w" ? ($w, ">")	1152	: $poll eq "w" ? ($w, ">")
1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";	1153	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1008		1154
1009	open my $fh2, "$mode&" . fileno $fh	1155	open my $fh2, "$mode&" . fileno $fh
1010	or die "cannot dup() filehandle: $!";	1156	or die "cannot dup() filehandle: $!,";
1011		1157
1012	# we assume CLOEXEC is already set by perl in all important cases	1158	# we assume CLOEXEC is already set by perl in all important cases
1013		1159
1014	($fh2, $rw)	1160	($fh2, $rw)
1015	}	1161	}
1016		1162
1017	package AnyEvent::Base;	1163	package AnyEvent::Base;
1018		1164
1019	# default implementation for now and time	1165	# default implementations for many methods
1020		1166
1021	use Time::HiRes ();	1167	BEGIN {
		1168	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1169	*_time = \&Time::HiRes::time;
		1170	# if (eval "use POSIX (); (POSIX::times())...
		1171	} else {
		1172	*_time = sub { time }; # epic fail
		1173	}
		1174	}
1022		1175
1023	sub time { Time::HiRes::time }	1176	sub time { _time }
1024	sub now { Time::HiRes::time }	1177	sub now { _time }
		1178	sub now_update { }
1025		1179
1026	# default implementation for ->condvar	1180	# default implementation for ->condvar
1027		1181
1028	sub condvar {	1182	sub condvar {
1029	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1183	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1030	}	1184	}
1031		1185
1032	# default implementation for ->signal	1186	# default implementation for ->signal
1033		1187
1034	our %SIG_CB;	1188	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1189
		1190	sub _signal_exec {
		1191	sysread $SIGPIPE_R, my $dummy, 4;
		1192
		1193	while (%SIG_EV) {
		1194	for (keys %SIG_EV) {
		1195	delete $SIG_EV{$_};
		1196	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1197	}
		1198	}
		1199	}
1035		1200
1036	sub signal {	1201	sub signal {
1037	my (undef, %arg) = @_;	1202	my (undef, %arg) = @_;
1038		1203
		1204	unless ($SIGPIPE_R) {
		1205	require Fcntl;
		1206
		1207	if (AnyEvent::WIN32) {
		1208	require AnyEvent::Util;
		1209
		1210	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1211	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1212	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1213	} else {
		1214	pipe $SIGPIPE_R, $SIGPIPE_W;
		1215	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1216	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1217
		1218	# not strictly required, as $^F is normally 2, but let's make sure...
		1219	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1220	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1221	}
		1222
		1223	$SIGPIPE_R
		1224	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1225
		1226	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1227	}
		1228
1039	my $signal = uc $arg{signal}	1229	my $signal = uc $arg{signal}
1040	or Carp::croak "required option 'signal' is missing";	1230	or Carp::croak "required option 'signal' is missing";
1041		1231
1042	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1232	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1043	$SIG{$signal} \|\|= sub {	1233	$SIG{$signal} \|\|= sub {
1044	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1234	local $!;
		1235	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1236	undef $SIG_EV{$signal};
1045	};	1237	};
1046		1238
1047	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1239	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1048	}	1240	}
1049		1241
1050	sub AnyEvent::Base::Signal::DESTROY {	1242	sub AnyEvent::Base::signal::DESTROY {
1051	my ($signal, $cb) = @{$_[0]};	1243	my ($signal, $cb) = @{$_[0]};
1052		1244
1053	delete $SIG_CB{$signal}{$cb};	1245	delete $SIG_CB{$signal}{$cb};
1054		1246
		1247	# delete doesn't work with older perls - they then
		1248	# print weird messages, or just unconditionally exit
		1249	# instead of getting the default action.
