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Comparing AnyEvent/README (file contents):
Revision 1.24 by root, Thu May 29 03:46:04 2008 UTC vs.
Revision 1.41 by root, Fri Jun 26 06:33:17 2009 UTC

…		…
1	=> NAME	1	NAME
2	AnyEvent - provide framework for multiple event loops	2	AnyEvent - provide framework for multiple event loops
3		3
4	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event	4	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
5	loops	5	event loops.
6		6
7	SYNOPSIS	7	SYNOPSIS
8	use AnyEvent;	8	use AnyEvent;
9		9
		10	# file descriptor readable
10	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		12
		13	# one-shot or repeating timers
		14	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		15	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		16
		17	print AnyEvent->now; # prints current event loop time
		18	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		19
		20	# POSIX signal
		21	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		22
		23	# child process exit
		24	my $w = AnyEvent->child (pid => $pid, cb => sub {
		25	my ($pid, $status) = @_;
11	...	26	...
12	});	27	});
13		28
14	my $w = AnyEvent->timer (after => $seconds, cb => sub {	29	# called when event loop idle (if applicable)
15	...	30	my $w = AnyEvent->idle (cb => sub { ... });
16	});
17		31
18	my $w = AnyEvent->condvar; # stores whether a condition was flagged	32	my $w = AnyEvent->condvar; # stores whether a condition was flagged
19	$w->send; # wake up current and all future recv's	33	$w->send; # wake up current and all future recv's
20	$w->recv; # enters "main loop" till $condvar gets ->send	34	$w->recv; # enters "main loop" till $condvar gets ->send
		35	# use a condvar in callback mode:
		36	$w->cb (sub { $_[0]->recv });
		37
		38	INTRODUCTION/TUTORIAL
		39	This manpage is mainly a reference manual. If you are interested in a
		40	tutorial or some gentle introduction, have a look at the AnyEvent::Intro
		41	manpage.
21		42
22	WHY YOU SHOULD USE THIS MODULE (OR NOT)	43	WHY YOU SHOULD USE THIS MODULE (OR NOT)
23	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	44	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
24	nowadays. So what is different about AnyEvent?	45	nowadays. So what is different about AnyEvent?
25		46
26	Executive Summary: AnyEvent is compatible, AnyEvent is *free of	47	Executive Summary: AnyEvent is compatible, AnyEvent is *free of
27	policy* and AnyEvent is small and efficient.	48	policy* and AnyEvent is small and efficient.
28		49
29	First and foremost, AnyEvent is not an event model itself, it only	50	First and foremost, AnyEvent is not an event model itself, it only
30	interfaces to whatever event model the main program happens to use in a	51	interfaces to whatever event model the main program happens to use, in a
31	pragmatic way. For event models and certain classes of immortals alike,	52	pragmatic way. For event models and certain classes of immortals alike,
32	the statement "there can only be one" is a bitter reality: In general,	53	the statement "there can only be one" is a bitter reality: In general,
33	only one event loop can be active at the same time in a process.	54	only one event loop can be active at the same time in a process.
34	AnyEvent helps hiding the differences between those event loops.	55	AnyEvent cannot change this, but it can hide the differences between
		56	those event loops.
35		57
36	The goal of AnyEvent is to offer module authors the ability to do event	58	The goal of AnyEvent is to offer module authors the ability to do event
37	programming (waiting for I/O or timer events) without subscribing to a	59	programming (waiting for I/O or timer events) without subscribing to a
38	religion, a way of living, and most importantly: without forcing your	60	religion, a way of living, and most importantly: without forcing your
39	module users into the same thing by forcing them to use the same event	61	module users into the same thing by forcing them to use the same event
40	model you use.	62	model you use.
41		63
42	For modules like POE or IO::Async (which is a total misnomer as it is	64	For modules like POE or IO::Async (which is a total misnomer as it is
43	actually doing all I/O synchronously...), using them in your module is	65	actually doing all I/O synchronously...), using them in your module is
44	like joining a cult: After you joined, you are dependent on them and you	66	like joining a cult: After you joined, you are dependent on them and you
45	cannot use anything else, as it is simply incompatible to everything	67	cannot use anything else, as they are simply incompatible to everything
46	that isn't itself. What's worse, all the potential users of your module	68	that isn't them. What's worse, all the potential users of your module
47	are also forced to use the same event loop you use.	69	are also forced to use the same event loop you use.
48		70
49	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	71	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
50	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	72	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
51	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your	73	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your
52	module uses one of those, every user of your module has to use it, too.	74	module uses one of those, every user of your module has to use it, too.
53	But if your module uses AnyEvent, it works transparently with all event	75	But if your module uses AnyEvent, it works transparently with all event
54	models it supports (including stuff like POE and IO::Async, as long as	76	models it supports (including stuff like IO::Async, as long as those use
55	those use one of the supported event loops. It is trivial to add new	77	one of the supported event loops. It is trivial to add new event loops
56	event loops to AnyEvent, too, so it is future-proof).	78	to AnyEvent, too, so it is future-proof).
57		79
58	In addition to being free of having to use *the one and only true event	80	In addition to being free of having to use *the one and only true event
59	model*, AnyEvent also is free of bloat and policy: with POE or similar	81	model*, AnyEvent also is free of bloat and policy: with POE or similar
60	modules, you get an enormous amount of code and strict rules you have to	82	modules, you get an enormous amount of code and strict rules you have to
61	follow. AnyEvent, on the other hand, is lean and up to the point, by	83	follow. AnyEvent, on the other hand, is lean and up to the point, by
117	These watchers are normal Perl objects with normal Perl lifetime. After	139	These watchers are normal Perl objects with normal Perl lifetime. After
118	creating a watcher it will immediately "watch" for events and invoke the	140	creating a watcher it will immediately "watch" for events and invoke the
119	callback when the event occurs (of course, only when the event model is	141	callback when the event occurs (of course, only when the event model is
120	in control).	142	in control).
