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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC vs.
Revision 1.213 by root, Sat Jun 20 07:14:35 2009 UTC

…		…
1	=head1 => NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops	5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported
		6	event loops.
6		7
7	=head1 SYNOPSIS	8	=head1 SYNOPSIS
8		9
9	use AnyEvent;	10	use AnyEvent;
10		11
		12	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		14
		15	# one-shot or repeating timers
		16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		18
		19	print AnyEvent->now; # prints current event loop time
		20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		21
		22	# POSIX signal
		23	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		24
		25	# child process exit
		26	my $w = AnyEvent->child (pid => $pid, cb => sub {
		27	my ($pid, $status) = @_;
12	...	28	...
13	});	29	});
14		30
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	31	# called when event loop idle (if applicable)
16	...	32	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		33
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	34	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	35	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	36	$w->recv; # enters "main loop" till $condvar gets ->send
		37	# use a condvar in callback mode:
		38	$w->cb (sub { $_[0]->recv });
		39
		40	=head1 INTRODUCTION/TUTORIAL
		41
		42	This manpage is mainly a reference manual. If you are interested
		43	in a tutorial or some gentle introduction, have a look at the
		44	L<AnyEvent::Intro> manpage.
22		45
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		47
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	49	nowadays. So what is different about AnyEvent?
27		50
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	51	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	52	policy> and AnyEvent is I<small and efficient>.
30		53
31	First and foremost, I<AnyEvent is not an event model> itself, it only	54	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	55	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,	56	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,	57	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	58	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	59	cannot change this, but it can hide the differences between those event
		60	loops.
37		61
38	The goal of AnyEvent is to offer module authors the ability to do event	62	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	63	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	64	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	65	module users into the same thing by forcing them to use the same event
42	model you use.	66	model you use.
43		67
44	For modules like POE or IO::Async (which is a total misnomer as it is	68	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	69	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	70	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	71	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	72	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.	73	module are I<also> forced to use the same event loop you use.
50		74
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	76	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	77	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,	78	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	79	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	80	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	81	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).	82	to AnyEvent, too, so it is future-proof).
59		83
60	In addition to being free of having to use I<the one and only true event	84	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	85	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enormous amount of code and strict rules you have to	86	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	87	follow. AnyEvent, on the other hand, is lean and up to the point, by only
121	These watchers are normal Perl objects with normal Perl lifetime. After	145	These watchers are normal Perl objects with normal Perl lifetime. After
122	creating a watcher it will immediately "watch" for events and invoke the	146	creating a watcher it will immediately "watch" for events and invoke the
123	callback when the event occurs (of course, only when the event model	147	callback when the event occurs (of course, only when the event model
124	is in control).	148	is in control).
125		149
		150	Note that B<callbacks must not permanently change global variables>
		151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		152	callbacks must not C<die> >>. The former is good programming practise in
		153	Perl and the latter stems from the fact that exception handling differs
		154	widely between event loops.
		155
126	To disable the watcher you have to destroy it (e.g. by setting the	156	To disable the watcher you have to destroy it (e.g. by setting the
127	variable you store it in to C<undef> or otherwise deleting all references	157	variable you store it in to C<undef> or otherwise deleting all references
128	to it).	158	to it).
129		159
130	All watchers are created by calling a method on the C<AnyEvent> class.	160	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
132	Many watchers either are used with "recursion" (repeating timers for	162	Many watchers either are used with "recursion" (repeating timers for
133	example), or need to refer to their watcher object in other ways.	163	example), or need to refer to their watcher object in other ways.
134		164
135	An any way to achieve that is this pattern:	165	An any way to achieve that is this pattern:
136		166
137	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138	# you can use $w here, for example to undef it	168	# you can use $w here, for example to undef it
139	undef $w;	169	undef $w;
140	});	170	});
141		171
142	Note that C<my $w; $w => combination. This is necessary because in Perl,	172	Note that C<my $w; $w => combination. This is necessary because in Perl,
143	my variables are only visible after the statement in which they are	173	my variables are only visible after the statement in which they are
144	declared.	174	declared.
145		175
146	=head2 I/O WATCHERS	176	=head2 I/O WATCHERS
147		177
148	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
149	with the following mandatory key-value pairs as arguments:	179	with the following mandatory key-value pairs as arguments:
150		180
151	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		182	for events (AnyEvent might or might not keep a reference to this file
		183	handle). Note that only file handles pointing to things for which
		184	non-blocking operation makes sense are allowed. This includes sockets,
		185	most character devices, pipes, fifos and so on, but not for example files
		186	or block devices.
		187
152	for events. C<poll> must be a string that is either C<r> or C<w>,	188	C<poll> must be a string that is either C<r> or C<w>, which creates a
153	which creates a watcher waiting for "r"eadable or "w"ritable events,	189	watcher waiting for "r"eadable or "w"ritable events, respectively.
		190
154	respectively. C<cb> is the callback to invoke each time the file handle	191	C<cb> is the callback to invoke each time the file handle becomes ready.
155	becomes ready.
156		192
157	Although the callback might get passed parameters, their value and	193	Although the callback might get passed parameters, their value and
158	presence is undefined and you cannot rely on them. Portable AnyEvent	194	presence is undefined and you cannot rely on them. Portable AnyEvent
159	callbacks cannot use arguments passed to I/O watcher callbacks.	195	callbacks cannot use arguments passed to I/O watcher callbacks.
