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Comparing AnyEvent/README (file contents):
Revision 1.61 by root, Wed Apr 28 14:15:55 2010 UTC vs.
Revision 1.67 by root, Fri Aug 26 05:33:53 2011 UTC

…		…
1	NAME	1	NAME
2	AnyEvent - the DBI of event loop programming	2	AnyEvent - the DBI of event loop programming
3		3
4	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,	4	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async,
5	Qt and POE are various supported event loops/environments.	5	Qt, FLTK and POE are various supported event loops/environments.
6		6
7	SYNOPSIS	7	SYNOPSIS
8	use AnyEvent;	8	use AnyEvent;
9		9
10	# if you prefer function calls, look at the L<AE> manpage for	10	# if you prefer function calls, look at the AE manpage for
11	# an alternative API.	11	# an alternative API.
12		12
13	# file handle or descriptor readable	13	# file handle or descriptor readable
14	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	14	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
15		15
16	# one-shot or repeating timers	16	# one-shot or repeating timers
17	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	17	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
18	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	18	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
19		19
20	print AnyEvent->now; # prints current event loop time	20	print AnyEvent->now; # prints current event loop time
21	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	21	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
22		22
23	# POSIX signal	23	# POSIX signal
42	This manpage is mainly a reference manual. If you are interested in a	42	This manpage is mainly a reference manual. If you are interested in a
43	tutorial or some gentle introduction, have a look at the AnyEvent::Intro	43	tutorial or some gentle introduction, have a look at the AnyEvent::Intro
44	manpage.	44	manpage.
45		45
46	SUPPORT	46	SUPPORT
		47	An FAQ document is available as AnyEvent::FAQ.
		48
47	There is a mailinglist for discussing all things AnyEvent, and an IRC	49	There also is a mailinglist for discussing all things AnyEvent, and an
48	channel, too.	50	IRC channel, too.
49		51
50	See the AnyEvent project page at the Schmorpforge Ta-Sa Software	52	See the AnyEvent project page at the Schmorpforge Ta-Sa Software
51	Repository, at <http://anyevent.schmorp.de>, for more info.	53	Repository, at <http://anyevent.schmorp.de>, for more info.
52		54
53	WHY YOU SHOULD USE THIS MODULE (OR NOT)	55	WHY YOU SHOULD USE THIS MODULE (OR NOT)
…		…
71	module users into the same thing by forcing them to use the same event	73	module users into the same thing by forcing them to use the same event
72	model you use.	74	model you use.
73		75
74	For modules like POE or IO::Async (which is a total misnomer as it is	76	For modules like POE or IO::Async (which is a total misnomer as it is
75	actually doing all I/O synchronously...), using them in your module is	77	actually doing all I/O synchronously...), using them in your module is
76	like joining a cult: After you joined, you are dependent on them and you	78	like joining a cult: After you join, you are dependent on them and you
77	cannot use anything else, as they are simply incompatible to everything	79	cannot use anything else, as they are simply incompatible to everything
78	that isn't them. What's worse, all the potential users of your module	80	that isn't them. What's worse, all the potential users of your module
79	are also forced to use the same event loop you use.	81	are also forced to use the same event loop you use.
80		82
81	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
82	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
83	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if your	85	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
84	module uses one of those, every user of your module has to use it, too.	86	uses one of those, every user of your module has to use it, too. But if
85	But if your module uses AnyEvent, it works transparently with all event	87	your module uses AnyEvent, it works transparently with all event models
86	models it supports (including stuff like IO::Async, as long as those use	88	it supports (including stuff like IO::Async, as long as those use one of
87	one of the supported event loops. It is trivial to add new event loops	89	the supported event loops. It is easy to add new event loops to
88	to AnyEvent, too, so it is future-proof).	90	AnyEvent, too, so it is future-proof).
89		91
90	In addition to being free of having to use *the one and only true event	92	In addition to being free of having to use *the one and only true event
91	model*, AnyEvent also is free of bloat and policy: with POE or similar	93	model*, AnyEvent also is free of bloat and policy: with POE or similar
92	modules, you get an enormous amount of code and strict rules you have to	94	modules, you get an enormous amount of code and strict rules you have to
93	follow. AnyEvent, on the other hand, is lean and up to the point, by	95	follow. AnyEvent, on the other hand, is lean and to the point, by only
94	only offering the functionality that is necessary, in as thin as a	96	offering the functionality that is necessary, in as thin as a wrapper as
95	wrapper as technically possible.	97	technically possible.
96		98
97	Of course, AnyEvent comes with a big (and fully optional!) toolbox of	99	Of course, AnyEvent comes with a big (and fully optional!) toolbox of
98	useful functionality, such as an asynchronous DNS resolver, 100%	100	useful functionality, such as an asynchronous DNS resolver, 100%
99	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms	101	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
100	such as Windows) and lots of real-world knowledge and workarounds for	102	such as Windows) and lots of real-world knowledge and workarounds for
…		…
103	Now, if you do want lots of policy (this can arguably be somewhat	105	Now, if you do want lots of policy (this can arguably be somewhat
104	useful) and you want to force your users to use the one and only event	106	useful) and you want to force your users to use the one and only event
105	model, you should not use this module.	107	model, you should not use this module.
106		108
107	DESCRIPTION	109	DESCRIPTION
108	AnyEvent provides an identical interface to multiple event loops. This	110	AnyEvent provides a uniform interface to various event loops. This
109	allows module authors to utilise an event loop without forcing module	111	allows module authors to use event loop functionality without forcing
110	users to use the same event loop (as only a single event loop can	112	module users to use a specific event loop implementation (since more
111	coexist peacefully at any one time).	113	than one event loop cannot coexist peacefully).
112		114
113	The interface itself is vaguely similar, but not identical to the Event	115	The interface itself is vaguely similar, but not identical to the Event
114	module.	116	module.
115		117
116	During the first call of any watcher-creation method, the module tries	118	During the first call of any watcher-creation method, the module tries
117	to detect the currently loaded event loop by probing whether one of the	119	to detect the currently loaded event loop by probing whether one of the
118	following modules is already loaded: EV, Event, Glib,	120	following modules is already loaded: EV, AnyEvent::Loop, Event, Glib,
119	AnyEvent::Impl::Perl, Tk, Event::Lib, Qt, POE. The first one found is	121	Tk, Event::Lib, Qt, POE. The first one found is used. If none are
120	used. If none are found, the module tries to load these modules	122	detected, the module tries to load the first four modules in the order
121	(excluding Tk, Event::Lib, Qt and POE as the pure perl adaptor should	123	given; but note that if EV is not available, the pure-perl
122	always succeed) in the order given. The first one that can be	124	AnyEvent::Loop should always work, so the other two are not normally
123	successfully loaded will be used. If, after this, still none could be	125	tried.
124	found, AnyEvent will fall back to a pure-perl event loop, which is not
125	very efficient, but should work everywhere.
126		126
127	Because AnyEvent first checks for modules that are already loaded,	127	Because AnyEvent first checks for modules that are already loaded,
128	loading an event model explicitly before first using AnyEvent will	128	loading an event model explicitly before first using AnyEvent will
129	likely make that model the default. For example:	129	likely make that model the default. For example:
130		130
…		…
132	use AnyEvent;	132	use AnyEvent;
133		133
134	# .. AnyEvent will likely default to Tk	134	# .. AnyEvent will likely default to Tk
135		135
136	The likely means that, if any module loads another event model and	136	The likely means that, if any module loads another event model and
137	starts using it, all bets are off. Maybe you should tell their authors	137	starts using it, all bets are off - this case should be very rare
138	to use AnyEvent so their modules work together with others seamlessly...	138	though, as very few modules hardcode event loops without announcing this
		139	very loudly.
139		140
140	The pure-perl implementation of AnyEvent is called	141	The pure-perl implementation of AnyEvent is called "AnyEvent::Loop".
141	"AnyEvent::Impl::Perl". Like other event modules you can load it	142	Like other event modules you can load it explicitly and enjoy the high
142	explicitly and enjoy the high availability of that event loop :)	143	availability of that event loop :)
143		144
144	WATCHERS	145	WATCHERS
145	AnyEvent has the central concept of a watcher, which is an object that	146	AnyEvent has the central concept of a watcher, which is an object that
146	stores relevant data for each kind of event you are waiting for, such as	147	stores relevant data for each kind of event you are waiting for, such as
147	the callback to call, the file handle to watch, etc.	148	the callback to call, the file handle to watch, etc.
…		…
151	callback when the event occurs (of course, only when the event model is	152	callback when the event occurs (of course, only when the event model is
152	in control).	153	in control).