121		143
		144	Note that callbacks must not permanently change global variables
		145	potentially in use by the event loop (such as $_ or $[) and that
		146	callbacks must not "die". The former is good programming practise in
		147	Perl and the latter stems from the fact that exception handling differs
		148	widely between event loops.
		149
122	To disable the watcher you have to destroy it (e.g. by setting the	150	To disable the watcher you have to destroy it (e.g. by setting the
123	variable you store it in to "undef" or otherwise deleting all references	151	variable you store it in to "undef" or otherwise deleting all references
124	to it).	152	to it).
125		153
126	All watchers are created by calling a method on the "AnyEvent" class.	154	All watchers are created by calling a method on the "AnyEvent" class.
…		…
128	Many watchers either are used with "recursion" (repeating timers for	156	Many watchers either are used with "recursion" (repeating timers for
129	example), or need to refer to their watcher object in other ways.	157	example), or need to refer to their watcher object in other ways.
130		158
131	An any way to achieve that is this pattern:	159	An any way to achieve that is this pattern:
132		160
133	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	161	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
134	# you can use $w here, for example to undef it	162	# you can use $w here, for example to undef it
135	undef $w;	163	undef $w;
136	});	164	});
137		165
138	Note that "my $w; $w =" combination. This is necessary because in Perl,	166	Note that "my $w; $w =" combination. This is necessary because in Perl,
139	my variables are only visible after the statement in which they are	167	my variables are only visible after the statement in which they are
140	declared.	168	declared.
141		169
142	I/O WATCHERS	170	I/O WATCHERS
143	You can create an I/O watcher by calling the "AnyEvent->io" method with	171	You can create an I/O watcher by calling the "AnyEvent->io" method with
144	the following mandatory key-value pairs as arguments:	172	the following mandatory key-value pairs as arguments:
145		173
146	"fh" the Perl file handle (not file descriptor) to watch for events.	174	"fh" is the Perl file handle (not file descriptor) to watch for
		175	events (AnyEvent might or might not keep a reference to this file
		176	handle). Note that only file handles pointing to things for which
		177	non-blocking operation makes sense are allowed. This includes sockets,
		178	most character devices, pipes, fifos and so on, but not for example
		179	files or block devices.
		180
147	"poll" must be a string that is either "r" or "w", which creates a	181	"poll" must be a string that is either "r" or "w", which creates a
148	watcher waiting for "r"eadable or "w"ritable events, respectively. "cb"	182	watcher waiting for "r"eadable or "w"ritable events, respectively.
		183
149	is the callback to invoke each time the file handle becomes ready.	184	"cb" is the callback to invoke each time the file handle becomes ready.
150		185
151	Although the callback might get passed parameters, their value and	186	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	187	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	188	callbacks cannot use arguments passed to I/O watcher callbacks.
154		189
…		…
158		193
159	Some event loops issue spurious readyness notifications, so you should	194	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	195	always use non-blocking calls when reading/writing from/to your file
161	handles.	196	handles.
162		197
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	198	Example: wait for readability of STDIN, then read a line and disable the
		199	watcher.
		200
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	201	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	202	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	203	warn "read: $input\n";
169	undef $w;	204	undef $w;
170	});	205	});
…		…
179		214
180	Although the callback might get passed parameters, their value and	215	Although the callback might get passed parameters, their value and
181	presence is undefined and you cannot rely on them. Portable AnyEvent	216	presence is undefined and you cannot rely on them. Portable AnyEvent
182	callbacks cannot use arguments passed to time watcher callbacks.	217	callbacks cannot use arguments passed to time watcher callbacks.
183		218
184	The timer callback will be invoked at most once: if you want a repeating	219	The callback will normally be invoked once only. If you specify another
185	timer you have to create a new watcher (this is a limitation by both Tk	220	parameter, "interval", as a strictly positive number (> 0), then the
186	and Glib).	221	callback will be invoked regularly at that interval (in fractional
		222	seconds) after the first invocation. If "interval" is specified with a
		223	false value, then it is treated as if it were missing.
187		224
188	Example:	225	The callback will be rescheduled before invoking the callback, but no
		226	attempt is done to avoid timer drift in most backends, so the interval
		227	is only approximate.
189		228
190	# fire an event after 7.7 seconds	229	Example: fire an event after 7.7 seconds.
		230
191	my $w = AnyEvent->timer (after => 7.7, cb => sub {	231	my $w = AnyEvent->timer (after => 7.7, cb => sub {
192	warn "timeout\n";	232	warn "timeout\n";
193	});	233	});
194		234
195	# to cancel the timer:	235	# to cancel the timer:
196	undef $w;	236	undef $w;
197		237
198	Example 2:
199
200	# fire an event after 0.5 seconds, then roughly every second	238	Example 2: fire an event after 0.5 seconds, then roughly every second.
201	my $w;
202		239
203	my $cb = sub {
204	# cancel the old timer while creating a new one
205	$w = AnyEvent->timer (after => 1, cb => $cb);	240	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		241	warn "timeout\n";
206	};	242	};
207
208	# start the "loop" by creating the first watcher
209	$w = AnyEvent->timer (after => 0.5, cb => $cb);
210		243
211	TIMING ISSUES	244	TIMING ISSUES
212	There are two ways to handle timers: based on real time (relative, "fire	245	There are two ways to handle timers: based on real time (relative, "fire
213	in 10 seconds") and based on wallclock time (absolute, "fire at 12	246	in 10 seconds") and based on wallclock time (absolute, "fire at 12
214	o'clock").	247	o'clock").
…		…
288	In either case, if you care (and in most cases, you don't), then you	321	In either case, if you care (and in most cases, you don't), then you
289	can get whatever behaviour you want with any event loop, by taking	322	can get whatever behaviour you want with any event loop, by taking
290	the difference between "AnyEvent->time" and "AnyEvent->now" into	323	the difference between "AnyEvent->time" and "AnyEvent->now" into
291	account.	324	account.
