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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs.
Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC

…		…
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	15	my $w = AnyEvent->timer (after => $seconds, cb => sub {
16	...	16	...
17	});	17	});
18		18
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	19	my $w = AnyEvent->condvar; # stores whether a condition was flagged
		20	$w->send; # wake up current and all future recv's
20	$w->wait; # enters "main loop" till $condvar gets ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
21	$w->send; # wake up current and all future wait's	22
		23	=head1 INTRODUCTION/TUTORIAL
		24
		25	This manpage is mainly a reference manual. If you are interested
		26	in a tutorial or some gentle introduction, have a look at the
		27	L<AnyEvent::Intro> manpage.
22		28
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	29	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		30
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	31	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	32	nowadays. So what is different about AnyEvent?
27		33
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	34	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	35	policy> and AnyEvent is I<small and efficient>.
30		36
31	First and foremost, I<AnyEvent is not an event model> itself, it only	37	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	38	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,	39	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,	40	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	41	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	42	cannot change this, but it can hide the differences between those event
		43	loops.
37		44
38	The goal of AnyEvent is to offer module authors the ability to do event	45	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	46	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	47	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	48	module users into the same thing by forcing them to use the same event
42	model you use.	49	model you use.
43		50
44	For modules like POE or IO::Async (which is a total misnomer as it is	51	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	52	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	53	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	54	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	55	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.	56	module are I<also> forced to use the same event loop you use.
50		57
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	58	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	59	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	60	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,	61	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	62	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	63	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	64	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).	65	to AnyEvent, too, so it is future-proof).
59		66
60	In addition to being free of having to use I<the one and only true event	67	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	68	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	69	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	70	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	71	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	72	technically possible.
66		73
		74	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		75	of useful functionality, such as an asynchronous DNS resolver, 100%
		76	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		77	such as Windows) and lots of real-world knowledge and workarounds for
		78	platform bugs and differences.
		79
67	Of course, if you want lots of policy (this can arguably be somewhat	80	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	81	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	82	model, you should I<not> use this module.
70		83
71	=head1 DESCRIPTION	84	=head1 DESCRIPTION
72		85
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	115	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...	116	use AnyEvent so their modules work together with others seamlessly...
104		117
105	The pure-perl implementation of AnyEvent is called	118	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	119	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	120	explicitly and enjoy the high availability of that event loop :)
108		121
109	=head1 WATCHERS	122	=head1 WATCHERS
110		123
111	AnyEvent has the central concept of a I<watcher>, which is an object that	124	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	125	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	126	the callback to call, the file handle to watch, etc.
114		127
115	These watchers are normal Perl objects with normal Perl lifetime. After	128	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	129	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	130	callback when the event occurs (of course, only when the event model
118	is in control).	131	is in control).
…		…
126	Many watchers either are used with "recursion" (repeating timers for	139	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	140	example), or need to refer to their watcher object in other ways.
128		141
129	An any way to achieve that is this pattern:	142	An any way to achieve that is this pattern:
130		143
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	144	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	145	# you can use $w here, for example to undef it
133	undef $w;	146	undef $w;
134	});	147	});
135		148
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	149	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	150	my variables are only visible after the statement in which they are
138	declared.	151	declared.
139		152
140	=head2 I/O WATCHERS	153	=head2 I/O WATCHERS
141		154
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	155	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	156	with the following mandatory key-value pairs as arguments:
144		157
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	158	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>,	159	(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,	160	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	161	waiting for "r"eadable or "w"ritable events, respectively. C<cb> is the
149	becomes ready.	162	callback to invoke each time the file handle becomes ready.
150		163
151	Although the callback might get passed parameters, their value and	164	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	165	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	166	callbacks cannot use arguments passed to I/O watcher callbacks.
154		167
…		…
158		171
159	Some event loops issue spurious readyness notifications, so you should	172	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	173	always use non-blocking calls when reading/writing from/to your file
161	handles.	174	handles.
162		175
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	176	Example: wait for readability of STDIN, then read a line and disable the
		177	watcher.
		178
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	179	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	180	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	181	warn "read: $input\n";
169	undef $w;	182	undef $w;
170	});	183	});
…		…
180		193
181	Although the callback might get passed parameters, their value and	194	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	195	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	196	callbacks cannot use arguments passed to time watcher callbacks.
184		197
185	The timer callback will be invoked at most once: if you want a repeating	198	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	199	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	200	callback will be invoked regularly at that interval (in fractional
		201	seconds) after the first invocation. If C<interval> is specified with a
		202	false value, then it is treated as if it were missing.
188		203
189	Example:	204	The callback will be rescheduled before invoking the callback, but no
		205	attempt is done to avoid timer drift in most backends, so the interval is
		206	only approximate.
190		207
191	# fire an event after 7.7 seconds	208	Example: fire an event after 7.7 seconds.
		209
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	210	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	211	warn "timeout\n";
194	});	212	});
195		213
196	# to cancel the timer:	214	# to cancel the timer:
197	undef $w;	215	undef $w;
198		216
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	217	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		218
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	219	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		220	warn "timeout\n";
207	};	221	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		222
212	=head3 TIMING ISSUES	223	=head3 TIMING ISSUES
213		224
214	There are two ways to handle timers: based on real time (relative, "fire	225	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	226	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	238	timers.
228		239
229	AnyEvent always prefers relative timers, if available, matching the	240	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	241	AnyEvent API.
231		242
		243	AnyEvent has two additional methods that return the "current time":
		244
		245	=over 4
		246
		247	=item AnyEvent->time
		248
		249	This returns the "current wallclock time" as a fractional number of
		250	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		251	return, and the result is guaranteed to be compatible with those).
		252
		253	It progresses independently of any event loop processing, i.e. each call
		254	will check the system clock, which usually gets updated frequently.
