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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.277 by root, Sun Aug 9 13:27:23 2009 UTC vs.
Revision 1.305 by root, Sun Dec 13 05:13:15 2009 UTC

…		…
363	might affect timers and time-outs.	363	might affect timers and time-outs.
364		364
365	When this is the case, you can call this method, which will update the	365	When this is the case, you can call this method, which will update the
366	event loop's idea of "current time".	366	event loop's idea of "current time".
367		367
		368	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		369	when mod_perl executes the script, then the event loop will have the wrong
		370	idea about the "current time" (being potentially far in the past, when the
		371	script ran the last time). In that case you should arrange a call to C<<
		372	AnyEvent->now_update >> each time the web server process wakes up again
		373	(e.g. at the start of your script, or in a handler).
		374
368	Note that updating the time I<might> cause some events to be handled.	375	Note that updating the time I<might> cause some events to be handled.
369		376
370	=back	377	=back
371		378
372	=head2 SIGNAL WATCHERS	379	=head2 SIGNAL WATCHERS
…		…
395	correctly.	402	correctly.
396		403
397	Example: exit on SIGINT	404	Example: exit on SIGINT
398		405
399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	406	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
		407
		408	=head3 Restart Behaviour
		409
		410	While restart behaviour is up to the event loop implementation, most will
		411	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		412	pure perl implementation).
		413
		414	=head3 Safe/Unsafe Signals
		415
		416	Perl signals can be either "safe" (synchronous to opcode handling) or
		417	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		418	latter might corrupt your memory.
		419
		420	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		421	i.e. they will not interrupt your running perl program but will only be
		422	called as part of the normal event handling (just like timer, I/O etc.
		423	callbacks, too).
400		424
401	=head3 Signal Races, Delays and Workarounds	425	=head3 Signal Races, Delays and Workarounds
402		426
403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	427	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404	callbacks to signals in a generic way, which is a pity, as you cannot	428	callbacks to signals in a generic way, which is a pity, as you cannot
…		…
592	after => 1,	616	after => 1,
593	cb => sub { $result_ready->send },	617	cb => sub { $result_ready->send },
594	);	618	);
595		619
596	# this "blocks" (while handling events) till the callback	620	# this "blocks" (while handling events) till the callback
597	# calls -<send	621	# calls ->send
598	$result_ready->recv;	622	$result_ready->recv;
599		623
600	Example: wait for a timer, but take advantage of the fact that condition	624	Example: wait for a timer, but take advantage of the fact that condition
601	variables are also callable directly.	625	variables are also callable directly.
602		626
…		…
666	one. For example, a function that pings many hosts in parallel might want	690	one. For example, a function that pings many hosts in parallel might want
667	to use a condition variable for the whole process.	691	to use a condition variable for the whole process.
668		692
669	Every call to C<< ->begin >> will increment a counter, and every call to	693	Every call to C<< ->begin >> will increment a counter, and every call to
670	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	694	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
671	>>, the (last) callback passed to C<begin> will be executed. That callback	695	>>, the (last) callback passed to C<begin> will be executed, passing the
672	is I<supposed> to call C<< ->send >>, but that is not required. If no	696	condvar as first argument. That callback is I<supposed> to call C<< ->send
673	callback was set, C<send> will be called without any arguments.	697	>>, but that is not required. If no group callback was set, C<send> will
		698	be called without any arguments.
674		699
675	You can think of C<< $cv->send >> giving you an OR condition (one call	700	You can think of C<< $cv->send >> giving you an OR condition (one call
676	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	701	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
677	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	702	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
678		703
…		…
705	begung can potentially be zero:	730	begung can potentially be zero:
706		731
707	my $cv = AnyEvent->condvar;	732	my $cv = AnyEvent->condvar;
708		733
709	my %result;	734	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	735	$cv->begin (sub { shift->send (\%result) });
711		736
712	for my $host (@list_of_hosts) {	737	for my $host (@list_of_hosts) {
713	$cv->begin;	738	$cv->begin;
714	ping_host_then_call_callback $host, sub {	739	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	740	$result{$host} = ...;
…		…
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	966	You should check C<$AnyEvent::MODEL> before adding to this array, though:
942	if it is defined then the event loop has already been detected, and the	967	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	968	array will be ignored.
