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

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.143 by root, Wed May 28 23:57:38 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
…		…
243		277
244	This returns the "current wallclock time" as a fractional number of	278	This returns the "current wallclock time" as a fractional number of
245	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>	279	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
246	return, and the result is guaranteed to be compatible with those).	280	return, and the result is guaranteed to be compatible with those).
247		281
248	It progresses independently of any event loop processing.	282	It progresses independently of any event loop processing, i.e. each call
249		283	will check the system clock, which usually gets updated frequently.
250	In almost all cases (in all cases if you don't care), this is the function
251	to call when you want to know the current time.
252		284
253	=item AnyEvent->now	285	=item AnyEvent->now
254		286
255	This also returns the "current wallclock time", but unlike C<time>, above,	287	This also returns the "current wallclock time", but unlike C<time>, above,
256	this value might change only once per event loop iteration, depending on	288	this value might change only once per event loop iteration, depending on
257	the event loop (most return the same time as C<time>, above). This is the	289	the event loop (most return the same time as C<time>, above). This is the
258	time that AnyEvent timers get scheduled against.	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.
259		301
260	For a practical example of when these times differ, consider L<Event::Lib>	302	For a practical example of when these times differ, consider L<Event::Lib>
261	and L<EV> and the following set-up:	303	and L<EV> and the following set-up:
262		304
263	The event loop is running and has just invoked one of your callback at	305	The event loop is running and has just invoked one of your callback at
…		…
268		310
269	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will	311	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
270	both return C<501>, because that is the current time, and the timer will	312	both return C<501>, because that is the current time, and the timer will
271	be scheduled to fire at time=504 (C<501> + C<3>).	313	be scheduled to fire at time=504 (C<501> + C<3>).
272		314
273	With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current	315	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
274	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the	316	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
275	last event processing phase started. With L<EV>, your timer gets scheduled	317	last event processing phase started. With L<EV>, your timer gets scheduled
276	to run at time=503 (C<500> + C<3>).	318	to run at time=503 (C<500> + C<3>).
277		319
278	In one sense, L<Event::Lib> is more exact, as it uses the current time	320	In one sense, L<Event::Lib> is more exact, as it uses the current time
279	regardless of any delays introduced by event processing. However, most	321	regardless of any delays introduced by event processing. However, most
280	callbacks do not expect large delays in processing, so this causes a	322	callbacks do not expect large delays in processing, so this causes a
281	higher drift (and a lot more syscalls to get the current time).	323	higher drift (and a lot more system calls to get the current time).
282		324
283	In another sense, L<EV> is more exact, as your timer will be scheduled at	325	In another sense, L<EV> is more exact, as your timer will be scheduled at
284	the same time, regardless of how long event processing actually took.	326	the same time, regardless of how long event processing actually took.
285		327
286	In either case, if you care (and in most cases, you don't), then you	328	In either case, if you care (and in most cases, you don't), then you
287	can get whatever behaviour you want with any event loop, by taking the	329	can get whatever behaviour you want with any event loop, by taking the
288	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
289	account.	331	account.
290		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
291	=back	348	=back
292		349
293	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
294		351
295	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
296	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
297	be invoked whenever a signal occurs.	354	callback to be invoked whenever a signal occurs.
298		355
299	Although the callback might get passed parameters, their value and	356	Although the callback might get passed parameters, their value and
300	presence is undefined and you cannot rely on them. Portable AnyEvent	357	presence is undefined and you cannot rely on them. Portable AnyEvent
301	callbacks cannot use arguments passed to signal watcher callbacks.	358	callbacks cannot use arguments passed to signal watcher callbacks.
302		359
…		…
318	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
319		376
320	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.
321		378
322	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
323	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
324	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
325	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
326	and exit status (as returned by waitpid), so unlike other watcher types,	383
327	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).
