[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 1.207 by root, Thu Apr 23 22:44:30 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, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
		11	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r\|w", cb => sub {	12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		13
		14	# one-shot or repeating timers
		15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		17
		18	print AnyEvent->now; # prints current event loop time
		19	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		20
		21	# POSIX signal
		22	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		23
		24	# child process exit
		25	my $w = AnyEvent->child (pid => $pid, cb => sub {
		26	my ($pid, $status) = @_;
12	...	27	...
13	});	28	});
14		29
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	30	# called when event loop idle (if applicable)
16	...	31	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		32
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	33	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	34	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	35	$w->recv; # enters "main loop" till $condvar gets ->send
		36	# use a condvar in callback mode:
		37	$w->cb (sub { $_[0]->recv });
		38
		39	=head1 INTRODUCTION/TUTORIAL
		40
		41	This manpage is mainly a reference manual. If you are interested
		42	in a tutorial or some gentle introduction, have a look at the
		43	L<AnyEvent::Intro> manpage.
22		44
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		46
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	47	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	48	nowadays. So what is different about AnyEvent?
27		49
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	50	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	51	policy> and AnyEvent is I<small and efficient>.
30		52
31	First and foremost, I<AnyEvent is not an event model> itself, it only	53	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	54	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,	55	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,	56	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	57	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	58	cannot change this, but it can hide the differences between those event
		59	loops.
37		60
38	The goal of AnyEvent is to offer module authors the ability to do event	61	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	62	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	63	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	64	module users into the same thing by forcing them to use the same event
42	model you use.	65	model you use.
43		66
44	For modules like POE or IO::Async (which is a total misnomer as it is	67	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	68	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	69	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	70	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	71	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.	72	module are I<also> forced to use the same event loop you use.
50		73
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	74	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	75	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	76	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,	77	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	78	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	79	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	80	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).	81	to AnyEvent, too, so it is future-proof).
59		82
60	In addition to being free of having to use I<the one and only true event	83	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	84	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	85	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	86	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	144	These watchers are normal Perl objects with normal Perl lifetime. After
122	creating a watcher it will immediately "watch" for events and invoke the	145	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	146	callback when the event occurs (of course, only when the event model
124	is in control).	147	is in control).
125		148
		149	Note that B<callbacks must not permanently change global variables>
		150	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		151	callbacks must not C<die> >>. The former is good programming practise in
		152	Perl and the latter stems from the fact that exception handling differs
		153	widely between event loops.
		154
126	To disable the watcher you have to destroy it (e.g. by setting the	155	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	156	variable you store it in to C<undef> or otherwise deleting all references
128	to it).	157	to it).
129		158
130	All watchers are created by calling a method on the C<AnyEvent> class.	159	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
132	Many watchers either are used with "recursion" (repeating timers for	161	Many watchers either are used with "recursion" (repeating timers for
133	example), or need to refer to their watcher object in other ways.	162	example), or need to refer to their watcher object in other ways.
134		163
135	An any way to achieve that is this pattern:	164	An any way to achieve that is this pattern:
136		165
137	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	166	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
138	# you can use $w here, for example to undef it	167	# you can use $w here, for example to undef it
139	undef $w;	168	undef $w;
140	});	169	});
141		170
142	Note that C<my $w; $w => combination. This is necessary because in Perl,	171	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	172	my variables are only visible after the statement in which they are
144	declared.	173	declared.
145		174
146	=head2 I/O WATCHERS	175	=head2 I/O WATCHERS
147		176
148	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
149	with the following mandatory key-value pairs as arguments:	178	with the following mandatory key-value pairs as arguments:
150		179
151	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		181	for events (AnyEvent might or might not keep a reference to this file
		182	handle). Note that only file handles pointing to things for which
		183	non-blocking operation makes sense are allowed. This includes sockets,
		184	most character devices, pipes, fifos and so on, but not for example files
		185	or block devices.
		186
152	for events. C<poll> must be a string that is either C<r> or C<w>,	187	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,	188	watcher waiting for "r"eadable or "w"ritable events, respectively.
		189
154	respectively. C<cb> is the callback to invoke each time the file handle	190	C<cb> is the callback to invoke each time the file handle becomes ready.
155	becomes ready.
156		191
157	Although the callback might get passed parameters, their value and	192	Although the callback might get passed parameters, their value and
158	presence is undefined and you cannot rely on them. Portable AnyEvent	193	presence is undefined and you cannot rely on them. Portable AnyEvent
159	callbacks cannot use arguments passed to I/O watcher callbacks.	194	callbacks cannot use arguments passed to I/O watcher callbacks.