292		325
		326	AnyEvent->now_update
		327	Some event loops (such as EV or AnyEvent::Impl::Perl) cache the
		328	current time for each loop iteration (see the discussion of
		329	AnyEvent->now, above).
		330
		331	When a callback runs for a long time (or when the process sleeps),
		332	then this "current" time will differ substantially from the real
		333	time, which might affect timers and time-outs.
		334
		335	When this is the case, you can call this method, which will update
		336	the event loop's idea of "current time".
		337
		338	Note that updating the time might cause some events to be handled.
		339
293	SIGNAL WATCHERS	340	SIGNAL WATCHERS
294	You can watch for signals using a signal watcher, "signal" is the signal	341	You can watch for signals using a signal watcher, "signal" is the signal
295	name without any "SIG" prefix, "cb" is the Perl callback to be invoked	342	name in uppercase and without any "SIG" prefix, "cb" is the Perl
296	whenever a signal occurs.	343	callback to be invoked whenever a signal occurs.
297		344
298	Although the callback might get passed parameters, their value and	345	Although the callback might get passed parameters, their value and
299	presence is undefined and you cannot rely on them. Portable AnyEvent	346	presence is undefined and you cannot rely on them. Portable AnyEvent
300	callbacks cannot use arguments passed to signal watcher callbacks.	347	callbacks cannot use arguments passed to signal watcher callbacks.
301		348
…		…
316		363
317	CHILD PROCESS WATCHERS	364	CHILD PROCESS WATCHERS
318	You can also watch on a child process exit and catch its exit status.	365	You can also watch on a child process exit and catch its exit status.
319		366
320	The child process is specified by the "pid" argument (if set to 0, it	367	The child process is specified by the "pid" argument (if set to 0, it
321	watches for any child process exit). The watcher will trigger as often	368	watches for any child process exit). The watcher will triggered only
322	as status change for the child are received. This works by installing a	369	when the child process has finished and an exit status is available, not
323	signal handler for "SIGCHLD". The callback will be called with the pid	370	on any trace events (stopped/continued).
324	and exit status (as returned by waitpid), so unlike other watcher types,	371
325	you can rely on child watcher callback arguments.	372	The callback will be called with the pid and exit status (as returned by
		373	waitpid), so unlike other watcher types, you can rely on child watcher
		374	callback arguments.
		375
		376	This watcher type works by installing a signal handler for "SIGCHLD",
		377	and since it cannot be shared, nothing else should use SIGCHLD or reap
		378	random child processes (waiting for specific child processes, e.g.
		379	inside "system", is just fine).
326		380
327	There is a slight catch to child watchers, however: you usually start	381	There is a slight catch to child watchers, however: you usually start
328	them after the child process was created, and this means the process	382	them after the child process was created, and this means the process
329	could have exited already (and no SIGCHLD will be sent anymore).	383	could have exited already (and no SIGCHLD will be sent anymore).
330		384
331	Not all event models handle this correctly (POE doesn't), but even for	385	Not all event models handle this correctly (neither POE nor IO::Async
		386	do, see their AnyEvent::Impl manpages for details), but even for event
332	event models that do handle this correctly, they usually need to be	387	models that do handle this correctly, they usually need to be loaded
333	loaded before the process exits (i.e. before you fork in the first	388	before the process exits (i.e. before you fork in the first place).
334	place).	389	AnyEvent's pure perl event loop handles all cases correctly regardless
		390	of when you start the watcher.
335		391
336	This means you cannot create a child watcher as the very first thing in	392	This means you cannot create a child watcher as the very first thing in
337	an AnyEvent program, you have to create at least one watcher before	393	an AnyEvent program, you have to create at least one watcher before
338	you "fork" the child (alternatively, you can call "AnyEvent::detect").	394	you "fork" the child (alternatively, you can call "AnyEvent::detect").
339		395
340	Example: fork a process and wait for it	396	Example: fork a process and wait for it
341		397
342	my $done = AnyEvent->condvar;	398	my $done = AnyEvent->condvar;
343		399
344	my $pid = fork or exit 5;	400	my $pid = fork or exit 5;
345		401
346	my $w = AnyEvent->child (	402	my $w = AnyEvent->child (
347	pid => $pid,	403	pid => $pid,
348	cb => sub {	404	cb => sub {
349	my ($pid, $status) = @_;	405	my ($pid, $status) = @_;
350	warn "pid $pid exited with status $status";	406	warn "pid $pid exited with status $status";
351	$done->send;	407	$done->send;
352	},	408	},
353	);	409	);
354		410
355	# do something else, then wait for process exit	411	# do something else, then wait for process exit
356	$done->recv;	412	$done->recv;
		413
		414	IDLE WATCHERS
		415	Sometimes there is a need to do something, but it is not so important to
		416	do it instantly, but only when there is nothing better to do. This
		417	"nothing better to do" is usually defined to be "no other events need
		418	attention by the event loop".
		419
		420	Idle watchers ideally get invoked when the event loop has nothing better
		421	to do, just before it would block the process to wait for new events.
		422	Instead of blocking, the idle watcher is invoked.
		423
		424	Most event loops unfortunately do not really support idle watchers (only
		425	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		426	will simply call the callback "from time to time".
		427
		428	Example: read lines from STDIN, but only process them when the program
		429	is otherwise idle:
		430
		431	my @lines; # read data
		432	my $idle_w;
		433	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		434	push @lines, scalar <STDIN>;
		435
		436	# start an idle watcher, if not already done
		437	$idle_w \|\|= AnyEvent->idle (cb => sub {
		438	# handle only one line, when there are lines left
		439	if (my $line = shift @lines) {
		440	print "handled when idle: $line";
		441	} else {
		442	# otherwise disable the idle watcher again
		443	undef $idle_w;
		444	}
		445	});
		446	});
357		447
358	CONDITION VARIABLES	448	CONDITION VARIABLES
359	If you are familiar with some event loops you will know that all of them	449	If you are familiar with some event loops you will know that all of them
360	require you to run some blocking "loop", "run" or similar function that	450	require you to run some blocking "loop", "run" or similar function that
361	will actively watch for new events and call your callbacks.	451	will actively watch for new events and call your callbacks.
