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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.114 by root, Sat May 10 21:12:49 2008 UTC vs.
Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC

…		…
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->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	21	$w->recv; # enters "main loop" till $condvar gets ->send
22		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.
		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	my $pid = fork or exit 5;	358	my $pid = fork or exit 5;
285		359
286	my $w = AnyEvent->child (	360	my $w = AnyEvent->child (
287	pid => $pid,	361	pid => $pid,
288	cb => sub {	362	cb => sub {
289	my ($pid, $status) = @_;	363	my ($pid, $status) = @_;
290	warn "pid $pid exited with status $status";	364	warn "pid $pid exited with status $status";
291	$done->send;	365	$done->send;
292	},	366	},
293	);	367	);
294		368
295	# do something else, then wait for process exit	369	# do something else, then wait for process exit
296	$done->recv;	370	$done->recv;
297		371
298	=head2 CONDITION VARIABLES	372	=head2 CONDITION VARIABLES
299		373
300	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
301	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
…		…
310	Condition variables can be created by calling the C<< AnyEvent->condvar	384	Condition variables can be created by calling the C<< AnyEvent->condvar
311	>> method, usually without arguments. The only argument pair allowed is	385	>> method, usually without arguments. The only argument pair allowed is
312	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
313	becomes true.	387	becomes true.
314		388
315	After creation, the conditon variable is "false" until it becomes "true"	389	After creation, the condition variable is "false" until it becomes "true"
316	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).
317		393
318	Condition variables are similar to callbacks, except that you can	394	Condition variables are similar to callbacks, except that you can
319	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
320	in time where multiple outstandign events have been processed. And yet	396	in time where multiple outstanding events have been processed. And yet
321	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
322	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
323	a result.	399	a result.
324		400
325	Condition variables are very useful to signal that something has finished,	401	Condition variables are very useful to signal that something has finished,
326	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,
…		…
332	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
333	could C<< ->recv >> in your main program until the user clicks the Quit	409	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.	410	button of your app, which would C<< ->send >> the "quit" event.
335		411
336	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
337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you	413	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	414	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,	415	you should avoid making a blocking wait yourself, at least in callbacks,
340	as this asks for trouble.	416	as this asks for trouble.
341		417
342	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
…		…
347		423
348	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
349	eventually calls C<< -> send >>, and the "consumer side", which waits	425	eventually calls C<< -> send >>, and the "consumer side", which waits
350	for the send to occur.	426	for the send to occur.
351		427
352	Example:	428	Example: wait for a timer.
353		429
354	# wait till the result is ready	430	# wait till the result is ready
355	my $result_ready = AnyEvent->condvar;	431	my $result_ready = AnyEvent->condvar;
356		432
357	# do something such as adding a timer	433	# do something such as adding a timer
…		…
365		441
366	# this "blocks" (while handling events) till the callback	442	# this "blocks" (while handling events) till the callback
367	# calls send	443	# calls send
368	$result_ready->recv;	444	$result_ready->recv;
369		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;
		452
370	=head3 METHODS FOR PRODUCERS	453	=head3 METHODS FOR PRODUCERS
371		454
372	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
373	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
374	the producer side which creates the condvar in most cases, but it isn't	457	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	468	If a callback has been set on the condition variable, it is called
386	immediately from within send.	469	immediately from within send.
387		470
388	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
389	future C<< ->recv >> 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).
390		482
391	=item $cv->croak ($error)	483	=item $cv->croak ($error)
392		484
393	Similar to send, but causes all call's to C<< ->recv >> to invoke	485	Similar to send, but causes all call's to C<< ->recv >> to invoke
394	C<Carp::croak> with the given error message/object/scalar.	486	C<Carp::croak> with the given error message/object/scalar.
…		…
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
…		…
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<< ->recv >> 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<< ->recv >>'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.