160		195
…		…
164		199
165	Some event loops issue spurious readyness notifications, so you should	200	Some event loops issue spurious readyness notifications, so you should
166	always use non-blocking calls when reading/writing from/to your file	201	always use non-blocking calls when reading/writing from/to your file
167	handles.	202	handles.
168		203
169	Example:
170
171	# wait for readability of STDIN, then read a line and disable the watcher	204	Example: wait for readability of STDIN, then read a line and disable the
		205	watcher.
		206
172	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	207	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
173	chomp (my $input = <STDIN>);	208	chomp (my $input = <STDIN>);
174	warn "read: $input\n";	209	warn "read: $input\n";
175	undef $w;	210	undef $w;
176	});	211	});
…		…
186		221
187	Although the callback might get passed parameters, their value and	222	Although the callback might get passed parameters, their value and
188	presence is undefined and you cannot rely on them. Portable AnyEvent	223	presence is undefined and you cannot rely on them. Portable AnyEvent
189	callbacks cannot use arguments passed to time watcher callbacks.	224	callbacks cannot use arguments passed to time watcher callbacks.
190		225
191	The timer callback will be invoked at most once: if you want a repeating	226	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	227	parameter, C<interval>, as a strictly positive number (> 0), then the
193	and Glib).	228	callback will be invoked regularly at that interval (in fractional
		229	seconds) after the first invocation. If C<interval> is specified with a
		230	false value, then it is treated as if it were missing.
194		231
195	Example:	232	The callback will be rescheduled before invoking the callback, but no
		233	attempt is done to avoid timer drift in most backends, so the interval is
		234	only approximate.
196		235
197	# fire an event after 7.7 seconds	236	Example: fire an event after 7.7 seconds.
		237
198	my $w = AnyEvent->timer (after => 7.7, cb => sub {	238	my $w = AnyEvent->timer (after => 7.7, cb => sub {
199	warn "timeout\n";	239	warn "timeout\n";
200	});	240	});
201		241
202	# to cancel the timer:	242	# to cancel the timer:
203	undef $w;	243	undef $w;
204		244
205	Example 2:
206
207	# fire an event after 0.5 seconds, then roughly every second	245	Example 2: fire an event after 0.5 seconds, then roughly every second.
208	my $w;
209		246
210	my $cb = sub {
211	# cancel the old timer while creating a new one
212	$w = AnyEvent->timer (after => 1, cb => $cb);	247	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		248	warn "timeout\n";
213	};	249	};
214
215	# start the "loop" by creating the first watcher
216	$w = AnyEvent->timer (after => 0.5, cb => $cb);
217		250
218	=head3 TIMING ISSUES	251	=head3 TIMING ISSUES
219		252
220	There are two ways to handle timers: based on real time (relative, "fire	253	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	254	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
243		276
244	This returns the "current wallclock time" as a fractional number of	277	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>	278	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).	279	return, and the result is guaranteed to be compatible with those).
247		280
248	It progresses independently of any event loop processing.	281	It progresses independently of any event loop processing, i.e. each call
249		282	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		283
253	=item AnyEvent->now	284	=item AnyEvent->now
254		285
255	This also returns the "current wallclock time", but unlike C<time>, above,	286	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	287	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	288	the event loop (most return the same time as C<time>, above). This is the
258	time that AnyEvent timers get scheduled against.	289	time that AnyEvent's timers get scheduled against.
		290
		291	I<In almost all cases (in all cases if you don't care), this is the
		292	function to call when you want to know the current time.>
		293
		294	This function is also often faster then C<< AnyEvent->time >>, and
		295	thus the preferred method if you want some timestamp (for example,
		296	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		297
		298	The rest of this section is only of relevance if you try to be very exact
		299	with your timing, you can skip it without bad conscience.
259		300
260	For a practical example of when these times differ, consider L<Event::Lib>	301	For a practical example of when these times differ, consider L<Event::Lib>
261	and L<EV> and the following set-up:	302	and L<EV> and the following set-up:
262		303
263	The event loop is running and has just invoked one of your callback at	304	The event loop is running and has just invoked one of your callback at
…		…
268		309
269	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will	310	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	311	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>).	312	be scheduled to fire at time=504 (C<501> + C<3>).
272		313
273	With L<EV>m C<< AnyEvent->time >> returns C<501> (as that is the current	314	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	315	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	316	last event processing phase started. With L<EV>, your timer gets scheduled
276	to run at time=503 (C<500> + C<3>).	317	to run at time=503 (C<500> + C<3>).
