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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.115 by root, Sat May 10 21:47:28 2008 UTC vs.
Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub { ... });
12	...
13	});
14		12
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	13	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		14	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		15
		16	print AnyEvent->now; # prints current event loop time
		17	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		18
		19	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		20
		21	my $w = AnyEvent->child (pid => $pid, cb => sub {
		22	my ($pid, $status) = @_;
16	...	23	...
17	});	24	});
18		25
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	26	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	27	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	28	$w->recv; # enters "main loop" till $condvar gets ->send
		29	# use a condvar in callback mode:
		30	$w->cb (sub { $_[0]->recv });
		31
		32	=head1 INTRODUCTION/TUTORIAL
		33
		34	This manpage is mainly a reference manual. If you are interested
		35	in a tutorial or some gentle introduction, have a look at the
		36	L<AnyEvent::Intro> manpage.
22		37
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	38	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		39
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	40	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	41	nowadays. So what is different about AnyEvent?
27		42
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	43	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	44	policy> and AnyEvent is I<small and efficient>.
30		45
31	First and foremost, I<AnyEvent is not an event model> itself, it only	46	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	47	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	48	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	49	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	50	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	51	cannot change this, but it can hide the differences between those event
		52	loops.
37		53
38	The goal of AnyEvent is to offer module authors the ability to do event	54	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	55	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	56	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	57	module users into the same thing by forcing them to use the same event
42	model you use.	58	model you use.
43		59
44	For modules like POE or IO::Async (which is a total misnomer as it is	60	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	61	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	62	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	63	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	64	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	65	module are I<also> forced to use the same event loop you use.
50		66
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	67	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	68	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	69	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	70	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	71	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	72	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	73	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	74	to AnyEvent, too, so it is future-proof).
59		75
60	In addition to being free of having to use I<the one and only true event	76	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	77	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	78	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	79	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	80	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	81	technically possible.
66		82
		83	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		84	of useful functionality, such as an asynchronous DNS resolver, 100%
		85	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		86	such as Windows) and lots of real-world knowledge and workarounds for
		87	platform bugs and differences.
		88
67	Of course, if you want lots of policy (this can arguably be somewhat	89	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	90	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	91	model, you should I<not> use this module.
70		92
71	=head1 DESCRIPTION	93	=head1 DESCRIPTION
72		94
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	124	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	125	use AnyEvent so their modules work together with others seamlessly...
104		126
105	The pure-perl implementation of AnyEvent is called	127	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	128	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	129	explicitly and enjoy the high availability of that event loop :)
108		130
109	=head1 WATCHERS	131	=head1 WATCHERS
110		132
111	AnyEvent has the central concept of a I<watcher>, which is an object that	133	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	134	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	135	the callback to call, the file handle to watch, etc.
114		136
115	These watchers are normal Perl objects with normal Perl lifetime. After	137	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	138	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	139	callback when the event occurs (of course, only when the event model
118	is in control).	140	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	148	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	149	example), or need to refer to their watcher object in other ways.
128		150
129	An any way to achieve that is this pattern:	151	An any way to achieve that is this pattern:
130		152
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	153	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	154	# you can use $w here, for example to undef it
133	undef $w;	155	undef $w;
134	});	156	});
135		157
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	158	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	159	my variables are only visible after the statement in which they are
138	declared.	160	declared.
139		161
140	=head2 I/O WATCHERS	162	=head2 I/O WATCHERS
141		163
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	164	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	165	with the following mandatory key-value pairs as arguments:
144		166
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	167	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for events
146	for events. C<poll> must be a string that is either C<r> or C<w>,	168	(AnyEvent might or might not keep a reference to this file handle). C<poll>
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	169	must be a string that is either C<r> or C<w>, which creates a watcher
148	respectively. C<cb> is the callback to invoke each time the file handle	170	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	171	callback to invoke each time the file handle becomes ready.
150		172
151	Although the callback might get passed parameters, their value and	173	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	174	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	175	callbacks cannot use arguments passed to I/O watcher callbacks.
154		176
…		…
158		180
159	Some event loops issue spurious readyness notifications, so you should	181	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	182	always use non-blocking calls when reading/writing from/to your file
161	handles.	183	handles.
162		184
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	185	Example: wait for readability of STDIN, then read a line and disable the
		186	watcher.
		187
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	188	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	189	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	190	warn "read: $input\n";
169	undef $w;	191	undef $w;
170	});	192	});
…		…
180		202
181	Although the callback might get passed parameters, their value and	203	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	204	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	205	callbacks cannot use arguments passed to time watcher callbacks.
184		206
185	The timer callback will be invoked at most once: if you want a repeating	207	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	208	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	209	callback will be invoked regularly at that interval (in fractional
		210	seconds) after the first invocation. If C<interval> is specified with a
		211	false value, then it is treated as if it were missing.
188		212
189	Example:	213	The callback will be rescheduled before invoking the callback, but no
		214	attempt is done to avoid timer drift in most backends, so the interval is
		215	only approximate.
190		216
191	# fire an event after 7.7 seconds	217	Example: fire an event after 7.7 seconds.
		218
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	219	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	220	warn "timeout\n";
194	});	221	});
195		222
196	# to cancel the timer:	223	# to cancel the timer:
197	undef $w;	224	undef $w;
198		225
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	226	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		227
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	228	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		229	warn "timeout\n";
207	};	230	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		231
212	=head3 TIMING ISSUES	232	=head3 TIMING ISSUES
213		233
214	There are two ways to handle timers: based on real time (relative, "fire	234	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	235	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	247	timers.
228		248
229	AnyEvent always prefers relative timers, if available, matching the	249	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	250	AnyEvent API.