…		…
366	The instrument to do that is called a "condition variable", so called	456	The instrument to do that is called a "condition variable", so called
367	because they represent a condition that must become true.	457	because they represent a condition that must become true.
368		458
369	Condition variables can be created by calling the "AnyEvent->condvar"	459	Condition variables can be created by calling the "AnyEvent->condvar"
370	method, usually without arguments. The only argument pair allowed is	460	method, usually without arguments. The only argument pair allowed is
		461
371	"cb", which specifies a callback to be called when the condition	462	"cb", which specifies a callback to be called when the condition
372	variable becomes true.	463	variable becomes true, with the condition variable as the first argument
		464	(but not the results).
373		465
374	After creation, the condition variable is "false" until it becomes	466	After creation, the condition variable is "false" until it becomes
375	"true" by calling the "send" method (or calling the condition variable	467	"true" by calling the "send" method (or calling the condition variable
376	as if it were a callback, read about the caveats in the description for	468	as if it were a callback, read about the caveats in the description for
377	the "->send" method).	469	the "->send" method).
…		…
433		525
434	my $done = AnyEvent->condvar;	526	my $done = AnyEvent->condvar;
435	my $delay = AnyEvent->timer (after => 5, cb => $done);	527	my $delay = AnyEvent->timer (after => 5, cb => $done);
436	$done->recv;	528	$done->recv;
437		529
		530	Example: Imagine an API that returns a condvar and doesn't support
		531	callbacks. This is how you make a synchronous call, for example from the
		532	main program:
		533
		534	use AnyEvent::CouchDB;
		535
		536	...
		537
		538	my @info = $couchdb->info->recv;
		539
		540	And this is how you would just ste a callback to be called whenever the
		541	results are available:
		542
		543	$couchdb->info->cb (sub {
		544	my @info = $_[0]->recv;
		545	});
		546
438	METHODS FOR PRODUCERS	547	METHODS FOR PRODUCERS
439	These methods should only be used by the producing side, i.e. the	548	These methods should only be used by the producing side, i.e. the
440	code/module that eventually sends the signal. Note that it is also the	549	code/module that eventually sends the signal. Note that it is also the
441	producer side which creates the condvar in most cases, but it isn't	550	producer side which creates the condvar in most cases, but it isn't
442	uncommon for the consumer to create it as well.	551	uncommon for the consumer to create it as well.
…		…
562		671
563	$bool = $cv->ready	672	$bool = $cv->ready
564	Returns true when the condition is "true", i.e. whether "send" or	673	Returns true when the condition is "true", i.e. whether "send" or
565	"croak" have been called.	674	"croak" have been called.
566		675
567	$cb = $cv->cb ([new callback])	676	$cb = $cv->cb ($cb->($cv))
568	This is a mutator function that returns the callback set and	677	This is a mutator function that returns the callback set and
569	optionally replaces it before doing so.	678	optionally replaces it before doing so.
570		679
571	The callback will be called when the condition becomes "true", i.e.	680	The callback will be called when the condition becomes "true", i.e.
572	when "send" or "croak" are called. Calling "recv" inside the	681	when "send" or "croak" are called, with the only argument being the
		682	condition variable itself. Calling "recv" inside the callback or at
573	callback or at any later time is guaranteed not to block.	683	any later time is guaranteed not to block.
574		684
575	GLOBAL VARIABLES AND FUNCTIONS	685	GLOBAL VARIABLES AND FUNCTIONS
576	$AnyEvent::MODEL	686	$AnyEvent::MODEL
577	Contains "undef" until the first watcher is being created. Then it	687	Contains "undef" until the first watcher is being created. Then it
578	contains the event model that is being used, which is the name of	688	contains the event model that is being used, which is the name of
…		…
589	AnyEvent::Impl::Tk based on Tk, very bad choice.	699	AnyEvent::Impl::Tk based on Tk, very bad choice.
590	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).	700	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
591	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	701	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
592	AnyEvent::Impl::POE based on POE, not generic enough for full support.	702	AnyEvent::Impl::POE based on POE, not generic enough for full support.
593		703
		704	# warning, support for IO::Async is only partial, as it is too broken
		705	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
		706	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
		707
594	There is no support for WxWidgets, as WxWidgets has no support for	708	There is no support for WxWidgets, as WxWidgets has no support for
595	watching file handles. However, you can use WxWidgets through the	709	watching file handles. However, you can use WxWidgets through the
596	POE Adaptor, as POE has a Wx backend that simply polls 20 times per	710	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
597	second, which was considered to be too horrible to even consider for	711	second, which was considered to be too horrible to even consider for
598	AnyEvent. Likewise, other POE backends can be used by AnyEvent by	712	AnyEvent. Likewise, other POE backends can be used by AnyEvent by
…		…
692	AnyEvent::Util	806	AnyEvent::Util
693	Contains various utility functions that replace often-used but	807	Contains various utility functions that replace often-used but
694	blocking functions such as "inet_aton" by event-/callback-based	808	blocking functions such as "inet_aton" by event-/callback-based
695	versions.	809	versions.
696		810
697	AnyEvent::Handle
698	Provide read and write buffers and manages watchers for reads and
699	writes.
700
701	AnyEvent::Socket	811	AnyEvent::Socket
702	Provides various utility functions for (internet protocol) sockets,	812	Provides various utility functions for (internet protocol) sockets,
703	addresses and name resolution. Also functions to create non-blocking	813	addresses and name resolution. Also functions to create non-blocking
704	tcp connections or tcp servers, with IPv6 and SRV record support and	814	tcp connections or tcp servers, with IPv6 and SRV record support and
705	more.	815	more.