944		969
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	970	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	971	it, as it takes care of these details.
947		972
948	This variable is mainly useful for modules that can do something useful	973	This variable is mainly useful for modules that can do something useful
949	when AnyEvent is used and thus want to know when it is initialised, but do	974	when AnyEvent is used and thus want to know when it is initialised, but do
950	not need to even load it by default. This array provides the means to hook	975	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	976	into AnyEvent passively, without loading it.
		977
		978	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		979	together, you could put this into Coro (this is the actual code used by
		980	Coro to accomplish this):
		981
		982	if (defined $AnyEvent::MODEL) {
		983	# AnyEvent already initialised, so load Coro::AnyEvent
		984	require Coro::AnyEvent;
		985	} else {
		986	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		987	# as soon as it is
		988	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		989	}
952		990
953	=back	991	=back
954		992
955	=head1 WHAT TO DO IN A MODULE	993	=head1 WHAT TO DO IN A MODULE
956		994
…		…
1105		1143
1106	package AnyEvent;	1144	package AnyEvent;
1107		1145
1108	# basically a tuned-down version of common::sense	1146	# basically a tuned-down version of common::sense
1109	sub common_sense {	1147	sub common_sense {
1110	# no warnings	1148	# from common:.sense 1.0
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};	1149	${^WARNING_BITS} = "\xfc\x3f\x33\x00\x0f\xf3\xcf\xc0\xf3\xfc\x33\x00";
1112	# use strict vars subs	1150	# use strict vars subs
1113	$^H \|= 0x00000600;	1151	$^H \|= 0x00000600;
1114	}	1152	}
1115		1153
1116	BEGIN { AnyEvent::common_sense }	1154	BEGIN { AnyEvent::common_sense }
1117		1155
1118	use Carp ();	1156	use Carp ();
1119		1157
1120	our $VERSION = 4.92;	1158	our $VERSION = '5.22';
1121	our $MODEL;	1159	our $MODEL;
1122		1160
1123	our $AUTOLOAD;	1161	our $AUTOLOAD;
1124	our @ISA;	1162	our @ISA;
1125		1163
1126	our @REGISTRY;	1164	our @REGISTRY;
1127
1128	our $WIN32;
1129		1165
1130	our $VERBOSE;	1166	our $VERBOSE;
1131		1167
1132	BEGIN {	1168	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1169	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
…		…
1288	# we assume CLOEXEC is already set by perl in all important cases	1324	# we assume CLOEXEC is already set by perl in all important cases
1289		1325
1290	($fh2, $rw)	1326	($fh2, $rw)
1291	}	1327	}
1292		1328
1293	#############################################################################	1329	=head1 SIMPLIFIED AE API
1294	# "new" API, currently only emulation of it	1330
1295	#############################################################################	1331	Starting with version 5.0, AnyEvent officially supports a second, much
		1332	simpler, API that is designed to reduce the calling, typing and memory
		1333	overhead.
		1334
		1335	See the L<AE> manpage for details.
		1336
		1337	=cut
1296		1338
1297	package AE;	1339	package AE;
1298		1340
1299	our $VERSION = $AnyEvent::VERSION;	1341	our $VERSION = $AnyEvent::VERSION;
1300		1342
…		…
1336		1378
1337	package AnyEvent::Base;	1379	package AnyEvent::Base;
1338		1380
1339	# default implementations for many methods	1381	# default implementations for many methods
1340		1382
1341	sub _time {	1383	sub _time() {
1342	# probe for availability of Time::HiRes	1384	# probe for availability of Time::HiRes
1343	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1385	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1344	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1386	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1345	*_time = \&Time::HiRes::time;	1387	*_time = \&Time::HiRes::time;
1346	# if (eval "use POSIX (); (POSIX::times())...	1388	# if (eval "use POSIX (); (POSIX::times())...