231		251
		252	AnyEvent has two additional methods that return the "current time":
		253
		254	=over 4
		255
		256	=item AnyEvent->time
		257
		258	This returns the "current wallclock time" as a fractional number of
		259	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		260	return, and the result is guaranteed to be compatible with those).
		261
		262	It progresses independently of any event loop processing, i.e. each call
		263	will check the system clock, which usually gets updated frequently.
		264
		265	=item AnyEvent->now
		266
		267	This also returns the "current wallclock time", but unlike C<time>, above,
		268	this value might change only once per event loop iteration, depending on
		269	the event loop (most return the same time as C<time>, above). This is the
		270	time that AnyEvent's timers get scheduled against.
		271
		272	I<In almost all cases (in all cases if you don't care), this is the
		273	function to call when you want to know the current time.>
		274
		275	This function is also often faster then C<< AnyEvent->time >>, and
		276	thus the preferred method if you want some timestamp (for example,
		277	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		278
		279	The rest of this section is only of relevance if you try to be very exact
		280	with your timing, you can skip it without bad conscience.
		281
		282	For a practical example of when these times differ, consider L<Event::Lib>
		283	and L<EV> and the following set-up:
		284
		285	The event loop is running and has just invoked one of your callback at
		286	time=500 (assume no other callbacks delay processing). In your callback,
		287	you wait a second by executing C<sleep 1> (blocking the process for a
		288	second) and then (at time=501) you create a relative timer that fires
		289	after three seconds.
		290
		291	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		292	both return C<501>, because that is the current time, and the timer will
		293	be scheduled to fire at time=504 (C<501> + C<3>).
		294
		295	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		296	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		297	last event processing phase started. With L<EV>, your timer gets scheduled
		298	to run at time=503 (C<500> + C<3>).
		299
		300	In one sense, L<Event::Lib> is more exact, as it uses the current time
		301	regardless of any delays introduced by event processing. However, most
		302	callbacks do not expect large delays in processing, so this causes a
		303	higher drift (and a lot more system calls to get the current time).
		304
		305	In another sense, L<EV> is more exact, as your timer will be scheduled at
		306	the same time, regardless of how long event processing actually took.
		307
		308	In either case, if you care (and in most cases, you don't), then you
		309	can get whatever behaviour you want with any event loop, by taking the
		310	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		311	account.
		312
		313	=back
		314
232	=head2 SIGNAL WATCHERS	315	=head2 SIGNAL WATCHERS
233		316
234	You can watch for signals using a signal watcher, C<signal> is the signal	317	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	318	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	319	callback to be invoked whenever a signal occurs.
237		320
238	Although the callback might get passed parameters, their value and	321	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	322	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	323	callbacks cannot use arguments passed to signal watcher callbacks.
241		324
242	Multiple signal occurances can be clumped together into one callback	325	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	326	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	327	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	328	but it is guaranteed not to interrupt any other callbacks.
246		329
247	The main advantage of using these watchers is that you can share a signal	330	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	331	between multiple watchers.
249		332
250	This watcher might use C<%SIG>, so programs overwriting those signals	333	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	360	AnyEvent program, you I<have> to create at least one watcher before you
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	361	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		362
280	Example: fork a process and wait for it	363	Example: fork a process and wait for it
281		364
282	my $done = AnyEvent->condvar;	365	my $done = AnyEvent->condvar;
283		366
284	my $pid = fork or exit 5;	367	my $pid = fork or exit 5;
285		368
286	my $w = AnyEvent->child (	369	my $w = AnyEvent->child (
287	pid => $pid,	370	pid => $pid,
288	cb => sub {	371	cb => sub {
289	my ($pid, $status) = @_;	372	my ($pid, $status) = @_;
290	warn "pid $pid exited with status $status";	373	warn "pid $pid exited with status $status";
291	$done->send;	374	$done->send;
292	},	375	},
293	);	376	);
294		377
295	# do something else, then wait for process exit	378	# do something else, then wait for process exit
296	$done->recv;	379	$done->recv;
297		380
298	=head2 CONDITION VARIABLES	381	=head2 CONDITION VARIABLES
299		382
300	If you are familiar with some event loops you will know that all of them	383	If you are familiar with some event loops you will know that all of them
301	require you to run some blocking "loop", "run" or similar function that	384	require you to run some blocking "loop", "run" or similar function that
…		…
307	The instrument to do that is called a "condition variable", so called	390	The instrument to do that is called a "condition variable", so called
308	because they represent a condition that must become true.	391	because they represent a condition that must become true.
309		392
310	Condition variables can be created by calling the C<< AnyEvent->condvar	393	Condition variables can be created by calling the C<< AnyEvent->condvar
311	>> method, usually without arguments. The only argument pair allowed is	394	>> method, usually without arguments. The only argument pair allowed is
		395
312	C<cb>, which specifies a callback to be called when the condition variable	396	C<cb>, which specifies a callback to be called when the condition variable
313	becomes true.	397	becomes true, with the condition variable as the first argument (but not
		398	the results).
314		399
315	After creation, the conditon variable is "false" until it becomes "true"	400	After creation, the condition variable is "false" until it becomes "true"
316	by calling the C<send> method.	401	by calling the C<send> method (or calling the condition variable as if it
		402	were a callback, read about the caveats in the description for the C<<
		403	->send >> method).
317		404
318	Condition variables are similar to callbacks, except that you can	405	Condition variables are similar to callbacks, except that you can
319	optionally wait for them. They can also be called merge points - points	406	optionally wait for them. They can also be called merge points - points
320	in time where multiple outstandign events have been processed. And yet	407	in time where multiple outstanding events have been processed. And yet
321	another way to call them is transations - each condition variable can be	408	another way to call them is transactions - each condition variable can be
322	used to represent a transaction, which finishes at some point and delivers	409	used to represent a transaction, which finishes at some point and delivers
323	a result.	410	a result.