277		318
278	In one sense, L<Event::Lib> is more exact, as it uses the current time	319	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	320	regardless of any delays introduced by event processing. However, most
280	callbacks do not expect large delays in processing, so this causes a	321	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).	322	higher drift (and a lot more system calls to get the current time).
282		323
283	In another sense, L<EV> is more exact, as your timer will be scheduled at	324	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.	325	the same time, regardless of how long event processing actually took.
285		326
286	In either case, if you care (and in most cases, you don't), then you	327	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	328	can get whatever behaviour you want with any event loop, by taking the
288	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	329	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
289	account.	330	account.
290		331
		332	=item AnyEvent->now_update
		333
		334	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		335	the current time for each loop iteration (see the discussion of L<<
		336	AnyEvent->now >>, above).
		337
		338	When a callback runs for a long time (or when the process sleeps), then
		339	this "current" time will differ substantially from the real time, which
		340	might affect timers and time-outs.
		341
		342	When this is the case, you can call this method, which will update the
		343	event loop's idea of "current time".
		344
		345	Note that updating the time I<might> cause some events to be handled.
		346
291	=back	347	=back
292		348
293	=head2 SIGNAL WATCHERS	349	=head2 SIGNAL WATCHERS
294		350
295	You can watch for signals using a signal watcher, C<signal> is the signal	351	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	352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
297	be invoked whenever a signal occurs.	353	callback to be invoked whenever a signal occurs.
298		354
299	Although the callback might get passed parameters, their value and	355	Although the callback might get passed parameters, their value and
300	presence is undefined and you cannot rely on them. Portable AnyEvent	356	presence is undefined and you cannot rely on them. Portable AnyEvent
301	callbacks cannot use arguments passed to signal watcher callbacks.	357	callbacks cannot use arguments passed to signal watcher callbacks.
302		358
…		…
318	=head2 CHILD PROCESS WATCHERS	374	=head2 CHILD PROCESS WATCHERS
319		375
320	You can also watch on a child process exit and catch its exit status.	376	You can also watch on a child process exit and catch its exit status.
321		377
322	The child process is specified by the C<pid> argument (if set to C<0>, it	378	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	379	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	380	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	381	any trace events (stopped/continued).
326	and exit status (as returned by waitpid), so unlike other watcher types,	382
327	you I<can> rely on child watcher callback arguments.	383	The callback will be called with the pid and exit status (as returned by
		384	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		385	callback arguments.
		386
		387	This watcher type works by installing a signal handler for C<SIGCHLD>,
		388	and since it cannot be shared, nothing else should use SIGCHLD or reap
		389	random child processes (waiting for specific child processes, e.g. inside
		390	C<system>, is just fine).
328		391
329	There is a slight catch to child watchers, however: you usually start them	392	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	393	I<after> the child process was created, and this means the process could
331	have exited already (and no SIGCHLD will be sent anymore).	394	have exited already (and no SIGCHLD will be sent anymore).
332		395
…		…
338	AnyEvent program, you I<have> to create at least one watcher before you	401	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>).	402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
340		403
341	Example: fork a process and wait for it	404	Example: fork a process and wait for it
342		405
343	my $done = AnyEvent->condvar;	406	my $done = AnyEvent->condvar;
344		407
345	my $pid = fork or exit 5;	408	my $pid = fork or exit 5;
346		409
347	my $w = AnyEvent->child (	410	my $w = AnyEvent->child (
348	pid => $pid,	411	pid => $pid,
349	cb => sub {	412	cb => sub {
350	my ($pid, $status) = @_;	413	my ($pid, $status) = @_;
351	warn "pid $pid exited with status $status";	414	warn "pid $pid exited with status $status";
352	$done->send;	415	$done->send;
353	},	416	},
354	);	417	);
355		418
356	# do something else, then wait for process exit	419	# do something else, then wait for process exit
357	$done->recv;	420	$done->recv;
		421
		422	=head2 IDLE WATCHERS
		423
		424	Sometimes there is a need to do something, but it is not so important
		425	to do it instantly, but only when there is nothing better to do. This
		426	"nothing better to do" is usually defined to be "no other events need
		427	attention by the event loop".
		428
		429	Idle watchers ideally get invoked when the event loop has nothing
		430	better to do, just before it would block the process to wait for new
		431	events. Instead of blocking, the idle watcher is invoked.
		432
		433	Most event loops unfortunately do not really support idle watchers (only
		434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		435	will simply call the callback "from time to time".