…		…
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<recv> 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
…		…
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	998	# default implementation for ->condvar
814		999
815	sub condvar {	1000	sub condvar {
816	bless {}, "AnyEvent::Base::CondVar"	1001	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::
817	}	1002	}
818		1003
819	# default implementation for ->signal	1004	# default implementation for ->signal
820		1005
821	our %SIG_CB;	1006	our %SIG_CB;
…		…
837	sub AnyEvent::Base::Signal::DESTROY {	1022	sub AnyEvent::Base::Signal::DESTROY {
838	my ($signal, $cb) = @{$_[0]};	1023	my ($signal, $cb) = @{$_[0]};
839		1024
840	delete $SIG_CB{$signal}{$cb};	1025	delete $SIG_CB{$signal}{$cb};
841		1026
842	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1027	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
843	}	1028	}
844		1029
845	# default implementation for ->child	1030	# default implementation for ->child
846		1031
847	our %PID_CB;	1032	our %PID_CB;
…		…
874	or Carp::croak "required option 'pid' is missing";	1059	or Carp::croak "required option 'pid' is missing";
875		1060
876	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1061	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
877		1062
878	unless ($WNOHANG) {	1063	unless ($WNOHANG) {
879	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } \|\| 1;	1064	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
880	}	1065	}
881		1066
882	unless ($CHLD_W) {	1067	unless ($CHLD_W) {
883	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1068	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
884	# 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
…		…
895	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1080	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
896		1081
897	undef $CHLD_W unless keys %PID_CB;	1082	undef $CHLD_W unless keys %PID_CB;
898	}	1083	}
899		1084
900	package AnyEvent::Base::CondVar;	1085	package AnyEvent::CondVar;
901		1086
902	# wake up the waiter	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
903	sub _send {	1095	sub _send {
904	&{ $_[0]{_ae_cb} } if $_[0]{_ae_cb};	1096	# nop
905	}	1097	}
906		1098
907	sub send {	1099	sub send {
		1100	my $cv = shift;
908	$_[0]{_ae_sent} = [@_];	1101	$cv->{_ae_sent} = [@_];
		1102	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
909	$_[0]->_send;	1103	$cv->_send;
910	}	1104	}
911		1105
912	sub croak {	1106	sub croak {
913	$_[0]{_ae_croak} = $_[0];	1107	$_[0]{_ae_croak} = $_[1];
914	$_[0]->send;	1108	$_[0]->send;
915	}	1109	}
916		1110
917	sub ready {	1111	sub ready {
918	$_[0]{_ae_sent}	1112	$_[0]{_ae_sent}
919	}	1113	}
920		1114
		1115	sub _wait {
		1116	AnyEvent->one_event while !$_[0]{_ae_sent};
		1117	}
		1118
921	sub recv {	1119	sub recv {
922	AnyEvent->one_event while !$_[0]{_ae_sent};	1120	$_[0]->_wait;
923		1121
924	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1122	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
925	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1123	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
926	}	1124	}
927		1125
…		…
935	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1133	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
936	}	1134	}
937		1135
938	sub end {	1136	sub end {
939	return if --$_[0]{_ae_counter};	1137	return if --$_[0]{_ae_counter};
940	&{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb};	1138	&{ $_[0]{_ae_end_cb} \|\| sub { $_[0]->send } };
941	}	1139	}
942		1140
943	# undocumented/compatibility with pre-3.4	1141	# undocumented/compatibility with pre-3.4
944	*broadcast = \&send;	1142	*broadcast = \&send;
945	*wait = \&recv;	1143	*wait = \&_wait;
946		1144
947	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1145	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
948		1146
949	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
950	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
…		…
1004	C<PERL_ANYEVENT_MODEL>.	1202	C<PERL_ANYEVENT_MODEL>.
1005		1203
1006	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
1007	model it chooses.	1205	model it chooses.
1008		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 load C<AnyEvent::Strict> and then to thoroughly
		1212	check the arguments passed to most method calls. If it finds any problems
		1213	it will croak.
		1214
		1215	In other words, enables "strict" mode.
		1216
		1217	Unlike C<use strict> it is definitely recommended ot keep it off in
		1218	production.
		1219
1009	=item C<PERL_ANYEVENT_MODEL>	1220	=item C<PERL_ANYEVENT_MODEL>
1010		1221
1011	This can be used to specify the event model to be used by AnyEvent, before	1222	This can be used to specify the event model to be used by AnyEvent, before
1012	autodetection and -probing kicks in. It must be a string consisting	1223	auto detection and -probing kicks in. It must be a string consisting
1013	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	1224	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1014	and the resulting module name is loaded and if the load was successful,	1225	and the resulting module name is loaded and if the load was successful,
1015	used as event model. If it fails to load AnyEvent will proceed with	1226	used as event model. If it fails to load AnyEvent will proceed with
1016	autodetection and -probing.	1227	auto detection and -probing.