324		411
325	Condition variables are very useful to signal that something has finished,	412	Condition variables are very useful to signal that something has finished,
326	for example, if you write a module that does asynchronous http requests,	413	for example, if you write a module that does asynchronous http requests,
…		…
332	you can block your main program until an event occurs - for example, you	419	you can block your main program until an event occurs - for example, you
333	could C<< ->recv >> in your main program until the user clicks the Quit	420	could C<< ->recv >> in your main program until the user clicks the Quit
334	button of your app, which would C<< ->send >> the "quit" event.	421	button of your app, which would C<< ->send >> the "quit" event.
335		422
336	Note that condition variables recurse into the event loop - if you have	423	Note that condition variables recurse into the event loop - if you have
337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you	424	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
338	lose. Therefore, condition variables are good to export to your caller, but	425	lose. Therefore, condition variables are good to export to your caller, but
339	you should avoid making a blocking wait yourself, at least in callbacks,	426	you should avoid making a blocking wait yourself, at least in callbacks,
340	as this asks for trouble.	427	as this asks for trouble.
341		428
342	Condition variables are represented by hash refs in perl, and the keys	429	Condition variables are represented by hash refs in perl, and the keys
…		…
347		434
348	There are two "sides" to a condition variable - the "producer side" which	435	There are two "sides" to a condition variable - the "producer side" which
349	eventually calls C<< -> send >>, and the "consumer side", which waits	436	eventually calls C<< -> send >>, and the "consumer side", which waits
350	for the send to occur.	437	for the send to occur.
351		438
352	Example:	439	Example: wait for a timer.
353		440
354	# wait till the result is ready	441	# wait till the result is ready
355	my $result_ready = AnyEvent->condvar;	442	my $result_ready = AnyEvent->condvar;
356		443
357	# do something such as adding a timer	444	# do something such as adding a timer
…		…
365		452
366	# this "blocks" (while handling events) till the callback	453	# this "blocks" (while handling events) till the callback
367	# calls send	454	# calls send
368	$result_ready->recv;	455	$result_ready->recv;
369		456
		457	Example: wait for a timer, but take advantage of the fact that
		458	condition variables are also code references.
		459
		460	my $done = AnyEvent->condvar;
		461	my $delay = AnyEvent->timer (after => 5, cb => $done);
		462	$done->recv;
		463
		464	Example: Imagine an API that returns a condvar and doesn't support
		465	callbacks. This is how you make a synchronous call, for example from
		466	the main program:
		467
		468	use AnyEvent::CouchDB;
		469
		470	...
		471
		472	my @info = $couchdb->info->recv;
		473
		474	And this is how you would just ste a callback to be called whenever the
		475	results are available:
		476
		477	$couchdb->info->cb (sub {
		478	my @info = $_[0]->recv;
		479	});
		480
370	=head3 METHODS FOR PRODUCERS	481	=head3 METHODS FOR PRODUCERS
371		482
372	These methods should only be used by the producing side, i.e. the	483	These methods should only be used by the producing side, i.e. the
373	code/module that eventually sends the signal. Note that it is also	484	code/module that eventually sends the signal. Note that it is also
374	the producer side which creates the condvar in most cases, but it isn't	485	the producer side which creates the condvar in most cases, but it isn't
…		…
385	If a callback has been set on the condition variable, it is called	496	If a callback has been set on the condition variable, it is called
386	immediately from within send.	497	immediately from within send.
387		498
388	Any arguments passed to the C<send> call will be returned by all	499	Any arguments passed to the C<send> call will be returned by all
389	future C<< ->recv >> calls.	500	future C<< ->recv >> calls.
		501
		502	Condition variables are overloaded so one can call them directly
		503	(as a code reference). Calling them directly is the same as calling
		504	C<send>. Note, however, that many C-based event loops do not handle
		505	overloading, so as tempting as it may be, passing a condition variable
		506	instead of a callback does not work. Both the pure perl and EV loops
		507	support overloading, however, as well as all functions that use perl to
		508	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		509	example).
390		510
391	=item $cv->croak ($error)	511	=item $cv->croak ($error)
392		512
393	Similar to send, but causes all call's to C<< ->recv >> to invoke	513	Similar to send, but causes all call's to C<< ->recv >> to invoke
394	C<Carp::croak> with the given error message/object/scalar.	514	C<Carp::croak> with the given error message/object/scalar.
…		…
443	doesn't execute once).	563	doesn't execute once).
444		564
445	This is the general pattern when you "fan out" into multiple subrequests:	565	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	566	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	567	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	568	C<begin> and for each subrequest you finish, call C<end>.
449		569
450	=back	570	=back
451		571
452	=head3 METHODS FOR CONSUMERS	572	=head3 METHODS FOR CONSUMERS
453		573
…		…
475	(programs might want to do that to stay interactive), so I<if you are	595	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	596	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	597	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	598	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	599	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	600	while still supporting blocking waits if the caller so desires).
481		601
482	Another reason I<never> to C<< ->recv >> in a module is that you cannot	602	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->recv >>'s in parallel, as that would require	603	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	604	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	605	can supply.
…		…
498	=item $bool = $cv->ready	618	=item $bool = $cv->ready
499		619
500	Returns true when the condition is "true", i.e. whether C<send> or	620	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	621	C<croak> have been called.
502		622
503	=item $cb = $cv->cb ([new callback])	623	=item $cb = $cv->cb ($cb->($cv))
504		624
505	This is a mutator function that returns the callback set and optionally	625	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	626	replaces it before doing so.
