ViewVC Help

View File | Revision Log | Show Annotations | Download File

/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 1.239 by root, Thu Jul 16 20:55:38 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> (or a naked 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
333	Not all event models handle this correctly (POE doesn't), but even for	397	Not all event models handle this correctly (neither POE nor IO::Async do,
		398	see their AnyEvent::Impl manpages for details), but even for event models
334	event models that I<do> handle this correctly, they usually need to be	399	that I<do> handle this correctly, they usually need to be loaded before
335	loaded before the process exits (i.e. before you fork in the first place).	400	the process exits (i.e. before you fork in the first place). AnyEvent's
		401	pure perl event loop handles all cases correctly regardless of when you
		402	start the watcher.
336		403
337	This means you cannot create a child watcher as the very first thing in an	404	This means you cannot create a child watcher as the very first
338	AnyEvent program, you I<have> to create at least one watcher before you	405	thing in an AnyEvent program, you I<have> to create at least one
339	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	406	watcher before you C<fork> the child (alternatively, you can call
		407	C<AnyEvent::detect>).
340		408
341	Example: fork a process and wait for it	409	Example: fork a process and wait for it
342		410
343	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
344		412
345	my $pid = fork or exit 5;	413	my $pid = fork or exit 5;
346		414
347	my $w = AnyEvent->child (	415	my $w = AnyEvent->child (
348	pid => $pid,	416	pid => $pid,
349	cb => sub {	417	cb => sub {
350	my ($pid, $status) = @_;	418	my ($pid, $status) = @_;
351	warn "pid $pid exited with status $status";	419	warn "pid $pid exited with status $status";
352	$done->send;	420	$done->send;
353	},	421	},
354	);	422	);
355		423
356	# do something else, then wait for process exit	424	# do something else, then wait for process exit
357	$done->recv;	425	$done->recv;
		426
		427	=head2 IDLE WATCHERS
		428
		429	Sometimes there is a need to do something, but it is not so important
		430	to do it instantly, but only when there is nothing better to do. This
		431	"nothing better to do" is usually defined to be "no other events need
		432	attention by the event loop".
		433
		434	Idle watchers ideally get invoked when the event loop has nothing
		435	better to do, just before it would block the process to wait for new
		436	events. Instead of blocking, the idle watcher is invoked.
		437
		438	Most event loops unfortunately do not really support idle watchers (only
		439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		440	will simply call the callback "from time to time".
		441
		442	Example: read lines from STDIN, but only process them when the
		443	program is otherwise idle:
		444
		445	my @lines; # read data
		446	my $idle_w;
		447	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		448	push @lines, scalar <STDIN>;
		449
		450	# start an idle watcher, if not already done
		451	$idle_w ||= AnyEvent->idle (cb => sub {
		452	# handle only one line, when there are lines left
		453	if (my $line = shift @lines) {
		454	print "handled when idle: $line";
		455	} else {
		456	# otherwise disable the idle watcher again
		457	undef $idle_w;
		458	}
		459	});
		460	});
358		461
359	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
360		463
361	If you are familiar with some event loops you will know that all of them	464	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	465	require you to run some blocking "loop", "run" or similar function that
363	will actively watch for new events and call your callbacks.	466	will actively watch for new events and call your callbacks.
364		467
365	AnyEvent is different, it expects somebody else to run the event loop and	468	AnyEvent is slightly different: it expects somebody else to run the event
366	will only block when necessary (usually when told by the user).	469	loop and will only block when necessary (usually when told by the user).
367		470
368	The instrument to do that is called a "condition variable", so called	471	The instrument to do that is called a "condition variable", so called
369	because they represent a condition that must become true.	472	because they represent a condition that must become true.
		473
		474	Now is probably a good time to look at the examples further below.
370		475
371	Condition variables can be created by calling the C<< AnyEvent->condvar	476	Condition variables can be created by calling the C<< AnyEvent->condvar
372	>> method, usually without arguments. The only argument pair allowed is	477	>> method, usually without arguments. The only argument pair allowed is
373	C<cb>, which specifies a callback to be called when the condition variable	478	C<cb>, which specifies a callback to be called when the condition variable
374	becomes true.	479	becomes true, with the condition variable as the first argument (but not
		480	the results).