1017		1228
1018	This functionality might change in future versions.	1229	This functionality might change in future versions.
1019		1230
1020	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1231	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1021	could start your program like this:	1232	could start your program like this:
1022		1233
1023	PERL_ANYEVENT_MODEL=Perl perl ...	1234	PERL_ANYEVENT_MODEL=Perl perl ...
		1235
		1236	=item C<PERL_ANYEVENT_PROTOCOLS>
		1237
		1238	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1239	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1240	of auto probing).
		1241
		1242	Must be set to a comma-separated list of protocols or address families,
		1243	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1244	used, and preference will be given to protocols mentioned earlier in the
		1245	list.
		1246
		1247	This variable can effectively be used for denial-of-service attacks
		1248	against local programs (e.g. when setuid), although the impact is likely
		1249	small, as the program has to handle connection errors already-
		1250
		1251	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1252	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1253	- only support IPv4, never try to resolve or contact IPv6
		1254	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1255	IPv6, but prefer IPv6 over IPv4.
		1256
		1257	=item C<PERL_ANYEVENT_EDNS0>
		1258
		1259	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1260	for DNS. This extension is generally useful to reduce DNS traffic, but
		1261	some (broken) firewalls drop such DNS packets, which is why it is off by
		1262	default.
		1263
		1264	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1265	EDNS0 in its DNS requests.
		1266
		1267	=item C<PERL_ANYEVENT_MAX_FORKS>
		1268
		1269	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1270	will create in parallel.
1024		1271
1025	=back	1272	=back
1026		1273
1027	=head1 EXAMPLE PROGRAM	1274	=head1 EXAMPLE PROGRAM
1028		1275
…		…
1039	poll => 'r',	1286	poll => 'r',
1040	cb => sub {	1287	cb => sub {
1041	warn "io event <$_[0]>\n"; # will always output <r>	1288	warn "io event <$_[0]>\n"; # will always output <r>
1042	chomp (my $input = <STDIN>); # read a line	1289	chomp (my $input = <STDIN>); # read a line
1043	warn "read: $input\n"; # output what has been read	1290	warn "read: $input\n"; # output what has been read
1044	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1291	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1045	},	1292	},
1046	);	1293	);
1047		1294
1048	my $time_watcher; # can only be used once	1295	my $time_watcher; # can only be used once
1049		1296
…		…
1054	});	1301	});
1055	}	1302	}
1056		1303
1057	new_timer; # create first timer	1304	new_timer; # create first timer
1058		1305
1059	$cv->wait; # wait until user enters /^q/i	1306	$cv->recv; # wait until user enters /^q/i
1060		1307
1061	=head1 REAL-WORLD EXAMPLE	1308	=head1 REAL-WORLD EXAMPLE
1062		1309
1063	Consider the L<Net::FCP> module. It features (among others) the following	1310	Consider the L<Net::FCP> module. It features (among others) the following
1064	API calls, which are to freenet what HTTP GET requests are to http:	1311	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1114	syswrite $txn->{fh}, $txn->{request}	1361	syswrite $txn->{fh}, $txn->{request}
1115	or die "connection or write error";	1362	or die "connection or write error";
1116	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1363	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1117		1364
1118	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1365	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1119	result and signals any possible waiters that the request ahs finished:	1366	result and signals any possible waiters that the request has finished:
1120		1367
1121	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1368	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1122		1369
1123	if (end-of-file or data complete) {	1370	if (end-of-file or data complete) {
1124	$txn->{result} = $txn->{buf};	1371	$txn->{result} = $txn->{buf};
1125	$txn->{finished}->broadcast;	1372	$txn->{finished}->send;
1126	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1373	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1127	}	1374	}
1128		1375
1129	The C<result> method, finally, just waits for the finished signal (if the	1376	The C<result> method, finally, just waits for the finished signal (if the
1130	request was already finished, it doesn't wait, of course, and returns the	1377	request was already finished, it doesn't wait, of course, and returns the
1131	data:	1378	data:
1132		1379
1133	$txn->{finished}->wait;	1380	$txn->{finished}->recv;
1134	return $txn->{result};	1381	return $txn->{result};
1135		1382
1136	The actual code goes further and collects all errors (C<die>s, exceptions)	1383	The actual code goes further and collects all errors (C<die>s, exceptions)
1137	that occured during request processing. The C<result> method detects	1384	that occurred during request processing. The C<result> method detects
1138	whether an exception as thrown (it is stored inside the $txn object)	1385	whether an exception as thrown (it is stored inside the $txn object)
1139	and just throws the exception, which means connection errors and other	1386	and just throws the exception, which means connection errors and other
1140	problems get reported tot he code that tries to use the result, not in a	1387	problems get reported tot he code that tries to use the result, not in a
1141	random callback.	1388	random callback.