		255
		256	=item AnyEvent->now
		257
		258	This also returns the "current wallclock time", but unlike C<time>, above,
		259	this value might change only once per event loop iteration, depending on
		260	the event loop (most return the same time as C<time>, above). This is the
		261	time that AnyEvent's timers get scheduled against.
		262
		263	I<In almost all cases (in all cases if you don't care), this is the
		264	function to call when you want to know the current time.>
		265
		266	This function is also often faster then C<< AnyEvent->time >>, and
		267	thus the preferred method if you want some timestamp (for example,
		268	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		269
		270	The rest of this section is only of relevance if you try to be very exact
		271	with your timing, you can skip it without bad conscience.
		272
		273	For a practical example of when these times differ, consider L<Event::Lib>
		274	and L<EV> and the following set-up:
		275
		276	The event loop is running and has just invoked one of your callback at
		277	time=500 (assume no other callbacks delay processing). In your callback,
		278	you wait a second by executing C<sleep 1> (blocking the process for a
		279	second) and then (at time=501) you create a relative timer that fires
		280	after three seconds.
		281
		282	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		283	both return C<501>, because that is the current time, and the timer will
		284	be scheduled to fire at time=504 (C<501> + C<3>).
		285
		286	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		287	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		288	last event processing phase started. With L<EV>, your timer gets scheduled
		289	to run at time=503 (C<500> + C<3>).
		290
		291	In one sense, L<Event::Lib> is more exact, as it uses the current time
		292	regardless of any delays introduced by event processing. However, most
		293	callbacks do not expect large delays in processing, so this causes a
		294	higher drift (and a lot more system calls to get the current time).
		295
		296	In another sense, L<EV> is more exact, as your timer will be scheduled at
		297	the same time, regardless of how long event processing actually took.
		298
		299	In either case, if you care (and in most cases, you don't), then you
		300	can get whatever behaviour you want with any event loop, by taking the
		301	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		302	account.
		303
		304	=back
		305
232	=head2 SIGNAL WATCHERS	306	=head2 SIGNAL WATCHERS
233		307
234	You can watch for signals using a signal watcher, C<signal> is the signal	308	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	309	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	310	callback to be invoked whenever a signal occurs.
237		311
238	Although the callback might get passed parameters, their value and	312	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	313	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	314	callbacks cannot use arguments passed to signal watcher callbacks.
241		315
242	Multiple signal occurances can be clumped together into one callback	316	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	317	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	318	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.	319	but it is guaranteed not to interrupt any other callbacks.
246		320
247	The main advantage of using these watchers is that you can share a signal	321	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	322	between multiple watchers.
249		323
250	This watcher might use C<%SIG>, so programs overwriting those signals	324	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	351	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>).	352	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		353
280	Example: fork a process and wait for it	354	Example: fork a process and wait for it
281		355
282	my $done = AnyEvent->condvar;	356	my $done = AnyEvent->condvar;
283		357
284	AnyEvent::detect; # force event module to be initialised
285
286	my $pid = fork or exit 5;	358	my $pid = fork or exit 5;
287		359
288	my $w = AnyEvent->child (	360	my $w = AnyEvent->child (
289	pid => $pid,	361	pid => $pid,
290	cb => sub {	362	cb => sub {
291	my ($pid, $status) = @_;	363	my ($pid, $status) = @_;
292	warn "pid $pid exited with status $status";	364	warn "pid $pid exited with status $status";
293	$done->send;	365	$done->send;
294	},	366	},
295	);	367	);
296		368
297	# do something else, then wait for process exit	369	# do something else, then wait for process exit
298	$done->wait;	370	$done->recv;
299		371
300	=head2 CONDITION VARIABLES	372	=head2 CONDITION VARIABLES
301		373
302	If you are familiar with some event loops you will know that all of them	374	If you are familiar with some event loops you will know that all of them
303	require you to run some blocking "loop", "run" or similar function that	375	require you to run some blocking "loop", "run" or similar function that
…		…
312	Condition variables can be created by calling the C<< AnyEvent->condvar	384	Condition variables can be created by calling the C<< AnyEvent->condvar
313	>> method, usually without arguments. The only argument pair allowed is	385	>> method, usually without arguments. The only argument pair allowed is
314	C<cb>, which specifies a callback to be called when the condition variable	386	C<cb>, which specifies a callback to be called when the condition variable
315	becomes true.	387	becomes true.
316		388
317	After creation, the conditon variable is "false" until it becomes "true"	389	After creation, the condition variable is "false" until it becomes "true"
318	by calling the C<send> method.	390	by calling the C<send> method (or calling the condition variable as if it
		391	were a callback, read about the caveats in the description for the C<<
		392	->send >> method).
319		393
320	Condition variables are similar to callbacks, except that you can	394	Condition variables are similar to callbacks, except that you can
321	optionally wait for them. They can also be called merge points - points	395	optionally wait for them. They can also be called merge points - points
322	in time where multiple outstandign events have been processed. And yet	396	in time where multiple outstanding events have been processed. And yet
323	another way to call them is transations - each condition variable can be	397	another way to call them is transactions - each condition variable can be
324	used to represent a transaction, which finishes at some point and delivers	398	used to represent a transaction, which finishes at some point and delivers
325	a result.	399	a result.
326		400
327	Condition variables are very useful to signal that something has finished,	401	Condition variables are very useful to signal that something has finished,
328	for example, if you write a module that does asynchronous http requests,	402	for example, if you write a module that does asynchronous http requests,
329	then a condition variable would be the ideal candidate to signal the	403	then a condition variable would be the ideal candidate to signal the
330	availability of results. The user can either act when the callback is	404	availability of results. The user can either act when the callback is
331	called or can synchronously C<< ->wait >> for the results.	405	called or can synchronously C<< ->recv >> for the results.
332		406
333	You can also use them to simulate traditional event loops - for example,	407	You can also use them to simulate traditional event loops - for example,
334	you can block your main program until an event occurs - for example, you	408	you can block your main program until an event occurs - for example, you
335	could C<< ->wait >> in your main program until the user clicks the Quit	409	could C<< ->recv >> in your main program until the user clicks the Quit
336	button of your app, which would C<< ->send >> the "quit" event.	410	button of your app, which would C<< ->send >> the "quit" event.