706		816
		817	AnyEvent::Handle
		818	Provide read and write buffers, manages watchers for reads and
		819	writes, supports raw and formatted I/O, I/O queued and fully
		820	transparent and non-blocking SSL/TLS.
		821
707	AnyEvent::DNS	822	AnyEvent::DNS
708	Provides rich asynchronous DNS resolver capabilities.	823	Provides rich asynchronous DNS resolver capabilities.
709		824
		825	AnyEvent::HTTP
		826	A simple-to-use HTTP library that is capable of making a lot of
		827	concurrent HTTP requests.
		828
710	AnyEvent::HTTPD	829	AnyEvent::HTTPD
711	Provides a simple web application server framework.	830	Provides a simple web application server framework.
712		831
713	AnyEvent::FastPing	832	AnyEvent::FastPing
714	The fastest ping in the west.	833	The fastest ping in the west.
715		834
		835	AnyEvent::DBI
		836	Executes DBI requests asynchronously in a proxy process.
		837
		838	AnyEvent::AIO
		839	Truly asynchronous I/O, should be in the toolbox of every event
		840	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
		841	together.
		842
		843	AnyEvent::BDB
		844	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently
		845	fuses BDB and AnyEvent together.
		846
		847	AnyEvent::GPSD
		848	A non-blocking interface to gpsd, a daemon delivering GPS
		849	information.
		850
		851	AnyEvent::IGS
		852	A non-blocking interface to the Internet Go Server protocol (used by
		853	App::IGS).
		854
		855	AnyEvent::IRC
		856	AnyEvent based IRC client module family (replacing the older
716	Net::IRC3	857	Net::IRC3).
717	AnyEvent based IRC client module family.
718		858
719	Net::XMPP2	859	Net::XMPP2
720	AnyEvent based XMPP (Jabber protocol) module family.	860	AnyEvent based XMPP (Jabber protocol) module family.
721		861
722	Net::FCP	862	Net::FCP
…		…
727	High level API for event-based execution flow control.	867	High level API for event-based execution flow control.
728		868
729	Coro	869	Coro
730	Has special support for AnyEvent via Coro::AnyEvent.	870	Has special support for AnyEvent via Coro::AnyEvent.
731		871
732	AnyEvent::AIO, IO::AIO
733	Truly asynchronous I/O, should be in the toolbox of every event
734	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
735	together.
736
737	AnyEvent::BDB, BDB
738	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently
739	fuses IO::AIO and AnyEvent together.
740
741	IO::Lambda	872	IO::Lambda
742	The lambda approach to I/O - don't ask, look there. Can use	873	The lambda approach to I/O - don't ask, look there. Can use
743	AnyEvent.	874	AnyEvent.
744		875
745	SUPPLYING YOUR OWN EVENT MODEL INTERFACE	876	ERROR AND EXCEPTION HANDLING
746	This is an advanced topic that you do not normally need to use AnyEvent	877	In general, AnyEvent does not do any error handling - it relies on the
747	in a module. This section is only of use to event loop authors who want	878	caller to do that if required. The AnyEvent::Strict module (see also the
748	to provide AnyEvent compatibility.	879	"PERL_ANYEVENT_STRICT" environment variable, below) provides strict
		880	checking of all AnyEvent methods, however, which is highly useful during
		881	development.
749		882
750	If you need to support another event library which isn't directly	883	As for exception handling (i.e. runtime errors and exceptions thrown
751	supported by AnyEvent, you can supply your own interface to it by	884	while executing a callback), this is not only highly event-loop
752	pushing, before the first watcher gets created, the package name of the	885	specific, but also not in any way wrapped by this module, as this is the
753	event module and the package name of the interface to use onto	886	job of the main program.
754	@AnyEvent::REGISTRY. You can do that before and even without loading
755	AnyEvent, so it is reasonably cheap.
756		887
757	Example:	888	The pure perl event loop simply re-throws the exception (usually within
758		889	"condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
759	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];	890	Glib uses "install_exception_handler" and so on.
760
761	This tells AnyEvent to (literally) use the "urxvt::anyevent::"
762	package/class when it finds the "urxvt" package/module is already
763	loaded.
764
765	When AnyEvent is loaded and asked to find a suitable event model, it
766	will first check for the presence of urxvt by trying to "use" the
767	"urxvt::anyevent" module.
768
769	The class should provide implementations for all watcher types. See
770	AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and
771	so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see
772	the sources.
773
774	If you don't provide "signal" and "child" watchers than AnyEvent will
775	provide suitable (hopefully) replacements.
776
777	The above example isn't fictitious, the rxvt-unicode (a.k.a. urxvt)
778	terminal emulator uses the above line as-is. An interface isn't included
779	in AnyEvent because it doesn't make sense outside the embedded
780	interpreter inside rxvt-unicode, and it is updated and maintained as
781	part of the rxvt-unicode distribution.
782
783	rxvt-unicode also cheats a bit by not providing blocking access to
784	condition variables: code blocking while waiting for a condition will
785	"die". This still works with most modules/usages, and blocking calls
786	must not be done in an interactive application, so it makes sense.
787		891
788	ENVIRONMENT VARIABLES	892	ENVIRONMENT VARIABLES
789	The following environment variables are used by this module:	893	The following environment variables are used by this module or its
		894	submodules.
		895
		896	Note that AnyEvent will remove all environment variables starting with
		897	"PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is
		898	enabled.
790		899
791	"PERL_ANYEVENT_VERBOSE"	900	"PERL_ANYEVENT_VERBOSE"
792	By default, AnyEvent will be completely silent except in fatal	901	By default, AnyEvent will be completely silent except in fatal
793	conditions. You can set this environment variable to make AnyEvent	902	conditions. You can set this environment variable to make AnyEvent
794	more talkative.	903	more talkative.