160		196
…		…
164		200
165	Some event loops issue spurious readyness notifications, so you should	201	Some event loops issue spurious readyness notifications, so you should
166	always use non-blocking calls when reading/writing from/to your file	202	always use non-blocking calls when reading/writing from/to your file
167	handles.	203	handles.
168		204
169	Example:
170
171	# wait for readability of STDIN, then read a line and disable the watcher	205	Example: wait for readability of STDIN, then read a line and disable the
		206	watcher.
		207
172	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	208	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
173	chomp (my $input = <STDIN>);	209	chomp (my $input = <STDIN>);
174	warn "read: $input\n";	210	warn "read: $input\n";
175	undef $w;	211	undef $w;
176	});	212	});
…		…
186		222
187	Although the callback might get passed parameters, their value and	223	Although the callback might get passed parameters, their value and
188	presence is undefined and you cannot rely on them. Portable AnyEvent	224	presence is undefined and you cannot rely on them. Portable AnyEvent
189	callbacks cannot use arguments passed to time watcher callbacks.	225	callbacks cannot use arguments passed to time watcher callbacks.
190		226
191	The timer callback will be invoked at most once: if you want a repeating	227	The callback will normally be invoked once only. If you specify another
192	timer you have to create a new watcher (this is a limitation by both Tk	228	parameter, C<interval>, as a strictly positive number (> 0), then the
193	and Glib).	229	callback will be invoked regularly at that interval (in fractional
		230	seconds) after the first invocation. If C<interval> is specified with a
		231	false value, then it is treated as if it were missing.
194		232
195	Example:	233	The callback will be rescheduled before invoking the callback, but no
		234	attempt is done to avoid timer drift in most backends, so the interval is
		235	only approximate.
196		236
197	# fire an event after 7.7 seconds	237	Example: fire an event after 7.7 seconds.
		238
198	my $w = AnyEvent->timer (after => 7.7, cb => sub {	239	my $w = AnyEvent->timer (after => 7.7, cb => sub {
199	warn "timeout\n";	240	warn "timeout\n";
200	});	241	});
201		242
202	# to cancel the timer:	243	# to cancel the timer:
203	undef $w;	244	undef $w;
204		245
205	Example 2:
206
207	# fire an event after 0.5 seconds, then roughly every second	246	Example 2: fire an event after 0.5 seconds, then roughly every second.
208	my $w;
209		247
210	my $cb = sub {
211	# cancel the old timer while creating a new one
212	$w = AnyEvent->timer (after => 1, cb => $cb);	248	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		249	warn "timeout\n";
213	};	250	};
214
215	# start the "loop" by creating the first watcher
216	$w = AnyEvent->timer (after => 0.5, cb => $cb);
217		251
218	=head3 TIMING ISSUES	252	=head3 TIMING ISSUES
219		253
220	There are two ways to handle timers: based on real time (relative, "fire	254	There are two ways to handle timers: based on real time (relative, "fire
221	in 10 seconds") and based on wallclock time (absolute, "fire at 12	255	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
233	timers.	267	timers.
234		268
235	AnyEvent always prefers relative timers, if available, matching the	269	AnyEvent always prefers relative timers, if available, matching the
236	AnyEvent API.	270	AnyEvent API.
237		271
		272	AnyEvent has two additional methods that return the "current time":
		273
		274	=over 4
		275
		276	=item AnyEvent->time
		277
		278	This returns the "current wallclock time" as a fractional number of
		279	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		280	return, and the result is guaranteed to be compatible with those).
		281
		282	It progresses independently of any event loop processing, i.e. each call
		283	will check the system clock, which usually gets updated frequently.
		284
		285	=item AnyEvent->now
		286
		287	This also returns the "current wallclock time", but unlike C<time>, above,
		288	this value might change only once per event loop iteration, depending on
		289	the event loop (most return the same time as C<time>, above). This is the
		290	time that AnyEvent's timers get scheduled against.
		291
		292	I<In almost all cases (in all cases if you don't care), this is the
		293	function to call when you want to know the current time.>
		294
		295	This function is also often faster then C<< AnyEvent->time >>, and
		296	thus the preferred method if you want some timestamp (for example,
		297	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		298
		299	The rest of this section is only of relevance if you try to be very exact
		300	with your timing, you can skip it without bad conscience.
		301
		302	For a practical example of when these times differ, consider L<Event::Lib>
		303	and L<EV> and the following set-up:
		304
		305	The event loop is running and has just invoked one of your callback at
		306	time=500 (assume no other callbacks delay processing). In your callback,
		307	you wait a second by executing C<sleep 1> (blocking the process for a
		308	second) and then (at time=501) you create a relative timer that fires
		309	after three seconds.
		310
		311	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		312	both return C<501>, because that is the current time, and the timer will
		313	be scheduled to fire at time=504 (C<501> + C<3>).
		314
		315	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		316	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		317	last event processing phase started. With L<EV>, your timer gets scheduled
		318	to run at time=503 (C<500> + C<3>).
		319
		320	In one sense, L<Event::Lib> is more exact, as it uses the current time
		321	regardless of any delays introduced by event processing. However, most
		322	callbacks do not expect large delays in processing, so this causes a
		323	higher drift (and a lot more system calls to get the current time).