153		154
154	Note that callbacks must not permanently change global variables	155	Note that callbacks must not permanently change global variables
155	potentially in use by the event loop (such as $_ or $[) and that	156	potentially in use by the event loop (such as $_ or $[) and that
156	callbacks must not "die". The former is good programming practise in	157	callbacks must not "die". The former is good programming practice in
157	Perl and the latter stems from the fact that exception handling differs	158	Perl and the latter stems from the fact that exception handling differs
158	widely between event loops.	159	widely between event loops.
159		160
160	To disable the watcher you have to destroy it (e.g. by setting the	161	To disable a watcher you have to destroy it (e.g. by setting the
161	variable you store it in to "undef" or otherwise deleting all references	162	variable you store it in to "undef" or otherwise deleting all references
162	to it).	163	to it).
163		164
164	All watchers are created by calling a method on the "AnyEvent" class.	165	All watchers are created by calling a method on the "AnyEvent" class.
165		166
166	Many watchers either are used with "recursion" (repeating timers for	167	Many watchers either are used with "recursion" (repeating timers for
167	example), or need to refer to their watcher object in other ways.	168	example), or need to refer to their watcher object in other ways.
168		169
169	An any way to achieve that is this pattern:	170	One way to achieve that is this pattern:
170		171
171	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	172	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
172	# you can use $w here, for example to undef it	173	# you can use $w here, for example to undef it
173	undef $w;	174	undef $w;
174	});	175	});
…		…
205		206
206	The I/O watcher might use the underlying file descriptor or a copy of	207	The I/O watcher might use the underlying file descriptor or a copy of
207	it. You must not close a file handle as long as any watcher is active on	208	it. You must not close a file handle as long as any watcher is active on
208	the underlying file descriptor.	209	the underlying file descriptor.
209		210
210	Some event loops issue spurious readyness notifications, so you should	211	Some event loops issue spurious readiness notifications, so you should
211	always use non-blocking calls when reading/writing from/to your file	212	always use non-blocking calls when reading/writing from/to your file
212	handles.	213	handles.
213		214
214	Example: wait for readability of STDIN, then read a line and disable the	215	Example: wait for readability of STDIN, then read a line and disable the
215	watcher.	216	watcher.
…		…
238		239
239	Although the callback might get passed parameters, their value and	240	Although the callback might get passed parameters, their value and
240	presence is undefined and you cannot rely on them. Portable AnyEvent	241	presence is undefined and you cannot rely on them. Portable AnyEvent
241	callbacks cannot use arguments passed to time watcher callbacks.	242	callbacks cannot use arguments passed to time watcher callbacks.
242		243
243	The callback will normally be invoked once only. If you specify another	244	The callback will normally be invoked only once. If you specify another
244	parameter, "interval", as a strictly positive number (> 0), then the	245	parameter, "interval", as a strictly positive number (> 0), then the
245	callback will be invoked regularly at that interval (in fractional	246	callback will be invoked regularly at that interval (in fractional
246	seconds) after the first invocation. If "interval" is specified with a	247	seconds) after the first invocation. If "interval" is specified with a
247	false value, then it is treated as if it were missing.	248	false value, then it is treated as if it were not specified at all.
248		249
249	The callback will be rescheduled before invoking the callback, but no	250	The callback will be rescheduled before invoking the callback, but no
250	attempt is done to avoid timer drift in most backends, so the interval	251	attempt is made to avoid timer drift in most backends, so the interval
251	is only approximate.	252	is only approximate.
252		253
253	Example: fire an event after 7.7 seconds.	254	Example: fire an event after 7.7 seconds.
254		255
255	my $w = AnyEvent->timer (after => 7.7, cb => sub {	256	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
272		273
273	While most event loops expect timers to specified in a relative way,	274	While most event loops expect timers to specified in a relative way,
274	they use absolute time internally. This makes a difference when your	275	they use absolute time internally. This makes a difference when your
275	clock "jumps", for example, when ntp decides to set your clock backwards	276	clock "jumps", for example, when ntp decides to set your clock backwards
276	from the wrong date of 2014-01-01 to 2008-01-01, a watcher that is	277	from the wrong date of 2014-01-01 to 2008-01-01, a watcher that is
277	supposed to fire "after" a second might actually take six years to	278	supposed to fire "after a second" might actually take six years to
278	finally fire.	279	finally fire.
279		280
280	AnyEvent cannot compensate for this. The only event loop that is	281	AnyEvent cannot compensate for this. The only event loop that is
281	conscious about these issues is EV, which offers both relative	282	conscious of these issues is EV, which offers both relative (ev_timer,
282	(ev_timer, based on true relative time) and absolute (ev_periodic, based	283	based on true relative time) and absolute (ev_periodic, based on
283	on wallclock time) timers.	284	wallclock time) timers.
284		285
285	AnyEvent always prefers relative timers, if available, matching the	286	AnyEvent always prefers relative timers, if available, matching the
286	AnyEvent API.	287	AnyEvent API.
287		288
288	AnyEvent has two additional methods that return the "current time":	289	AnyEvent has two additional methods that return the "current time":
…		…
307	*In almost all cases (in all cases if you don't care), this is the	308	*In almost all cases (in all cases if you don't care), this is the
308	function to call when you want to know the current time.*	309	function to call when you want to know the current time.*
309		310
310	This function is also often faster then "AnyEvent->time", and thus	311	This function is also often faster then "AnyEvent->time", and thus
311	the preferred method if you want some timestamp (for example,	312	the preferred method if you want some timestamp (for example,
312	AnyEvent::Handle uses this to update it's activity timeouts).	313	AnyEvent::Handle uses this to update its activity timeouts).
313		314
314	The rest of this section is only of relevance if you try to be very	315	The rest of this section is only of relevance if you try to be very
315	exact with your timing, you can skip it without bad conscience.	316	exact with your timing; you can skip it without a bad conscience.
316		317
317	For a practical example of when these times differ, consider	318	For a practical example of when these times differ, consider
318	Event::Lib and EV and the following set-up:	319	Event::Lib and EV and the following set-up:
319		320
320	The event loop is running and has just invoked one of your callback	321	The event loop is running and has just invoked one of your callbacks
321	at time=500 (assume no other callbacks delay processing). In your	322	at time=500 (assume no other callbacks delay processing). In your
322	callback, you wait a second by executing "sleep 1" (blocking the	323	callback, you wait a second by executing "sleep 1" (blocking the
323	process for a second) and then (at time=501) you create a relative	324	process for a second) and then (at time=501) you create a relative
324	timer that fires after three seconds.	325	timer that fires after three seconds.
325		326
…		…
346	can get whatever behaviour you want with any event loop, by taking	347	can get whatever behaviour you want with any event loop, by taking
347	the difference between "AnyEvent->time" and "AnyEvent->now" into	348	the difference between "AnyEvent->time" and "AnyEvent->now" into
348	account.	349	account.
349		350
350	AnyEvent->now_update	351	AnyEvent->now_update
351	Some event loops (such as EV or AnyEvent::Impl::Perl) cache the	352	Some event loops (such as EV or AnyEvent::Loop) cache the current
352	current time for each loop iteration (see the discussion of	353	time for each loop iteration (see the discussion of AnyEvent->now,
353	AnyEvent->now, above).	354	above).
354		355
355	When a callback runs for a long time (or when the process sleeps),	356	When a callback runs for a long time (or when the process sleeps),
356	then this "current" time will differ substantially from the real	357	then this "current" time will differ substantially from the real
357	time, which might affect timers and time-outs.	358	time, which might affect timers and time-outs.
358		359
…		…
414		415
415	Signal Races, Delays and Workarounds	416	Signal Races, Delays and Workarounds
416	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	417	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
417	callbacks to signals in a generic way, which is a pity, as you cannot do	418	callbacks to signals in a generic way, which is a pity, as you cannot do
418	race-free signal handling in perl, requiring C libraries for this.	419	race-free signal handling in perl, requiring C libraries for this.
419	AnyEvent will try to do it's best, which means in some cases, signals	420	AnyEvent will try to do its best, which means in some cases, signals
420	will be delayed. The maximum time a signal might be delayed is specified	421	will be delayed. The maximum time a signal might be delayed is specified
421	in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable	422	in $AnyEvent::MAX_SIGNAL_LATENCY (default: 10 seconds). This variable
422	can be changed only before the first signal watcher is created, and	423	can be changed only before the first signal watcher is created, and
423	should be left alone otherwise. This variable determines how often	424	should be left alone otherwise. This variable determines how often
424	AnyEvent polls for signals (in case a wake-up was missed). Higher values	425	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
426	saving.	427	saving.