1055	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };	1250	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1056	}	1251	}
1057		1252
1058	# default implementation for ->child	1253	# default implementation for ->child
1059		1254
1060	our %PID_CB;	1255	our %PID_CB;
1061	our $CHLD_W;	1256	our $CHLD_W;
1062	our $CHLD_DELAY_W;	1257	our $CHLD_DELAY_W;
1063	our $PID_IDLE;
1064	our $WNOHANG;	1258	our $WNOHANG;
1065		1259
1066	sub _child_wait {	1260	sub _sigchld {
1067	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1261	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
1068	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1262	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
1069	(values %{ $PID_CB{0} \|\| {} });	1263	(values %{ $PID_CB{0} \|\| {} });
1070	}	1264	}
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	}	1265	}
1082		1266
1083	sub child {	1267	sub child {
1084	my (undef, %arg) = @_;	1268	my (undef, %arg) = @_;
1085		1269
1086	defined (my $pid = $arg{pid} + 0)	1270	defined (my $pid = $arg{pid} + 0)
1087	or Carp::croak "required option 'pid' is missing";	1271	or Carp::croak "required option 'pid' is missing";
1088		1272
1089	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1273	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1090		1274
1091	unless ($WNOHANG) {
1092	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1275	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1093	}
1094		1276
1095	unless ($CHLD_W) {	1277	unless ($CHLD_W) {
1096	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1278	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1097	# child could be a zombie already, so make at least one round	1279	# child could be a zombie already, so make at least one round
1098	&_sigchld;	1280	&_sigchld;
1099	}	1281	}
1100		1282
1101	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1283	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1102	}	1284	}
1103		1285
1104	sub AnyEvent::Base::Child::DESTROY {	1286	sub AnyEvent::Base::child::DESTROY {
1105	my ($pid, $cb) = @{$_[0]};	1287	my ($pid, $cb) = @{$_[0]};
1106		1288
1107	delete $PID_CB{$pid}{$cb};	1289	delete $PID_CB{$pid}{$cb};
1108	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1290	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1109		1291
1110	undef $CHLD_W unless keys %PID_CB;	1292	undef $CHLD_W unless keys %PID_CB;
		1293	}
		1294
		1295	# idle emulation is done by simply using a timer, regardless
		1296	# of whether the process is idle or not, and not letting
		1297	# the callback use more than 50% of the time.
		1298	sub idle {
		1299	my (undef, %arg) = @_;
		1300
		1301	my ($cb, $w, $rcb) = $arg{cb};
		1302
		1303	$rcb = sub {
		1304	if ($cb) {
		1305	$w = _time;
		1306	&$cb;
		1307	$w = _time - $w;
		1308
		1309	# never use more then 50% of the time for the idle watcher,
		1310	# within some limits
		1311	$w = 0.0001 if $w < 0.0001;
		1312	$w = 5 if $w > 5;
		1313
		1314	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1315	} else {
		1316	# clean up...
		1317	undef $w;
		1318	undef $rcb;
		1319	}
		1320	};
		1321
		1322	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1323
		1324	bless \\$cb, "AnyEvent::Base::idle"
		1325	}
		1326
		1327	sub AnyEvent::Base::idle::DESTROY {
		1328	undef $${$_[0]};
1111	}	1329	}
1112		1330
1113	package AnyEvent::CondVar;	1331	package AnyEvent::CondVar;
1114		1332
1115	our @ISA = AnyEvent::CondVar::Base::;	1333	our @ISA = AnyEvent::CondVar::Base::;
…		…
1167	}	1385	}
1168		1386
1169	# undocumented/compatibility with pre-3.4	1387	# undocumented/compatibility with pre-3.4
1170	*broadcast = \&send;	1388	*broadcast = \&send;
1171	*wait = \&_wait;	1389	*wait = \&_wait;
		1390
		1391	=head1 ERROR AND EXCEPTION HANDLING
		1392
		1393	In general, AnyEvent does not do any error handling - it relies on the
		1394	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1395	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1396	checking of all AnyEvent methods, however, which is highly useful during
		1397	development.
		1398
		1399	As for exception handling (i.e. runtime errors and exceptions thrown while
		1400	executing a callback), this is not only highly event-loop specific, but
		1401	also not in any way wrapped by this module, as this is the job of the main
		1402	program.
		1403
		1404	The pure perl event loop simply re-throws the exception (usually
		1405	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1406	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1407	so on.