		324
		325	In another sense, L<EV> is more exact, as your timer will be scheduled at
		326	the same time, regardless of how long event processing actually took.
		327
		328	In either case, if you care (and in most cases, you don't), then you
		329	can get whatever behaviour you want with any event loop, by taking the
		330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		331	account.
		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
		348	=back
		349
238	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
239		351
240	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
241	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
242	be invoked whenever a signal occurs.	354	callback to be invoked whenever a signal occurs.
243		355
244	Although the callback might get passed parameters, their value and	356	Although the callback might get passed parameters, their value and
245	presence is undefined and you cannot rely on them. Portable AnyEvent	357	presence is undefined and you cannot rely on them. Portable AnyEvent
246	callbacks cannot use arguments passed to signal watcher callbacks.	358	callbacks cannot use arguments passed to signal watcher callbacks.
247		359
…		…
263	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
264		376
265	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
266		378
267	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
268	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
269	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
270	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
271	and exit status (as returned by waitpid), so unlike other watcher types,	383
272	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
273		392
274	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
275	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
276	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
277		396
…		…
283	AnyEvent program, you I<have> to create at least one watcher before you	402	AnyEvent program, you I<have> to create at least one watcher before you
284	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
285		404
286	Example: fork a process and wait for it	405	Example: fork a process and wait for it
287		406
288	my $done = AnyEvent->condvar;	407	my $done = AnyEvent->condvar;
289		408
290	my $pid = fork or exit 5;	409	my $pid = fork or exit 5;
291		410
292	my $w = AnyEvent->child (	411	my $w = AnyEvent->child (
293	pid => $pid,	412	pid => $pid,
294	cb => sub {	413	cb => sub {
295	my ($pid, $status) = @_;	414	my ($pid, $status) = @_;
296	warn "pid $pid exited with status $status";	415	warn "pid $pid exited with status $status";
297	$done->send;	416	$done->send;
298	},	417	},
299	);	418	);
300		419
301	# do something else, then wait for process exit	420	# do something else, then wait for process exit
302	$done->recv;	421	$done->recv;
		422
		423	=head2 IDLE WATCHERS
		424
		425	Sometimes there is a need to do something, but it is not so important
		426	to do it instantly, but only when there is nothing better to do. This
		427	"nothing better to do" is usually defined to be "no other events need
		428	attention by the event loop".
		429
		430	Idle watchers ideally get invoked when the event loop has nothing
		431	better to do, just before it would block the process to wait for new
		432	events. Instead of blocking, the idle watcher is invoked.
		433
		434	Most event loops unfortunately do not really support idle watchers (only
		435	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		436	will simply call the callback "from time to time".
		437
		438	Example: read lines from STDIN, but only process them when the
		439	program is otherwise idle:
		440
		441	my @lines; # read data
		442	my $idle_w;
		443	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		444	push @lines, scalar <STDIN>;
		445
		446	# start an idle watcher, if not already done
		447	$idle_w \|\|= AnyEvent->idle (cb => sub {
		448	# handle only one line, when there are lines left
		449	if (my $line = shift @lines) {
		450	print "handled when idle: $line";
		451	} else {
		452	# otherwise disable the idle watcher again
		453	undef $idle_w;
		454	}
		455	});
		456	});
303		457
304	=head2 CONDITION VARIABLES	458	=head2 CONDITION VARIABLES
305		459
306	If you are familiar with some event loops you will know that all of them	460	If you are familiar with some event loops you will know that all of them
307	require you to run some blocking "loop", "run" or similar function that	461	require you to run some blocking "loop", "run" or similar function that
…		…
313	The instrument to do that is called a "condition variable", so called	467	The instrument to do that is called a "condition variable", so called
314	because they represent a condition that must become true.	468	because they represent a condition that must become true.
315		469
316	Condition variables can be created by calling the C<< AnyEvent->condvar	470	Condition variables can be created by calling the C<< AnyEvent->condvar
317	>> method, usually without arguments. The only argument pair allowed is	471	>> method, usually without arguments. The only argument pair allowed is
		472
318	C<cb>, which specifies a callback to be called when the condition variable	473	C<cb>, which specifies a callback to be called when the condition variable
319	becomes true.	474	becomes true, with the condition variable as the first argument (but not
		475	the results).
320		476
321	After creation, the condition variable is "false" until it becomes "true"	477	After creation, the condition variable is "false" until it becomes "true"
322	by calling the C<send> method (or calling the condition variable as if it	478	by calling the C<send> method (or calling the condition variable as if it
323	were a callback, read about the caveats in the description for the C<<	479	were a callback, read about the caveats in the description for the C<<
324	->send >> method).	480	->send >> method).
…		…
380		536
381	my $done = AnyEvent->condvar;	537	my $done = AnyEvent->condvar;
382	my $delay = AnyEvent->timer (after => 5, cb => $done);	538	my $delay = AnyEvent->timer (after => 5, cb => $done);
383	$done->recv;	539	$done->recv;
384		540
		541	Example: Imagine an API that returns a condvar and doesn't support
		542	callbacks. This is how you make a synchronous call, for example from
		543	the main program:
		544
		545	use AnyEvent::CouchDB;
		546
		547	...