427		428
428	All these problems can be avoided by installing the optional	429	All these problems can be avoided by installing the optional
429	Async::Interrupt module, which works with most event loops. It will not	430	Async::Interrupt module, which works with most event loops. It will not
430	work with inherently broken event loops such as Event or Event::Lib (and	431	work with inherently broken event loops such as Event or Event::Lib (and
431	not with POE currently, as POE does it's own workaround with one-second	432	not with POE currently, as POE does its own workaround with one-second
432	latency). For those, you just have to suffer the delays.	433	latency). For those, you just have to suffer the delays.
433		434
434	CHILD PROCESS WATCHERS	435	CHILD PROCESS WATCHERS
435	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	436	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
436		437
437	You can also watch on a child process exit and catch its exit status.	438	You can also watch for a child process exit and catch its exit status.
438		439
439	The child process is specified by the "pid" argument (one some backends,	440	The child process is specified by the "pid" argument (on some backends,
440	using 0 watches for any child process exit, on others this will croak).	441	using 0 watches for any child process exit, on others this will croak).
441	The watcher will be triggered only when the child process has finished	442	The watcher will be triggered only when the child process has finished
442	and an exit status is available, not on any trace events	443	and an exit status is available, not on any trace events
443	(stopped/continued).	444	(stopped/continued).
444		445
…		…
465	This means you cannot create a child watcher as the very first thing in	466	This means you cannot create a child watcher as the very first thing in
466	an AnyEvent program, you have to create at least one watcher before	467	an AnyEvent program, you have to create at least one watcher before
467	you "fork" the child (alternatively, you can call "AnyEvent::detect").	468	you "fork" the child (alternatively, you can call "AnyEvent::detect").
468		469
469	As most event loops do not support waiting for child events, they will	470	As most event loops do not support waiting for child events, they will
470	be emulated by AnyEvent in most cases, in which the latency and race	471	be emulated by AnyEvent in most cases, in which case the latency and
471	problems mentioned in the description of signal watchers apply.	472	race problems mentioned in the description of signal watchers apply.
472		473
473	Example: fork a process and wait for it	474	Example: fork a process and wait for it
474		475
475	my $done = AnyEvent->condvar;	476	my $done = AnyEvent->condvar;
476		477
477	my $pid = fork or exit 5;	478	my $pid = fork or exit 5;
478		479
479	my $w = AnyEvent->child (	480	my $w = AnyEvent->child (
480	pid => $pid,	481	pid => $pid,
481	cb => sub {	482	cb => sub {
482	my ($pid, $status) = @_;	483	my ($pid, $status) = @_;
483	warn "pid $pid exited with status $status";	484	warn "pid $pid exited with status $status";
484	$done->send;	485	$done->send;
485	},	486	},
486	);	487	);
487		488
488	# do something else, then wait for process exit	489	# do something else, then wait for process exit
489	$done->recv;	490	$done->recv;
490		491
491	IDLE WATCHERS	492	IDLE WATCHERS
492	$w = AnyEvent->idle (cb => <callback>);	493	$w = AnyEvent->idle (cb => <callback>);
493		494
494	Repeatedly invoke the callback after the process becomes idle, until	495	This will repeatedly invoke the callback after the process becomes idle,
495	either the watcher is destroyed or new events have been detected.	496	until either the watcher is destroyed or new events have been detected.
496		497
497	Idle watchers are useful when there is a need to do something, but it is	498	Idle watchers are useful when there is a need to do something, but it is
498	not so important (or wise) to do it instantly. The callback will be	499	not so important (or wise) to do it instantly. The callback will be
499	invoked only when there is "nothing better to do", which is usually	500	invoked only when there is "nothing better to do", which is usually
500	defined as "all outstanding events have been handled and no new events	501	defined as "all outstanding events have been handled and no new events
…		…
539		540
540	AnyEvent is slightly different: it expects somebody else to run the	541	AnyEvent is slightly different: it expects somebody else to run the
541	event loop and will only block when necessary (usually when told by the	542	event loop and will only block when necessary (usually when told by the
542	user).	543	user).
543		544
544	The instrument to do that is called a "condition variable", so called	545	The tool to do that is called a "condition variable", so called because
545	because they represent a condition that must become true.	546	they represent a condition that must become true.
546		547
547	Now is probably a good time to look at the examples further below.	548	Now is probably a good time to look at the examples further below.
548		549
549	Condition variables can be created by calling the "AnyEvent->condvar"	550	Condition variables can be created by calling the "AnyEvent->condvar"
550	method, usually without arguments. The only argument pair allowed is	551	method, usually without arguments. The only argument pair allowed is
…		…
555	After creation, the condition variable is "false" until it becomes	556	After creation, the condition variable is "false" until it becomes
556	"true" by calling the "send" method (or calling the condition variable	557	"true" by calling the "send" method (or calling the condition variable
557	as if it were a callback, read about the caveats in the description for	558	as if it were a callback, read about the caveats in the description for
558	the "->send" method).	559	the "->send" method).
559		560
560	Condition variables are similar to callbacks, except that you can	561	Since condition variables are the most complex part of the AnyEvent API,
561	optionally wait for them. They can also be called merge points - points	562	here are some different mental models of what they are - pick the ones
562	in time where multiple outstanding events have been processed. And yet	563	you can connect to:
563	another way to call them is transactions - each condition variable can	564
564	be used to represent a transaction, which finishes at some point and	565	* Condition variables are like callbacks - you can call them (and pass
565	delivers a result. And yet some people know them as "futures" - a	566	them instead of callbacks). Unlike callbacks however, you can also
566	promise to compute/deliver something that you can wait for.	567	wait for them to be called.
		568
		569	* Condition variables are signals - one side can emit or send them,
		570	the other side can wait for them, or install a handler that is
		571	called when the signal fires.
		572
		573	* Condition variables are like "Merge Points" - points in your program
		574	where you merge multiple independent results/control flows into one.
		575
		576	* Condition variables represent a transaction - functions that start
		577	some kind of transaction can return them, leaving the caller the
		578	choice between waiting in a blocking fashion, or setting a callback.
		579
		580	* Condition variables represent future values, or promises to deliver
		581	some result, long before the result is available.
567		582
568	Condition variables are very useful to signal that something has	583	Condition variables are very useful to signal that something has
569	finished, for example, if you write a module that does asynchronous http	584	finished, for example, if you write a module that does asynchronous http
570	requests, then a condition variable would be the ideal candidate to	585	requests, then a condition variable would be the ideal candidate to
571	signal the availability of results. The user can either act when the	586	signal the availability of results. The user can either act when the
…		…
584		599
585	Condition variables are represented by hash refs in perl, and the keys	600	Condition variables are represented by hash refs in perl, and the keys
586	used by AnyEvent itself are all named "_ae_XXX" to make subclassing easy	601	used by AnyEvent itself are all named "_ae_XXX" to make subclassing easy
587	(it is often useful to build your own transaction class on top of	602	(it is often useful to build your own transaction class on top of
588	AnyEvent). To subclass, use "AnyEvent::CondVar" as base class and call	603	AnyEvent). To subclass, use "AnyEvent::CondVar" as base class and call
589	it's "new" method in your own "new" method.	604	its "new" method in your own "new" method.
590		605
591	There are two "sides" to a condition variable - the "producer side"	606	There are two "sides" to a condition variable - the "producer side"
592	which eventually calls "-> send", and the "consumer side", which waits	607	which eventually calls "-> send", and the "consumer side", which waits
593	for the send to occur.	608	for the send to occur.
594		609
…		…
654	Condition variables are overloaded so one can call them directly (as	669	Condition variables are overloaded so one can call them directly (as
655	if they were a code reference). Calling them directly is the same as	670	if they were a code reference). Calling them directly is the same as
656	calling "send".	671	calling "send".
657		672
658	$cv->croak ($error)	673	$cv->croak ($error)
659	Similar to send, but causes all call's to "->recv" to invoke	674	Similar to send, but causes all calls to "->recv" to invoke
660	"Carp::croak" with the given error message/object/scalar.	675	"Carp::croak" with the given error message/object/scalar.
661		676
662	This can be used to signal any errors to the condition variable	677	This can be used to signal any errors to the condition variable
663	user/consumer. Doing it this way instead of calling "croak" directly	678	user/consumer. Doing it this way instead of calling "croak" directly
664	delays the error detetcion, but has the overwhelmign advantage that	679	delays the error detection, but has the overwhelming advantage that
665	it diagnoses the error at the place where the result is expected,	680	it diagnoses the error at the place where the result is expected,
666	and not deep in some event clalback without connection to the actual	681	and not deep in some event callback with no connection to the actual
667	code causing the problem.	682	code causing the problem.