…		…
1366		1408
1367	our $HAVE_ASYNC_INTERRUPT;	1409	our $HAVE_ASYNC_INTERRUPT;
1368		1410
1369	sub _have_async_interrupt() {	1411	sub _have_async_interrupt() {
1370	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1412	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1371	&& eval "use Async::Interrupt 1.0 (); 1")	1413	&& eval "use Async::Interrupt 1.02 (); 1")
1372	unless defined $HAVE_ASYNC_INTERRUPT;	1414	unless defined $HAVE_ASYNC_INTERRUPT;
1373		1415
1374	$HAVE_ASYNC_INTERRUPT	1416	$HAVE_ASYNC_INTERRUPT
1375	}	1417	}
1376		1418
…		…
1379	our ($SIG_COUNT, $SIG_TW);	1421	our ($SIG_COUNT, $SIG_TW);
1380		1422
1381	sub _signal_exec {	1423	sub _signal_exec {
1382	$HAVE_ASYNC_INTERRUPT	1424	$HAVE_ASYNC_INTERRUPT
1383	? $SIGPIPE_R->drain	1425	? $SIGPIPE_R->drain
1384	: sysread $SIGPIPE_R, my $dummy, 9;	1426	: sysread $SIGPIPE_R, (my $dummy), 9;
1385		1427
1386	while (%SIG_EV) {	1428	while (%SIG_EV) {
1387	for (keys %SIG_EV) {	1429	for (keys %SIG_EV) {
1388	delete $SIG_EV{$_};	1430	delete $SIG_EV{$_};
1389	$_->() for values %{ $SIG_CB{$_} \|\| {} };	1431	$_->() for values %{ $SIG_CB{$_} \|\| {} };
…		…
1905	warn "read: $input\n"; # output what has been read	1947	warn "read: $input\n"; # output what has been read
1906	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1948	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1907	},	1949	},
1908	);	1950	);
1909		1951
1910	my $time_watcher; # can only be used once
1911
1912	sub new_timer {
1913	$timer = AnyEvent->timer (after => 1, cb => sub {	1952	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1914	warn "timeout\n"; # print 'timeout' about every second	1953	warn "timeout\n"; # print 'timeout' at most every second
1915	&new_timer; # and restart the time
1916	});	1954	});
1917	}
1918
1919	new_timer; # create first timer
1920		1955
1921	$cv->recv; # wait until user enters /^q/i	1956	$cv->recv; # wait until user enters /^q/i
1922		1957
1923	=head1 REAL-WORLD EXAMPLE	1958	=head1 REAL-WORLD EXAMPLE
1924		1959
…		…
2055	through AnyEvent. The benchmark creates a lot of timers (with a zero	2090	through AnyEvent. The benchmark creates a lot of timers (with a zero
2056	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2091	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
2057	which it is), lets them fire exactly once and destroys them again.	2092	which it is), lets them fire exactly once and destroys them again.
2058		2093
2059	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2094	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2060	distribution.	2095	distribution. It uses the L<AE> interface, which makes a real difference
		2096	for the EV and Perl backends only.
2061		2097
2062	=head3 Explanation of the columns	2098	=head3 Explanation of the columns
2063		2099
2064	I<watcher> is the number of event watchers created/destroyed. Since	2100	I<watcher> is the number of event watchers created/destroyed. Since
2065	different event models feature vastly different performances, each event	2101	different event models feature vastly different performances, each event
…		…
2086	watcher.	2122	watcher.
2087		2123
2088	=head3 Results	2124	=head3 Results
2089		2125
2090	name watchers bytes create invoke destroy comment	2126	name watchers bytes create invoke destroy comment
2091	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2127	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2092	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2128	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2093	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2129	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2094	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2130	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2095	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2131	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2096	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2132	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2097	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2133	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2098	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2134	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2099	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2135	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2100	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2136	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2101	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2137	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2102	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2138	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2103		2139
2104	=head3 Discussion	2140	=head3 Discussion
2105		2141
2106	The benchmark does I<not> measure scalability of the event loop very	2142	The benchmark does I<not> measure scalability of the event loop very
2107	well. For example, a select-based event loop (such as the pure perl one)	2143	well. For example, a select-based event loop (such as the pure perl one)
…		…
2119	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2155	benchmark machine, handling an event takes roughly 1600 CPU cycles with
2120	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2156	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2121	cycles with POE.	2157	cycles with POE.