		548
		549	my @info = $couchdb->info->recv;
		550
		551	And this is how you would just ste a callback to be called whenever the
		552	results are available:
		553
		554	$couchdb->info->cb (sub {
		555	my @info = $_[0]->recv;
		556	});
		557
385	=head3 METHODS FOR PRODUCERS	558	=head3 METHODS FOR PRODUCERS
386		559
387	These methods should only be used by the producing side, i.e. the	560	These methods should only be used by the producing side, i.e. the
388	code/module that eventually sends the signal. Note that it is also	561	code/module that eventually sends the signal. Note that it is also
389	the producer side which creates the condvar in most cases, but it isn't	562	the producer side which creates the condvar in most cases, but it isn't
…		…
522	=item $bool = $cv->ready	695	=item $bool = $cv->ready
523		696
524	Returns true when the condition is "true", i.e. whether C<send> or	697	Returns true when the condition is "true", i.e. whether C<send> or
525	C<croak> have been called.	698	C<croak> have been called.
526		699
527	=item $cb = $cv->cb ([new callback])	700	=item $cb = $cv->cb ($cb->($cv))
528		701
529	This is a mutator function that returns the callback set and optionally	702	This is a mutator function that returns the callback set and optionally
530	replaces it before doing so.	703	replaces it before doing so.
531		704
532	The callback will be called when the condition becomes "true", i.e. when	705	The callback will be called when the condition becomes "true", i.e. when
533	C<send> or C<croak> are called. Calling C<recv> inside the callback	706	C<send> or C<croak> are called, with the only argument being the condition
534	or at any later time is guaranteed not to block.	707	variable itself. Calling C<recv> inside the callback or at any later time
		708	is guaranteed not to block.
535		709
536	=back	710	=back
537		711
538	=head1 GLOBAL VARIABLES AND FUNCTIONS	712	=head1 GLOBAL VARIABLES AND FUNCTIONS
539		713
…		…
668	=item L<AnyEvent::Util>	842	=item L<AnyEvent::Util>
669		843
670	Contains various utility functions that replace often-used but blocking	844	Contains various utility functions that replace often-used but blocking
671	functions such as C<inet_aton> by event-/callback-based versions.	845	functions such as C<inet_aton> by event-/callback-based versions.
672		846
673	=item L<AnyEvent::Handle>
674
675	Provide read and write buffers and manages watchers for reads and writes.
676
677	=item L<AnyEvent::Socket>	847	=item L<AnyEvent::Socket>
678		848
679	Provides various utility functions for (internet protocol) sockets,	849	Provides various utility functions for (internet protocol) sockets,
680	addresses and name resolution. Also functions to create non-blocking tcp	850	addresses and name resolution. Also functions to create non-blocking tcp
681	connections or tcp servers, with IPv6 and SRV record support and more.	851	connections or tcp servers, with IPv6 and SRV record support and more.
682		852
		853	=item L<AnyEvent::Handle>
		854
		855	Provide read and write buffers, manages watchers for reads and writes,
		856	supports raw and formatted I/O, I/O queued and fully transparent and
		857	non-blocking SSL/TLS.
		858
683	=item L<AnyEvent::DNS>	859	=item L<AnyEvent::DNS>
684		860
685	Provides rich asynchronous DNS resolver capabilities.	861	Provides rich asynchronous DNS resolver capabilities.
686		862
		863	=item L<AnyEvent::HTTP>
		864
		865	A simple-to-use HTTP library that is capable of making a lot of concurrent
		866	HTTP requests.
		867
687	=item L<AnyEvent::HTTPD>	868	=item L<AnyEvent::HTTPD>
688		869
689	Provides a simple web application server framework.	870	Provides a simple web application server framework.
690		871
691	=item L<AnyEvent::FastPing>	872	=item L<AnyEvent::FastPing>
692		873
693	The fastest ping in the west.	874	The fastest ping in the west.
694		875
		876	=item L<AnyEvent::DBI>
		877
		878	Executes L<DBI> requests asynchronously in a proxy process.
		879
		880	=item L<AnyEvent::AIO>
		881
		882	Truly asynchronous I/O, should be in the toolbox of every event
		883	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		884	together.
		885
		886	=item L<AnyEvent::BDB>
		887
		888	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		889	L<BDB> and AnyEvent together.
		890
		891	=item L<AnyEvent::GPSD>
		892
		893	A non-blocking interface to gpsd, a daemon delivering GPS information.
		894
		895	=item L<AnyEvent::IGS>
		896
		897	A non-blocking interface to the Internet Go Server protocol (used by
		898	L<App::IGS>).
		899
695	=item L<Net::IRC3>	900	=item L<AnyEvent::IRC>
696		901
697	AnyEvent based IRC client module family.	902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
698		903
699	=item L<Net::XMPP2>	904	=item L<Net::XMPP2>
700		905
701	AnyEvent based XMPP (Jabber protocol) module family.	906	AnyEvent based XMPP (Jabber protocol) module family.
702		907
…		…
711		916
712	=item L<Coro>	917	=item L<Coro>
713		918
714	Has special support for AnyEvent via L<Coro::AnyEvent>.	919	Has special support for AnyEvent via L<Coro::AnyEvent>.
715		920
716	=item L<AnyEvent::AIO>, L<IO::AIO>
717
718	Truly asynchronous I/O, should be in the toolbox of every event
719	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
720	together.