		1408
		1409	=head1 ENVIRONMENT VARIABLES
		1410
		1411	The following environment variables are used by this module or its
		1412	submodules.
		1413
		1414	Note that AnyEvent will remove I<all> environment variables starting with
		1415	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1416	enabled.
		1417
		1418	=over 4
		1419
		1420	=item C<PERL_ANYEVENT_VERBOSE>
		1421
		1422	By default, AnyEvent will be completely silent except in fatal
		1423	conditions. You can set this environment variable to make AnyEvent more
		1424	talkative.
		1425
		1426	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1427	conditions, such as not being able to load the event model specified by
		1428	C<PERL_ANYEVENT_MODEL>.
		1429
		1430	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1431	model it chooses.
		1432
		1433	=item C<PERL_ANYEVENT_STRICT>
		1434
		1435	AnyEvent does not do much argument checking by default, as thorough
		1436	argument checking is very costly. Setting this variable to a true value
		1437	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1438	check the arguments passed to most method calls. If it finds any problems,
		1439	it will croak.
		1440
		1441	In other words, enables "strict" mode.
		1442
		1443	Unlike C<use strict>, it is definitely recommended to keep it off in
		1444	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1445	developing programs can be very useful, however.
		1446
		1447	=item C<PERL_ANYEVENT_MODEL>
		1448
		1449	This can be used to specify the event model to be used by AnyEvent, before
		1450	auto detection and -probing kicks in. It must be a string consisting
		1451	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1452	and the resulting module name is loaded and if the load was successful,
		1453	used as event model. If it fails to load AnyEvent will proceed with
		1454	auto detection and -probing.
		1455
		1456	This functionality might change in future versions.
		1457
		1458	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1459	could start your program like this:
		1460
		1461	PERL_ANYEVENT_MODEL=Perl perl ...
		1462
		1463	=item C<PERL_ANYEVENT_PROTOCOLS>
		1464
		1465	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1466	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1467	of auto probing).
		1468
		1469	Must be set to a comma-separated list of protocols or address families,
		1470	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1471	used, and preference will be given to protocols mentioned earlier in the
		1472	list.
		1473
		1474	This variable can effectively be used for denial-of-service attacks
		1475	against local programs (e.g. when setuid), although the impact is likely
		1476	small, as the program has to handle conenction and other failures anyways.
		1477
		1478	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1479	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1480	- only support IPv4, never try to resolve or contact IPv6
		1481	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1482	IPv6, but prefer IPv6 over IPv4.
		1483
		1484	=item C<PERL_ANYEVENT_EDNS0>
		1485
		1486	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1487	for DNS. This extension is generally useful to reduce DNS traffic, but
		1488	some (broken) firewalls drop such DNS packets, which is why it is off by
		1489	default.
		1490
		1491	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1492	EDNS0 in its DNS requests.
		1493
		1494	=item C<PERL_ANYEVENT_MAX_FORKS>
		1495
		1496	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1497	will create in parallel.
		1498
		1499	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1500
		1501	The default value for the C<max_outstanding> parameter for the default DNS
		1502	resolver - this is the maximum number of parallel DNS requests that are
		1503	sent to the DNS server.
		1504
		1505	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1506
		1507	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1508	configuration) in the default resolver. When set to the empty string, no
		1509	default config will be used.
		1510
		1511	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1512
		1513	When neither C<ca_file> nor C<ca_path> was specified during
		1514	L<AnyEvent::TLS> context creation, and either of these environment
		1515	variables exist, they will be used to specify CA certificate locations
		1516	instead of a system-dependent default.
		1517
		1518	=back
1172		1519
1173	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1520	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1174		1521
1175	This is an advanced topic that you do not normally need to use AnyEvent in	1522	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	1523	a module. This section is only of use to event loop authors who want to
…		…
1210		1557
1211	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1558	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1212	condition variables: code blocking while waiting for a condition will	1559	condition variables: code blocking while waiting for a condition will
1213	C<die>. This still works with most modules/usages, and blocking calls must	1560	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.	1561	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		1562
1302	=head1 EXAMPLE PROGRAM	1563	=head1 EXAMPLE PROGRAM
1303		1564
1304	The following program uses an I/O watcher to read data from STDIN, a timer	1565	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	1566	to display a message once per second, and a condition variable to quit the
…		…
1499	watcher.	1760	watcher.