668		683
669	$cv->begin ([group callback])	684	$cv->begin ([group callback])
670	$cv->end	685	$cv->end
671	These two methods can be used to combine many transactions/events	686	These two methods can be used to combine many transactions/events
…		…
708	there is one call to "begin", so the condvar waits for all calls to	723	there is one call to "begin", so the condvar waits for all calls to
709	"end" before sending.	724	"end" before sending.
710		725
711	The ping example mentioned above is slightly more complicated, as	726	The ping example mentioned above is slightly more complicated, as
712	the there are results to be passwd back, and the number of tasks	727	the there are results to be passwd back, and the number of tasks
713	that are begung can potentially be zero:	728	that are begun can potentially be zero:
714		729
715	my $cv = AnyEvent->condvar;	730	my $cv = AnyEvent->condvar;
716		731
717	my %result;	732	my %result;
718	$cv->begin (sub { shift->send (\%result) });	733	$cv->begin (sub { shift->send (\%result) });
…		…
739	callback to be called once the counter reaches 0, and second, it	754	callback to be called once the counter reaches 0, and second, it
740	ensures that "send" is called even when "no" hosts are being pinged	755	ensures that "send" is called even when "no" hosts are being pinged
741	(the loop doesn't execute once).	756	(the loop doesn't execute once).
742		757
743	This is the general pattern when you "fan out" into multiple (but	758	This is the general pattern when you "fan out" into multiple (but
744	potentially none) subrequests: use an outer "begin"/"end" pair to	759	potentially zero) subrequests: use an outer "begin"/"end" pair to
745	set the callback and ensure "end" is called at least once, and then,	760	set the callback and ensure "end" is called at least once, and then,
746	for each subrequest you start, call "begin" and for each subrequest	761	for each subrequest you start, call "begin" and for each subrequest
747	you finish, call "end".	762	you finish, call "end".
748		763
749	METHODS FOR CONSUMERS	764	METHODS FOR CONSUMERS
750	These methods should only be used by the consuming side, i.e. the code	765	These methods should only be used by the consuming side, i.e. the code
751	awaits the condition.	766	awaits the condition.
752		767
753	$cv->recv	768	$cv->recv
754	Wait (blocking if necessary) until the "->send" or "->croak" methods	769	Wait (blocking if necessary) until the "->send" or "->croak" methods
755	have been called on c<$cv>, while servicing other watchers normally.	770	have been called on $cv, while servicing other watchers normally.
756		771
757	You can only wait once on a condition - additional calls are valid	772	You can only wait once on a condition - additional calls are valid
758	but will return immediately.	773	but will return immediately.
759		774
760	If an error condition has been set by calling "->croak", then this	775	If an error condition has been set by calling "->croak", then this
…		…
777	example, by coupling condition variables with some kind of request	792	example, by coupling condition variables with some kind of request
778	results and supporting callbacks so the caller knows that getting	793	results and supporting callbacks so the caller knows that getting
779	the result will not block, while still supporting blocking waits if	794	the result will not block, while still supporting blocking waits if
780	the caller so desires).	795	the caller so desires).
781		796
782	You can ensure that "-recv" never blocks by setting a callback and	797	You can ensure that "->recv" never blocks by setting a callback and
783	only calling "->recv" from within that callback (or at a later	798	only calling "->recv" from within that callback (or at a later
784	time). This will work even when the event loop does not support	799	time). This will work even when the event loop does not support
785	blocking waits otherwise.	800	blocking waits otherwise.
786		801
787	$bool = $cv->ready	802	$bool = $cv->ready
…		…
790		805
791	$cb = $cv->cb ($cb->($cv))	806	$cb = $cv->cb ($cb->($cv))
792	This is a mutator function that returns the callback set and	807	This is a mutator function that returns the callback set and
793	optionally replaces it before doing so.	808	optionally replaces it before doing so.
794		809
795	The callback will be called when the condition becomes (or already	810	The callback will be called when the condition becomes "true", i.e.
796	was) "true", i.e. when "send" or "croak" are called (or were	811	when "send" or "croak" are called, with the only argument being the
797	called), with the only argument being the condition variable itself.	812	condition variable itself. If the condition is already true, the
798	Calling "recv" inside the callback or at any later time is	813	callback is called immediately when it is set. Calling "recv" inside
799	guaranteed not to block.	814	the callback or at any later time is guaranteed not to block.
800		815
801	SUPPORTED EVENT LOOPS/BACKENDS	816	SUPPORTED EVENT LOOPS/BACKENDS
802	The available backend classes are (every class has its own manpage):	817	The available backend classes are (every class has its own manpage):
803		818
804	Backends that are autoprobed when no other event loop can be found.	819	Backends that are autoprobed when no other event loop can be found.
…		…
806	use. If EV is not installed, then AnyEvent will fall back to its own	821	use. If EV is not installed, then AnyEvent will fall back to its own
807	pure-perl implementation, which is available everywhere as it comes	822	pure-perl implementation, which is available everywhere as it comes
808	with AnyEvent itself.	823	with AnyEvent itself.
809		824
810	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	825	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
811	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	826	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
812		827
813	Backends that are transparently being picked up when they are used.	828	Backends that are transparently being picked up when they are used.
814	These will be used when they are currently loaded when the first	829	These will be used if they are already loaded when the first watcher
815	watcher is created, in which case it is assumed that the application	830	is created, in which case it is assumed that the application is
816	is using them. This means that AnyEvent will automatically pick the	831	using them. This means that AnyEvent will automatically pick the
817	right backend when the main program loads an event module before	832	right backend when the main program loads an event module before
818	anything starts to create watchers. Nothing special needs to be done	833	anything starts to create watchers. Nothing special needs to be done
819	by the main program.	834	by the main program.
820		835
821	AnyEvent::Impl::Event based on Event, very stable, few glitches.	836	AnyEvent::Impl::Event based on Event, very stable, few glitches.
822	AnyEvent::Impl::Glib based on Glib, slow but very stable.	837	AnyEvent::Impl::Glib based on Glib, slow but very stable.
823	AnyEvent::Impl::Tk based on Tk, very broken.	838	AnyEvent::Impl::Tk based on Tk, very broken.
824	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	839	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
825	AnyEvent::Impl::POE based on POE, very slow, some limitations.	840	AnyEvent::Impl::POE based on POE, very slow, some limitations.
826	AnyEvent::Impl::Irssi used when running within irssi.	841	AnyEvent::Impl::Irssi used when running within irssi.
		842	AnyEvent::Impl::IOAsync based on IO::Async.
		843	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		844	AnyEvent::Impl::FLTK2 based on FLTK (fltk 2 binding).
827		845
828	Backends with special needs.	846	Backends with special needs.
829	Qt requires the Qt::Application to be instantiated first, but will	847	Qt requires the Qt::Application to be instantiated first, but will
830	otherwise be picked up automatically. As long as the main program	848	otherwise be picked up automatically. As long as the main program
831	instantiates the application before any AnyEvent watchers are	849	instantiates the application before any AnyEvent watchers are
832	created, everything should just work.	850	created, everything should just work.
833		851
834	AnyEvent::Impl::Qt based on Qt.	852	AnyEvent::Impl::Qt based on Qt.
835		853
836	Support for IO::Async can only be partial, as it is too broken and
837	architecturally limited to even support the AnyEvent API. It also is
838	the only event loop that needs the loop to be set explicitly, so it
839	can only be used by a main program knowing about AnyEvent. See
840	AnyEvent::Impl::Async for the gory details.
841
842	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
843
844	Event loops that are indirectly supported via other backends.	854	Event loops that are indirectly supported via other backends.
845	Some event loops can be supported via other modules:	855	Some event loops can be supported via other modules:
846		856
847	There is no direct support for WxWidgets (Wx) or Prima.	857	There is no direct support for WxWidgets (Wx) or Prima.
848		858
…		…
866	Contains "undef" until the first watcher is being created, before	876	Contains "undef" until the first watcher is being created, before
867	the backend has been autodetected.	877	the backend has been autodetected.
868		878
869	Afterwards it contains the event model that is being used, which is	879	Afterwards it contains the event model that is being used, which is
870	the name of the Perl class implementing the model. This class is	880	the name of the Perl class implementing the model. This class is
871	usually one of the "AnyEvent::Impl:xxx" modules, but can be any	881	usually one of the "AnyEvent::Impl::xxx" modules, but can be any
872	other class in the case AnyEvent has been extended at runtime (e.g.	882	other class in the case AnyEvent has been extended at runtime (e.g.
873	in rxvt-unicode it will be "urxvt::anyevent").	883	in rxvt-unicode it will be "urxvt::anyevent").