…		…
797	conditions, such as not being able to load the event model specified	906	conditions, such as not being able to load the event model specified
798	by "PERL_ANYEVENT_MODEL".	907	by "PERL_ANYEVENT_MODEL".
799		908
800	When set to 2 or higher, cause AnyEvent to report to STDERR which	909	When set to 2 or higher, cause AnyEvent to report to STDERR which
801	event model it chooses.	910	event model it chooses.
		911
		912	"PERL_ANYEVENT_STRICT"
		913	AnyEvent does not do much argument checking by default, as thorough
		914	argument checking is very costly. Setting this variable to a true
		915	value will cause AnyEvent to load "AnyEvent::Strict" and then to
		916	thoroughly check the arguments passed to most method calls. If it
		917	finds any problems, it will croak.
		918
		919	In other words, enables "strict" mode.
		920
		921	Unlike "use strict", it is definitely recommended to keep it off in
		922	production. Keeping "PERL_ANYEVENT_STRICT=1" in your environment
		923	while developing programs can be very useful, however.
802		924
803	"PERL_ANYEVENT_MODEL"	925	"PERL_ANYEVENT_MODEL"
804	This can be used to specify the event model to be used by AnyEvent,	926	This can be used to specify the event model to be used by AnyEvent,
805	before auto detection and -probing kicks in. It must be a string	927	before auto detection and -probing kicks in. It must be a string
806	consisting entirely of ASCII letters. The string "AnyEvent::Impl::"	928	consisting entirely of ASCII letters. The string "AnyEvent::Impl::"
…		…
811	This functionality might change in future versions.	933	This functionality might change in future versions.
812		934
813	For example, to force the pure perl model (AnyEvent::Impl::Perl) you	935	For example, to force the pure perl model (AnyEvent::Impl::Perl) you
814	could start your program like this:	936	could start your program like this:
815		937
816	PERL_ANYEVENT_MODEL=Perl perl ...	938	PERL_ANYEVENT_MODEL=Perl perl ...
817		939
818	"PERL_ANYEVENT_PROTOCOLS"	940	"PERL_ANYEVENT_PROTOCOLS"
819	Used by both AnyEvent::DNS and AnyEvent::Socket to determine	941	Used by both AnyEvent::DNS and AnyEvent::Socket to determine
820	preferences for IPv4 or IPv6. The default is unspecified (and might	942	preferences for IPv4 or IPv6. The default is unspecified (and might
821	change, or be the result of auto probing).	943	change, or be the result of auto probing).
…		…
825	mentioned will be used, and preference will be given to protocols	947	mentioned will be used, and preference will be given to protocols
826	mentioned earlier in the list.	948	mentioned earlier in the list.
827		949
828	This variable can effectively be used for denial-of-service attacks	950	This variable can effectively be used for denial-of-service attacks
829	against local programs (e.g. when setuid), although the impact is	951	against local programs (e.g. when setuid), although the impact is
830	likely small, as the program has to handle connection errors	952	likely small, as the program has to handle conenction and other
831	already-	953	failures anyways.
832		954
833	Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over	955	Examples: "PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6" - prefer IPv4 over
834	IPv6, but support both and try to use both.	956	IPv6, but support both and try to use both.
835	"PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to	957	"PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
836	resolve or contact IPv6 addresses.	958	resolve or contact IPv6 addresses.
…		…
847	EDNS0 in its DNS requests.	969	EDNS0 in its DNS requests.
848		970
849	"PERL_ANYEVENT_MAX_FORKS"	971	"PERL_ANYEVENT_MAX_FORKS"
850	The maximum number of child processes that	972	The maximum number of child processes that
851	"AnyEvent::Util::fork_call" will create in parallel.	973	"AnyEvent::Util::fork_call" will create in parallel.
		974
		975	SUPPLYING YOUR OWN EVENT MODEL INTERFACE
		976	This is an advanced topic that you do not normally need to use AnyEvent
		977	in a module. This section is only of use to event loop authors who want
		978	to provide AnyEvent compatibility.
		979
		980	If you need to support another event library which isn't directly
		981	supported by AnyEvent, you can supply your own interface to it by
		982	pushing, before the first watcher gets created, the package name of the
		983	event module and the package name of the interface to use onto
		984	@AnyEvent::REGISTRY. You can do that before and even without loading
		985	AnyEvent, so it is reasonably cheap.
		986
		987	Example:
		988
		989	push @AnyEvent::REGISTRY, [urxvt => urxvt::anyevent::];
		990
		991	This tells AnyEvent to (literally) use the "urxvt::anyevent::"
		992	package/class when it finds the "urxvt" package/module is already
		993	loaded.
		994
		995	When AnyEvent is loaded and asked to find a suitable event model, it
		996	will first check for the presence of urxvt by trying to "use" the
		997	"urxvt::anyevent" module.
		998
		999	The class should provide implementations for all watcher types. See
		1000	AnyEvent::Impl::EV (source code), AnyEvent::Impl::Glib (Source code) and
		1001	so on for actual examples. Use "perldoc -m AnyEvent::Impl::Glib" to see
		1002	the sources.
		1003
		1004	If you don't provide "signal" and "child" watchers than AnyEvent will
		1005	provide suitable (hopefully) replacements.
		1006
		1007	The above example isn't fictitious, the rxvt-unicode (a.k.a. urxvt)
		1008	terminal emulator uses the above line as-is. An interface isn't included
		1009	in AnyEvent because it doesn't make sense outside the embedded
		1010	interpreter inside rxvt-unicode, and it is updated and maintained as
		1011	part of the rxvt-unicode distribution.
		1012
		1013	rxvt-unicode also cheats a bit by not providing blocking access to
		1014	condition variables: code blocking while waiting for a condition will
		1015	"die". This still works with most modules/usages, and blocking calls
		1016	must not be done in an interactive application, so it makes sense.