375		481
376	After creation, the condition variable is "false" until it becomes "true"	482	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	483	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<<	484	were a callback, read about the caveats in the description for the C<<
379	->send >> method).	485	->send >> method).
…		…
425	after => 1,	531	after => 1,
426	cb => sub { $result_ready->send },	532	cb => sub { $result_ready->send },
427	);	533	);
428		534
429	# this "blocks" (while handling events) till the callback	535	# this "blocks" (while handling events) till the callback
430	# calls send	536	# calls -<send
431	$result_ready->recv;	537	$result_ready->recv;
432		538
433	Example: wait for a timer, but take advantage of the fact that	539	Example: wait for a timer, but take advantage of the fact that condition
434	condition variables are also code references.	540	variables are also callable directly.
435		541
436	my $done = AnyEvent->condvar;	542	my $done = AnyEvent->condvar;
437	my $delay = AnyEvent->timer (after => 5, cb => $done);	543	my $delay = AnyEvent->timer (after => 5, cb => $done);
438	$done->recv;	544	$done->recv;
		545
		546	Example: Imagine an API that returns a condvar and doesn't support
		547	callbacks. This is how you make a synchronous call, for example from
		548	the main program:
		549
		550	use AnyEvent::CouchDB;
		551
		552	...
		553
		554	my @info = $couchdb->info->recv;
		555
		556	And this is how you would just set a callback to be called whenever the
		557	results are available:
		558
		559	$couchdb->info->cb (sub {
		560	my @info = $_[0]->recv;
		561	});
439		562
440	=head3 METHODS FOR PRODUCERS	563	=head3 METHODS FOR PRODUCERS
441		564
442	These methods should only be used by the producing side, i.e. the	565	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	566	code/module that eventually sends the signal. Note that it is also
…		…
456	immediately from within send.	579	immediately from within send.
457		580
458	Any arguments passed to the C<send> call will be returned by all	581	Any arguments passed to the C<send> call will be returned by all
459	future C<< ->recv >> calls.	582	future C<< ->recv >> calls.
460		583
461	Condition variables are overloaded so one can call them directly	584	Condition variables are overloaded so one can call them directly (as if
462	(as a code reference). Calling them directly is the same as calling	585	they were a code reference). Calling them directly is the same as calling
463	C<send>. Note, however, that many C-based event loops do not handle	586	C<send>.
464	overloading, so as tempting as it may be, passing a condition variable
465	instead of a callback does not work. Both the pure perl and EV loops
466	support overloading, however, as well as all functions that use perl to
467	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
468	example).
469		587
470	=item $cv->croak ($error)	588	=item $cv->croak ($error)
471		589
472	Similar to send, but causes all call's to C<< ->recv >> to invoke	590	Similar to send, but causes all call's to C<< ->recv >> to invoke
473	C<Carp::croak> with the given error message/object/scalar.	591	C<Carp::croak> with the given error message/object/scalar.
474		592
475	This can be used to signal any errors to the condition variable	593	This can be used to signal any errors to the condition variable
476	user/consumer.	594	user/consumer. Doing it this way instead of calling C<croak> directly
		595	delays the error detetcion, but has the overwhelmign advantage that it
		596	diagnoses the error at the place where the result is expected, and not
		597	deep in some event clalback without connection to the actual code causing
		598	the problem.