874		884
875	AnyEvent::detect	885	AnyEvent::detect
876	Returns $AnyEvent::MODEL, forcing autodetection of the event model	886	Returns $AnyEvent::MODEL, forcing autodetection of the event model
877	if necessary. You should only call this function right before you	887	if necessary. You should only call this function right before you
878	would have created an AnyEvent watcher anyway, that is, as late as	888	would have created an AnyEvent watcher anyway, that is, as late as
879	possible at runtime, and not e.g. while initialising of your module.	889	possible at runtime, and not e.g. during initialisation of your
		890	module.
		891
		892	The effect of calling this function is as if a watcher had been
		893	created (specifically, actions that happen "when the first watcher
		894	is created" happen when calling detetc as well).
880		895
881	If you need to do some initialisation before AnyEvent watchers are	896	If you need to do some initialisation before AnyEvent watchers are
882	created, use "post_detect".	897	created, use "post_detect".
883		898
884	$guard = AnyEvent::post_detect { BLOCK }	899	$guard = AnyEvent::post_detect { BLOCK }
885	Arranges for the code block to be executed as soon as the event	900	Arranges for the code block to be executed as soon as the event
886	model is autodetected (or immediately if this has already happened).	901	model is autodetected (or immediately if that has already happened).
887		902
888	The block will be executed after the actual backend has been	903	The block will be executed after the actual backend has been
889	detected ($AnyEvent::MODEL is set), but before any watchers have	904	detected ($AnyEvent::MODEL is set), but before any watchers have
890	been created, so it is possible to e.g. patch @AnyEvent::ISA or do	905	been created, so it is possible to e.g. patch @AnyEvent::ISA or do
891	other initialisations - see the sources of AnyEvent::Strict or	906	other initialisations - see the sources of AnyEvent::Strict or
…		…
900	object that automatically removes the callback again when it is	915	object that automatically removes the callback again when it is
901	destroyed (or "undef" when the hook was immediately executed). See	916	destroyed (or "undef" when the hook was immediately executed). See
902	AnyEvent::AIO for a case where this is useful.	917	AnyEvent::AIO for a case where this is useful.
903		918
904	Example: Create a watcher for the IO::AIO module and store it in	919	Example: Create a watcher for the IO::AIO module and store it in
905	$WATCHER. Only do so after the event loop is initialised, though.	920	$WATCHER, but do so only do so after the event loop is initialised.
906		921
907	our WATCHER;	922	our WATCHER;
908		923
909	my $guard = AnyEvent::post_detect {	924	my $guard = AnyEvent::post_detect {
910	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
917		932
918	$WATCHER \|\|= $guard;	933	$WATCHER \|\|= $guard;
919		934
920	@AnyEvent::post_detect	935	@AnyEvent::post_detect
921	If there are any code references in this array (you can "push" to it	936	If there are any code references in this array (you can "push" to it
922	before or after loading AnyEvent), then they will called directly	937	before or after loading AnyEvent), then they will be called directly
923	after the event loop has been chosen.	938	after the event loop has been chosen.
924		939
925	You should check $AnyEvent::MODEL before adding to this array,	940	You should check $AnyEvent::MODEL before adding to this array,
926	though: if it is defined then the event loop has already been	941	though: if it is defined then the event loop has already been
927	detected, and the array will be ignored.	942	detected, and the array will be ignored.
…		…
946	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent	961	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
947	# as soon as it is	962	# as soon as it is
948	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };	963	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
949	}	964	}
950		965
		966	AnyEvent::postpone { BLOCK }
		967	Arranges for the block to be executed as soon as possible, but not
		968	before the call itself returns. In practise, the block will be
		969	executed just before the event loop polls for new events, or shortly
		970	afterwards.
		971
		972	This function never returns anything (to make the "return postpone {
		973	... }" idiom more useful.
		974
		975	To understand the usefulness of this function, consider a function
		976	that asynchronously does something for you and returns some
		977	transaction object or guard to let you cancel the operation. For
		978	example, "AnyEvent::Socket::tcp_connect":
		979
		980	# start a conenction attempt unless one is active
		981	$self->{connect_guard} \|\|= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		982	delete $self->{connect_guard};
		983	...
		984	};
		985
		986	Imagine that this function could instantly call the callback, for
		987	example, because it detects an obvious error such as a negative port
		988	number. Invoking the callback before the function returns causes
		989	problems however: the callback will be called and will try to delete
		990	the guard object. But since the function hasn't returned yet, there
		991	is nothing to delete. When the function eventually returns it will
		992	assign the guard object to "$self->{connect_guard}", where it will
		993	likely never be deleted, so the program thinks it is still trying to
		994	connect.
		995
		996	This is where "AnyEvent::postpone" should be used. Instead of
		997	calling the callback directly on error:
		998
		999	$cb->(undef), return # signal error to callback, BAD!
		1000	if $some_error_condition;
		1001
		1002	It should use "postpone":
		1003
		1004	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1005	if $some_error_condition;
		1006
		1007	AnyEvent::log $level, $msg[, @args]
		1008	Log the given $msg at the given $level.
		1009
		1010	If AnyEvent::Log is not loaded then this function makes a simple
		1011	test to see whether the message will be logged. If the test succeeds
		1012	it will load AnyEvent::Log and call "AnyEvent::Log::log" -
		1013	consequently, look at the AnyEvent::Log documentation for details.
		1014
		1015	If the test fails it will simply return.
		1016
		1017	If you want to sprinkle loads of logging calls around your code,
		1018	consider creating a logger callback with the "AnyEvent::Log::logger"
		1019	function, which can reduce typing, codesize and can reduce the
		1020	logging overhead enourmously.
		1021
951	WHAT TO DO IN A MODULE	1022	WHAT TO DO IN A MODULE
952	As a module author, you should "use AnyEvent" and call AnyEvent methods	1023	As a module author, you should "use AnyEvent" and call AnyEvent methods
953	freely, but you should not load a specific event module or rely on it.	1024	freely, but you should not load a specific event module or rely on it.
954		1025
955	Be careful when you create watchers in the module body - AnyEvent will	1026	Be careful when you create watchers in the module body - AnyEvent will
…		…
962	stall the whole program, and the whole point of using events is to stay	1033	stall the whole program, and the whole point of using events is to stay
963	interactive.	1034	interactive.
964		1035
965	It is fine, however, to call "->recv" when the user of your module	1036	It is fine, however, to call "->recv" when the user of your module
966	requests it (i.e. if you create a http request object ad have a method	1037	requests it (i.e. if you create a http request object ad have a method
967	called "results" that returns the results, it should call "->recv"	1038	called "results" that returns the results, it may call "->recv" freely,
968	freely, as the user of your module knows what she is doing. always).	1039	as the user of your module knows what she is doing. Always).
969		1040
970	WHAT TO DO IN THE MAIN PROGRAM	1041	WHAT TO DO IN THE MAIN PROGRAM
971	There will always be a single main program - the only place that should	1042	There will always be a single main program - the only place that should
972	dictate which event model to use.	1043	dictate which event model to use.
973		1044
974	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1045	If the program is not event-based, it need not do anything special, even
975	do anything special (it does not need to be event-based) and let	1046	when it depends on a module that uses an AnyEvent. If the program itself
976	AnyEvent decide which implementation to chose if some module relies on	1047	uses AnyEvent, but does not care which event loop is used, all it needs
977	it.	1048	to do is "use AnyEvent". In either case, AnyEvent will choose the best
		1049	available loop implementation.
978		1050
979	If the main program relies on a specific event model - for example, in	1051	If the main program relies on a specific event model - for example, in
980	Gtk2 programs you have to rely on the Glib module - you should load the	1052	Gtk2 programs you have to rely on the Glib module - you should load the
981	event module before loading AnyEvent or any module that uses it:	1053	event module before loading AnyEvent or any module that uses it:
982	generally speaking, you should load it as early as possible. The reason	1054	generally speaking, you should load it as early as possible. The reason
983	is that modules might create watchers when they are loaded, and AnyEvent	1055	is that modules might create watchers when they are loaded, and AnyEvent
984	will decide on the event model to use as soon as it creates watchers,	1056	will decide on the event model to use as soon as it creates watchers,
985	and it might chose the wrong one unless you load the correct one	1057	and it might choose the wrong one unless you load the correct one
986	yourself.	1058	yourself.
987		1059
988	You can chose to use a pure-perl implementation by loading the	1060	You can chose to use a pure-perl implementation by loading the
989	"AnyEvent::Impl::Perl" module, which gives you similar behaviour	1061	"AnyEvent::Loop" module, which gives you similar behaviour everywhere,
990	everywhere, but letting AnyEvent chose the model is generally better.	1062	but letting AnyEvent chose the model is generally better.