721
722	=item L<AnyEvent::BDB>, L<BDB>
723
724	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
725	IO::AIO and AnyEvent together.
726
727	=item L<IO::Lambda>	921	=item L<IO::Lambda>
728		922
729	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	923	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
730		924
731	=back	925	=back
…		…
733	=cut	927	=cut
734		928
735	package AnyEvent;	929	package AnyEvent;
736		930
737	no warnings;	931	no warnings;
738	use strict;	932	use strict qw(vars subs);
739		933
740	use Carp;	934	use Carp;
741		935
742	our $VERSION = '4.05';	936	our $VERSION = 4.411;
743	our $MODEL;	937	our $MODEL;
744		938
745	our $AUTOLOAD;	939	our $AUTOLOAD;
746	our @ISA;	940	our @ISA;
747		941
…		…
779	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
780	[Wx:: => AnyEvent::Impl::POE::],	974	[Wx:: => AnyEvent::Impl::POE::],
781	[Prima:: => AnyEvent::Impl::POE::],	975	[Prima:: => AnyEvent::Impl::POE::],
782	);	976	);
783		977
784	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	978	our %method = map +($_ => 1),
		979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
785		980
786	our @post_detect;	981	our @post_detect;
787		982
788	sub post_detect(&) {	983	sub post_detect(&) {
789	my ($cb) = @_;	984	my ($cb) = @_;
…		…
794	1	989	1
795	} else {	990	} else {
796	push @post_detect, $cb;	991	push @post_detect, $cb;
797		992
798	defined wantarray	993	defined wantarray
799	? bless \$cb, "AnyEvent::Util::PostDetect"	994	? bless \$cb, "AnyEvent::Util::postdetect"
800	: ()	995	: ()
801	}	996	}
802	}	997	}
803		998
804	sub AnyEvent::Util::PostDetect::DESTROY {	999	sub AnyEvent::Util::postdetect::DESTROY {
805	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;
806	}	1001	}
807		1002
808	sub detect() {	1003	sub detect() {
809	unless ($MODEL) {	1004	unless ($MODEL) {
…		…
846	last;	1041	last;
847	}	1042	}
848	}	1043	}
849		1044
850	$MODEL	1045	$MODEL
851	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1046	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
852	}	1047	}
853	}	1048	}
854		1049
		1050	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1051
855	unshift @ISA, $MODEL;	1052	unshift @ISA, $MODEL;
856	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1053
		1054	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
857		1055
858	(shift @post_detect)->() while @post_detect;	1056	(shift @post_detect)->() while @post_detect;
859	}	1057	}
860		1058
861	$MODEL	1059	$MODEL
…		…
871		1069
872	my $class = shift;	1070	my $class = shift;
873	$class->$func (@_);	1071	$class->$func (@_);
874	}	1072	}
875		1073
		1074	# utility function to dup a filehandle. this is used by many backends
		1075	# to support binding more than one watcher per filehandle (they usually
		1076	# allow only one watcher per fd, so we dup it to get a different one).
		1077	sub _dupfh($$$$) {
		1078	my ($poll, $fh, $r, $w) = @_;
		1079
		1080	# cygwin requires the fh mode to be matching, unix doesn't
		1081	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1082	: $poll eq "w" ? ($w, ">")
		1083	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1084
		1085	open my $fh2, "$mode&" . fileno $fh
		1086	or die "cannot dup() filehandle: $!,";
		1087
		1088	# we assume CLOEXEC is already set by perl in all important cases
		1089
		1090	($fh2, $rw)
		1091	}
		1092
876	package AnyEvent::Base;	1093	package AnyEvent::Base;
877		1094
		1095	# default implementations for many methods
		1096
		1097	BEGIN {
		1098	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1099	*_time = \&Time::HiRes::time;
		1100	# if (eval "use POSIX (); (POSIX::times())...
		1101	} else {
		1102	*_time = sub { time }; # epic fail
		1103	}
		1104	}
		1105
		1106	sub time { _time }
		1107	sub now { _time }
		1108	sub now_update { }
		1109
878	# default implementation for ->condvar	1110	# default implementation for ->condvar
879		1111
880	sub condvar {	1112	sub condvar {
881	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
882	}	1114	}
883		1115
884	# default implementation for ->signal	1116	# default implementation for ->signal
885		1117
886	our %SIG_CB;	1118	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1119
		1120	sub _signal_exec {
		1121	sysread $SIGPIPE_R, my $dummy, 4;
		1122
		1123	while (%SIG_EV) {
		1124	for (keys %SIG_EV) {
		1125	delete $SIG_EV{$_};
		1126	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1127	}
		1128	}
		1129	}
887		1130
888	sub signal {	1131	sub signal {
889	my (undef, %arg) = @_;	1132	my (undef, %arg) = @_;
890		1133
		1134	unless ($SIGPIPE_R) {
		1135	require Fcntl;
		1136
		1137	if (AnyEvent::WIN32) {
		1138	require AnyEvent::Util;
		1139
		1140	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1142	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1143	} else {
		1144	pipe $SIGPIPE_R, $SIGPIPE_W;
		1145	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1146	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1147
		1148	# not strictly required, as $^F is normally 2, but let's make sure...