507		627
508	The callback will be called when the condition becomes "true", i.e. when	628	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<recv> inside the callback	629	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	630	variable itself. Calling C<recv> inside the callback or at any later time
		631	is guaranteed not to block.
511		632
512	=back	633	=back
513		634
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	635	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		636
…		…
601		722
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	723	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603	do anything special (it does not need to be event-based) and let AnyEvent	724	do anything special (it does not need to be event-based) and let AnyEvent
604	decide which implementation to chose if some module relies on it.	725	decide which implementation to chose if some module relies on it.
605		726
606	If the main program relies on a specific event model. For example, in	727	If the main program relies on a specific event model - for example, in
607	Gtk2 programs you have to rely on the Glib module. You should load the	728	Gtk2 programs you have to rely on the Glib module - you should load the
608	event module before loading AnyEvent or any module that uses it: generally	729	event module before loading AnyEvent or any module that uses it: generally
609	speaking, you should load it as early as possible. The reason is that	730	speaking, you should load it as early as possible. The reason is that
610	modules might create watchers when they are loaded, and AnyEvent will	731	modules might create watchers when they are loaded, and AnyEvent will
611	decide on the event model to use as soon as it creates watchers, and it	732	decide on the event model to use as soon as it creates watchers, and it
612	might chose the wrong one unless you load the correct one yourself.	733	might chose the wrong one unless you load the correct one yourself.
613		734
614	You can chose to use a rather inefficient pure-perl implementation by	735	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	736	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	737	everywhere, but letting AnyEvent chose the model is generally better.
		738
		739	=head2 MAINLOOP EMULATION
		740
		741	Sometimes (often for short test scripts, or even standalone programs who
		742	only want to use AnyEvent), you do not want to run a specific event loop.
		743
		744	In that case, you can use a condition variable like this:
		745
		746	AnyEvent->condvar->recv;
		747
		748	This has the effect of entering the event loop and looping forever.
		749
		750	Note that usually your program has some exit condition, in which case
		751	it is better to use the "traditional" approach of storing a condition
		752	variable somewhere, waiting for it, and sending it when the program should
		753	exit cleanly.
		754
617		755
618	=head1 OTHER MODULES	756	=head1 OTHER MODULES
619		757
620	The following is a non-exhaustive list of additional modules that use	758	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	759	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	765	=item L<AnyEvent::Util>
628		766
629	Contains various utility functions that replace often-used but blocking	767	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	768	functions such as C<inet_aton> by event-/callback-based versions.
631		769
		770	=item L<AnyEvent::Socket>
		771
		772	Provides various utility functions for (internet protocol) sockets,
		773	addresses and name resolution. Also functions to create non-blocking tcp
		774	connections or tcp servers, with IPv6 and SRV record support and more.
		775
632	=item L<AnyEvent::Handle>	776	=item L<AnyEvent::Handle>
633		777
634	Provide read and write buffers and manages watchers for reads and writes.	778	Provide read and write buffers, manages watchers for reads and writes,
		779	supports raw and formatted I/O, I/O queued and fully transparent and
		780	non-blocking SSL/TLS.
		781
		782	=item L<AnyEvent::DNS>
		783
		784	Provides rich asynchronous DNS resolver capabilities.
		785
		786	=item L<AnyEvent::HTTP>
		787
		788	A simple-to-use HTTP library that is capable of making a lot of concurrent
		789	HTTP requests.
635		790
636	=item L<AnyEvent::HTTPD>	791	=item L<AnyEvent::HTTPD>
637		792
638	Provides a simple web application server framework.	793	Provides a simple web application server framework.
639		794
640	=item L<AnyEvent::DNS>
641
642	Provides asynchronous DNS resolver capabilities, beyond what
643	L<AnyEvent::Util> offers.
644
645	=item L<AnyEvent::FastPing>	795	=item L<AnyEvent::FastPing>
646		796
647	The fastest ping in the west.	797	The fastest ping in the west.
		798
		799	=item L<AnyEvent::DBI>
		800
		801	Executes L<DBI> requests asynchronously in a proxy process.
		802
		803	=item L<AnyEvent::AIO>
		804
		805	Truly asynchronous I/O, should be in the toolbox of every event
		806	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		807	together.
		808
		809	=item L<AnyEvent::BDB>
		810
		811	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		812	L<BDB> and AnyEvent together.
		813
		814	=item L<AnyEvent::GPSD>
		815
		816	A non-blocking interface to gpsd, a daemon delivering GPS information.
		817
		818	=item L<AnyEvent::IGS>
		819
		820	A non-blocking interface to the Internet Go Server protocol (used by
		821	L<App::IGS>).
648		822
649	=item L<Net::IRC3>	823	=item L<Net::IRC3>
650		824
651	AnyEvent based IRC client module family.	825	AnyEvent based IRC client module family.
652		826
…		…
665		839
666	=item L<Coro>	840	=item L<Coro>
667		841
668	Has special support for AnyEvent via L<Coro::AnyEvent>.	842	Has special support for AnyEvent via L<Coro::AnyEvent>.
669		843
670	=item L<AnyEvent::AIO>, L<IO::AIO>
671
672	Truly asynchronous I/O, should be in the toolbox of every event
673	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
674	together.