991		1063
992	MAINLOOP EMULATION	1064	MAINLOOP EMULATION
993	Sometimes (often for short test scripts, or even standalone programs who	1065	Sometimes (often for short test scripts, or even standalone programs who
994	only want to use AnyEvent), you do not want to run a specific event	1066	only want to use AnyEvent), you do not want to run a specific event
995	loop.	1067	loop.
…		…
1007		1079
1008	OTHER MODULES	1080	OTHER MODULES
1009	The following is a non-exhaustive list of additional modules that use	1081	The following is a non-exhaustive list of additional modules that use
1010	AnyEvent as a client and can therefore be mixed easily with other	1082	AnyEvent as a client and can therefore be mixed easily with other
1011	AnyEvent modules and other event loops in the same program. Some of the	1083	AnyEvent modules and other event loops in the same program. Some of the
1012	modules come with AnyEvent, most are available via CPAN.	1084	modules come as part of AnyEvent, the others are available via CPAN (see
		1085	<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for a longer
		1086	non-exhaustive list), and the list is heavily biased towards modules of
		1087	the AnyEvent author himself :)
1013		1088
1014	AnyEvent::Util	1089	AnyEvent::Util
1015	Contains various utility functions that replace often-used but	1090	Contains various utility functions that replace often-used blocking
1016	blocking functions such as "inet_aton" by event-/callback-based	1091	functions such as "inet_aton" with event/callback-based versions.
1017	versions.
1018		1092
1019	AnyEvent::Socket	1093	AnyEvent::Socket
1020	Provides various utility functions for (internet protocol) sockets,	1094	Provides various utility functions for (internet protocol) sockets,
1021	addresses and name resolution. Also functions to create non-blocking	1095	addresses and name resolution. Also functions to create non-blocking
1022	tcp connections or tcp servers, with IPv6 and SRV record support and	1096	tcp connections or tcp servers, with IPv6 and SRV record support and
1023	more.	1097	more.
1024		1098
1025	AnyEvent::Handle	1099	AnyEvent::Handle
1026	Provide read and write buffers, manages watchers for reads and	1100	Provide read and write buffers, manages watchers for reads and
1027	writes, supports raw and formatted I/O, I/O queued and fully	1101	writes, supports raw and formatted I/O, I/O queued and fully
1028	transparent and non-blocking SSL/TLS (via AnyEvent::TLS.	1102	transparent and non-blocking SSL/TLS (via AnyEvent::TLS).
1029		1103
1030	AnyEvent::DNS	1104	AnyEvent::DNS
1031	Provides rich asynchronous DNS resolver capabilities.	1105	Provides rich asynchronous DNS resolver capabilities.
1032		1106
		1107	AnyEvent::HTTP, AnyEvent::IRC, AnyEvent::XMPP, AnyEvent::GPSD,
		1108	AnyEvent::IGS, AnyEvent::FCP
		1109	Implement event-based interfaces to the protocols of the same name
		1110	(for the curious, IGS is the International Go Server and FCP is the
		1111	Freenet Client Protocol).
		1112
1033	AnyEvent::HTTP	1113	AnyEvent::AIO
1034	A simple-to-use HTTP library that is capable of making a lot of	1114	Truly asynchronous (as opposed to non-blocking) I/O, should be in
1035	concurrent HTTP requests.	1115	the toolbox of every event programmer. AnyEvent::AIO transparently
		1116	fuses IO::AIO and AnyEvent together, giving AnyEvent access to
		1117	event-based file I/O, and much more.
		1118
		1119	AnyEvent::Filesys::Notify
		1120	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1121	path changes (e.g. "watch this directory for new files", "watch this
		1122	file for changes"). The AnyEvent::Filesys::Notify module promises to
		1123	do just that in a portbale fashion, supporting inotify on GNU/Linux
		1124	and some weird, without doubt broken, stuff on OS X to monitor
		1125	files. It can fall back to blocking scans at regular intervals
		1126	transparently on other platforms, so it's about as portable as it
		1127	gets.
		1128
		1129	(I haven't used it myself, but I haven't heard anybody complaining
		1130	about it yet).
		1131
		1132	AnyEvent::DBI
		1133	Executes DBI requests asynchronously in a proxy process for you,
		1134	notifying you in an event-based way when the operation is finished.
1036		1135
1037	AnyEvent::HTTPD	1136	AnyEvent::HTTPD
1038	Provides a simple web application server framework.	1137	A simple embedded webserver.
1039		1138
1040	AnyEvent::FastPing	1139	AnyEvent::FastPing
1041	The fastest ping in the west.	1140	The fastest ping in the west.
1042		1141
1043	AnyEvent::DBI
1044	Executes DBI requests asynchronously in a proxy process.
1045
1046	AnyEvent::AIO
1047	Truly asynchronous I/O, should be in the toolbox of every event
1048	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
1049	together.
1050
1051	AnyEvent::BDB
1052	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently
1053	fuses BDB and AnyEvent together.
1054
1055	AnyEvent::GPSD
1056	A non-blocking interface to gpsd, a daemon delivering GPS
1057	information.
1058
1059	AnyEvent::IRC
1060	AnyEvent based IRC client module family (replacing the older
1061	Net::IRC3).
1062
1063	AnyEvent::XMPP
1064	AnyEvent based XMPP (Jabber protocol) module family (replacing the
1065	older Net::XMPP2>.
1066
1067	AnyEvent::IGS
1068	A non-blocking interface to the Internet Go Server protocol (used by
1069	App::IGS).
1070
1071	Net::FCP
1072	AnyEvent-based implementation of the Freenet Client Protocol,
1073	birthplace of AnyEvent.
1074
1075	Event::ExecFlow
1076	High level API for event-based execution flow control.
1077
1078	Coro	1142	Coro
1079	Has special support for AnyEvent via Coro::AnyEvent.	1143	Has special support for AnyEvent via Coro::AnyEvent, which allows
		1144	you to simply invert the flow control - don't call us, we will call
		1145	you:
		1146
		1147	async {
		1148	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1149	print "5 seconds later!\n";
		1150
		1151	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1152	my $line = <STDIN>; # works for ttys
		1153
		1154	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1155	my ($body, $hdr) = Coro::rouse_wait;
		1156	};
1080		1157
1081	SIMPLIFIED AE API	1158	SIMPLIFIED AE API
1082	Starting with version 5.0, AnyEvent officially supports a second, much	1159	Starting with version 5.0, AnyEvent officially supports a second, much
1083	simpler, API that is designed to reduce the calling, typing and memory	1160	simpler, API that is designed to reduce the calling, typing and memory
1084	overhead by using function call syntax and a fixed number of parameters.	1161	overhead by using function call syntax and a fixed number of parameters.
…		…
1100	The pure perl event loop simply re-throws the exception (usually within	1177	The pure perl event loop simply re-throws the exception (usually within
1101	"condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",	1178	"condvar->recv"), the Event and EV modules call "$Event/EV::DIED->()",
1102	Glib uses "install_exception_handler" and so on.	1179	Glib uses "install_exception_handler" and so on.
1103		1180
1104	ENVIRONMENT VARIABLES	1181	ENVIRONMENT VARIABLES
1105	The following environment variables are used by this module or its	1182	AnyEvent supports a number of environment variables that tune the
1106	submodules.	1183	runtime behaviour. They are usually evaluated when AnyEvent is loaded,
		1184	initialised, or a submodule that uses them is loaded. Many of them also
		1185	cause AnyEvent to load additional modules - for example,
		1186	"PERL_ANYEVENT_DEBUG_WRAP" causes the AnyEvent::Debug module to be
		1187	loaded.
1107		1188
1108	Note that AnyEvent will remove all environment variables starting with	1189	All the environment variables documented here start with
1109	"PERL_ANYEVENT_" from %ENV when it is loaded while taint mode is	1190	"PERL_ANYEVENT_", which is what AnyEvent considers its own namespace.
1110	enabled.	1191	Other modules are encouraged (but by no means required) to use
		1192	"PERL_ANYEVENT_SUBMODULE" if they have registered the
		1193	AnyEvent::Submodule namespace on CPAN, for any submodule. For example,
		1194	AnyEvent::HTTP could be expected to use "PERL_ANYEVENT_HTTP_PROXY" (it
		1195	should not access env variables starting with "AE_", see below).
		1196
		1197	All variables can also be set via the "AE_" prefix, that is, instead of
		1198	setting "PERL_ANYEVENT_VERBOSE" you can also set "AE_VERBOSE". In case
		1199	there is a clash btween anyevent and another program that uses
		1200	"AE_something" you can set the corresponding "PERL_ANYEVENT_something"
		1201	variable to the empty string, as those variables take precedence.