328		392
329	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
330	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
331	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
332		396
…		…
338	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
339	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	403	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
340		404
341	Example: fork a process and wait for it	405	Example: fork a process and wait for it
342		406
343	my $done = AnyEvent->condvar;	407	my $done = AnyEvent->condvar;
344		408
345	my $pid = fork or exit 5;	409	my $pid = fork or exit 5;
346		410
347	my $w = AnyEvent->child (	411	my $w = AnyEvent->child (
348	pid => $pid,	412	pid => $pid,
349	cb => sub {	413	cb => sub {
350	my ($pid, $status) = @_;	414	my ($pid, $status) = @_;
351	warn "pid $pid exited with status $status";	415	warn "pid $pid exited with status $status";
352	$done->send;	416	$done->send;
353	},	417	},
354	);	418	);
355		419
356	# do something else, then wait for process exit	420	# do something else, then wait for process exit
357	$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	});
358		457
359	=head2 CONDITION VARIABLES	458	=head2 CONDITION VARIABLES
360		459
361	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
362	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
…		…
368	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
369	because they represent a condition that must become true.	468	because they represent a condition that must become true.
370		469
371	Condition variables can be created by calling the C<< AnyEvent->condvar	470	Condition variables can be created by calling the C<< AnyEvent->condvar
372	>> method, usually without arguments. The only argument pair allowed is	471	>> method, usually without arguments. The only argument pair allowed is
		472
373	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
374	becomes true.	474	becomes true, with the condition variable as the first argument (but not
		475	the results).
375		476
376	After creation, the condition variable is "false" until it becomes "true"	477	After creation, the condition variable is "false" until it becomes "true"
377	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
378	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<<
379	->send >> method).	480	->send >> method).
…		…
435		536
436	my $done = AnyEvent->condvar;	537	my $done = AnyEvent->condvar;
437	my $delay = AnyEvent->timer (after => 5, cb => $done);	538	my $delay = AnyEvent->timer (after => 5, cb => $done);
438	$done->recv;	539	$done->recv;
439		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
440	=head3 METHODS FOR PRODUCERS	558	=head3 METHODS FOR PRODUCERS
441		559
442	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
443	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
444	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
…		…
577	=item $bool = $cv->ready	695	=item $bool = $cv->ready
578		696
579	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
580	C<croak> have been called.	698	C<croak> have been called.
581		699
582	=item $cb = $cv->cb ([new callback])	700	=item $cb = $cv->cb ($cb->($cv))
583		701
584	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
585	replaces it before doing so.	703	replaces it before doing so.
586		704
587	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
588	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
589	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.
590		709
591	=back	710	=back
592		711
593	=head1 GLOBAL VARIABLES AND FUNCTIONS	712	=head1 GLOBAL VARIABLES AND FUNCTIONS
594		713
…		…
723	=item L<AnyEvent::Util>	842	=item L<AnyEvent::Util>
724		843
725	Contains various utility functions that replace often-used but blocking	844	Contains various utility functions that replace often-used but blocking
726	functions such as C<inet_aton> by event-/callback-based versions.	845	functions such as C<inet_aton> by event-/callback-based versions.
727		846
728	=item L<AnyEvent::Handle>
729
730	Provide read and write buffers and manages watchers for reads and writes.
731
732	=item L<AnyEvent::Socket>	847	=item L<AnyEvent::Socket>
733		848
734	Provides various utility functions for (internet protocol) sockets,	849	Provides various utility functions for (internet protocol) sockets,
735	addresses and name resolution. Also functions to create non-blocking tcp	850	addresses and name resolution. Also functions to create non-blocking tcp
736	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.
737		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
738	=item L<AnyEvent::DNS>	859	=item L<AnyEvent::DNS>
739		860
740	Provides rich asynchronous DNS resolver capabilities.	861	Provides rich asynchronous DNS resolver capabilities.
741		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
742	=item L<AnyEvent::HTTPD>	868	=item L<AnyEvent::HTTPD>
743		869
744	Provides a simple web application server framework.	870	Provides a simple web application server framework.
745		871
746	=item L<AnyEvent::FastPing>	872	=item L<AnyEvent::FastPing>
747		873
748	The fastest ping in the west.	874	The fastest ping in the west.
749		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
750	=item L<Net::IRC3>	900	=item L<AnyEvent::IRC>
751		901
752	AnyEvent based IRC client module family.	902	AnyEvent based IRC client module family (replacing the older Net::IRC3).