1500		1761
1501	=head3 Results	1762	=head3 Results
1502		1763
1503	name watchers bytes create invoke destroy comment	1764	name watchers bytes create invoke destroy comment
1504	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1765	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	1766	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	1767	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	1768	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	1769	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	1770	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1771	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1772	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	1773	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	1774	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	1775	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	1776	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1514		1777
1515	=head3 Discussion	1778	=head3 Discussion
1516		1779
1517	The benchmark does I<not> measure scalability of the event loop very	1780	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)	1781	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	1806	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.	1807	them active), of course, but this was not subject of this benchmark.
1545		1808
1546	The C<Event> module has a relatively high setup and callback invocation	1809	The C<Event> module has a relatively high setup and callback invocation
1547	cost, but overall scores in on the third place.	1810	cost, but overall scores in on the third place.
		1811
		1812	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1813	when using its pure perl backend.
1548		1814
1549	C<Glib>'s memory usage is quite a bit higher, but it features a	1815	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	1816	faster callback invocation and overall ends up in the same class as
1551	C<Event>. However, Glib scales extremely badly, doubling the number of	1817	C<Event>. However, Glib scales extremely badly, doubling the number of
1552	watchers increases the processing time by more than a factor of four,	1818	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	1896	it to another server. This includes deleting the old timeout and creating
1631	a new one that moves the timeout into the future.	1897	a new one that moves the timeout into the future.
1632		1898
1633	=head3 Results	1899	=head3 Results
1634		1900
1635	name sockets create request	1901	name sockets create request
1636	EV 20000 69.01 11.16	1902	EV 20000 69.01 11.16
1637	Perl 20000 73.32 35.87	1903	Perl 20000 73.32 35.87
		1904	IOAsync 20000 157.00 98.14 epoll
		1905	IOAsync 20000 159.31 616.06 poll
1638	Event 20000 212.62 257.32	1906	Event 20000 212.62 257.32
1639	Glib 20000 651.16 1896.30	1907	Glib 20000 651.16 1896.30
1640	POE 20000 349.67 12317.24 uses POE::Loop::Event	1908	POE 20000 349.67 12317.24 uses POE::Loop::Event
1641		1909
1642	=head3 Discussion	1910	=head3 Discussion
1643		1911
1644	This benchmark I<does> measure scalability and overall performance of the	1912	This benchmark I<does> measure scalability and overall performance of the
1645	particular event loop.	1913	particular event loop.
…		…
1647	EV is again fastest. Since it is using epoll on my system, the setup time	1915	EV is again fastest. Since it is using epoll on my system, the setup time
1648	is relatively high, though.	1916	is relatively high, though.
1649		1917
1650	Perl surprisingly comes second. It is much faster than the C-based event	1918	Perl surprisingly comes second. It is much faster than the C-based event
1651	loops Event and Glib.	1919	loops Event and Glib.
		1920
		1921	IO::Async performs very well when using its epoll backend, and still quite
		1922	good compared to Glib when using its pure perl backend.
1652		1923
1653	Event suffers from high setup time as well (look at its code and you will	1924	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	1925	understand why). Callback invocation also has a high overhead compared to
1655	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1926	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1656	uses select or poll in basically all documented configurations.	1927	uses select or poll in basically all documented configurations.
…		…
1719	=item * C-based event loops perform very well with small number of	1990	=item * C-based event loops perform very well with small number of
1720	watchers, as the management overhead dominates.	1991	watchers, as the management overhead dominates.