		1202
		1203	When AnyEvent is first loaded, it copies all "AE_xxx" env variables to
		1204	their "PERL_ANYEVENT_xxx" counterpart unless that variable already
		1205	exists. If taint mode is on, then AnyEvent will remove all environment
		1206	variables starting with "PERL_ANYEVENT_" from %ENV (or replace them with
		1207	"undef" or the empty string, if the corresaponding "AE_" variable is
		1208	set).
		1209
		1210	The exact algorithm is currently:
		1211
		1212	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		1213	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		1214	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		1215
		1216	This ensures that child processes will not see the "AE_" variables.
		1217
		1218	The following environment variables are currently known to AnyEvent:
1111		1219
1112	"PERL_ANYEVENT_VERBOSE"	1220	"PERL_ANYEVENT_VERBOSE"
1113	By default, AnyEvent will be completely silent except in fatal	1221	By default, AnyEvent will be completely silent except in fatal
1114	conditions. You can set this environment variable to make AnyEvent	1222	conditions. You can set this environment variable to make AnyEvent
1115	more talkative.	1223	more talkative. If you want to do more than just set the global
		1224	logging level you should have a look at "PERL_ANYEVENT_LOG", which
		1225	allows much more complex specifications.
1116		1226
1117	When set to 1 or higher, causes AnyEvent to warn about unexpected	1227	When set to 5 or higher (warn), causes AnyEvent to warn about
1118	conditions, such as not being able to load the event model specified	1228	unexpected conditions, such as not being able to load the event
1119	by "PERL_ANYEVENT_MODEL".	1229	model specified by "PERL_ANYEVENT_MODEL", or a guard callback
		1230	throwing an exception - this is the minimum recommended level.
1120		1231
1121	When set to 2 or higher, cause AnyEvent to report to STDERR which	1232	When set to 7 or higher (info), cause AnyEvent to report which event
1122	event model it chooses.	1233	model it chooses.
1123		1234
1124	When set to 8 or higher, then AnyEvent will report extra information	1235	When set to 8 or higher (debug), then AnyEvent will report extra
1125	on which optional modules it loads and how it implements certain	1236	information on which optional modules it loads and how it implements
1126	features.	1237	certain features.
		1238
		1239	"PERL_ANYEVENT_LOG"
		1240	Accepts rather complex logging specifications. For example, you
		1241	could log all "debug" messages of some module to stderr, warnings
		1242	and above to stderr, and errors and above to syslog, with:
		1243
		1244	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		1245
		1246	For the rather extensive details, see AnyEvent::Log.
		1247
		1248	This variable is evaluated when AnyEvent (or AnyEvent::Log) is
		1249	loaded, so will take effect even before AnyEvent has initialised
		1250	itself.
		1251
		1252	Note that specifying this environment variable causes the
		1253	AnyEvent::Log module to be loaded, while "PERL_ANYEVENT_VERBOSE"
		1254	does not, so only using the latter saves a few hundred kB of memory
		1255	until the first message is being logged.
1127		1256
1128	"PERL_ANYEVENT_STRICT"	1257	"PERL_ANYEVENT_STRICT"
1129	AnyEvent does not do much argument checking by default, as thorough	1258	AnyEvent does not do much argument checking by default, as thorough
1130	argument checking is very costly. Setting this variable to a true	1259	argument checking is very costly. Setting this variable to a true
1131	value will cause AnyEvent to load "AnyEvent::Strict" and then to	1260	value will cause AnyEvent to load "AnyEvent::Strict" and then to
1132	thoroughly check the arguments passed to most method calls. If it	1261	thoroughly check the arguments passed to most method calls. If it
1133	finds any problems, it will croak.	1262	finds any problems, it will croak.
1134		1263
1135	In other words, enables "strict" mode.	1264	In other words, enables "strict" mode.
1136		1265
1137	Unlike "use strict" (or it's modern cousin, "use common::sense", it	1266	Unlike "use strict" (or its modern cousin, "use common::sense", it
1138	is definitely recommended to keep it off in production. Keeping	1267	is definitely recommended to keep it off in production. Keeping
1139	"PERL_ANYEVENT_STRICT=1" in your environment while developing	1268	"PERL_ANYEVENT_STRICT=1" in your environment while developing
1140	programs can be very useful, however.	1269	programs can be very useful, however.
1141		1270
		1271	"PERL_ANYEVENT_DEBUG_SHELL"
		1272	If this env variable is set, then its contents will be interpreted
		1273	by "AnyEvent::Socket::parse_hostport" (after replacing every
		1274	occurance of $$ by the process pid) and an "AnyEvent::Debug::shell"
		1275	is bound on that port. The shell object is saved in
		1276	$AnyEvent::Debug::SHELL.
		1277
		1278	This happens when the first watcher is created.
		1279
		1280	For example, to bind a debug shell on a unix domain socket in
		1281	/tmp/debug<pid>.sock, you could use this:
		1282
		1283	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		1284
		1285	Note that creating sockets in /tmp is very unsafe on multiuser
		1286	systems.
		1287
		1288	"PERL_ANYEVENT_DEBUG_WRAP"
		1289	Can be set to 0, 1 or 2 and enables wrapping of all watchers for
		1290	debugging purposes. See "AnyEvent::Debug::wrap" for details.
		1291
1142	"PERL_ANYEVENT_MODEL"	1292	"PERL_ANYEVENT_MODEL"
1143	This can be used to specify the event model to be used by AnyEvent,	1293	This can be used to specify the event model to be used by AnyEvent,
1144	before auto detection and -probing kicks in. It must be a string	1294	before auto detection and -probing kicks in.
1145	consisting entirely of ASCII letters. The string "AnyEvent::Impl::"	1295
1146	gets prepended and the resulting module name is loaded and if the	1296	It normally is a string consisting entirely of ASCII letters (e.g.
1147	load was successful, used as event model. If it fails to load	1297	"EV" or "IOAsync"). The string "AnyEvent::Impl::" gets prepended and
		1298	the resulting module name is loaded and - if the load was successful
		1299	- used as event model backend. If it fails to load then AnyEvent
1148	AnyEvent will proceed with auto detection and -probing.	1300	will proceed with auto detection and -probing.
1149		1301
1150	This functionality might change in future versions.	1302	If the string ends with "::" instead (e.g. "AnyEvent::Impl::EV::")
		1303	then nothing gets prepended and the module name is used as-is (hint:
		1304	"::" at the end of a string designates a module name and quotes it
		1305	appropriately).
1151		1306
1152	For example, to force the pure perl model (AnyEvent::Impl::Perl) you	1307	For example, to force the pure perl model (AnyEvent::Loop::Perl) you
1153	could start your program like this:	1308	could start your program like this:
1154		1309
1155	PERL_ANYEVENT_MODEL=Perl perl ...	1310	PERL_ANYEVENT_MODEL=Perl perl ...
1156		1311
1157	"PERL_ANYEVENT_PROTOCOLS"	1312	"PERL_ANYEVENT_PROTOCOLS"
…		…
1174	"PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to	1329	"PERL_ANYEVENT_PROTOCOLS=ipv4" - only support IPv4, never try to
1175	resolve or contact IPv6 addresses.	1330	resolve or contact IPv6 addresses.
1176	"PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but	1331	"PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4" support either IPv4 or IPv6, but
1177	prefer IPv6 over IPv4.	1332	prefer IPv6 over IPv4.
1178		1333
		1334	"PERL_ANYEVENT_HOSTS"
		1335	This variable, if specified, overrides the /etc/hosts file used by
		1336	AnyEvent::Socket"::resolve_sockaddr", i.e. hosts aliases will be
		1337	read from that file instead.
		1338
1179	"PERL_ANYEVENT_EDNS0"	1339	"PERL_ANYEVENT_EDNS0"
1180	Used by AnyEvent::DNS to decide whether to use the EDNS0 extension	1340	Used by AnyEvent::DNS to decide whether to use the EDNS0 extension
1181	for DNS. This extension is generally useful to reduce DNS traffic,	1341	for DNS. This extension is generally useful to reduce DNS traffic,
1182	but some (broken) firewalls drop such DNS packets, which is why it	1342	especially when DNSSEC is involved, but some (broken) firewalls drop
1183	is off by default.	1343	such DNS packets, which is why it is off by default.
1184		1344
1185	Setting this variable to 1 will cause AnyEvent::DNS to announce	1345	Setting this variable to 1 will cause AnyEvent::DNS to announce
1186	EDNS0 in its DNS requests.	1346	EDNS0 in its DNS requests.
1187		1347
1188	"PERL_ANYEVENT_MAX_FORKS"	1348	"PERL_ANYEVENT_MAX_FORKS"
…		…
1193	The default value for the "max_outstanding" parameter for the	1353	The default value for the "max_outstanding" parameter for the
1194	default DNS resolver - this is the maximum number of parallel DNS	1354	default DNS resolver - this is the maximum number of parallel DNS
1195	requests that are sent to the DNS server.	1355	requests that are sent to the DNS server.