		436
		437	Example: read lines from STDIN, but only process them when the
		438	program is otherwise idle:
		439
		440	my @lines; # read data
		441	my $idle_w;
		442	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		443	push @lines, scalar <STDIN>;
		444
		445	# start an idle watcher, if not already done
		446	$idle_w \|\|= AnyEvent->idle (cb => sub {
		447	# handle only one line, when there are lines left
		448	if (my $line = shift @lines) {
		449	print "handled when idle: $line";
		450	} else {
		451	# otherwise disable the idle watcher again
		452	undef $idle_w;
		453	}
		454	});
		455	});
358		456
359	=head2 CONDITION VARIABLES	457	=head2 CONDITION VARIABLES
360		458
361	If you are familiar with some event loops you will know that all of them	459	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	460	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	466	The instrument to do that is called a "condition variable", so called
369	because they represent a condition that must become true.	467	because they represent a condition that must become true.
370		468
371	Condition variables can be created by calling the C<< AnyEvent->condvar	469	Condition variables can be created by calling the C<< AnyEvent->condvar
372	>> method, usually without arguments. The only argument pair allowed is	470	>> method, usually without arguments. The only argument pair allowed is
		471
373	C<cb>, which specifies a callback to be called when the condition variable	472	C<cb>, which specifies a callback to be called when the condition variable
374	becomes true.	473	becomes true, with the condition variable as the first argument (but not
		474	the results).
375		475
376	After creation, the condition variable is "false" until it becomes "true"	476	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	477	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<<	478	were a callback, read about the caveats in the description for the C<<
379	->send >> method).	479	->send >> method).
…		…
435		535
436	my $done = AnyEvent->condvar;	536	my $done = AnyEvent->condvar;
437	my $delay = AnyEvent->timer (after => 5, cb => $done);	537	my $delay = AnyEvent->timer (after => 5, cb => $done);
438	$done->recv;	538	$done->recv;
439		539
		540	Example: Imagine an API that returns a condvar and doesn't support
		541	callbacks. This is how you make a synchronous call, for example from
		542	the main program:
		543
		544	use AnyEvent::CouchDB;
		545
		546	...
		547
		548	my @info = $couchdb->info->recv;
		549
		550	And this is how you would just ste a callback to be called whenever the
		551	results are available:
		552
		553	$couchdb->info->cb (sub {
		554	my @info = $_[0]->recv;
		555	});
		556
440	=head3 METHODS FOR PRODUCERS	557	=head3 METHODS FOR PRODUCERS
441		558
442	These methods should only be used by the producing side, i.e. the	559	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	560	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	561	the producer side which creates the condvar in most cases, but it isn't
…		…
577	=item $bool = $cv->ready	694	=item $bool = $cv->ready
578		695
579	Returns true when the condition is "true", i.e. whether C<send> or	696	Returns true when the condition is "true", i.e. whether C<send> or
580	C<croak> have been called.	697	C<croak> have been called.
581		698
582	=item $cb = $cv->cb ([new callback])	699	=item $cb = $cv->cb ($cb->($cv))
583		700
584	This is a mutator function that returns the callback set and optionally	701	This is a mutator function that returns the callback set and optionally
585	replaces it before doing so.	702	replaces it before doing so.
586		703
587	The callback will be called when the condition becomes "true", i.e. when	704	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	705	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.	706	variable itself. Calling C<recv> inside the callback or at any later time
		707	is guaranteed not to block.
590		708
591	=back	709	=back
592		710
593	=head1 GLOBAL VARIABLES AND FUNCTIONS	711	=head1 GLOBAL VARIABLES AND FUNCTIONS
594		712
…		…
723	=item L<AnyEvent::Util>	841	=item L<AnyEvent::Util>
724		842
725	Contains various utility functions that replace often-used but blocking	843	Contains various utility functions that replace often-used but blocking
726	functions such as C<inet_aton> by event-/callback-based versions.	844	functions such as C<inet_aton> by event-/callback-based versions.
727		845
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>	846	=item L<AnyEvent::Socket>
733		847
734	Provides various utility functions for (internet protocol) sockets,	848	Provides various utility functions for (internet protocol) sockets,
735	addresses and name resolution. Also functions to create non-blocking tcp	849	addresses and name resolution. Also functions to create non-blocking tcp
736	connections or tcp servers, with IPv6 and SRV record support and more.	850	connections or tcp servers, with IPv6 and SRV record support and more.
737		851
		852	=item L<AnyEvent::Handle>
		853
		854	Provide read and write buffers, manages watchers for reads and writes,
		855	supports raw and formatted I/O, I/O queued and fully transparent and
		856	non-blocking SSL/TLS.