		1149	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1150	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1151	}
		1152
		1153	$SIGPIPE_R
		1154	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1155
		1156	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1157	}
		1158
891	my $signal = uc $arg{signal}	1159	my $signal = uc $arg{signal}
892	or Carp::croak "required option 'signal' is missing";	1160	or Carp::croak "required option 'signal' is missing";
893		1161
894	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
895	$SIG{$signal} \|\|= sub {	1163	$SIG{$signal} \|\|= sub {
896	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1164	local $!;
		1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1166	undef $SIG_EV{$signal};
897	};	1167	};
898		1168
899	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
900	}	1170	}
901		1171
902	sub AnyEvent::Base::Signal::DESTROY {	1172	sub AnyEvent::Base::signal::DESTROY {
903	my ($signal, $cb) = @{$_[0]};	1173	my ($signal, $cb) = @{$_[0]};
904		1174
905	delete $SIG_CB{$signal}{$cb};	1175	delete $SIG_CB{$signal}{$cb};
906		1176
		1177	# delete doesn't work with older perls - they then
		1178	# print weird messages, or just unconditionally exit
		1179	# instead of getting the default action.
907	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
908	}	1181	}
909		1182
910	# default implementation for ->child	1183	# default implementation for ->child
911		1184
912	our %PID_CB;	1185	our %PID_CB;
913	our $CHLD_W;	1186	our $CHLD_W;
914	our $CHLD_DELAY_W;	1187	our $CHLD_DELAY_W;
915	our $PID_IDLE;
916	our $WNOHANG;	1188	our $WNOHANG;
917		1189
918	sub _child_wait {	1190	sub _sigchld {
919	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
920	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
921	(values %{ $PID_CB{0} \|\| {} });	1193	(values %{ $PID_CB{0} \|\| {} });
922	}	1194	}
923
924	undef $PID_IDLE;
925	}
926
927	sub _sigchld {
928	# make sure we deliver these changes "synchronous" with the event loop.
929	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
930	undef $CHLD_DELAY_W;
931	&_child_wait;
932	});
933	}	1195	}
934		1196
935	sub child {	1197	sub child {
936	my (undef, %arg) = @_;	1198	my (undef, %arg) = @_;
937		1199
938	defined (my $pid = $arg{pid} + 0)	1200	defined (my $pid = $arg{pid} + 0)
939	or Carp::croak "required option 'pid' is missing";	1201	or Carp::croak "required option 'pid' is missing";
940		1202
941	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
942		1204
943	unless ($WNOHANG) {
944	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1205	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
945	}
946		1206
947	unless ($CHLD_W) {	1207	unless ($CHLD_W) {
948	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
949	# child could be a zombie already, so make at least one round	1209	# child could be a zombie already, so make at least one round
950	&_sigchld;	1210	&_sigchld;
951	}	1211	}
952		1212
953	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1213	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
954	}	1214	}
955		1215
956	sub AnyEvent::Base::Child::DESTROY {	1216	sub AnyEvent::Base::child::DESTROY {
957	my ($pid, $cb) = @{$_[0]};	1217	my ($pid, $cb) = @{$_[0]};
958		1218
959	delete $PID_CB{$pid}{$cb};	1219	delete $PID_CB{$pid}{$cb};
960	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1220	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
961		1221
962	undef $CHLD_W unless keys %PID_CB;	1222	undef $CHLD_W unless keys %PID_CB;
		1223	}
		1224
		1225	# idle emulation is done by simply using a timer, regardless
		1226	# of whether the process is idle or not, and not letting
		1227	# the callback use more than 50% of the time.
		1228	sub idle {
		1229	my (undef, %arg) = @_;
		1230
		1231	my ($cb, $w, $rcb) = $arg{cb};
		1232
		1233	$rcb = sub {
		1234	if ($cb) {
		1235	$w = _time;
		1236	&$cb;
		1237	$w = _time - $w;
		1238
		1239	# never use more then 50% of the time for the idle watcher,
		1240	# within some limits
		1241	$w = 0.0001 if $w < 0.0001;
		1242	$w = 5 if $w > 5;
		1243
		1244	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1245	} else {
		1246	# clean up...
		1247	undef $w;
		1248	undef $rcb;
		1249	}
		1250	};
		1251
		1252	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1253
		1254	bless \\$cb, "AnyEvent::Base::idle"
		1255	}
		1256
		1257	sub AnyEvent::Base::idle::DESTROY {
		1258	undef $${$_[0]};
963	}	1259	}
964		1260
965	package AnyEvent::CondVar;	1261	package AnyEvent::CondVar;
966		1262
967	our @ISA = AnyEvent::CondVar::Base::;	1263	our @ISA = AnyEvent::CondVar::Base::;
…		…
1019	}	1315	}
1020		1316
1021	# undocumented/compatibility with pre-3.4	1317	# undocumented/compatibility with pre-3.4
1022	*broadcast = \&send;	1318	*broadcast = \&send;
1023	*wait = \&_wait;	1319	*wait = \&_wait;
		1320
		1321	=head1 ERROR AND EXCEPTION HANDLING
		1322
		1323	In general, AnyEvent does not do any error handling - it relies on the
		1324	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1325	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1326	checking of all AnyEvent methods, however, which is highly useful during
		1327	development.