1721		1992
1722	=back	1993	=back
1723		1994
		1995	=head2 THE IO::Lambda BENCHMARK
		1996
		1997	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1998	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		1999	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2000	shouldn't come as a surprise to anybody). As such, the benchmark is
		2001	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2002	very optimal. But how would AnyEvent compare when used without the extra
		2003	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2004
		2005	The benchmark itself creates an echo-server, and then, for 500 times,
		2006	connects to the echo server, sends a line, waits for the reply, and then
		2007	creates the next connection. This is a rather bad benchmark, as it doesn't
		2008	test the efficiency of the framework or much non-blocking I/O, but it is a
		2009	benchmark nevertheless.
		2010
		2011	name runtime
		2012	Lambda/select 0.330 sec
		2013	+ optimized 0.122 sec
		2014	Lambda/AnyEvent 0.327 sec
		2015	+ optimized 0.138 sec
		2016	Raw sockets/select 0.077 sec
		2017	POE/select, components 0.662 sec
		2018	POE/select, raw sockets 0.226 sec
		2019	POE/select, optimized 0.404 sec
		2020
		2021	AnyEvent/select/nb 0.085 sec
		2022	AnyEvent/EV/nb 0.068 sec
		2023	+state machine 0.134 sec
		2024
		2025	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2026	benchmarks actually make blocking connects and use 100% blocking I/O,
		2027	defeating the purpose of an event-based solution. All of the newly
		2028	written AnyEvent benchmarks use 100% non-blocking connects (using
		2029	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2030	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2031	generally require a lot more bookkeeping and event handling than blocking
		2032	connects (which involve a single syscall only).
		2033
		2034	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2035	offers similar expressive power as POE and IO::Lambda, using conventional
		2036	Perl syntax. This means that both the echo server and the client are 100%
		2037	non-blocking, further placing it at a disadvantage.
		2038
		2039	As you can see, the AnyEvent + EV combination even beats the
		2040	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2041	backend easily beats IO::Lambda and POE.
		2042
		2043	And even the 100% non-blocking version written using the high-level (and
		2044	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2045	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2046	in a non-blocking way.
		2047
		2048	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2049	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2050	part of the IO::lambda distribution and were used without any changes.
		2051
		2052
		2053	=head1 SIGNALS
		2054
		2055	AnyEvent currently installs handlers for these signals:
		2056
		2057	=over 4
		2058
		2059	=item SIGCHLD
		2060
		2061	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2062	emulation for event loops that do not support them natively. Also, some
		2063	event loops install a similar handler.
		2064
		2065	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will
		2066	reset it to default, to avoid losing child exit statuses.
		2067
		2068	=item SIGPIPE
		2069
		2070	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2071	when AnyEvent gets loaded.
		2072
		2073	The rationale for this is that AnyEvent users usually do not really depend
		2074	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2075	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2076	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2077	some random socket.
		2078
		2079	The rationale for installing a no-op handler as opposed to ignoring it is
		2080	that this way, the handler will be restored to defaults on exec.
		2081
		2082	Feel free to install your own handler, or reset it to defaults.
		2083
		2084	=back
		2085
		2086	=cut
		2087
		2088	undef $SIG{CHLD}
		2089	if $SIG{CHLD} eq 'IGNORE';
		2090
		2091	$SIG{PIPE} = sub { }
		2092	unless defined $SIG{PIPE};
1724		2093
1725	=head1 FORK	2094	=head1 FORK
1726		2095
1727	Most event libraries are not fork-safe. The ones who are usually are	2096	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>	2097	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1749	use AnyEvent;	2118	use AnyEvent;
1750		2119
1751	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2120	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	2121	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	2122	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
1754	$ENV{PERL_ANYEGENT_STRICT}.	2123	$ENV{PERL_ANYEVENT_STRICT}.
		2124
		2125	Note that AnyEvent will remove I<all> environment variables starting with
		2126	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2127	enabled.
1755		2128
1756		2129
1757	=head1 BUGS	2130	=head1 BUGS
1758		2131
1759	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard	2132	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	2133	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	2134	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	2135	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
1763	pronounced).	2136	pronounced).
1764		2137
1765		2138
1766	=head1 SEE ALSO	2139	=head1 SEE ALSO
1767		2140

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
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Revision 1.228 by root, Wed Jul 8 01:11:12 2009 UTC