1142		1389
…		…
1173		1420
1174	my $quit = AnyEvent->condvar;	1421	my $quit = AnyEvent->condvar;
1175		1422
1176	$fcp->txn_client_get ($url)->cb (sub {	1423	$fcp->txn_client_get ($url)->cb (sub {
1177	...	1424	...
1178	$quit->broadcast;	1425	$quit->send;
1179	});	1426	});
1180		1427
1181	$quit->wait;	1428	$quit->recv;
1182		1429
1183		1430
1184	=head1 BENCHMARKS	1431	=head1 BENCHMARKS
1185		1432
1186	To give you an idea of the performance and overheads that AnyEvent adds	1433	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1188	of various event loops I prepared some benchmarks.	1435	of various event loops I prepared some benchmarks.
1189		1436
1190	=head2 BENCHMARKING ANYEVENT OVERHEAD	1437	=head2 BENCHMARKING ANYEVENT OVERHEAD
1191		1438
1192	Here is a benchmark of various supported event models used natively and	1439	Here is a benchmark of various supported event models used natively and
1193	through anyevent. The benchmark creates a lot of timers (with a zero	1440	through AnyEvent. The benchmark creates a lot of timers (with a zero
1194	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1441	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1195	which it is), lets them fire exactly once and destroys them again.	1442	which it is), lets them fire exactly once and destroys them again.
1196		1443
1197	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1444	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1198	distribution.	1445	distribution.
…		…
1215	all watchers, to avoid adding memory overhead. That means closure creation	1462	all watchers, to avoid adding memory overhead. That means closure creation
1216	and memory usage is not included in the figures.	1463	and memory usage is not included in the figures.
1217		1464
1218	I<invoke> is the time, in microseconds, used to invoke a simple	1465	I<invoke> is the time, in microseconds, used to invoke a simple
1219	callback. The callback simply counts down a Perl variable and after it was	1466	callback. The callback simply counts down a Perl variable and after it was
1220	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1467	invoked "watcher" times, it would C<< ->send >> a condvar once to
1221	signal the end of this phase.	1468	signal the end of this phase.
1222		1469
1223	I<destroy> is the time, in microseconds, that it takes to destroy a single	1470	I<destroy> is the time, in microseconds, that it takes to destroy a single
1224	watcher.	1471	watcher.
1225		1472
…		…
1321		1568
1322	=back	1569	=back
1323		1570
1324	=head2 BENCHMARKING THE LARGE SERVER CASE	1571	=head2 BENCHMARKING THE LARGE SERVER CASE
1325		1572
1326	This benchmark atcually benchmarks the event loop itself. It works by	1573	This benchmark actually benchmarks the event loop itself. It works by
1327	creating a number of "servers": each server consists of a socketpair, a	1574	creating a number of "servers": each server consists of a socket pair, a
1328	timeout watcher that gets reset on activity (but never fires), and an I/O	1575	timeout watcher that gets reset on activity (but never fires), and an I/O
1329	watcher waiting for input on one side of the socket. Each time the socket	1576	watcher waiting for input on one side of the socket. Each time the socket
1330	watcher reads a byte it will write that byte to a random other "server".	1577	watcher reads a byte it will write that byte to a random other "server".
1331		1578
1332	The effect is that there will be a lot of I/O watchers, only part of which	1579	The effect is that there will be a lot of I/O watchers, only part of which
1333	are active at any one point (so there is a constant number of active	1580	are active at any one point (so there is a constant number of active
1334	fds for each loop iterstaion, but which fds these are is random). The	1581	fds for each loop iteration, but which fds these are is random). The
1335	timeout is reset each time something is read because that reflects how	1582	timeout is reset each time something is read because that reflects how
1336	most timeouts work (and puts extra pressure on the event loops).	1583	most timeouts work (and puts extra pressure on the event loops).