2122		2158
2123	C<EV> is the sole leader regarding speed and memory use, which are both	2159	C<EV> is the sole leader regarding speed and memory use, which are both
2124	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2160	maximal/minimal, respectively. When using the L<AE> API there is zero
		2161	overhead (when going through the AnyEvent API create is about 5-6 times
		2162	slower, with other times being equal, so still uses far less memory than
2125	far less memory than any other event loop and is still faster than Event	2163	any other event loop and is still faster than Event natively).
2126	natively.
2127		2164
2128	The pure perl implementation is hit in a few sweet spots (both the	2165	The pure perl implementation is hit in a few sweet spots (both the
2129	constant timeout and the use of a single fd hit optimisations in the perl	2166	constant timeout and the use of a single fd hit optimisations in the perl
2130	interpreter and the backend itself). Nevertheless this shows that it	2167	interpreter and the backend itself). Nevertheless this shows that it
2131	adds very little overhead in itself. Like any select-based backend its	2168	adds very little overhead in itself. Like any select-based backend its
…		…
2205	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2242	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2206	(1%) are active. This mirrors the activity of large servers with many	2243	(1%) are active. This mirrors the activity of large servers with many
2207	connections, most of which are idle at any one point in time.	2244	connections, most of which are idle at any one point in time.
2208		2245
2209	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2246	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2210	distribution.	2247	distribution. It uses the L<AE> interface, which makes a real difference
		2248	for the EV and Perl backends only.
2211		2249
2212	=head3 Explanation of the columns	2250	=head3 Explanation of the columns
2213		2251
2214	I<sockets> is the number of sockets, and twice the number of "servers" (as	2252	I<sockets> is the number of sockets, and twice the number of "servers" (as
2215	each server has a read and write socket end).	2253	each server has a read and write socket end).
…		…
2223	a new one that moves the timeout into the future.	2261	a new one that moves the timeout into the future.
2224		2262
2225	=head3 Results	2263	=head3 Results
2226		2264
2227	name sockets create request	2265	name sockets create request
2228	EV 20000 69.01 11.16	2266	EV 20000 62.66 7.99
2229	Perl 20000 73.32 35.87	2267	Perl 20000 68.32 32.64
2230	IOAsync 20000 157.00 98.14 epoll	2268	IOAsync 20000 174.06 101.15 epoll
2231	IOAsync 20000 159.31 616.06 poll	2269	IOAsync 20000 174.67 610.84 poll
2232	Event 20000 212.62 257.32	2270	Event 20000 202.69 242.91
2233	Glib 20000 651.16 1896.30	2271	Glib 20000 557.01 1689.52
2234	POE 20000 349.67 12317.24 uses POE::Loop::Event	2272	POE 20000 341.54 12086.32 uses POE::Loop::Event
2235		2273
2236	=head3 Discussion	2274	=head3 Discussion
2237		2275
2238	This benchmark I<does> measure scalability and overall performance of the	2276	This benchmark I<does> measure scalability and overall performance of the
2239	particular event loop.	2277	particular event loop.
…		…
2365	As you can see, the AnyEvent + EV combination even beats the	2403	As you can see, the AnyEvent + EV combination even beats the
2366	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2404	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2367	backend easily beats IO::Lambda and POE.	2405	backend easily beats IO::Lambda and POE.
2368		2406
2369	And even the 100% non-blocking version written using the high-level (and	2407	And even the 100% non-blocking version written using the high-level (and
2370	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2408	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2371	large margin, even though it does all of DNS, tcp-connect and socket I/O	2409	higher level ("unoptimised") abstractions by a large margin, even though
2372	in a non-blocking way.	2410	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2373		2411
2374	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2412	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2375	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2413	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2376	part of the IO::lambda distribution and were used without any changes.	2414	part of the IO::Lambda distribution and were used without any changes.