753		903
754	=item L<Net::XMPP2>	904	=item L<Net::XMPP2>
755		905
756	AnyEvent based XMPP (Jabber protocol) module family.	906	AnyEvent based XMPP (Jabber protocol) module family.
757		907
…		…
766		916
767	=item L<Coro>	917	=item L<Coro>
768		918
769	Has special support for AnyEvent via L<Coro::AnyEvent>.	919	Has special support for AnyEvent via L<Coro::AnyEvent>.
770		920
771	=item L<AnyEvent::AIO>, L<IO::AIO>
772
773	Truly asynchronous I/O, should be in the toolbox of every event
774	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
775	together.
776
777	=item L<AnyEvent::BDB>, L<BDB>
778
779	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
780	IO::AIO and AnyEvent together.
781
782	=item L<IO::Lambda>	921	=item L<IO::Lambda>
783		922
784	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.
785		924
786	=back	925	=back
…		…
788	=cut	927	=cut
789		928
790	package AnyEvent;	929	package AnyEvent;
791		930
792	no warnings;	931	no warnings;
793	use strict;	932	use strict qw(vars subs);
794		933
795	use Carp;	934	use Carp;
796		935
797	our $VERSION = '4.05';	936	our $VERSION = 4.411;
798	our $MODEL;	937	our $MODEL;
799		938
800	our $AUTOLOAD;	939	our $AUTOLOAD;
801	our @ISA;	940	our @ISA;
802		941
…		…
834	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	973	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
835	[Wx:: => AnyEvent::Impl::POE::],	974	[Wx:: => AnyEvent::Impl::POE::],
836	[Prima:: => AnyEvent::Impl::POE::],	975	[Prima:: => AnyEvent::Impl::POE::],
837	);	976	);
838		977
839	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	978	our %method = map +($_ => 1),
		979	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
840		980
841	our @post_detect;	981	our @post_detect;
842		982
843	sub post_detect(&) {	983	sub post_detect(&) {
844	my ($cb) = @_;	984	my ($cb) = @_;
…		…
849	1	989	1
850	} else {	990	} else {
851	push @post_detect, $cb;	991	push @post_detect, $cb;
852		992
853	defined wantarray	993	defined wantarray
854	? bless \$cb, "AnyEvent::Util::PostDetect"	994	? bless \$cb, "AnyEvent::Util::postdetect"
855	: ()	995	: ()
856	}	996	}
857	}	997	}
858		998
859	sub AnyEvent::Util::PostDetect::DESTROY {	999	sub AnyEvent::Util::postdetect::DESTROY {
860	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1000	@post_detect = grep $_ != ${$_[0]}, @post_detect;
861	}	1001	}
862		1002
863	sub detect() {	1003	sub detect() {
864	unless ($MODEL) {	1004	unless ($MODEL) {
…		…
901	last;	1041	last;
902	}	1042	}
903	}	1043	}
904		1044
905	$MODEL	1045	$MODEL
906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1046	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
907	}	1047	}
908	}	1048	}
909		1049
		1050	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1051
910	unshift @ISA, $MODEL;	1052	unshift @ISA, $MODEL;
911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1053
		1054	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
912		1055
913	(shift @post_detect)->() while @post_detect;	1056	(shift @post_detect)->() while @post_detect;
914	}	1057	}
915		1058
916	$MODEL	1059	$MODEL
…		…
926		1069
927	my $class = shift;	1070	my $class = shift;
928	$class->$func (@_);	1071	$class->$func (@_);
929	}	1072	}
930		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
931	package AnyEvent::Base;	1093	package AnyEvent::Base;
932		1094
933	# default implementation for now and time	1095	# default implementations for many methods
934		1096
935	use Time::HiRes ();	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	}
936		1105
937	sub time { Time::HiRes::time }	1106	sub time { _time }
938	sub now { Time::HiRes::time }	1107	sub now { _time }
		1108	sub now_update { }
939		1109
940	# default implementation for ->condvar	1110	# default implementation for ->condvar
941		1111
942	sub condvar {	1112	sub condvar {
943	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1113	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
944	}	1114	}
945		1115
946	# default implementation for ->signal	1116	# default implementation for ->signal
947		1117
948	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	}
949		1130
950	sub signal {	1131	sub signal {
951	my (undef, %arg) = @_;	1132	my (undef, %arg) = @_;
952		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
953	my $signal = uc $arg{signal}	1159	my $signal = uc $arg{signal}
954	or Carp::croak "required option 'signal' is missing";	1160	or Carp::croak "required option 'signal' is missing";
955		1161
956	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1162	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
957	$SIG{$signal} \|\|= sub {	1163	$SIG{$signal} \|\|= sub {
958	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1164	local $!;
		1165	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1166	undef $SIG_EV{$signal};
959	};	1167	};
960		1168
961	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1169	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
962	}	1170	}
963		1171
964	sub AnyEvent::Base::Signal::DESTROY {	1172	sub AnyEvent::Base::signal::DESTROY {
965	my ($signal, $cb) = @{$_[0]};	1173	my ($signal, $cb) = @{$_[0]};
966		1174
967	delete $SIG_CB{$signal}{$cb};	1175	delete $SIG_CB{$signal}{$cb};
968		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.