477		599
478	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
479		601
480	=item $cv->end	602	=item $cv->end
481
482	These two methods are EXPERIMENTAL and MIGHT CHANGE.
483		603
484	These two methods can be used to combine many transactions/events into	604	These two methods can be used to combine many transactions/events into
485	one. For example, a function that pings many hosts in parallel might want	605	one. For example, a function that pings many hosts in parallel might want
486	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
487		607
…		…
489	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
490	>>, the (last) callback passed to C<begin> will be executed. That callback	610	>>, the (last) callback passed to C<begin> will be executed. That callback
491	is I<supposed> to call C<< ->send >>, but that is not required. If no	611	is I<supposed> to call C<< ->send >>, but that is not required. If no
492	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
493		613
494	Let's clarify this with the ping example:	614	You can think of C<< $cv->send >> giving you an OR condition (one call
		615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
		616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
		617
		618	Let's start with a simple example: you have two I/O watchers (for example,
		619	STDOUT and STDERR for a program), and you want to wait for both streams to
		620	close before activating a condvar:
		621
		622	my $cv = AnyEvent->condvar;
		623
		624	$cv->begin; # first watcher
		625	my $w1 = AnyEvent->io (fh => $fh1, cb => sub {
		626	defined sysread $fh1, my $buf, 4096
		627	or $cv->end;
		628	});
		629
		630	$cv->begin; # second watcher
		631	my $w2 = AnyEvent->io (fh => $fh2, cb => sub {
		632	defined sysread $fh2, my $buf, 4096
		633	or $cv->end;
		634	});
		635
		636	$cv->recv;
		637
		638	This works because for every event source (EOF on file handle), there is
		639	one call to C<begin>, so the condvar waits for all calls to C<end> before
		640	sending.
		641
		642	The ping example mentioned above is slightly more complicated, as the
		643	there are results to be passwd back, and the number of tasks that are
		644	begung can potentially be zero:
495		645
496	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
497		647
498	my %result;	648	my %result;
499	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
519	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
520	to be called once the counter reaches C<0>, and second, it ensures that	670	to be called once the counter reaches C<0>, and second, it ensures that
521	C<send> is called even when C<no> hosts are being pinged (the loop	671	C<send> is called even when C<no> hosts are being pinged (the loop
522	doesn't execute once).	672	doesn't execute once).
523		673
524	This is the general pattern when you "fan out" into multiple subrequests:	674	This is the general pattern when you "fan out" into multiple (but
525	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set
526	is called at least once, and then, for each subrequest you start, call	676	the callback and ensure C<end> is called at least once, and then, for each
527	C<begin> and for each subrequest you finish, call C<end>.	677	subrequest you start, call C<begin> and for each subrequest you finish,
		678	call C<end>.
528		679
529	=back	680	=back
530		681
531	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
532		683
…		…
548	function will call C<croak>.	699	function will call C<croak>.
549		700
550	In list context, all parameters passed to C<send> will be returned,	701	In list context, all parameters passed to C<send> will be returned,
551	in scalar context only the first one will be returned.	702	in scalar context only the first one will be returned.
552		703
		704	Note that doing a blocking wait in a callback is not supported by any
		705	event loop, that is, recursive invocation of a blocking C<< ->recv
		706	>> is not allowed, and the C<recv> call will C<croak> if such a
		707	condition is detected. This condition can be slightly loosened by using
		708	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		709	any thread that doesn't run the event loop itself.
		710
553	Not all event models support a blocking wait - some die in that case	711	Not all event models support a blocking wait - some die in that case
554	(programs might want to do that to stay interactive), so I<if you are	712	(programs might want to do that to stay interactive), so I<if you are
555	using this from a module, never require a blocking wait>, but let the	713	using this from a module, never require a blocking wait>. Instead, let the
556	caller decide whether the call will block or not (for example, by coupling	714	caller decide whether the call will block or not (for example, by coupling
557	condition variables with some kind of request results and supporting	715	condition variables with some kind of request results and supporting
558	callbacks so the caller knows that getting the result will not block,	716	callbacks so the caller knows that getting the result will not block,
559	while still supporting blocking waits if the caller so desires).	717	while still supporting blocking waits if the caller so desires).
560		718
561	Another reason I<never> to C<< ->recv >> in a module is that you cannot
562	sensibly have two C<< ->recv >>'s in parallel, as that would require
563	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
564	can supply.
565
566	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
567	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
568	versions and also integrates coroutines into AnyEvent, making blocking
569	C<< ->recv >> calls perfectly safe as long as they are done from another
570	coroutine (one that doesn't run the event loop).
571
572	You can ensure that C<< -recv >> never blocks by setting a callback and	719	You can ensure that C<< -recv >> never blocks by setting a callback and
573	only calling C<< ->recv >> from within that callback (or at a later	720	only calling C<< ->recv >> from within that callback (or at a later
574	time). This will work even when the event loop does not support blocking	721	time). This will work even when the event loop does not support blocking
575	waits otherwise.	722	waits otherwise.