337		411
338	Note that condition variables recurse into the event loop - if you have	412	Note that condition variables recurse into the event loop - if you have
339	two pieces of code that call C<< ->wait >> in a round-robbin fashion, you	413	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
340	lose. Therefore, condition variables are good to export to your caller, but	414	lose. Therefore, condition variables are good to export to your caller, but
341	you should avoid making a blocking wait yourself, at least in callbacks,	415	you should avoid making a blocking wait yourself, at least in callbacks,
342	as this asks for trouble.	416	as this asks for trouble.
343		417
344	Condition variables are represented by hash refs in perl, and the keys	418	Condition variables are represented by hash refs in perl, and the keys
…		…
349		423
350	There are two "sides" to a condition variable - the "producer side" which	424	There are two "sides" to a condition variable - the "producer side" which
351	eventually calls C<< -> send >>, and the "consumer side", which waits	425	eventually calls C<< -> send >>, and the "consumer side", which waits
352	for the send to occur.	426	for the send to occur.
353		427
354	Example:	428	Example: wait for a timer.
355		429
356	# wait till the result is ready	430	# wait till the result is ready
357	my $result_ready = AnyEvent->condvar;	431	my $result_ready = AnyEvent->condvar;
358		432
359	# do something such as adding a timer	433	# do something such as adding a timer
…		…
365	cb => sub { $result_ready->send },	439	cb => sub { $result_ready->send },
366	);	440	);
367		441
368	# this "blocks" (while handling events) till the callback	442	# this "blocks" (while handling events) till the callback
369	# calls send	443	# calls send
370	$result_ready->wait;	444	$result_ready->recv;
		445
		446	Example: wait for a timer, but take advantage of the fact that
		447	condition variables are also code references.
		448
		449	my $done = AnyEvent->condvar;
		450	my $delay = AnyEvent->timer (after => 5, cb => $done);
		451	$done->recv;
371		452
372	=head3 METHODS FOR PRODUCERS	453	=head3 METHODS FOR PRODUCERS
373		454
374	These methods should only be used by the producing side, i.e. the	455	These methods should only be used by the producing side, i.e. the
375	code/module that eventually sends the signal. Note that it is also	456	code/module that eventually sends the signal. Note that it is also
…		…
378		459
379	=over 4	460	=over 4
380		461
381	=item $cv->send (...)	462	=item $cv->send (...)
382		463
383	Flag the condition as ready - a running C<< ->wait >> and all further	464	Flag the condition as ready - a running C<< ->recv >> and all further
384	calls to C<wait> will (eventually) return after this method has been	465	calls to C<recv> will (eventually) return after this method has been
385	called. If nobody is waiting the send will be remembered.	466	called. If nobody is waiting the send will be remembered.
386		467
387	If a callback has been set on the condition variable, it is called	468	If a callback has been set on the condition variable, it is called
388	immediately from within send.	469	immediately from within send.
389		470
390	Any arguments passed to the C<send> call will be returned by all	471	Any arguments passed to the C<send> call will be returned by all
391	future C<< ->wait >> calls.	472	future C<< ->recv >> calls.
		473
		474	Condition variables are overloaded so one can call them directly
		475	(as a code reference). Calling them directly is the same as calling
		476	C<send>. Note, however, that many C-based event loops do not handle
		477	overloading, so as tempting as it may be, passing a condition variable
		478	instead of a callback does not work. Both the pure perl and EV loops
		479	support overloading, however, as well as all functions that use perl to
		480	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		481	example).
392		482
393	=item $cv->croak ($error)	483	=item $cv->croak ($error)
394		484
395	Similar to send, but causes all call's wait C<< ->wait >> to invoke	485	Similar to send, but causes all call's to C<< ->recv >> to invoke
396	C<Carp::croak> with the given error message/object/scalar.	486	C<Carp::croak> with the given error message/object/scalar.
397		487
398	This can be used to signal any errors to the condition variable	488	This can be used to signal any errors to the condition variable
399	user/consumer.	489	user/consumer.
400		490
401	=item $cv->begin ([group callback])	491	=item $cv->begin ([group callback])
402		492
403	=item $cv->end	493	=item $cv->end
		494
		495	These two methods are EXPERIMENTAL and MIGHT CHANGE.
404		496
405	These two methods can be used to combine many transactions/events into	497	These two methods can be used to combine many transactions/events into
406	one. For example, a function that pings many hosts in parallel might want	498	one. For example, a function that pings many hosts in parallel might want
407	to use a condition variable for the whole process.	499	to use a condition variable for the whole process.
408		500
…		…
443	doesn't execute once).	535	doesn't execute once).
444		536
445	This is the general pattern when you "fan out" into multiple subrequests:	537	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>	538	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	539	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>.	540	C<begin> and for each subrequest you finish, call C<end>.
449		541
450	=back	542	=back
451		543
452	=head3 METHODS FOR CONSUMERS	544	=head3 METHODS FOR CONSUMERS
453		545
454	These methods should only be used by the consuming side, i.e. the	546	These methods should only be used by the consuming side, i.e. the
455	code awaits the condition.	547	code awaits the condition.
456		548
457	=over 4	549	=over 4
458		550
459	=item $cv->wait	551	=item $cv->recv
460		552
461	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	553	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
462	>> methods have been called on c<$cv>, while servicing other watchers	554	>> methods have been called on c<$cv>, while servicing other watchers
463	normally.	555	normally.
464		556
…		…
475	(programs might want to do that to stay interactive), so I<if you are	567	(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	568	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	569	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	570	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	571	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	572	while still supporting blocking waits if the caller so desires).
481		573
482	Another reason I<never> to C<< ->wait >> in a module is that you cannot	574	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->wait >>'s in parallel, as that would require	575	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	576	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	577	can supply.