		857
738	=item L<AnyEvent::DNS>	858	=item L<AnyEvent::DNS>
739		859
740	Provides rich asynchronous DNS resolver capabilities.	860	Provides rich asynchronous DNS resolver capabilities.
741		861
		862	=item L<AnyEvent::HTTP>
		863
		864	A simple-to-use HTTP library that is capable of making a lot of concurrent
		865	HTTP requests.
		866
742	=item L<AnyEvent::HTTPD>	867	=item L<AnyEvent::HTTPD>
743		868
744	Provides a simple web application server framework.	869	Provides a simple web application server framework.
745		870
746	=item L<AnyEvent::FastPing>	871	=item L<AnyEvent::FastPing>
747		872
748	The fastest ping in the west.	873	The fastest ping in the west.
749		874
		875	=item L<AnyEvent::DBI>
		876
		877	Executes L<DBI> requests asynchronously in a proxy process.
		878
		879	=item L<AnyEvent::AIO>
		880
		881	Truly asynchronous I/O, should be in the toolbox of every event
		882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		883	together.
		884
		885	=item L<AnyEvent::BDB>
		886
		887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		888	L<BDB> and AnyEvent together.
		889
		890	=item L<AnyEvent::GPSD>
		891
		892	A non-blocking interface to gpsd, a daemon delivering GPS information.
		893
		894	=item L<AnyEvent::IGS>
		895
		896	A non-blocking interface to the Internet Go Server protocol (used by
		897	L<App::IGS>).
		898
750	=item L<Net::IRC3>	899	=item L<AnyEvent::IRC>
751		900
752	AnyEvent based IRC client module family.	901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
753		902
754	=item L<Net::XMPP2>	903	=item L<Net::XMPP2>
755		904
756	AnyEvent based XMPP (Jabber protocol) module family.	905	AnyEvent based XMPP (Jabber protocol) module family.
757		906
…		…
766		915
767	=item L<Coro>	916	=item L<Coro>
768		917
769	Has special support for AnyEvent via L<Coro::AnyEvent>.	918	Has special support for AnyEvent via L<Coro::AnyEvent>.
770		919
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>	920	=item L<IO::Lambda>
783		921
784	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
785		923
786	=back	924	=back
…		…
788	=cut	926	=cut
789		927
790	package AnyEvent;	928	package AnyEvent;
791		929
792	no warnings;	930	no warnings;
793	use strict;	931	use strict qw(vars subs);
794		932
795	use Carp;	933	use Carp;
796		934
797	our $VERSION = '4.05';	935	our $VERSION = 4.352;
798	our $MODEL;	936	our $MODEL;
799		937
800	our $AUTOLOAD;	938	our $AUTOLOAD;
801	our @ISA;	939	our @ISA;
802		940
…		…
834	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
835	[Wx:: => AnyEvent::Impl::POE::],	973	[Wx:: => AnyEvent::Impl::POE::],
836	[Prima:: => AnyEvent::Impl::POE::],	974	[Prima:: => AnyEvent::Impl::POE::],
837	);	975	);
838		976
839	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	977	our %method = map +($_ => 1),
		978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
840		979
841	our @post_detect;	980	our @post_detect;
842		981
843	sub post_detect(&) {	982	sub post_detect(&) {
844	my ($cb) = @_;	983	my ($cb) = @_;
…		…
849	1	988	1
850	} else {	989	} else {
851	push @post_detect, $cb;	990	push @post_detect, $cb;
852		991
853	defined wantarray	992	defined wantarray
854	? bless \$cb, "AnyEvent::Util::PostDetect"	993	? bless \$cb, "AnyEvent::Util::postdetect"
855	: ()	994	: ()
856	}	995	}
857	}	996	}
858		997
859	sub AnyEvent::Util::PostDetect::DESTROY {	998	sub AnyEvent::Util::postdetect::DESTROY {
860	@post_detect = grep $_ != ${$_[0]}, @post_detect;	999	@post_detect = grep $_ != ${$_[0]}, @post_detect;
861	}	1000	}
862		1001
863	sub detect() {	1002	sub detect() {
864	unless ($MODEL) {	1003	unless ($MODEL) {
…		…
901	last;	1040	last;
902	}	1041	}
903	}	1042	}
904		1043
905	$MODEL	1044	$MODEL
906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
907	}	1046	}
908	}	1047	}
909		1048
		1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1050
910	unshift @ISA, $MODEL;	1051	unshift @ISA, $MODEL;
911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1052
		1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
912		1054
913	(shift @post_detect)->() while @post_detect;	1055	(shift @post_detect)->() while @post_detect;
914	}	1056	}
915		1057
916	$MODEL	1058	$MODEL
…		…
926		1068
927	my $class = shift;	1069	my $class = shift;
928	$class->$func (@_);	1070	$class->$func (@_);
929	}	1071	}
930		1072
		1073	# utility function to dup a filehandle. this is used by many backends
		1074	# to support binding more than one watcher per filehandle (they usually
		1075	# allow only one watcher per fd, so we dup it to get a different one).