2377		2415
2378		2416
2379	=head1 SIGNALS	2417	=head1 SIGNALS
2380		2418
2381	AnyEvent currently installs handlers for these signals:	2419	AnyEvent currently installs handlers for these signals:
…		…
2423	it's built-in modules) are required to use it.	2461	it's built-in modules) are required to use it.
2424		2462
2425	That does not mean that AnyEvent won't take advantage of some additional	2463	That does not mean that AnyEvent won't take advantage of some additional
2426	modules if they are installed.	2464	modules if they are installed.
2427		2465
2428	This section epxlains which additional modules will be used, and how they	2466	This section explains which additional modules will be used, and how they
2429	affect AnyEvent's operetion.	2467	affect AnyEvent's operation.
2430		2468
2431	=over 4	2469	=over 4
2432		2470
2433	=item L<Async::Interrupt>	2471	=item L<Async::Interrupt>
2434		2472
…		…
2439	catch the signals) with some delay (default is 10 seconds, look for	2477	catch the signals) with some delay (default is 10 seconds, look for
2440	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2478	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2441		2479
2442	If this module is available, then it will be used to implement signal	2480	If this module is available, then it will be used to implement signal
2443	catching, which means that signals will not be delayed, and the event loop	2481	catching, which means that signals will not be delayed, and the event loop
2444	will not be interrupted regularly, which is more efficient (And good for	2482	will not be interrupted regularly, which is more efficient (and good for
2445	battery life on laptops).	2483	battery life on laptops).
2446		2484
2447	This affects not just the pure-perl event loop, but also other event loops	2485	This affects not just the pure-perl event loop, but also other event loops
2448	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2486	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2449		2487
…		…
2470	lot less memory), but otherwise doesn't affect guard operation much. It is	2508	lot less memory), but otherwise doesn't affect guard operation much. It is
2471	purely used for performance.	2509	purely used for performance.
2472		2510
2473	=item L<JSON> and L<JSON::XS>	2511	=item L<JSON> and L<JSON::XS>
2474		2512
2475	This module is required when you want to read or write JSON data via	2513	One of these modules is required when you want to read or write JSON data
2476	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2514	via L<AnyEvent::Handle>. It is also written in pure-perl, but can take
2477	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2515	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2478		2516
2479	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is	2517	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2480	installed.	2518	installed.
2481		2519
…		…
2499		2537
2500	Most event libraries are not fork-safe. The ones who are usually are	2538	Most event libraries are not fork-safe. The ones who are usually are
2501	because they rely on inefficient but fork-safe C<select> or C<poll>	2539	because they rely on inefficient but fork-safe C<select> or C<poll>
2502	calls. Only L<EV> is fully fork-aware.	2540	calls. Only L<EV> is fully fork-aware.
2503		2541
		2542	This means that, in general, you cannot fork and do event processing
		2543	in the child if a watcher was created before the fork (which in turn
		2544	initialises the event library).
		2545
2504	If you have to fork, you must either do so I<before> creating your first	2546	If you have to fork, you must either do so I<before> creating your first
2505	watcher OR you must not use AnyEvent at all in the child OR you must do	2547	watcher OR you must not use AnyEvent at all in the child OR you must do
2506	something completely out of the scope of AnyEvent.	2548	something completely out of the scope of AnyEvent.
		2549
		2550	The problem of doing event processing in the parent I<and> the child
		2551	is much more complicated: even for backends that I<are> fork-aware or
		2552	fork-safe, their behaviour is not usually what you want: fork clones all
		2553	watchers, that means all timers, I/O watchers etc. are active in both
		2554	parent and child, which is almost never what you want.
2507		2555
2508		2556
2509	=head1 SECURITY CONSIDERATIONS	2557	=head1 SECURITY CONSIDERATIONS
2510		2558
2511	AnyEvent can be forced to load any event model via	2559	AnyEvent can be forced to load any event model via

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.277 by root, Sun Aug 9 13:27:23 2009 UTC vs. Revision 1.305 by root, Sun Dec 13 05:13:15 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.277 by root, Sun Aug 9 13:27:23 2009 UTC vs.
Revision 1.305 by root, Sun Dec 13 05:13:15 2009 UTC