486		578
487	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in	579	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
488	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe	580	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
489	versions and also integrates coroutines into AnyEvent, making blocking	581	versions and also integrates coroutines into AnyEvent, making blocking
490	C<< ->wait >> calls perfectly safe as long as they are done from another	582	C<< ->recv >> calls perfectly safe as long as they are done from another
491	coroutine (one that doesn't run the event loop).	583	coroutine (one that doesn't run the event loop).
492		584
493	You can ensure that C<< -wait >> never blocks by setting a callback and	585	You can ensure that C<< -recv >> never blocks by setting a callback and
494	only calling C<< ->wait >> from within that callback (or at a later	586	only calling C<< ->recv >> from within that callback (or at a later
495	time). This will work even when the event loop does not support blocking	587	time). This will work even when the event loop does not support blocking
496	waits otherwise.	588	waits otherwise.
497		589
498	=item $bool = $cv->ready	590	=item $bool = $cv->ready
499		591
…		…
504		596
505	This is a mutator function that returns the callback set and optionally	597	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	598	replaces it before doing so.
507		599
508	The callback will be called when the condition becomes "true", i.e. when	600	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<wait> inside the callback	601	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.	602	variable itself. Calling C<recv> inside the callback or at any later time
		603	is guaranteed not to block.
511		604
512	=back	605	=back
513		606
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	607	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		608
…		…
582	Be careful when you create watchers in the module body - AnyEvent will	675	Be careful when you create watchers in the module body - AnyEvent will
583	decide which event module to use as soon as the first method is called, so	676	decide which event module to use as soon as the first method is called, so
584	by calling AnyEvent in your module body you force the user of your module	677	by calling AnyEvent in your module body you force the user of your module
585	to load the event module first.	678	to load the event module first.
586		679
587	Never call C<< ->wait >> on a condition variable unless you I<know> that	680	Never call C<< ->recv >> on a condition variable unless you I<know> that
588	the C<< ->send >> method has been called on it already. This is	681	the C<< ->send >> method has been called on it already. This is
589	because it will stall the whole program, and the whole point of using	682	because it will stall the whole program, and the whole point of using
590	events is to stay interactive.	683	events is to stay interactive.
591		684
592	It is fine, however, to call C<< ->wait >> when the user of your module	685	It is fine, however, to call C<< ->recv >> when the user of your module
593	requests it (i.e. if you create a http request object ad have a method	686	requests it (i.e. if you create a http request object ad have a method
594	called C<results> that returns the results, it should call C<< ->wait >>	687	called C<results> that returns the results, it should call C<< ->recv >>
595	freely, as the user of your module knows what she is doing. always).	688	freely, as the user of your module knows what she is doing. always).
596		689
597	=head1 WHAT TO DO IN THE MAIN PROGRAM	690	=head1 WHAT TO DO IN THE MAIN PROGRAM
598		691
599	There will always be a single main program - the only place that should	692	There will always be a single main program - the only place that should
…		…
601		694
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	695	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	696	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.	697	decide which implementation to chose if some module relies on it.
605		698
606	If the main program relies on a specific event model. For example, in	699	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	700	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	701	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	702	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	703	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	704	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.	705	might chose the wrong one unless you load the correct one yourself.
613		706
614	You can chose to use a rather inefficient pure-perl implementation by	707	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	708	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	709	everywhere, but letting AnyEvent chose the model is generally better.
		710
		711	=head2 MAINLOOP EMULATION
		712
		713	Sometimes (often for short test scripts, or even standalone programs who
		714	only want to use AnyEvent), you do not want to run a specific event loop.
		715
		716	In that case, you can use a condition variable like this:
		717
		718	AnyEvent->condvar->recv;
		719
		720	This has the effect of entering the event loop and looping forever.
		721
		722	Note that usually your program has some exit condition, in which case
		723	it is better to use the "traditional" approach of storing a condition
		724	variable somewhere, waiting for it, and sending it when the program should
		725	exit cleanly.
		726
617		727
618	=head1 OTHER MODULES	728	=head1 OTHER MODULES
619		729
620	The following is a non-exhaustive list of additional modules that use	730	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	731	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	737	=item L<AnyEvent::Util>
628		738
629	Contains various utility functions that replace often-used but blocking	739	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	740	functions such as C<inet_aton> by event-/callback-based versions.
631		741
		742	=item L<AnyEvent::Socket>
		743
		744	Provides various utility functions for (internet protocol) sockets,
		745	addresses and name resolution. Also functions to create non-blocking tcp
		746	connections or tcp servers, with IPv6 and SRV record support and more.
		747
632	=item L<AnyEvent::Handle>	748	=item L<AnyEvent::Handle>
633		749
634	Provide read and write buffers and manages watchers for reads and writes.	750	Provide read and write buffers, manages watchers for reads and writes,
		751	supports raw and formatted I/O, I/O queued and fully transparent and
		752	non-blocking SSL/TLS.
		753
		754	=item L<AnyEvent::DNS>
		755
		756	Provides rich asynchronous DNS resolver capabilities.
		757
		758	=item L<AnyEvent::HTTP>
		759
		760	A simple-to-use HTTP library that is capable of making a lot of concurrent
		761	HTTP requests.
635		762
636	=item L<AnyEvent::HTTPD>	763	=item L<AnyEvent::HTTPD>
637		764
638	Provides a simple web application server framework.	765	Provides a simple web application server framework.
639		766
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>	767	=item L<AnyEvent::FastPing>
646		768
647	The fastest ping in the west.	769	The fastest ping in the west.
		770
		771	=item L<AnyEvent::DBI>
		772
		773	Executes L<DBI> requests asynchronously in a proxy process.
		774
		775	=item L<AnyEvent::AIO>
		776
		777	Truly asynchronous I/O, should be in the toolbox of every event
		778	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		779	together.