1196		1356
1197	"PERL_ANYEVENT_RESOLV_CONF"	1357	"PERL_ANYEVENT_RESOLV_CONF"
1198	The file to use instead of /etc/resolv.conf (or OS-specific	1358	The absolute path to a resolv.conf-style file to use instead of
1199	configuration) in the default resolver. When set to the empty	1359	/etc/resolv.conf (or the OS-specific configuration) in the default
1200	string, no default config will be used.	1360	resolver, or the empty string to select the default configuration.
1201		1361
1202	"PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".	1362	"PERL_ANYEVENT_CA_FILE", "PERL_ANYEVENT_CA_PATH".
1203	When neither "ca_file" nor "ca_path" was specified during	1363	When neither "ca_file" nor "ca_path" was specified during
1204	AnyEvent::TLS context creation, and either of these environment	1364	AnyEvent::TLS context creation, and either of these environment
1205	variables exist, they will be used to specify CA certificate	1365	variables are nonempty, they will be used to specify CA certificate
1206	locations instead of a system-dependent default.	1366	locations instead of a system-dependent default.
1207		1367
1208	"PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"	1368	"PERL_ANYEVENT_AVOID_GUARD" and "PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT"
1209	When these are set to 1, then the respective modules are not loaded.	1369	When these are set to 1, then the respective modules are not loaded.
1210	Mostly good for testing AnyEvent itself.	1370	Mostly good for testing AnyEvent itself.
…		…
1530	when used without AnyEvent), but most event loops have acceptable	1690	when used without AnyEvent), but most event loops have acceptable
1531	performance with or without AnyEvent.	1691	performance with or without AnyEvent.
1532		1692
1533	* The overhead AnyEvent adds is usually much smaller than the overhead	1693	* The overhead AnyEvent adds is usually much smaller than the overhead
1534	of the actual event loop, only with extremely fast event loops such	1694	of the actual event loop, only with extremely fast event loops such
1535	as EV adds AnyEvent significant overhead.	1695	as EV does AnyEvent add significant overhead.
1536		1696
1537	* You should avoid POE like the plague if you want performance or	1697	* You should avoid POE like the plague if you want performance or
1538	reasonable memory usage.	1698	reasonable memory usage.
1539		1699
1540	BENCHMARKING THE LARGE SERVER CASE	1700	BENCHMARKING THE LARGE SERVER CASE
…		…
1738		1898
1739	Feel free to install your own handler, or reset it to defaults.	1899	Feel free to install your own handler, or reset it to defaults.
1740		1900
1741	RECOMMENDED/OPTIONAL MODULES	1901	RECOMMENDED/OPTIONAL MODULES
1742	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	1902	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
1743	it's built-in modules) are required to use it.	1903	its built-in modules) are required to use it.
1744		1904
1745	That does not mean that AnyEvent won't take advantage of some additional	1905	That does not mean that AnyEvent won't take advantage of some additional
1746	modules if they are installed.	1906	modules if they are installed.
1747		1907
1748	This section explains which additional modules will be used, and how	1908	This section explains which additional modules will be used, and how
…		…
1799	worthwhile: If this module is installed, then AnyEvent::Handle (with	1959	worthwhile: If this module is installed, then AnyEvent::Handle (with
1800	the help of AnyEvent::TLS), gains the ability to do TLS/SSL.	1960	the help of AnyEvent::TLS), gains the ability to do TLS/SSL.
1801		1961
1802	Time::HiRes	1962	Time::HiRes
1803	This module is part of perl since release 5.008. It will be used	1963	This module is part of perl since release 5.008. It will be used
1804	when the chosen event library does not come with a timing source on	1964	when the chosen event library does not come with a timing source of
1805	it's own. The pure-perl event loop (AnyEvent::Impl::Perl) will	1965	its own. The pure-perl event loop (AnyEvent::Loop) will additionally
1806	additionally use it to try to use a monotonic clock for timing	1966	load it to try to use a monotonic clock for timing stability.
1807	stability.
1808		1967
1809	FORK	1968	FORK
1810	Most event libraries are not fork-safe. The ones who are usually are	1969	Most event libraries are not fork-safe. The ones who are usually are
1811	because they rely on inefficient but fork-safe "select" or "poll" calls	1970	because they rely on inefficient but fork-safe "select" or "poll" calls
1812	- higher performance APIs such as BSD's kqueue or the dreaded Linux	1971	- higher performance APIs such as BSD's kqueue or the dreaded Linux
…		…
1843		2002
1844	You can make AnyEvent completely ignore this variable by deleting it	2003	You can make AnyEvent completely ignore this variable by deleting it
1845	before the first watcher gets created, e.g. with a "BEGIN" block:	2004	before the first watcher gets created, e.g. with a "BEGIN" block:
1846		2005
1847	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	2006	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1848		2007
1849	use AnyEvent;	2008	use AnyEvent;
1850		2009
1851	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2010	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1852	be used to probe what backend is used and gain other information (which	2011	be used to probe what backend is used and gain other information (which
1853	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL),	2012	is probably even less useful to an attacker than PERL_ANYEVENT_MODEL),
1854	and $ENV{PERL_ANYEVENT_STRICT}.	2013	and $ENV{PERL_ANYEVENT_STRICT}.
…		…
1863	5.10 and check wether the leaks still show up. (Perl 5.10.0 has other	2022	5.10 and check wether the leaks still show up. (Perl 5.10.0 has other
1864	annoying memleaks, such as leaking on "map" and "grep" but it is usually	2023	annoying memleaks, such as leaking on "map" and "grep" but it is usually
1865	not as pronounced).	2024	not as pronounced).
1866		2025
1867	SEE ALSO	2026	SEE ALSO
1868	Utility functions: AnyEvent::Util.	2027	Tutorial/Introduction: AnyEvent::Intro.
1869		2028
1870	Event modules: EV, EV::Glib, Glib::EV, Event, Glib::Event, Glib, Tk,	2029	FAQ: AnyEvent::FAQ.
1871	Event::Lib, Qt, POE.	2030
		2031	Utility functions: AnyEvent::Util (misc. grab-bag), AnyEvent::Log
		2032	(simply logging).
		2033
		2034	Development/Debugging: AnyEvent::Strict (stricter checking),
		2035	AnyEvent::Debug (interactive shell, watcher tracing).
		2036
		2037	Supported event modules: AnyEvent::Loop, EV, EV::Glib, Glib::EV, Event,
		2038	Glib::Event, Glib, Tk, Event::Lib, Qt, POE, FLTK.
1872		2039
1873	Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,	2040	Implementations: AnyEvent::Impl::EV, AnyEvent::Impl::Event,
1874	AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,	2041	AnyEvent::Impl::Glib, AnyEvent::Impl::Tk, AnyEvent::Impl::Perl,
1875	AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,	2042	AnyEvent::Impl::EventLib, AnyEvent::Impl::Qt, AnyEvent::Impl::POE,
1876	AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi.	2043	AnyEvent::Impl::IOAsync, Anyevent::Impl::Irssi, AnyEvent::Impl::FLTK.
1877		2044
1878	Non-blocking file handles, sockets, TCP clients and servers:	2045	Non-blocking handles, pipes, stream sockets, TCP clients and servers:
1879	AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.	2046	AnyEvent::Handle, AnyEvent::Socket, AnyEvent::TLS.
1880		2047
1881	Asynchronous DNS: AnyEvent::DNS.	2048	Asynchronous DNS: AnyEvent::DNS.
1882		2049
1883	Coroutine support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event,	2050	Thread support: Coro, Coro::AnyEvent, Coro::EV, Coro::Event.
1884		2051
1885	Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::XMPP,	2052	Nontrivial usage examples: AnyEvent::GPSD, AnyEvent::IRC,
1886	AnyEvent::HTTP.	2053	AnyEvent::HTTP.
1887		2054
1888	AUTHOR	2055	AUTHOR
1889	Marc Lehmann <schmorp@schmorp.de>	2056	Marc Lehmann <schmorp@schmorp.de>
1890	http://home.schmorp.de/	2057	http://home.schmorp.de/

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Comparing AnyEvent/README (file contents): Revision 1.61 by root, Wed Apr 28 14:15:55 2010 UTC vs. Revision 1.67 by root, Fri Aug 26 05:33:53 2011 UTC

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Comparing AnyEvent/README (file contents):
Revision 1.61 by root, Wed Apr 28 14:15:55 2010 UTC vs.
Revision 1.67 by root, Fri Aug 26 05:33:53 2011 UTC