		1328
		1329	As for exception handling (i.e. runtime errors and exceptions thrown while
		1330	executing a callback), this is not only highly event-loop specific, but
		1331	also not in any way wrapped by this module, as this is the job of the main
		1332	program.
		1333
		1334	The pure perl event loop simply re-throws the exception (usually
		1335	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1336	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1337	so on.
		1338
		1339	=head1 ENVIRONMENT VARIABLES
		1340
		1341	The following environment variables are used by this module or its
		1342	submodules:
		1343
		1344	=over 4
		1345
		1346	=item C<PERL_ANYEVENT_VERBOSE>
		1347
		1348	By default, AnyEvent will be completely silent except in fatal
		1349	conditions. You can set this environment variable to make AnyEvent more
		1350	talkative.
		1351
		1352	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1353	conditions, such as not being able to load the event model specified by
		1354	C<PERL_ANYEVENT_MODEL>.
		1355
		1356	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1357	model it chooses.
		1358
		1359	=item C<PERL_ANYEVENT_STRICT>
		1360
		1361	AnyEvent does not do much argument checking by default, as thorough
		1362	argument checking is very costly. Setting this variable to a true value
		1363	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1364	check the arguments passed to most method calls. If it finds any problems
		1365	it will croak.
		1366
		1367	In other words, enables "strict" mode.
		1368
		1369	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1370	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1371	developing programs can be very useful, however.
		1372
		1373	=item C<PERL_ANYEVENT_MODEL>
		1374
		1375	This can be used to specify the event model to be used by AnyEvent, before
		1376	auto detection and -probing kicks in. It must be a string consisting
		1377	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1378	and the resulting module name is loaded and if the load was successful,
		1379	used as event model. If it fails to load AnyEvent will proceed with
		1380	auto detection and -probing.
		1381
		1382	This functionality might change in future versions.
		1383
		1384	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1385	could start your program like this:
		1386
		1387	PERL_ANYEVENT_MODEL=Perl perl ...
		1388
		1389	=item C<PERL_ANYEVENT_PROTOCOLS>
		1390
		1391	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1392	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1393	of auto probing).
		1394
		1395	Must be set to a comma-separated list of protocols or address families,
		1396	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1397	used, and preference will be given to protocols mentioned earlier in the
		1398	list.
		1399
		1400	This variable can effectively be used for denial-of-service attacks
		1401	against local programs (e.g. when setuid), although the impact is likely
		1402	small, as the program has to handle conenction and other failures anyways.
		1403
		1404	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1405	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1406	- only support IPv4, never try to resolve or contact IPv6
		1407	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1408	IPv6, but prefer IPv6 over IPv4.
		1409
		1410	=item C<PERL_ANYEVENT_EDNS0>
		1411
		1412	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1413	for DNS. This extension is generally useful to reduce DNS traffic, but
		1414	some (broken) firewalls drop such DNS packets, which is why it is off by
		1415	default.
		1416
		1417	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1418	EDNS0 in its DNS requests.
		1419
		1420	=item C<PERL_ANYEVENT_MAX_FORKS>
		1421
		1422	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1423	will create in parallel.
		1424
		1425	=back
1024		1426
1025	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1026		1428
1027	This is an advanced topic that you do not normally need to use AnyEvent in	1429	This is an advanced topic that you do not normally need to use AnyEvent in
1028	a module. This section is only of use to event loop authors who want to	1430	a module. This section is only of use to event loop authors who want to
…		…
1062		1464
1063	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1465	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1064	condition variables: code blocking while waiting for a condition will	1466	condition variables: code blocking while waiting for a condition will
1065	C<die>. This still works with most modules/usages, and blocking calls must	1467	C<die>. This still works with most modules/usages, and blocking calls must
1066	not be done in an interactive application, so it makes sense.	1468	not be done in an interactive application, so it makes sense.
1067
1068	=head1 ENVIRONMENT VARIABLES
1069
1070	The following environment variables are used by this module:
1071
1072	=over 4
1073
1074	=item C<PERL_ANYEVENT_VERBOSE>
1075
1076	By default, AnyEvent will be completely silent except in fatal
1077	conditions. You can set this environment variable to make AnyEvent more
1078	talkative.
1079
1080	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1081	conditions, such as not being able to load the event model specified by
1082	C<PERL_ANYEVENT_MODEL>.
1083
1084	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1085	model it chooses.
1086
1087	=item C<PERL_ANYEVENT_MODEL>
1088
1089	This can be used to specify the event model to be used by AnyEvent, before
1090	auto detection and -probing kicks in. It must be a string consisting
1091	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1092	and the resulting module name is loaded and if the load was successful,
1093	used as event model. If it fails to load AnyEvent will proceed with
1094	auto detection and -probing.
1095
1096	This functionality might change in future versions.
1097
1098	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1099	could start your program like this:
1100
1101	PERL_ANYEVENT_MODEL=Perl perl ...
1102
1103	=item C<PERL_ANYEVENT_PROTOCOLS>
1104
1105	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1106	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1107	of auto probing).
1108
1109	Must be set to a comma-separated list of protocols or address families,
1110	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1111	used, and preference will be given to protocols mentioned earlier in the
1112	list.