		1076	sub _dupfh($$$$) {
		1077	my ($poll, $fh, $r, $w) = @_;
		1078
		1079	# cygwin requires the fh mode to be matching, unix doesn't
		1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1081	: $poll eq "w" ? ($w, ">")
		1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1083
		1084	open my $fh2, "$mode&" . fileno $fh
		1085	or die "cannot dup() filehandle: $!,";
		1086
		1087	# we assume CLOEXEC is already set by perl in all important cases
		1088
		1089	($fh2, $rw)
		1090	}
		1091
931	package AnyEvent::Base;	1092	package AnyEvent::Base;
932		1093
933	# default implementation for now and time	1094	# default implementations for many methods
934		1095
935	use Time::HiRes ();	1096	BEGIN {
		1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1098	*_time = \&Time::HiRes::time;
		1099	# if (eval "use POSIX (); (POSIX::times())...
		1100	} else {
		1101	*_time = sub { time }; # epic fail
		1102	}
		1103	}
936		1104
937	sub time { Time::HiRes::time }	1105	sub time { _time }
938	sub now { Time::HiRes::time }	1106	sub now { _time }
		1107	sub now_update { }
939		1108
940	# default implementation for ->condvar	1109	# default implementation for ->condvar
941		1110
942	sub condvar {	1111	sub condvar {
943	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
944	}	1113	}
945		1114
946	# default implementation for ->signal	1115	# default implementation for ->signal
947		1116
948	our %SIG_CB;	1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1118
		1119	sub _signal_exec {
		1120	sysread $SIGPIPE_R, my $dummy, 4;
		1121
		1122	while (%SIG_EV) {
		1123	for (keys %SIG_EV) {
		1124	delete $SIG_EV{$_};
		1125	$_->() for values %{ $SIG_CB{$_} \|\| {} };
		1126	}
		1127	}
		1128	}
949		1129
950	sub signal {	1130	sub signal {
951	my (undef, %arg) = @_;	1131	my (undef, %arg) = @_;
952		1132
		1133	unless ($SIGPIPE_R) {
		1134	require Fcntl;
		1135
		1136	if (AnyEvent::WIN32) {
		1137	require AnyEvent::Util;
		1138
		1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1142	} else {
		1143	pipe $SIGPIPE_R, $SIGPIPE_W;
		1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1146	}
		1147
		1148	$SIGPIPE_R
		1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1150
		1151	# not strictly required, as $^F is normally 2, but let's make sure...
		1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1154
		1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1156	}
		1157
953	my $signal = uc $arg{signal}	1158	my $signal = uc $arg{signal}
954	or Carp::croak "required option 'signal' is missing";	1159	or Carp::croak "required option 'signal' is missing";
955		1160
956	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
957	$SIG{$signal} \|\|= sub {	1162	$SIG{$signal} \|\|= sub {
958	$_->() for values %{ $SIG_CB{$signal} \|\| {} };	1163	local $!;
		1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1165	undef $SIG_EV{$signal};
959	};	1166	};
960		1167
961	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
962	}	1169	}
963		1170
964	sub AnyEvent::Base::Signal::DESTROY {	1171	sub AnyEvent::Base::signal::DESTROY {
965	my ($signal, $cb) = @{$_[0]};	1172	my ($signal, $cb) = @{$_[0]};
966		1173
967	delete $SIG_CB{$signal}{$cb};	1174	delete $SIG_CB{$signal}{$cb};
968		1175
969	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1176	delete $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
970	}	1177	}
971		1178
972	# default implementation for ->child	1179	# default implementation for ->child
973		1180
974	our %PID_CB;	1181	our %PID_CB;
…		…
1010	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1217	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1011	# child could be a zombie already, so make at least one round	1218	# child could be a zombie already, so make at least one round
1012	&_sigchld;	1219	&_sigchld;
1013	}	1220	}
1014		1221
1015	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1222	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1016	}	1223	}
1017		1224
1018	sub AnyEvent::Base::Child::DESTROY {	1225	sub AnyEvent::Base::child::DESTROY {
1019	my ($pid, $cb) = @{$_[0]};	1226	my ($pid, $cb) = @{$_[0]};
1020		1227
1021	delete $PID_CB{$pid}{$cb};	1228	delete $PID_CB{$pid}{$cb};
1022	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1229	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1023		1230
1024	undef $CHLD_W unless keys %PID_CB;	1231	undef $CHLD_W unless keys %PID_CB;
		1232	}
		1233
		1234	# idle emulation is done by simply using a timer, regardless
		1235	# of whether the proces sis idle or not, and not letting
		1236	# the callback use more than 50% of the time.