		780
		781	=item L<AnyEvent::BDB>
		782
		783	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		784	L<BDB> and AnyEvent together.
		785
		786	=item L<AnyEvent::GPSD>
		787
		788	A non-blocking interface to gpsd, a daemon delivering GPS information.
		789
		790	=item L<AnyEvent::IGS>
		791
		792	A non-blocking interface to the Internet Go Server protocol (used by
		793	L<App::IGS>).
648		794
649	=item L<Net::IRC3>	795	=item L<Net::IRC3>
650		796
651	AnyEvent based IRC client module family.	797	AnyEvent based IRC client module family.
652		798
…		…
665		811
666	=item L<Coro>	812	=item L<Coro>
667		813
668	Has special support for AnyEvent via L<Coro::AnyEvent>.	814	Has special support for AnyEvent via L<Coro::AnyEvent>.
669		815
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>	816	=item L<IO::Lambda>
682		817
683	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	818	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
684		819
685	=back	820	=back
…		…
691	no warnings;	826	no warnings;
692	use strict;	827	use strict;
693		828
694	use Carp;	829	use Carp;
695		830
696	our $VERSION = '3.4';	831	our $VERSION = 4.2;
697	our $MODEL;	832	our $MODEL;
698		833
699	our $AUTOLOAD;	834	our $AUTOLOAD;
700	our @ISA;	835	our @ISA;
701		836
		837	our @REGISTRY;
		838
		839	our $WIN32;
		840
		841	BEGIN {
		842	my $win32 = ! ! ($^O =~ /mswin32/i);
		843	eval "sub WIN32(){ $win32 }";
		844	}
		845
702	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	846	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703		847
704	our @REGISTRY;	848	our %PROTOCOL; # (ipv4\|ipv6) => (1\|2), higher numbers are preferred
		849
		850	{
		851	my $idx;
		852	$PROTOCOL{$_} = ++$idx
		853	for reverse split /\s,\s/,
		854	$ENV{PERL_ANYEVENT_PROTOCOLS} \|\| "ipv4,ipv6";
		855	}
705		856
706	my @models = (	857	my @models = (
707	[EV:: => AnyEvent::Impl::EV::],	858	[EV:: => AnyEvent::Impl::EV::],
708	[Event:: => AnyEvent::Impl::Event::],	859	[Event:: => AnyEvent::Impl::Event::],
709	[Tk:: => AnyEvent::Impl::Tk::],
710	[Wx:: => AnyEvent::Impl::POE::],
711	[Prima:: => AnyEvent::Impl::POE::],
712	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	860	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713	# everything below here will not be autoprobed as the pureperl backend should work everywhere	861	# everything below here will not be autoprobed
714	[Glib:: => AnyEvent::Impl::Glib::],	862	# as the pureperl backend should work everywhere
		863	# and is usually faster
		864	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		865	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	866	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	867	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	868	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		869	[Wx:: => AnyEvent::Impl::POE::],
		870	[Prima:: => AnyEvent::Impl::POE::],
718	);	871	);
719		872
720	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	873	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);
721		874
722	our @post_detect;	875	our @post_detect;
723		876
724	sub post_detect(&) {	877	sub post_detect(&) {
725	my ($cb) = @_;	878	my ($cb) = @_;
…		…
730	1	883	1
731	} else {	884	} else {
732	push @post_detect, $cb;	885	push @post_detect, $cb;
733		886
734	defined wantarray	887	defined wantarray
735	? bless \$cb, "AnyEvent::Util::Guard"	888	? bless \$cb, "AnyEvent::Util::PostDetect"
736	: ()	889	: ()
737	}	890	}
738	}	891	}
739		892
740	sub AnyEvent::Util::Guard::DESTROY {	893	sub AnyEvent::Util::PostDetect::DESTROY {
741	@post_detect = grep $_ != ${$_[0]}, @post_detect;	894	@post_detect = grep $_ != ${$_[0]}, @post_detect;
742	}	895	}
743		896
744	sub detect() {	897	sub detect() {
745	unless ($MODEL) {	898	unless ($MODEL) {
746	no strict 'refs';	899	no strict 'refs';
		900	local $SIG{__DIE__};
747		901
748	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	902	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749	my $model = "AnyEvent::Impl::$1";	903	my $model = "AnyEvent::Impl::$1";
750	if (eval "require $model") {	904	if (eval "require $model") {
751	$MODEL = $model;	905	$MODEL = $model;
…		…
785	$MODEL	939	$MODEL
786	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	940	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";
787	}	941	}
788	}	942	}
789		943
		944	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		945
790	unshift @ISA, $MODEL;	946	unshift @ISA, $MODEL;
791	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	947
		948	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
792		949
793	(shift @post_detect)->() while @post_detect;	950	(shift @post_detect)->() while @post_detect;
794	}	951	}
795		952
796	$MODEL	953	$MODEL
…		…
806		963
807	my $class = shift;	964	my $class = shift;
808	$class->$func (@_);	965	$class->$func (@_);
809	}	966	}
810		967
		968	# utility function to dup a filehandle. this is used by many backends
		969	# to support binding more than one watcher per filehandle (they usually
		970	# allow only one watcher per fd, so we dup it to get a different one).