576		723
577	=item $bool = $cv->ready	724	=item $bool = $cv->ready
578		725
579	Returns true when the condition is "true", i.e. whether C<send> or	726	Returns true when the condition is "true", i.e. whether C<send> or
580	C<croak> have been called.	727	C<croak> have been called.
581		728
582	=item $cb = $cv->cb ([new callback])	729	=item $cb = $cv->cb ($cb->($cv))
583		730
584	This is a mutator function that returns the callback set and optionally	731	This is a mutator function that returns the callback set and optionally
585	replaces it before doing so.	732	replaces it before doing so.
586		733
587	The callback will be called when the condition becomes "true", i.e. when	734	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	735	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.	736	variable itself. Calling C<recv> inside the callback or at any later time
		737	is guaranteed not to block.
590		738
591	=back	739	=back
592		740
		741	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		742
		743	The available backend classes are (every class has its own manpage):
		744
		745	=over 4
		746
		747	=item Backends that are autoprobed when no other event loop can be found.
		748
		749	EV is the preferred backend when no other event loop seems to be in
		750	use. If EV is not installed, then AnyEvent will try Event, and, failing
		751	that, will fall back to its own pure-perl implementation, which is
		752	available everywhere as it comes with AnyEvent itself.
		753
		754	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		755	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		756	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		757
		758	=item Backends that are transparently being picked up when they are used.
		759
		760	These will be used when they are currently loaded when the first watcher
		761	is created, in which case it is assumed that the application is using
		762	them. This means that AnyEvent will automatically pick the right backend
		763	when the main program loads an event module before anything starts to
		764	create watchers. Nothing special needs to be done by the main program.
		765
		766	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		767	AnyEvent::Impl::Tk based on Tk, very broken.
		768	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		769	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		770
		771	=item Backends with special needs.
		772
		773	Qt requires the Qt::Application to be instantiated first, but will
		774	otherwise be picked up automatically. As long as the main program
		775	instantiates the application before any AnyEvent watchers are created,
		776	everything should just work.
		777
		778	AnyEvent::Impl::Qt based on Qt.
		779
		780	Support for IO::Async can only be partial, as it is too broken and
		781	architecturally limited to even support the AnyEvent API. It also
		782	is the only event loop that needs the loop to be set explicitly, so
		783	it can only be used by a main program knowing about AnyEvent. See
		784	L<AnyEvent::Impl::Async> for the gory details.
		785
		786	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		787
		788	=item Event loops that are indirectly supported via other backends.
		789
		790	Some event loops can be supported via other modules:
		791
		792	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		793
		794	B<WxWidgets> has no support for watching file handles. However, you can
		795	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		796	polls 20 times per second, which was considered to be too horrible to even
		797	consider for AnyEvent.
		798
		799	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		800	backend, so it can be supported through POE.
		801
		802	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		803	load L<POE> when detecting them, in the hope that POE will pick them up,
		804	in which case everything will be automatic.
		805
		806	=back
		807
593	=head1 GLOBAL VARIABLES AND FUNCTIONS	808	=head1 GLOBAL VARIABLES AND FUNCTIONS
594		809
		810	These are not normally required to use AnyEvent, but can be useful to
		811	write AnyEvent extension modules.
		812
595	=over 4	813	=over 4
596		814
597	=item $AnyEvent::MODEL	815	=item $AnyEvent::MODEL
598		816
599	Contains C<undef> until the first watcher is being created. Then it	817	Contains C<undef> until the first watcher is being created, before the
		818	backend has been autodetected.
		819
600	contains the event model that is being used, which is the name of the	820	Afterwards it contains the event model that is being used, which is the
601	Perl class implementing the model. This class is usually one of the	821	name of the Perl class implementing the model. This class is usually one
602	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	822	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
603	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	823	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
604		824	will be C<urxvt::anyevent>).
605	The known classes so far are:
606
607	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
608	AnyEvent::Impl::Event based on Event, second best choice.
609	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
610	AnyEvent::Impl::Glib based on Glib, third-best choice.
611	AnyEvent::Impl::Tk based on Tk, very bad choice.
612	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
613	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
614	AnyEvent::Impl::POE based on POE, not generic enough for full support.
615
616	There is no support for WxWidgets, as WxWidgets has no support for
617	watching file handles. However, you can use WxWidgets through the
618	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
619	second, which was considered to be too horrible to even consider for
620	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
621	it's adaptor.