1113
1114	This variable can effectively be used for denial-of-service attacks
1115	against local programs (e.g. when setuid), although the impact is likely
1116	small, as the program has to handle connection errors already-
1117
1118	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1119	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1120	- only support IPv4, never try to resolve or contact IPv6
1121	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1122	IPv6, but prefer IPv6 over IPv4.
1123
1124	=item C<PERL_ANYEVENT_EDNS0>
1125
1126	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1127	for DNS. This extension is generally useful to reduce DNS traffic, but
1128	some (broken) firewalls drop such DNS packets, which is why it is off by
1129	default.
1130
1131	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1132	EDNS0 in its DNS requests.
1133
1134	=item C<PERL_ANYEVENT_MAX_FORKS>
1135
1136	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1137	will create in parallel.
1138
1139	=back
1140		1469
1141	=head1 EXAMPLE PROGRAM	1470	=head1 EXAMPLE PROGRAM
1142		1471
1143	The following program uses an I/O watcher to read data from STDIN, a timer	1472	The following program uses an I/O watcher to read data from STDIN, a timer
1144	to display a message once per second, and a condition variable to quit the	1473	to display a message once per second, and a condition variable to quit the
…		…
1338	watcher.	1667	watcher.
1339		1668
1340	=head3 Results	1669	=head3 Results
1341		1670
1342	name watchers bytes create invoke destroy comment	1671	name watchers bytes create invoke destroy comment
1343	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1672	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1344	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1673	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1345	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1674	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1346	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1675	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1347	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1676	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1348	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1677	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1349	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1678	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1350	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1679	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1351	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1680	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1352	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1681	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1353		1682
1354	=head3 Discussion	1683	=head3 Discussion
1355		1684
1356	The benchmark does I<not> measure scalability of the event loop very	1685	The benchmark does I<not> measure scalability of the event loop very
1357	well. For example, a select-based event loop (such as the pure perl one)	1686	well. For example, a select-based event loop (such as the pure perl one)
…		…
1559	watchers, as the management overhead dominates.	1888	watchers, as the management overhead dominates.
1560		1889
1561	=back	1890	=back
1562		1891
1563		1892
		1893	=head1 SIGNALS
		1894
		1895	AnyEvent currently installs handlers for these signals:
		1896
		1897	=over 4
		1898
		1899	=item SIGCHLD
		1900
		1901	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1902	emulation for event loops that do not support them natively. Also, some
		1903	event loops install a similar handler.
		1904
		1905	=item SIGPIPE
		1906
		1907	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1908	when AnyEvent gets loaded.
		1909
		1910	The rationale for this is that AnyEvent users usually do not really depend
		1911	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1912	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1913	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1914	some random socket.
		1915
		1916	The rationale for installing a no-op handler as opposed to ignoring it is
		1917	that this way, the handler will be restored to defaults on exec.
		1918
		1919	Feel free to install your own handler, or reset it to defaults.
		1920
		1921	=back
		1922
		1923	=cut
		1924
		1925	$SIG{PIPE} = sub { }
		1926	unless defined $SIG{PIPE};
		1927
		1928
1564	=head1 FORK	1929	=head1 FORK
1565		1930
1566	Most event libraries are not fork-safe. The ones who are usually are	1931	Most event libraries are not fork-safe. The ones who are usually are
1567	because they rely on inefficient but fork-safe C<select> or C<poll>	1932	because they rely on inefficient but fork-safe C<select> or C<poll>
1568	calls. Only L<EV> is fully fork-aware.	1933	calls. Only L<EV> is fully fork-aware.
…		…
1581	specified in the variable.	1946	specified in the variable.
1582		1947
1583	You can make AnyEvent completely ignore this variable by deleting it	1948	You can make AnyEvent completely ignore this variable by deleting it
1584	before the first watcher gets created, e.g. with a C<BEGIN> block:	1949	before the first watcher gets created, e.g. with a C<BEGIN> block:
1585		1950
1586	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1951	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1587		1952
1588	use AnyEvent;	1953	use AnyEvent;
1589		1954
1590	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1591	be used to probe what backend is used and gain other information (which is	1956	be used to probe what backend is used and gain other information (which is
1592	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1957	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1958	$ENV{PERL_ANYEVENT_STRICT}.
		1959
		1960
		1961	=head1 BUGS
		1962
		1963	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1964	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1965	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1966	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1967	pronounced).
1593		1968
1594		1969
1595	=head1 SEE ALSO	1970	=head1 SEE ALSO
1596		1971
1597	Utility functions: L<AnyEvent::Util>.	1972	Utility functions: L<AnyEvent::Util>.
…		…
1614	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1989	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1615		1990
1616		1991
1617	=head1 AUTHOR	1992	=head1 AUTHOR
1618		1993
1619	Marc Lehmann <schmorp@schmorp.de>	1994	Marc Lehmann <schmorp@schmorp.de>
1620	http://home.schmorp.de/	1995	http://home.schmorp.de/
1621		1996
1622	=cut	1997	=cut
1623		1998
1624	1	1999	1
1625		2000

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC vs. Revision 1.213 by root, Sat Jun 20 07:14:35 2009 UTC

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Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC vs.
Revision 1.213 by root, Sat Jun 20 07:14:35 2009 UTC