969	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1180	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
970	}	1181	}
971		1182
972	# default implementation for ->child	1183	# default implementation for ->child
973		1184
974	our %PID_CB;	1185	our %PID_CB;
975	our $CHLD_W;	1186	our $CHLD_W;
976	our $CHLD_DELAY_W;	1187	our $CHLD_DELAY_W;
977	our $PID_IDLE;
978	our $WNOHANG;	1188	our $WNOHANG;
979		1189
980	sub _child_wait {	1190	sub _sigchld {
981	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1191	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
982	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),	1192	$_->($pid, $?) for (values %{ $PID_CB{$pid} \|\| {} }),
983	(values %{ $PID_CB{0} \|\| {} });	1193	(values %{ $PID_CB{0} \|\| {} });
984	}	1194	}
985
986	undef $PID_IDLE;
987	}
988
989	sub _sigchld {
990	# make sure we deliver these changes "synchronous" with the event loop.
991	$CHLD_DELAY_W \|\|= AnyEvent->timer (after => 0, cb => sub {
992	undef $CHLD_DELAY_W;
993	&_child_wait;
994	});
995	}	1195	}
996		1196
997	sub child {	1197	sub child {
998	my (undef, %arg) = @_;	1198	my (undef, %arg) = @_;
999		1199
1000	defined (my $pid = $arg{pid} + 0)	1200	defined (my $pid = $arg{pid} + 0)
1001	or Carp::croak "required option 'pid' is missing";	1201	or Carp::croak "required option 'pid' is missing";
1002		1202
1003	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1203	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1004		1204
1005	unless ($WNOHANG) {
1006	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;	1205	$WNOHANG \|\|= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } \|\| 1;
1007	}
1008		1206
1009	unless ($CHLD_W) {	1207	unless ($CHLD_W) {
1010	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1208	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1011	# 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
1012	&_sigchld;	1210	&_sigchld;
1013	}	1211	}
1014		1212
1015	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1213	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1016	}	1214	}
1017		1215
1018	sub AnyEvent::Base::Child::DESTROY {	1216	sub AnyEvent::Base::child::DESTROY {
1019	my ($pid, $cb) = @{$_[0]};	1217	my ($pid, $cb) = @{$_[0]};
1020		1218
1021	delete $PID_CB{$pid}{$cb};	1219	delete $PID_CB{$pid}{$cb};
1022	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1220	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1023		1221
1024	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]};
1025	}	1259	}
1026		1260
1027	package AnyEvent::CondVar;	1261	package AnyEvent::CondVar;
1028		1262
1029	our @ISA = AnyEvent::CondVar::Base::;	1263	our @ISA = AnyEvent::CondVar::Base::;
…		…
1081	}	1315	}
1082		1316
1083	# undocumented/compatibility with pre-3.4	1317	# undocumented/compatibility with pre-3.4
1084	*broadcast = \&send;	1318	*broadcast = \&send;
1085	*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
1086		1426
1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1427	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1088		1428
1089	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
1090	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
…		…
1124		1464
1125	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
1126	condition variables: code blocking while waiting for a condition will	1466	condition variables: code blocking while waiting for a condition will
1127	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
1128	not be done in an interactive application, so it makes sense.	1468	not be done in an interactive application, so it makes sense.
1129
1130	=head1 ENVIRONMENT VARIABLES
1131
1132	The following environment variables are used by this module:
1133
1134	=over 4
1135
1136	=item C<PERL_ANYEVENT_VERBOSE>
1137
1138	By default, AnyEvent will be completely silent except in fatal
1139	conditions. You can set this environment variable to make AnyEvent more
1140	talkative.