		971	sub _dupfh($$$$) {
		972	my ($poll, $fh, $r, $w) = @_;
		973
		974	require Fcntl;
		975
		976	# cygwin requires the fh mode to be matching, unix doesn't
		977	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		978	: $poll eq "w" ? ($w, ">")
		979	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		980
		981	open my $fh2, "$mode&" . fileno $fh
		982	or die "cannot dup() filehandle: $!";
		983
		984	# we assume CLOEXEC is already set by perl in all important cases
		985
		986	($fh2, $rw)
		987	}
		988
811	package AnyEvent::Base;	989	package AnyEvent::Base;
812		990
		991	# default implementation for now and time
		992
		993	use Time::HiRes ();
		994
		995	sub time { Time::HiRes::time }
		996	sub now { Time::HiRes::time }
		997
813	# default implementation for ->condvar, ->wait, ->broadcast	998	# default implementation for ->condvar
814		999
815	sub condvar {	1000	sub condvar {
816	bless \my $flag, "AnyEvent::Base::CondVar"	1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817	}
818
819	sub AnyEvent::Base::CondVar::broadcast {
820	${$_[0]}++;
821	}
822
823	sub AnyEvent::Base::CondVar::wait {
824	AnyEvent->one_event while !${$_[0]};
825	}	1002	}
826		1003
827	# default implementation for ->signal	1004	# default implementation for ->signal
828		1005
829	our %SIG_CB;	1006	our %SIG_CB;
…		…
845	sub AnyEvent::Base::Signal::DESTROY {	1022	sub AnyEvent::Base::Signal::DESTROY {
846	my ($signal, $cb) = @{$_[0]};	1023	my ($signal, $cb) = @{$_[0]};
847		1024
848	delete $SIG_CB{$signal}{$cb};	1025	delete $SIG_CB{$signal}{$cb};
849		1026
850	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
851	}	1028	}
852		1029
853	# default implementation for ->child	1030	# default implementation for ->child
854		1031
855	our %PID_CB;	1032	our %PID_CB;
…		…
882	or Carp::croak "required option 'pid' is missing";	1059	or Carp::croak "required option 'pid' is missing";
883		1060
884	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
885		1062
886	unless ($WNOHANG) {	1063	unless ($WNOHANG) {
887	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
888	}	1065	}
889		1066
890	unless ($CHLD_W) {	1067	unless ($CHLD_W) {
891	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
892	# child could be a zombie already, so make at least one round	1069	# child could be a zombie already, so make at least one round
…		…
902	delete $PID_CB{$pid}{$cb};	1079	delete $PID_CB{$pid}{$cb};
903	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
904		1081
905	undef $CHLD_W unless keys %PID_CB;	1082	undef $CHLD_W unless keys %PID_CB;
906	}	1083	}
		1084
		1085	package AnyEvent::CondVar;
		1086
		1087	our @ISA = AnyEvent::CondVar::Base::;
		1088
		1089	package AnyEvent::CondVar::Base;
		1090
		1091	use overload
		1092	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1093	fallback => 1;
		1094
		1095	sub _send {
		1096	# nop
		1097	}
		1098
		1099	sub send {
		1100	my $cv = shift;
		1101	$cv->{_ae_sent} = [@_];
		1102	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
		1103	$cv->_send;
		1104	}
		1105
		1106	sub croak {
		1107	$_[0]{_ae_croak} = $_[1];
		1108	$_[0]->send;
		1109	}
		1110
		1111	sub ready {
		1112	$_[0]{_ae_sent}
		1113	}
		1114
		1115	sub _wait {
		1116	AnyEvent->one_event while !$_[0]{_ae_sent};
		1117	}
		1118
		1119	sub recv {
		1120	$_[0]->_wait;
		1121
		1122	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
		1123	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
		1124	}
		1125
		1126	sub cb {
		1127	$_[0]{_ae_cb} = $_[1] if @_ > 1;
		1128	$_[0]{_ae_cb}
		1129	}
		1130
		1131	sub begin {
		1132	++$_[0]{_ae_counter};
		1133	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
		1134	}
		1135
		1136	sub end {
		1137	return if --$_[0]{_ae_counter};
		1138	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
		1139	}
		1140
		1141	# undocumented/compatibility with pre-3.4
		1142	*broadcast = \&send;
		1143	*wait = \&_wait;
907		1144
908	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
909		1146
910	This is an advanced topic that you do not normally need to use AnyEvent in	1147	This is an advanced topic that you do not normally need to use AnyEvent in
911	a module. This section is only of use to event loop authors who want to	1148	a module. This section is only of use to event loop authors who want to
…		…
965	C<PERL_ANYEVENT_MODEL>.	1202	C<PERL_ANYEVENT_MODEL>.
966		1203
967	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1204	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
968	model it chooses.	1205	model it chooses.
969		1206
		1207	=item C<PERL_ANYEVENT_STRICT>
		1208
		1209	AnyEvent does not do much argument checking by default, as thorough
		1210	argument checking is very costly. Setting this variable to a true value
		1211	will cause AnyEvent to thoroughly check the arguments passed to most
		1212	method calls and croaks if it finds any problems. In other words, enables
		1213	"strict" mode. Unlike C<use strict> it is definitely recommended ot keep
		1214	it off in production.
		1215
970	=item C<PERL_ANYEVENT_MODEL>	1216	=item C<PERL_ANYEVENT_MODEL>
971		1217
972	This can be used to specify the event model to be used by AnyEvent, before	1218	This can be used to specify the event model to be used by AnyEvent, before
973	autodetection and -probing kicks in. It must be a string consisting	1219	auto detection and -probing kicks in. It must be a string consisting
974	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1220	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
975	and the resulting module name is loaded and if the load was successful,	1221	and the resulting module name is loaded and if the load was successful,
976	used as event model. If it fails to load AnyEvent will proceed with	1222	used as event model. If it fails to load AnyEvent will proceed with
977	autodetection and -probing.	1223	auto detection and -probing.
978		1224
979	This functionality might change in future versions.	1225	This functionality might change in future versions.
980		1226
981	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1227	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
982	could start your program like this:	1228	could start your program like this:
983		1229
984	PERL_ANYEVENT_MODEL=Perl perl ...	1230	PERL_ANYEVENT_MODEL=Perl perl ...
		1231
		1232	=item C<PERL_ANYEVENT_PROTOCOLS>
		1233
		1234	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1235	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1236	of auto probing).
		1237
		1238	Must be set to a comma-separated list of protocols or address families,
		1239	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1240	used, and preference will be given to protocols mentioned earlier in the
		1241	list.