		1237	sub idle {
		1238	my (undef, %arg) = @_;
		1239
		1240	my ($cb, $w, $rcb) = $arg{cb};
		1241
		1242	$rcb = sub {
		1243	if ($cb) {
		1244	$w = _time;
		1245	&$cb;
		1246	$w = _time - $w;
		1247
		1248	# never use more then 50% of the time for the idle watcher,
		1249	# within some limits
		1250	$w = 0.0001 if $w < 0.0001;
		1251	$w = 5 if $w > 5;
		1252
		1253	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1254	} else {
		1255	# clean up...
		1256	undef $w;
		1257	undef $rcb;
		1258	}
		1259	};
		1260
		1261	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1262
		1263	bless \\$cb, "AnyEvent::Base::idle"
		1264	}
		1265
		1266	sub AnyEvent::Base::idle::DESTROY {
		1267	undef $${$_[0]};
1025	}	1268	}
1026		1269
1027	package AnyEvent::CondVar;	1270	package AnyEvent::CondVar;
1028		1271
1029	our @ISA = AnyEvent::CondVar::Base::;	1272	our @ISA = AnyEvent::CondVar::Base::;
…		…
1081	}	1324	}
1082		1325
1083	# undocumented/compatibility with pre-3.4	1326	# undocumented/compatibility with pre-3.4
1084	*broadcast = \&send;	1327	*broadcast = \&send;
1085	*wait = \&_wait;	1328	*wait = \&_wait;
		1329
		1330	=head1 ERROR AND EXCEPTION HANDLING
		1331
		1332	In general, AnyEvent does not do any error handling - it relies on the
		1333	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1334	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1335	checking of all AnyEvent methods, however, which is highly useful during
		1336	development.
		1337
		1338	As for exception handling (i.e. runtime errors and exceptions thrown while
		1339	executing a callback), this is not only highly event-loop specific, but
		1340	also not in any way wrapped by this module, as this is the job of the main
		1341	program.
		1342
		1343	The pure perl event loop simply re-throws the exception (usually
		1344	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1345	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1346	so on.
		1347
		1348	=head1 ENVIRONMENT VARIABLES
		1349
		1350	The following environment variables are used by this module or its
		1351	submodules:
		1352
		1353	=over 4
		1354
		1355	=item C<PERL_ANYEVENT_VERBOSE>
		1356
		1357	By default, AnyEvent will be completely silent except in fatal
		1358	conditions. You can set this environment variable to make AnyEvent more
		1359	talkative.
		1360
		1361	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1362	conditions, such as not being able to load the event model specified by
		1363	C<PERL_ANYEVENT_MODEL>.
		1364
		1365	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1366	model it chooses.
		1367
		1368	=item C<PERL_ANYEVENT_STRICT>
		1369
		1370	AnyEvent does not do much argument checking by default, as thorough
		1371	argument checking is very costly. Setting this variable to a true value
		1372	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1373	check the arguments passed to most method calls. If it finds any problems
		1374	it will croak.
		1375
		1376	In other words, enables "strict" mode.
		1377
		1378	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1379	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1380	developing programs can be very useful, however.
		1381
		1382	=item C<PERL_ANYEVENT_MODEL>
		1383
		1384	This can be used to specify the event model to be used by AnyEvent, before
		1385	auto detection and -probing kicks in. It must be a string consisting
		1386	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1387	and the resulting module name is loaded and if the load was successful,
		1388	used as event model. If it fails to load AnyEvent will proceed with
		1389	auto detection and -probing.
		1390
		1391	This functionality might change in future versions.
		1392
		1393	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1394	could start your program like this:
		1395
		1396	PERL_ANYEVENT_MODEL=Perl perl ...
		1397
		1398	=item C<PERL_ANYEVENT_PROTOCOLS>
		1399
		1400	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1401	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1402	of auto probing).
		1403
		1404	Must be set to a comma-separated list of protocols or address families,
		1405	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1406	used, and preference will be given to protocols mentioned earlier in the
		1407	list.
		1408
		1409	This variable can effectively be used for denial-of-service attacks
		1410	against local programs (e.g. when setuid), although the impact is likely
		1411	small, as the program has to handle conenction and other failures anyways.
		1412
		1413	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1414	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1415	- only support IPv4, never try to resolve or contact IPv6
		1416	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1417	IPv6, but prefer IPv6 over IPv4.