1337		1584
1338	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1585	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1339	(1%) are active. This mirrors the activity of large servers with many	1586	(1%) are active. This mirrors the activity of large servers with many
1340	connections, most of which are idle at any one point in time.	1587	connections, most of which are idle at any one point in time.
1341		1588
1342	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1589	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1343	distribution.	1590	distribution.
…		…
1345	=head3 Explanation of the columns	1592	=head3 Explanation of the columns
1346		1593
1347	I<sockets> is the number of sockets, and twice the number of "servers" (as	1594	I<sockets> is the number of sockets, and twice the number of "servers" (as
1348	each server has a read and write socket end).	1595	each server has a read and write socket end).
1349		1596
1350	I<create> is the time it takes to create a socketpair (which is	1597	I<create> is the time it takes to create a socket pair (which is
1351	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1598	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1352		1599
1353	I<request>, the most important value, is the time it takes to handle a	1600	I<request>, the most important value, is the time it takes to handle a
1354	single "request", that is, reading the token from the pipe and forwarding	1601	single "request", that is, reading the token from the pipe and forwarding
1355	it to another server. This includes deleting the old timeout and creating	1602	it to another server. This includes deleting the old timeout and creating
…		…
1428	speed most when you have lots of watchers, not when you only have a few of	1675	speed most when you have lots of watchers, not when you only have a few of
1429	them).	1676	them).
1430		1677
1431	EV is again fastest.	1678	EV is again fastest.
1432		1679
1433	Perl again comes second. It is noticably faster than the C-based event	1680	Perl again comes second. It is noticeably faster than the C-based event
1434	loops Event and Glib, although the difference is too small to really	1681	loops Event and Glib, although the difference is too small to really
1435	matter.	1682	matter.
1436		1683
1437	POE also performs much better in this case, but is is still far behind the	1684	POE also performs much better in this case, but is is still far behind the
1438	others.	1685	others.
…		…
1467	specified in the variable.	1714	specified in the variable.
1468		1715
1469	You can make AnyEvent completely ignore this variable by deleting it	1716	You can make AnyEvent completely ignore this variable by deleting it
1470	before the first watcher gets created, e.g. with a C<BEGIN> block:	1717	before the first watcher gets created, e.g. with a C<BEGIN> block:
1471		1718
1472	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1719	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1473		1720
1474	use AnyEvent;	1721	use AnyEvent;
1475		1722
1476	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1723	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1477	be used to probe what backend is used and gain other information (which is	1724	be used to probe what backend is used and gain other information (which is
1478	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1725	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1726	$ENV{PERL_ANYEGENT_STRICT}.
		1727
		1728
		1729	=head1 BUGS
		1730
		1731	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1732	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1733	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1734	mamleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1735	pronounced).
1479		1736
1480		1737
1481	=head1 SEE ALSO	1738	=head1 SEE ALSO
		1739
		1740	Utility functions: L<AnyEvent::Util>.
1482		1741
1483	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1742	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1484	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1743	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1485		1744
1486	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1745	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1487	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1746	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1488	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1747	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1489	L<AnyEvent::Impl::POE>.	1748	L<AnyEvent::Impl::POE>.
1490		1749
		1750	Non-blocking file handles, sockets, TCP clients and
		1751	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1752
		1753	Asynchronous DNS: L<AnyEvent::DNS>.
		1754
1491	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1755	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1492		1756
1493	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1757	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1494		1758
1495		1759
1496	=head1 AUTHOR	1760	=head1 AUTHOR
1497		1761
1498	Marc Lehmann <schmorp@schmorp.de>	1762	Marc Lehmann <schmorp@schmorp.de>
1499	http://home.schmorp.de/	1763	http://home.schmorp.de/
1500		1764
1501	=cut	1765	=cut
1502		1766
1503	1	1767	1
1504		1768

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.114 by root, Sat May 10 21:12:49 2008 UTC vs. Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.114 by root, Sat May 10 21:12:49 2008 UTC vs.
Revision 1.170 by root, Wed Jul 9 11:53:40 2008 UTC