		1242
		1243	This variable can effectively be used for denial-of-service attacks
		1244	against local programs (e.g. when setuid), although the impact is likely
		1245	small, as the program has to handle connection errors already-
		1246
		1247	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1248	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1249	- only support IPv4, never try to resolve or contact IPv6
		1250	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1251	IPv6, but prefer IPv6 over IPv4.
		1252
		1253	=item C<PERL_ANYEVENT_EDNS0>
		1254
		1255	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1256	for DNS. This extension is generally useful to reduce DNS traffic, but
		1257	some (broken) firewalls drop such DNS packets, which is why it is off by
		1258	default.
		1259
		1260	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1261	EDNS0 in its DNS requests.
		1262
		1263	=item C<PERL_ANYEVENT_MAX_FORKS>
		1264
		1265	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1266	will create in parallel.
985		1267
986	=back	1268	=back
987		1269
988	=head1 EXAMPLE PROGRAM	1270	=head1 EXAMPLE PROGRAM
989		1271
…		…
1000	poll => 'r',	1282	poll => 'r',
1001	cb => sub {	1283	cb => sub {
1002	warn "io event <$_[0]>\n"; # will always output <r>	1284	warn "io event <$_[0]>\n"; # will always output <r>
1003	chomp (my $input = <STDIN>); # read a line	1285	chomp (my $input = <STDIN>); # read a line
1004	warn "read: $input\n"; # output what has been read	1286	warn "read: $input\n"; # output what has been read
1005	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1287	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1006	},	1288	},
1007	);	1289	);
1008		1290
1009	my $time_watcher; # can only be used once	1291	my $time_watcher; # can only be used once
1010		1292
…		…
1015	});	1297	});
1016	}	1298	}
1017		1299
1018	new_timer; # create first timer	1300	new_timer; # create first timer
1019		1301
1020	$cv->wait; # wait until user enters /^q/i	1302	$cv->recv; # wait until user enters /^q/i
1021		1303
1022	=head1 REAL-WORLD EXAMPLE	1304	=head1 REAL-WORLD EXAMPLE
1023		1305
1024	Consider the L<Net::FCP> module. It features (among others) the following	1306	Consider the L<Net::FCP> module. It features (among others) the following
1025	API calls, which are to freenet what HTTP GET requests are to http:	1307	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1075	syswrite $txn->{fh}, $txn->{request}	1357	syswrite $txn->{fh}, $txn->{request}
1076	or die "connection or write error";	1358	or die "connection or write error";
1077	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1359	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1078		1360
1079	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1361	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1080	result and signals any possible waiters that the request ahs finished:	1362	result and signals any possible waiters that the request has finished:
1081		1363
1082	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1364	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1083		1365
1084	if (end-of-file or data complete) {	1366	if (end-of-file or data complete) {
1085	$txn->{result} = $txn->{buf};	1367	$txn->{result} = $txn->{buf};
1086	$txn->{finished}->broadcast;	1368	$txn->{finished}->send;
1087	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1369	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1088	}	1370	}
1089		1371
1090	The C<result> method, finally, just waits for the finished signal (if the	1372	The C<result> method, finally, just waits for the finished signal (if the
1091	request was already finished, it doesn't wait, of course, and returns the	1373	request was already finished, it doesn't wait, of course, and returns the
1092	data:	1374	data:
1093		1375
1094	$txn->{finished}->wait;	1376	$txn->{finished}->recv;
1095	return $txn->{result};	1377	return $txn->{result};
1096		1378
1097	The actual code goes further and collects all errors (C<die>s, exceptions)	1379	The actual code goes further and collects all errors (C<die>s, exceptions)
1098	that occured during request processing. The C<result> method detects	1380	that occurred during request processing. The C<result> method detects
1099	whether an exception as thrown (it is stored inside the $txn object)	1381	whether an exception as thrown (it is stored inside the $txn object)
1100	and just throws the exception, which means connection errors and other	1382	and just throws the exception, which means connection errors and other
1101	problems get reported tot he code that tries to use the result, not in a	1383	problems get reported tot he code that tries to use the result, not in a
1102	random callback.	1384	random callback.
1103		1385
…		…
1134		1416
1135	my $quit = AnyEvent->condvar;	1417	my $quit = AnyEvent->condvar;
1136		1418
1137	$fcp->txn_client_get ($url)->cb (sub {	1419	$fcp->txn_client_get ($url)->cb (sub {
1138	...	1420	...
1139	$quit->broadcast;	1421	$quit->send;
1140	});	1422	});
1141		1423
1142	$quit->wait;	1424	$quit->recv;
1143		1425
1144		1426
1145	=head1 BENCHMARKS	1427	=head1 BENCHMARKS
1146		1428
1147	To give you an idea of the performance and overheads that AnyEvent adds	1429	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1149	of various event loops I prepared some benchmarks.	1431	of various event loops I prepared some benchmarks.
1150		1432
1151	=head2 BENCHMARKING ANYEVENT OVERHEAD	1433	=head2 BENCHMARKING ANYEVENT OVERHEAD
1152		1434
1153	Here is a benchmark of various supported event models used natively and	1435	Here is a benchmark of various supported event models used natively and
1154	through anyevent. The benchmark creates a lot of timers (with a zero	1436	through AnyEvent. The benchmark creates a lot of timers (with a zero
1155	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1437	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1156	which it is), lets them fire exactly once and destroys them again.	1438	which it is), lets them fire exactly once and destroys them again.
1157		1439
1158	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1440	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1159	distribution.	1441	distribution.
…		…
1176	all watchers, to avoid adding memory overhead. That means closure creation	1458	all watchers, to avoid adding memory overhead. That means closure creation
1177	and memory usage is not included in the figures.	1459	and memory usage is not included in the figures.