675
676	=item L<AnyEvent::BDB>, L<BDB>
677
678	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
679	IO::AIO and AnyEvent together.
680
681	=item L<IO::Lambda>	844	=item L<IO::Lambda>
682		845
683	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	846	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
684		847
685	=back	848	=back
…		…
691	no warnings;	854	no warnings;
692	use strict;	855	use strict;
693		856
694	use Carp;	857	use Carp;
695		858
696	our $VERSION = '3.4';	859	our $VERSION = 4.233;
697	our $MODEL;	860	our $MODEL;
698		861
699	our $AUTOLOAD;	862	our $AUTOLOAD;
700	our @ISA;	863	our @ISA;
701		864
		865	our @REGISTRY;
		866
		867	our $WIN32;
		868
		869	BEGIN {
		870	my $win32 = ! ! ($^O =~ /mswin32/i);
		871	eval "sub WIN32(){ $win32 }";
		872	}
		873
702	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	874	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703		875
704	our @REGISTRY;	876	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		877
		878	{
		879	my $idx;
		880	$PROTOCOL{$_} = ++$idx
		881	for reverse split /\s,\s/,
		882	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		883	}
705		884
706	my @models = (	885	my @models = (
707	[EV:: => AnyEvent::Impl::EV::],	886	[EV:: => AnyEvent::Impl::EV::],
708	[Event:: => AnyEvent::Impl::Event::],	887	[Event:: => AnyEvent::Impl::Event::],
709	[Tk:: => AnyEvent::Impl::Tk::],
710	[Wx:: => AnyEvent::Impl::POE::],
711	[Prima:: => AnyEvent::Impl::POE::],
712	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	888	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713	# everything below here will not be autoprobed as the pureperl backend should work everywhere	889	# everything below here will not be autoprobed
714	[Glib:: => AnyEvent::Impl::Glib::],	890	# as the pureperl backend should work everywhere
		891	# and is usually faster
		892	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		893	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	894	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	895	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	896	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		897	[Wx:: => AnyEvent::Impl::POE::],
		898	[Prima:: => AnyEvent::Impl::POE::],
718	);	899	);
719		900
720	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	901	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
721		902
722	our @post_detect;	903	our @post_detect;
723		904
724	sub post_detect(&) {	905	sub post_detect(&) {
725	my ($cb) = @_;	906	my ($cb) = @_;
…		…
730	1	911	1
731	} else {	912	} else {
732	push @post_detect, $cb;	913	push @post_detect, $cb;
733		914
734	defined wantarray	915	defined wantarray
735	? bless \$cb, "AnyEvent::Util::Guard"	916	? bless \$cb, "AnyEvent::Util::PostDetect"
736	: ()	917	: ()
737	}	918	}
738	}	919	}
739		920
740	sub AnyEvent::Util::Guard::DESTROY {	921	sub AnyEvent::Util::PostDetect::DESTROY {
741	@post_detect = grep $_ != ${$_[0]}, @post_detect;	922	@post_detect = grep $_ != ${$_[0]}, @post_detect;
742	}	923	}
743		924
744	sub detect() {	925	sub detect() {
745	unless ($MODEL) {	926	unless ($MODEL) {
746	no strict 'refs';	927	no strict 'refs';
		928	local $SIG{__DIE__};
747		929
748	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	930	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749	my $model = "AnyEvent::Impl::$1";	931	my $model = "AnyEvent::Impl::$1";
750	if (eval "require $model") {	932	if (eval "require $model") {
751	$MODEL = $model;	933	$MODEL = $model;
…		…
785	$MODEL	967	$MODEL
786	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	968	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
787	}	969	}
788	}	970	}
789		971
		972	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		973
790	unshift @ISA, $MODEL;	974	unshift @ISA, $MODEL;
791	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	975
		976	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
792		977
793	(shift @post_detect)->() while @post_detect;	978	(shift @post_detect)->() while @post_detect;
794	}	979	}
795		980
796	$MODEL	981	$MODEL
…		…
806		991
807	my $class = shift;	992	my $class = shift;
808	$class->$func (@_);	993	$class->$func (@_);
809	}	994	}
810		995
		996	# utility function to dup a filehandle. this is used by many backends
		997	# to support binding more than one watcher per filehandle (they usually
		998	# allow only one watcher per fd, so we dup it to get a different one).
		999	sub _dupfh($$$$) {
		1000	my ($poll, $fh, $r, $w) = @_;
		1001
		1002	require Fcntl;
		1003
		1004	# cygwin requires the fh mode to be matching, unix doesn't
		1005	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1006	: $poll eq "w" ? ($w, ">")
		1007	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1008
		1009	open my $fh2, "$mode&" . fileno $fh
		1010	or die "cannot dup() filehandle: $!";
		1011
		1012	# we assume CLOEXEC is already set by perl in all important cases
		1013
		1014	($fh2, $rw)
		1015	}
		1016
811	package AnyEvent::Base;	1017	package AnyEvent::Base;
812		1018
		1019	# default implementation for now and time
		1020
		1021	BEGIN {
		1022	if (eval "use Time::HiRes (); time (); 1") {
		1023	*_time = \&Time::HiRes::time;
		1024	# if (eval "use POSIX (); (POSIX::times())...