		1418
		1419	=item C<PERL_ANYEVENT_EDNS0>
		1420
		1421	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1422	for DNS. This extension is generally useful to reduce DNS traffic, but
		1423	some (broken) firewalls drop such DNS packets, which is why it is off by
		1424	default.
		1425
		1426	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1427	EDNS0 in its DNS requests.
		1428
		1429	=item C<PERL_ANYEVENT_MAX_FORKS>
		1430
		1431	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1432	will create in parallel.
		1433
		1434	=back
1086		1435
1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1436	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1088		1437
1089	This is an advanced topic that you do not normally need to use AnyEvent in	1438	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	1439	a module. This section is only of use to event loop authors who want to
…		…
1124		1473
1125	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1474	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1126	condition variables: code blocking while waiting for a condition will	1475	condition variables: code blocking while waiting for a condition will
1127	C<die>. This still works with most modules/usages, and blocking calls must	1476	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.	1477	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		1478
1203	=head1 EXAMPLE PROGRAM	1479	=head1 EXAMPLE PROGRAM
1204		1480
1205	The following program uses an I/O watcher to read data from STDIN, a timer	1481	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	1482	to display a message once per second, and a condition variable to quit the
…		…
1400	watcher.	1676	watcher.
1401		1677
1402	=head3 Results	1678	=head3 Results
1403		1679
1404	name watchers bytes create invoke destroy comment	1680	name watchers bytes create invoke destroy comment
1405	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1681	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	1682	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	1683	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	1684	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	1685	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	1686	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	1687	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	1688	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	1689	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	1690	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1415		1691
1416	=head3 Discussion	1692	=head3 Discussion
1417		1693
1418	The benchmark does I<not> measure scalability of the event loop very	1694	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)	1695	well. For example, a select-based event loop (such as the pure perl one)
…		…
1621	watchers, as the management overhead dominates.	1897	watchers, as the management overhead dominates.
1622		1898
1623	=back	1899	=back
1624		1900
1625		1901
		1902	=head1 SIGNALS
		1903
		1904	AnyEvent currently installs handlers for these signals:
		1905
		1906	=over 4
		1907
		1908	=item SIGCHLD
		1909
		1910	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1911	emulation for event loops that do not support them natively. Also, some
		1912	event loops install a similar handler.
		1913
		1914	=item SIGPIPE
		1915
		1916	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1917	when AnyEvent gets loaded.
		1918
		1919	The rationale for this is that AnyEvent users usually do not really depend
		1920	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1921	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1922	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1923	some random socket.
		1924
		1925	The rationale for installing a no-op handler as opposed to ignoring it is
		1926	that this way, the handler will be restored to defaults on exec.
		1927
		1928	Feel free to install your own handler, or reset it to defaults.
		1929
		1930	=back
		1931
		1932	=cut
		1933
		1934	$SIG{PIPE} = sub { }
		1935	unless defined $SIG{PIPE};
		1936
		1937
1626	=head1 FORK	1938	=head1 FORK
1627		1939
1628	Most event libraries are not fork-safe. The ones who are usually are	1940	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>	1941	because they rely on inefficient but fork-safe C<select> or C<poll>
1630	calls. Only L<EV> is fully fork-aware.	1942	calls. Only L<EV> is fully fork-aware.
…		…
1643	specified in the variable.	1955	specified in the variable.
1644		1956
1645	You can make AnyEvent completely ignore this variable by deleting it	1957	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:	1958	before the first watcher gets created, e.g. with a C<BEGIN> block:
1647		1959
1648	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1960	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1649		1961
1650	use AnyEvent;	1962	use AnyEvent;
1651		1963
1652	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1964	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	1965	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).	1966	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1967	$ENV{PERL_ANYEGENT_STRICT}.
		1968
		1969
		1970	=head1 BUGS
		1971
		1972	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1973	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1974	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1975	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1976	pronounced).
1655		1977
1656		1978
1657	=head1 SEE ALSO	1979	=head1 SEE ALSO
1658		1980
1659	Utility functions: L<AnyEvent::Util>.	1981	Utility functions: L<AnyEvent::Util>.
…		…
1676	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	1998	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1677		1999
1678		2000
1679	=head1 AUTHOR	2001	=head1 AUTHOR
1680		2002
1681	Marc Lehmann <schmorp@schmorp.de>	2003	Marc Lehmann <schmorp@schmorp.de>
1682	http://home.schmorp.de/	2004	http://home.schmorp.de/
1683		2005
1684	=cut	2006	=cut
1685		2007
1686	1	2008	1
1687		2009

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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 1.207 by root, Thu Apr 23 22:44:30 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 1.207 by root, Thu Apr 23 22:44:30 2009 UTC