1141
1142	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1143	conditions, such as not being able to load the event model specified by
1144	C<PERL_ANYEVENT_MODEL>.
1145
1146	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1147	model it chooses.
1148
1149	=item C<PERL_ANYEVENT_MODEL>
1150
1151	This can be used to specify the event model to be used by AnyEvent, before
1152	auto detection and -probing kicks in. It must be a string consisting
1153	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1154	and the resulting module name is loaded and if the load was successful,
1155	used as event model. If it fails to load AnyEvent will proceed with
1156	auto detection and -probing.
1157
1158	This functionality might change in future versions.
1159
1160	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1161	could start your program like this:
1162
1163	PERL_ANYEVENT_MODEL=Perl perl ...
1164
1165	=item C<PERL_ANYEVENT_PROTOCOLS>
1166
1167	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1168	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1169	of auto probing).
1170
1171	Must be set to a comma-separated list of protocols or address families,
1172	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1173	used, and preference will be given to protocols mentioned earlier in the
1174	list.
1175
1176	This variable can effectively be used for denial-of-service attacks
1177	against local programs (e.g. when setuid), although the impact is likely
1178	small, as the program has to handle connection errors already-
1179
1180	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1181	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1182	- only support IPv4, never try to resolve or contact IPv6
1183	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1184	IPv6, but prefer IPv6 over IPv4.
1185
1186	=item C<PERL_ANYEVENT_EDNS0>
1187
1188	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1189	for DNS. This extension is generally useful to reduce DNS traffic, but
1190	some (broken) firewalls drop such DNS packets, which is why it is off by
1191	default.
1192
1193	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1194	EDNS0 in its DNS requests.
1195
1196	=item C<PERL_ANYEVENT_MAX_FORKS>
1197
1198	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1199	will create in parallel.
1200
1201	=back
1202		1469
1203	=head1 EXAMPLE PROGRAM	1470	=head1 EXAMPLE PROGRAM
1204		1471
1205	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
1206	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
…		…
1400	watcher.	1667	watcher.
1401		1668
1402	=head3 Results	1669	=head3 Results
1403		1670
1404	name watchers bytes create invoke destroy comment	1671	name watchers bytes create invoke destroy comment
1405	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
1406	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
1407	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
1408	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
1409	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
1410	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
1411	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
1412	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
1413	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
1414	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
1415		1682
1416	=head3 Discussion	1683	=head3 Discussion
1417		1684
1418	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
1419	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)
…		…
1621	watchers, as the management overhead dominates.	1888	watchers, as the management overhead dominates.
1622		1889
1623	=back	1890	=back
1624		1891
1625		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
1626	=head1 FORK	1929	=head1 FORK
1627		1930
1628	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
1629	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>
1630	calls. Only L<EV> is fully fork-aware.	1933	calls. Only L<EV> is fully fork-aware.
…		…
1643	specified in the variable.	1946	specified in the variable.
1644		1947
1645	You can make AnyEvent completely ignore this variable by deleting it	1948	You can make AnyEvent completely ignore this variable by deleting it
1646	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:
1647		1950
1648	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1951	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1649		1952
1650	use AnyEvent;	1953	use AnyEvent;
1651		1954
1652	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1955	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1653	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
1654	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).
1655		1968
1656		1969
1657	=head1 SEE ALSO	1970	=head1 SEE ALSO
1658		1971
1659	Utility functions: L<AnyEvent::Util>.	1972	Utility functions: L<AnyEvent::Util>.
…		…
1676	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>.
1677		1990
1678		1991
1679	=head1 AUTHOR	1992	=head1 AUTHOR
1680		1993
1681	Marc Lehmann <schmorp@schmorp.de>	1994	Marc Lehmann <schmorp@schmorp.de>
1682	http://home.schmorp.de/	1995	http://home.schmorp.de/
1683		1996
1684	=cut	1997	=cut
1685		1998
1686	1	1999	1
1687		2000

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs. Revision 1.213 by root, Sat Jun 20 07:14:35 2009 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.143 by root, Wed May 28 23:57:38 2008 UTC vs.
Revision 1.213 by root, Sat Jun 20 07:14:35 2009 UTC