852		1017
853	EXAMPLE PROGRAM	1018	EXAMPLE PROGRAM
854	The following program uses an I/O watcher to read data from STDIN, a	1019	The following program uses an I/O watcher to read data from STDIN, a
855	timer to display a message once per second, and a condition variable to	1020	timer to display a message once per second, and a condition variable to
856	quit the program when the user enters quit:	1021	quit the program when the user enters quit:
…		…
1043	destroy is the time, in microseconds, that it takes to destroy a	1208	destroy is the time, in microseconds, that it takes to destroy a
1044	single watcher.	1209	single watcher.
1045		1210
1046	Results	1211	Results
1047	name watchers bytes create invoke destroy comment	1212	name watchers bytes create invoke destroy comment
1048	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1213	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1049	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1214	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1050	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1215	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1051	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1216	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1052	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1217	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1053	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1218	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1219	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1220	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1054	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1221	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1055	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1222	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1056	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1223	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1057	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1224	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1058		1225
1059	Discussion	1226	Discussion
1060	The benchmark does not measure scalability of the event loop very	1227	The benchmark does not measure scalability of the event loop very
1061	well. For example, a select-based event loop (such as the pure perl one)	1228	well. For example, a select-based event loop (such as the pure perl one)
1062	can never compete with an event loop that uses epoll when the number of	1229	can never compete with an event loop that uses epoll when the number of
…		…
1087	few of them active), of course, but this was not subject of this	1254	few of them active), of course, but this was not subject of this
1088	benchmark.	1255	benchmark.
1089		1256
1090	The "Event" module has a relatively high setup and callback invocation	1257	The "Event" module has a relatively high setup and callback invocation
1091	cost, but overall scores in on the third place.	1258	cost, but overall scores in on the third place.
		1259
		1260	"IO::Async" performs admirably well, about on par with "Event", even
		1261	when using its pure perl backend.
1092		1262
1093	"Glib"'s memory usage is quite a bit higher, but it features a faster	1263	"Glib"'s memory usage is quite a bit higher, but it features a faster
1094	callback invocation and overall ends up in the same class as "Event".	1264	callback invocation and overall ends up in the same class as "Event".
1095	However, Glib scales extremely badly, doubling the number of watchers	1265	However, Glib scales extremely badly, doubling the number of watchers
1096	increases the processing time by more than a factor of four, making it	1266	increases the processing time by more than a factor of four, making it
…		…
1167	single "request", that is, reading the token from the pipe and	1337	single "request", that is, reading the token from the pipe and
1168	forwarding it to another server. This includes deleting the old timeout	1338	forwarding it to another server. This includes deleting the old timeout
1169	and creating a new one that moves the timeout into the future.	1339	and creating a new one that moves the timeout into the future.
1170		1340
1171	Results	1341	Results
1172	name sockets create request	1342	name sockets create request
1173	EV 20000 69.01 11.16	1343	EV 20000 69.01 11.16
1174	Perl 20000 73.32 35.87	1344	Perl 20000 73.32 35.87
		1345	IOAsync 20000 157.00 98.14 epoll
		1346	IOAsync 20000 159.31 616.06 poll
1175	Event 20000 212.62 257.32	1347	Event 20000 212.62 257.32
1176	Glib 20000 651.16 1896.30	1348	Glib 20000 651.16 1896.30
1177	POE 20000 349.67 12317.24 uses POE::Loop::Event	1349	POE 20000 349.67 12317.24 uses POE::Loop::Event
1178		1350
1179	Discussion	1351	Discussion
1180	This benchmark does measure scalability and overall performance of the	1352	This benchmark does measure scalability and overall performance of the
1181	particular event loop.	1353	particular event loop.
1182		1354
1183	EV is again fastest. Since it is using epoll on my system, the setup	1355	EV is again fastest. Since it is using epoll on my system, the setup
1184	time is relatively high, though.	1356	time is relatively high, though.
1185		1357
1186	Perl surprisingly comes second. It is much faster than the C-based event	1358	Perl surprisingly comes second. It is much faster than the C-based event
1187	loops Event and Glib.	1359	loops Event and Glib.
		1360
		1361	IO::Async performs very well when using its epoll backend, and still
		1362	quite good compared to Glib when using its pure perl backend.
1188		1363
1189	Event suffers from high setup time as well (look at its code and you	1364	Event suffers from high setup time as well (look at its code and you
1190	will understand why). Callback invocation also has a high overhead	1365	will understand why). Callback invocation also has a high overhead
1191	compared to the "$_->() for .."-style loop that the Perl event loop	1366	compared to the "$_->() for .."-style loop that the Perl event loop
1192	uses. Event uses select or poll in basically all documented	1367	uses. Event uses select or poll in basically all documented
…		…
1243		1418
1244	Summary	1419	Summary
1245	* C-based event loops perform very well with small number of watchers,	1420	* C-based event loops perform very well with small number of watchers,
1246	as the management overhead dominates.	1421	as the management overhead dominates.
1247		1422
		1423	THE IO::Lambda BENCHMARK
		1424	Recently I was told about the benchmark in the IO::Lambda manpage, which
		1425	could be misinterpreted to make AnyEvent look bad. In fact, the
		1426	benchmark simply compares IO::Lambda with POE, and IO::Lambda looks
		1427	better (which shouldn't come as a surprise to anybody). As such, the
		1428	benchmark is fine, and mostly shows that the AnyEvent backend from
		1429	IO::Lambda isn't very optimal. But how would AnyEvent compare when used
		1430	without the extra baggage? To explore this, I wrote the equivalent
		1431	benchmark for AnyEvent.
		1432
		1433	The benchmark itself creates an echo-server, and then, for 500 times,
		1434	connects to the echo server, sends a line, waits for the reply, and then
		1435	creates the next connection. This is a rather bad benchmark, as it
		1436	doesn't test the efficiency of the framework or much non-blocking I/O,
		1437	but it is a benchmark nevertheless.