		1025	} else {
		1026	*_time = \&CORE::time; # epic fail
		1027	}
		1028	}
		1029
		1030	sub time { _time }
		1031	sub now { _time }
		1032
813	# default implementation for ->condvar	1033	# default implementation for ->condvar
814		1034
815	sub condvar {	1035	sub condvar {
816	bless {}, "AnyEvent::Base::CondVar"	1036	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817	}	1037	}
818		1038
819	# default implementation for ->signal	1039	# default implementation for ->signal
820		1040
821	our %SIG_CB;	1041	our %SIG_CB;
…		…
837	sub AnyEvent::Base::Signal::DESTROY {	1057	sub AnyEvent::Base::Signal::DESTROY {
838	my ($signal, $cb) = @{$_[0]};	1058	my ($signal, $cb) = @{$_[0]};
839		1059
840	delete $SIG_CB{$signal}{$cb};	1060	delete $SIG_CB{$signal}{$cb};
841		1061
842	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1062	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
843	}	1063	}
844		1064
845	# default implementation for ->child	1065	# default implementation for ->child
846		1066
847	our %PID_CB;	1067	our %PID_CB;
…		…
874	or Carp::croak "required option 'pid' is missing";	1094	or Carp::croak "required option 'pid' is missing";
875		1095
876	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1096	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
877		1097
878	unless ($WNOHANG) {	1098	unless ($WNOHANG) {
879	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1099	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
880	}	1100	}
881		1101
882	unless ($CHLD_W) {	1102	unless ($CHLD_W) {
883	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1103	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
884	# child could be a zombie already, so make at least one round	1104	# child could be a zombie already, so make at least one round
…		…
895	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1115	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
896		1116
897	undef $CHLD_W unless keys %PID_CB;	1117	undef $CHLD_W unless keys %PID_CB;
898	}	1118	}
899		1119
900	package AnyEvent::Base::CondVar;	1120	package AnyEvent::CondVar;
901		1121
902	# wake up the waiter	1122	our @ISA = AnyEvent::CondVar::Base::;
		1123
		1124	package AnyEvent::CondVar::Base;
		1125
		1126	use overload
		1127	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1128	fallback => 1;
		1129
903	sub _send {	1130	sub _send {
904	&{ delete $_[0]{_ae_cb} } if $_[0]{_ae_cb};	1131	# nop
905	}	1132	}
906		1133
907	sub send {	1134	sub send {
908	my $cv = shift;	1135	my $cv = shift;
909	$cv->{_ae_sent} = [@_];	1136	$cv->{_ae_sent} = [@_];
		1137	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
910	$cv->_send;	1138	$cv->_send;
911	}	1139	}
912		1140
913	sub croak {	1141	sub croak {
914	$_[0]{_ae_croak} = $_[1];	1142	$_[0]{_ae_croak} = $_[1];
…		…
917		1145
918	sub ready {	1146	sub ready {
919	$_[0]{_ae_sent}	1147	$_[0]{_ae_sent}
920	}	1148	}
921		1149
		1150	sub _wait {
		1151	AnyEvent->one_event while !$_[0]{_ae_sent};
		1152	}
		1153
922	sub recv {	1154	sub recv {
923	AnyEvent->one_event while !$_[0]{_ae_sent};	1155	$_[0]->_wait;
924		1156
925	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1157	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
926	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1158	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
927	}	1159	}
928		1160
…		…
936	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1168	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
937	}	1169	}
938		1170
939	sub end {	1171	sub end {
940	return if --$_[0]{_ae_counter};	1172	return if --$_[0]{_ae_counter};
941	&{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb};	1173	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
942	}	1174	}
943		1175
944	# undocumented/compatibility with pre-3.4	1176	# undocumented/compatibility with pre-3.4
945	*broadcast = \&send;	1177	*broadcast = \&send;
946	*wait = \&recv;	1178	*wait = \&_wait;
947		1179
948	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1180	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
949		1181
950	This is an advanced topic that you do not normally need to use AnyEvent in	1182	This is an advanced topic that you do not normally need to use AnyEvent in
951	a module. This section is only of use to event loop authors who want to	1183	a module. This section is only of use to event loop authors who want to
…		…
1005	C<PERL_ANYEVENT_MODEL>.	1237	C<PERL_ANYEVENT_MODEL>.
1006		1238
1007	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1239	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1008	model it chooses.	1240	model it chooses.
1009		1241
		1242	=item C<PERL_ANYEVENT_STRICT>
		1243
		1244	AnyEvent does not do much argument checking by default, as thorough
		1245	argument checking is very costly. Setting this variable to a true value
		1246	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1247	check the arguments passed to most method calls. If it finds any problems
		1248	it will croak.
		1249
		1250	In other words, enables "strict" mode.
		1251
		1252	Unlike C<use strict> it is definitely recommended ot keep it off in
		1253	production.
		1254
1010	=item C<PERL_ANYEVENT_MODEL>	1255	=item C<PERL_ANYEVENT_MODEL>
1011		1256
1012	This can be used to specify the event model to be used by AnyEvent, before	1257	This can be used to specify the event model to be used by AnyEvent, before
1013	autodetection and -probing kicks in. It must be a string consisting	1258	auto detection and -probing kicks in. It must be a string consisting
1014	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1259	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1015	and the resulting module name is loaded and if the load was successful,	1260	and the resulting module name is loaded and if the load was successful,
1016	used as event model. If it fails to load AnyEvent will proceed with	1261	used as event model. If it fails to load AnyEvent will proceed with
1017	autodetection and -probing.	1262	auto detection and -probing.
1018		1263
1019	This functionality might change in future versions.	1264	This functionality might change in future versions.
1020		1265
1021	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1266	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1022	could start your program like this:	1267	could start your program like this:
1023		1268
1024	PERL_ANYEVENT_MODEL=Perl perl ...	1269	PERL_ANYEVENT_MODEL=Perl perl ...
		1270
		1271	=item C<PERL_ANYEVENT_PROTOCOLS>
		1272
		1273	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1274	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1275	of auto probing).
		1276
		1277	Must be set to a comma-separated list of protocols or address families,
		1278	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1279	used, and preference will be given to protocols mentioned earlier in the
		1280	list.
		1281
		1282	This variable can effectively be used for denial-of-service attacks
		1283	against local programs (e.g. when setuid), although the impact is likely
		1284	small, as the program has to handle connection errors already-
		1285
		1286	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1287	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1288	- only support IPv4, never try to resolve or contact IPv6
		1289	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1290	IPv6, but prefer IPv6 over IPv4.
		1291
		1292	=item C<PERL_ANYEVENT_EDNS0>
		1293
		1294	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1295	for DNS. This extension is generally useful to reduce DNS traffic, but
		1296	some (broken) firewalls drop such DNS packets, which is why it is off by
		1297	default.