1178		1460
1179	I<invoke> is the time, in microseconds, used to invoke a simple	1461	I<invoke> is the time, in microseconds, used to invoke a simple
1180	callback. The callback simply counts down a Perl variable and after it was	1462	callback. The callback simply counts down a Perl variable and after it was
1181	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1463	invoked "watcher" times, it would C<< ->send >> a condvar once to
1182	signal the end of this phase.	1464	signal the end of this phase.
1183		1465
1184	I<destroy> is the time, in microseconds, that it takes to destroy a single	1466	I<destroy> is the time, in microseconds, that it takes to destroy a single
1185	watcher.	1467	watcher.
1186		1468
…		…
1282		1564
1283	=back	1565	=back
1284		1566
1285	=head2 BENCHMARKING THE LARGE SERVER CASE	1567	=head2 BENCHMARKING THE LARGE SERVER CASE
1286		1568
1287	This benchmark atcually benchmarks the event loop itself. It works by	1569	This benchmark actually benchmarks the event loop itself. It works by
1288	creating a number of "servers": each server consists of a socketpair, a	1570	creating a number of "servers": each server consists of a socket pair, a
1289	timeout watcher that gets reset on activity (but never fires), and an I/O	1571	timeout watcher that gets reset on activity (but never fires), and an I/O
1290	watcher waiting for input on one side of the socket. Each time the socket	1572	watcher waiting for input on one side of the socket. Each time the socket
1291	watcher reads a byte it will write that byte to a random other "server".	1573	watcher reads a byte it will write that byte to a random other "server".
1292		1574
1293	The effect is that there will be a lot of I/O watchers, only part of which	1575	The effect is that there will be a lot of I/O watchers, only part of which
1294	are active at any one point (so there is a constant number of active	1576	are active at any one point (so there is a constant number of active
1295	fds for each loop iterstaion, but which fds these are is random). The	1577	fds for each loop iteration, but which fds these are is random). The
1296	timeout is reset each time something is read because that reflects how	1578	timeout is reset each time something is read because that reflects how
1297	most timeouts work (and puts extra pressure on the event loops).	1579	most timeouts work (and puts extra pressure on the event loops).
1298		1580
1299	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1581	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1300	(1%) are active. This mirrors the activity of large servers with many	1582	(1%) are active. This mirrors the activity of large servers with many
1301	connections, most of which are idle at any one point in time.	1583	connections, most of which are idle at any one point in time.
1302		1584
1303	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1585	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1304	distribution.	1586	distribution.
…		…
1306	=head3 Explanation of the columns	1588	=head3 Explanation of the columns
1307		1589
1308	I<sockets> is the number of sockets, and twice the number of "servers" (as	1590	I<sockets> is the number of sockets, and twice the number of "servers" (as
1309	each server has a read and write socket end).	1591	each server has a read and write socket end).
1310		1592
1311	I<create> is the time it takes to create a socketpair (which is	1593	I<create> is the time it takes to create a socket pair (which is
1312	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1594	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1313		1595
1314	I<request>, the most important value, is the time it takes to handle a	1596	I<request>, the most important value, is the time it takes to handle a
1315	single "request", that is, reading the token from the pipe and forwarding	1597	single "request", that is, reading the token from the pipe and forwarding
1316	it to another server. This includes deleting the old timeout and creating	1598	it to another server. This includes deleting the old timeout and creating
…		…
1389	speed most when you have lots of watchers, not when you only have a few of	1671	speed most when you have lots of watchers, not when you only have a few of
1390	them).	1672	them).
1391		1673
1392	EV is again fastest.	1674	EV is again fastest.
1393		1675
1394	Perl again comes second. It is noticably faster than the C-based event	1676	Perl again comes second. It is noticeably faster than the C-based event
1395	loops Event and Glib, although the difference is too small to really	1677	loops Event and Glib, although the difference is too small to really
1396	matter.	1678	matter.
1397		1679
1398	POE also performs much better in this case, but is is still far behind the	1680	POE also performs much better in this case, but is is still far behind the
1399	others.	1681	others.
…		…
1428	specified in the variable.	1710	specified in the variable.
1429		1711
1430	You can make AnyEvent completely ignore this variable by deleting it	1712	You can make AnyEvent completely ignore this variable by deleting it
1431	before the first watcher gets created, e.g. with a C<BEGIN> block:	1713	before the first watcher gets created, e.g. with a C<BEGIN> block:
1432		1714
1433	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1715	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1434		1716
1435	use AnyEvent;	1717	use AnyEvent;
1436		1718
1437	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1719	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1438	be used to probe what backend is used and gain other information (which is	1720	be used to probe what backend is used and gain other information (which is
1439	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1721	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1722	$ENV{PERL_ANYEGENT_STRICT}.
		1723
		1724
		1725	=head1 BUGS
		1726
		1727	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1728	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1729	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1730	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1731	pronounced).
1440		1732
1441		1733
1442	=head1 SEE ALSO	1734	=head1 SEE ALSO
		1735
		1736	Utility functions: L<AnyEvent::Util>.
1443		1737
1444	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1738	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1445	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1739	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1446		1740
1447	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1741	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1448	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1742	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1449	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1743	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1450	L<AnyEvent::Impl::POE>.	1744	L<AnyEvent::Impl::POE>.
1451		1745
		1746	Non-blocking file handles, sockets, TCP clients and
		1747	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1748
		1749	Asynchronous DNS: L<AnyEvent::DNS>.
		1750
1452	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1751	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1453		1752
1454	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1753	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1455		1754
1456		1755
1457	=head1 AUTHOR	1756	=head1 AUTHOR
1458		1757
1459	Marc Lehmann <schmorp@schmorp.de>	1758	Marc Lehmann <schmorp@schmorp.de>
1460	http://home.schmorp.de/	1759	http://home.schmorp.de/
1461		1760
1462	=cut	1761	=cut
1463		1762
1464	1	1763	1
1465		1764

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs. Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.113 by root, Sat May 10 20:30:35 2008 UTC vs.
Revision 1.169 by root, Wed Jul 9 10:36:22 2008 UTC