		1438
		1439	name runtime
		1440	Lambda/select 0.330 sec
		1441	+ optimized 0.122 sec
		1442	Lambda/AnyEvent 0.327 sec
		1443	+ optimized 0.138 sec
		1444	Raw sockets/select 0.077 sec
		1445	POE/select, components 0.662 sec
		1446	POE/select, raw sockets 0.226 sec
		1447	POE/select, optimized 0.404 sec
		1448
		1449	AnyEvent/select/nb 0.085 sec
		1450	AnyEvent/EV/nb 0.068 sec
		1451	+state machine 0.134 sec
		1452
		1453	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		1454	benchmarks actually make blocking connects and use 100% blocking I/O,
		1455	defeating the purpose of an event-based solution. All of the newly
		1456	written AnyEvent benchmarks use 100% non-blocking connects (using
		1457	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		1458	resolver), so AnyEvent is at a disadvantage here, as non-blocking
		1459	connects generally require a lot more bookkeeping and event handling
		1460	than blocking connects (which involve a single syscall only).
		1461
		1462	The last AnyEvent benchmark additionally uses AnyEvent::Handle, which
		1463	offers similar expressive power as POE and IO::Lambda, using
		1464	conventional Perl syntax. This means that both the echo server and the
		1465	client are 100% non-blocking, further placing it at a disadvantage.
		1466
		1467	As you can see, the AnyEvent + EV combination even beats the
		1468	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		1469	backend easily beats IO::Lambda and POE.
		1470
		1471	And even the 100% non-blocking version written using the high-level (and
		1472	slow :) AnyEvent::Handle abstraction beats both POE and IO::Lambda by a
		1473	large margin, even though it does all of DNS, tcp-connect and socket I/O
		1474	in a non-blocking way.
		1475
		1476	The two AnyEvent benchmarks programs can be found as eg/ae0.pl and
		1477	eg/ae2.pl in the AnyEvent distribution, the remaining benchmarks are
		1478	part of the IO::lambda distribution and were used without any changes.
		1479
		1480	SIGNALS
		1481	AnyEvent currently installs handlers for these signals:
		1482
		1483	SIGCHLD
		1484	A handler for "SIGCHLD" is installed by AnyEvent's child watcher
		1485	emulation for event loops that do not support them natively. Also,
		1486	some event loops install a similar handler.
		1487
		1488	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent
		1489	will reset it to default, to avoid losing child exit statuses.
		1490
		1491	SIGPIPE
		1492	A no-op handler is installed for "SIGPIPE" when $SIG{PIPE} is
		1493	"undef" when AnyEvent gets loaded.
		1494
		1495	The rationale for this is that AnyEvent users usually do not really
		1496	depend on SIGPIPE delivery (which is purely an optimisation for
		1497	shell use, or badly-written programs), but "SIGPIPE" can cause
		1498	spurious and rare program exits as a lot of people do not expect
		1499	"SIGPIPE" when writing to some random socket.
		1500
		1501	The rationale for installing a no-op handler as opposed to ignoring
		1502	it is that this way, the handler will be restored to defaults on
		1503	exec.
		1504
		1505	Feel free to install your own handler, or reset it to defaults.
		1506
1248	FORK	1507	FORK
1249	Most event libraries are not fork-safe. The ones who are usually are	1508	Most event libraries are not fork-safe. The ones who are usually are
1250	because they rely on inefficient but fork-safe "select" or "poll" calls.	1509	because they rely on inefficient but fork-safe "select" or "poll" calls.
1251	Only EV is fully fork-aware.	1510	Only EV is fully fork-aware.
1252		1511
…		…
1262	model than specified in the variable.	1521	model than specified in the variable.
1263		1522
1264	You can make AnyEvent completely ignore this variable by deleting it	1523	You can make AnyEvent completely ignore this variable by deleting it
1265	before the first watcher gets created, e.g. with a "BEGIN" block:	1524	before the first watcher gets created, e.g. with a "BEGIN" block:
1266		1525
1267	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1526	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1268		1527
1269	use AnyEvent;	1528	use AnyEvent;
1270		1529
1271	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1530	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1272	be used to probe what backend is used and gain other information (which	1531	be used to probe what backend is used and gain other information (which
1273	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1532	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL),
		1533	and $ENV{PERL_ANYEVENT_STRICT}.
		1534
		1535	Note that AnyEvent will remove all environment variables starting with
		1536	"PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is
		1537	enabled.
		1538
		1539	BUGS
		1540	Perl 5.8 has numerous memleaks that sometimes hit this module and are
		1541	hard to work around. If you suffer from memleaks, first upgrade to Perl
		1542	5.10 and check wether the leaks still show up. (Perl 5.10.0 has other
		1543	annoying memleaks, such as leaking on "map" and "grep" but it is usually
		1544	not as pronounced).
1274		1545
1275	SEE ALSO	1546	SEE ALSO
1276	Utility functions: AnyEvent::Util.	1547	Utility functions: AnyEvent::Util.
1277		1548
1278	Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk,	1549	Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk,
…		…
1290	Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event,	1561	Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event,
1291		1562
1292	Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS.	1563	Nontrivial usage examples: Net::FCP, Net::XMPP2, AnyEvent::DNS.
1293		1564
1294	AUTHOR	1565	AUTHOR
1295	Marc Lehmann <schmorp@schmorp.de>	1566	Marc Lehmann <schmorp@schmorp.de>
1296	http://home.schmorp.de/	1567	http://home.schmorp.de/
1297		1568

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Comparing AnyEvent/README (file contents): Revision 1.24 by root, Thu May 29 03:46:04 2008 UTC vs. Revision 1.41 by root, Fri Jun 26 06:33:17 2009 UTC

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Comparing AnyEvent/README (file contents):
Revision 1.24 by root, Thu May 29 03:46:04 2008 UTC vs.
Revision 1.41 by root, Fri Jun 26 06:33:17 2009 UTC