		1298
		1299	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1300	EDNS0 in its DNS requests.
		1301
		1302	=item C<PERL_ANYEVENT_MAX_FORKS>
		1303
		1304	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1305	will create in parallel.
1025		1306
1026	=back	1307	=back
1027		1308
1028	=head1 EXAMPLE PROGRAM	1309	=head1 EXAMPLE PROGRAM
1029		1310
…		…
1040	poll => 'r',	1321	poll => 'r',
1041	cb => sub {	1322	cb => sub {
1042	warn "io event <$_[0]>\n"; # will always output <r>	1323	warn "io event <$_[0]>\n"; # will always output <r>
1043	chomp (my $input = <STDIN>); # read a line	1324	chomp (my $input = <STDIN>); # read a line
1044	warn "read: $input\n"; # output what has been read	1325	warn "read: $input\n"; # output what has been read
1045	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1326	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1046	},	1327	},
1047	);	1328	);
1048		1329
1049	my $time_watcher; # can only be used once	1330	my $time_watcher; # can only be used once
1050		1331
…		…
1055	});	1336	});
1056	}	1337	}
1057		1338
1058	new_timer; # create first timer	1339	new_timer; # create first timer
1059		1340
1060	$cv->wait; # wait until user enters /^q/i	1341	$cv->recv; # wait until user enters /^q/i
1061		1342
1062	=head1 REAL-WORLD EXAMPLE	1343	=head1 REAL-WORLD EXAMPLE
1063		1344
1064	Consider the L<Net::FCP> module. It features (among others) the following	1345	Consider the L<Net::FCP> module. It features (among others) the following
1065	API calls, which are to freenet what HTTP GET requests are to http:	1346	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1115	syswrite $txn->{fh}, $txn->{request}	1396	syswrite $txn->{fh}, $txn->{request}
1116	or die "connection or write error";	1397	or die "connection or write error";
1117	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1398	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1118		1399
1119	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1400	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1120	result and signals any possible waiters that the request ahs finished:	1401	result and signals any possible waiters that the request has finished:
1121		1402
1122	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1403	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1123		1404
1124	if (end-of-file or data complete) {	1405	if (end-of-file or data complete) {
1125	$txn->{result} = $txn->{buf};	1406	$txn->{result} = $txn->{buf};
1126	$txn->{finished}->broadcast;	1407	$txn->{finished}->send;
1127	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1408	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1128	}	1409	}
1129		1410
1130	The C<result> method, finally, just waits for the finished signal (if the	1411	The C<result> method, finally, just waits for the finished signal (if the
1131	request was already finished, it doesn't wait, of course, and returns the	1412	request was already finished, it doesn't wait, of course, and returns the
1132	data:	1413	data:
1133		1414
1134	$txn->{finished}->wait;	1415	$txn->{finished}->recv;
1135	return $txn->{result};	1416	return $txn->{result};
1136		1417
1137	The actual code goes further and collects all errors (C<die>s, exceptions)	1418	The actual code goes further and collects all errors (C<die>s, exceptions)
1138	that occured during request processing. The C<result> method detects	1419	that occurred during request processing. The C<result> method detects
1139	whether an exception as thrown (it is stored inside the $txn object)	1420	whether an exception as thrown (it is stored inside the $txn object)
1140	and just throws the exception, which means connection errors and other	1421	and just throws the exception, which means connection errors and other
1141	problems get reported tot he code that tries to use the result, not in a	1422	problems get reported tot he code that tries to use the result, not in a
1142	random callback.	1423	random callback.
1143		1424
…		…
1174		1455
1175	my $quit = AnyEvent->condvar;	1456	my $quit = AnyEvent->condvar;
1176		1457
1177	$fcp->txn_client_get ($url)->cb (sub {	1458	$fcp->txn_client_get ($url)->cb (sub {
1178	...	1459	...
1179	$quit->broadcast;	1460	$quit->send;
1180	});	1461	});
1181		1462
1182	$quit->wait;	1463	$quit->recv;
1183		1464
1184		1465
1185	=head1 BENCHMARKS	1466	=head1 BENCHMARKS
1186		1467
1187	To give you an idea of the performance and overheads that AnyEvent adds	1468	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1189	of various event loops I prepared some benchmarks.	1470	of various event loops I prepared some benchmarks.
1190		1471
1191	=head2 BENCHMARKING ANYEVENT OVERHEAD	1472	=head2 BENCHMARKING ANYEVENT OVERHEAD
1192		1473
1193	Here is a benchmark of various supported event models used natively and	1474	Here is a benchmark of various supported event models used natively and
1194	through anyevent. The benchmark creates a lot of timers (with a zero	1475	through AnyEvent. The benchmark creates a lot of timers (with a zero
1195	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1476	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1196	which it is), lets them fire exactly once and destroys them again.	1477	which it is), lets them fire exactly once and destroys them again.
1197		1478
1198	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1479	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1199	distribution.	1480	distribution.
…		…
1216	all watchers, to avoid adding memory overhead. That means closure creation	1497	all watchers, to avoid adding memory overhead. That means closure creation
1217	and memory usage is not included in the figures.	1498	and memory usage is not included in the figures.
1218		1499
1219	I<invoke> is the time, in microseconds, used to invoke a simple	1500	I<invoke> is the time, in microseconds, used to invoke a simple
1220	callback. The callback simply counts down a Perl variable and after it was	1501	callback. The callback simply counts down a Perl variable and after it was
1221	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1502	invoked "watcher" times, it would C<< ->send >> a condvar once to
1222	signal the end of this phase.	1503	signal the end of this phase.
1223		1504
1224	I<destroy> is the time, in microseconds, that it takes to destroy a single	1505	I<destroy> is the time, in microseconds, that it takes to destroy a single
1225	watcher.	1506	watcher.
1226		1507
…		…
1322		1603
1323	=back	1604	=back
1324		1605
1325	=head2 BENCHMARKING THE LARGE SERVER CASE	1606	=head2 BENCHMARKING THE LARGE SERVER CASE
1326		1607
1327	This benchmark atcually benchmarks the event loop itself. It works by	1608	This benchmark actually benchmarks the event loop itself. It works by
1328	creating a number of "servers": each server consists of a socketpair, a	1609	creating a number of "servers": each server consists of a socket pair, a
1329	timeout watcher that gets reset on activity (but never fires), and an I/O	1610	timeout watcher that gets reset on activity (but never fires), and an I/O
1330	watcher waiting for input on one side of the socket. Each time the socket	1611	watcher waiting for input on one side of the socket. Each time the socket
1331	watcher reads a byte it will write that byte to a random other "server".	1612	watcher reads a byte it will write that byte to a random other "server".
1332		1613
1333	The effect is that there will be a lot of I/O watchers, only part of which	1614	The effect is that there will be a lot of I/O watchers, only part of which
1334	are active at any one point (so there is a constant number of active	1615	are active at any one point (so there is a constant number of active
1335	fds for each loop iterstaion, but which fds these are is random). The	1616	fds for each loop iteration, but which fds these are is random). The
1336	timeout is reset each time something is read because that reflects how	1617	timeout is reset each time something is read because that reflects how
1337	most timeouts work (and puts extra pressure on the event loops).	1618	most timeouts work (and puts extra pressure on the event loops).
1338		1619
1339	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1620	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1340	(1%) are active. This mirrors the activity of large servers with many	1621	(1%) are active. This mirrors the activity of large servers with many
1341	connections, most of which are idle at any one point in time.	1622	connections, most of which are idle at any one point in time.
1342		1623
1343	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1624	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1344	distribution.	1625	distribution.
…		…
1346	=head3 Explanation of the columns	1627	=head3 Explanation of the columns
1347		1628
1348	I<sockets> is the number of sockets, and twice the number of "servers" (as	1629	I<sockets> is the number of sockets, and twice the number of "servers" (as
1349	each server has a read and write socket end).	1630	each server has a read and write socket end).
1350		1631
1351	I<create> is the time it takes to create a socketpair (which is	1632	I<create> is the time it takes to create a socket pair (which is
1352	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1633	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1353		1634
1354	I<request>, the most important value, is the time it takes to handle a	1635	I<request>, the most important value, is the time it takes to handle a
1355	single "request", that is, reading the token from the pipe and forwarding	1636	single "request", that is, reading the token from the pipe and forwarding
1356	it to another server. This includes deleting the old timeout and creating	1637	it to another server. This includes deleting the old timeout and creating
…		…
1429	speed most when you have lots of watchers, not when you only have a few of	1710	speed most when you have lots of watchers, not when you only have a few of
1430	them).	1711	them).
1431		1712
1432	EV is again fastest.	1713	EV is again fastest.
1433		1714
1434	Perl again comes second. It is noticably faster than the C-based event	1715	Perl again comes second. It is noticeably faster than the C-based event
1435	loops Event and Glib, although the difference is too small to really	1716	loops Event and Glib, although the difference is too small to really
1436	matter.	1717	matter.
1437		1718
1438	POE also performs much better in this case, but is is still far behind the	1719	POE also performs much better in this case, but is is still far behind the
1439	others.	1720	others.
…		…
1468	specified in the variable.	1749	specified in the variable.
1469		1750
1470	You can make AnyEvent completely ignore this variable by deleting it	1751	You can make AnyEvent completely ignore this variable by deleting it
1471	before the first watcher gets created, e.g. with a C<BEGIN> block:	1752	before the first watcher gets created, e.g. with a C<BEGIN> block:
1472		1753
1473	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1754	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1474		1755
1475	use AnyEvent;	1756	use AnyEvent;
1476		1757
1477	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1758	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1478	be used to probe what backend is used and gain other information (which is	1759	be used to probe what backend is used and gain other information (which is
1479	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1760	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1761	$ENV{PERL_ANYEGENT_STRICT}.
		1762
		1763
		1764	=head1 BUGS
		1765
		1766	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1767	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1768	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1769	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1770	pronounced).
1480		1771
1481		1772
1482	=head1 SEE ALSO	1773	=head1 SEE ALSO
		1774
		1775	Utility functions: L<AnyEvent::Util>.
1483		1776
1484	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1777	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1485	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1778	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1486		1779
1487	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1780	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1488	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1781	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1489	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1782	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1490	L<AnyEvent::Impl::POE>.	1783	L<AnyEvent::Impl::POE>.
1491		1784
		1785	Non-blocking file handles, sockets, TCP clients and
		1786	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1787
		1788	Asynchronous DNS: L<AnyEvent::DNS>.
		1789
1492	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1790	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1493		1791
1494	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1792	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1495		1793
1496		1794
1497	=head1 AUTHOR	1795	=head1 AUTHOR
1498		1796
1499	Marc Lehmann <schmorp@schmorp.de>	1797	Marc Lehmann <schmorp@schmorp.de>
1500	http://home.schmorp.de/	1798	http://home.schmorp.de/
1501		1799
1502	=cut	1800	=cut
1503		1801
1504	1	1802	1
1505		1803

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.115 by root, Sat May 10 21:47:28 2008 UTC vs. Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.115 by root, Sat May 10 21:47:28 2008 UTC vs.
Revision 1.179 by root, Thu Sep 4 10:58:58 2008 UTC