622
623	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
624	autodetecting them.
625		825
626	=item AnyEvent::detect	826	=item AnyEvent::detect
627		827
628	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	828	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
629	if necessary. You should only call this function right before you would	829	if necessary. You should only call this function right before you would
630	have created an AnyEvent watcher anyway, that is, as late as possible at	830	have created an AnyEvent watcher anyway, that is, as late as possible at
631	runtime.	831	runtime, and not e.g. while initialising of your module.
		832
		833	If you need to do some initialisation before AnyEvent watchers are
		834	created, use C<post_detect>.
632		835
633	=item $guard = AnyEvent::post_detect { BLOCK }	836	=item $guard = AnyEvent::post_detect { BLOCK }
634		837
635	Arranges for the code block to be executed as soon as the event model is	838	Arranges for the code block to be executed as soon as the event model is
636	autodetected (or immediately if this has already happened).	839	autodetected (or immediately if this has already happened).
		840
		841	The block will be executed I<after> the actual backend has been detected
		842	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		843	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		844	other initialisations - see the sources of L<AnyEvent::Strict> or
		845	L<AnyEvent::AIO> to see how this is used.
		846
		847	The most common usage is to create some global watchers, without forcing
		848	event module detection too early, for example, L<AnyEvent::AIO> creates
		849	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		850	avoid autodetecting the event module at load time.
637		851
638	If called in scalar or list context, then it creates and returns an object	852	If called in scalar or list context, then it creates and returns an object
639	that automatically removes the callback again when it is destroyed. See	853	that automatically removes the callback again when it is destroyed. See
640	L<Coro::BDB> for a case where this is useful.	854	L<Coro::BDB> for a case where this is useful.
641		855
…		…
644	If there are any code references in this array (you can C<push> to it	858	If there are any code references in this array (you can C<push> to it
645	before or after loading AnyEvent), then they will called directly after	859	before or after loading AnyEvent), then they will called directly after
646	the event loop has been chosen.	860	the event loop has been chosen.
647		861
648	You should check C<$AnyEvent::MODEL> before adding to this array, though:	862	You should check C<$AnyEvent::MODEL> before adding to this array, though:
649	if it contains a true value then the event loop has already been detected,	863	if it is defined then the event loop has already been detected, and the
650	and the array will be ignored.	864	array will be ignored.
651		865
652	Best use C<AnyEvent::post_detect { BLOCK }> instead.	866	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		867	it,as it takes care of these details.
		868
		869	This variable is mainly useful for modules that can do something useful
		870	when AnyEvent is used and thus want to know when it is initialised, but do
		871	not need to even load it by default. This array provides the means to hook
		872	into AnyEvent passively, without loading it.
653		873
654	=back	874	=back
655		875
656	=head1 WHAT TO DO IN A MODULE	876	=head1 WHAT TO DO IN A MODULE
657		877
…		…
712		932
713		933
714	=head1 OTHER MODULES	934	=head1 OTHER MODULES
715		935
716	The following is a non-exhaustive list of additional modules that use	936	The following is a non-exhaustive list of additional modules that use
717	AnyEvent and can therefore be mixed easily with other AnyEvent modules	937	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
718	in the same program. Some of the modules come with AnyEvent, some are	938	modules and other event loops in the same program. Some of the modules
719	available via CPAN.	939	come with AnyEvent, most are available via CPAN.
720		940
721	=over 4	941	=over 4
722		942
723	=item L<AnyEvent::Util>	943	=item L<AnyEvent::Util>
724		944
725	Contains various utility functions that replace often-used but blocking	945	Contains various utility functions that replace often-used but blocking
726	functions such as C<inet_aton> by event-/callback-based versions.	946	functions such as C<inet_aton> by event-/callback-based versions.
727
728	=item L<AnyEvent::Handle>
729
730	Provide read and write buffers and manages watchers for reads and writes.
731		947
732	=item L<AnyEvent::Socket>	948	=item L<AnyEvent::Socket>
733		949
734	Provides various utility functions for (internet protocol) sockets,	950	Provides various utility functions for (internet protocol) sockets,
735	addresses and name resolution. Also functions to create non-blocking tcp	951	addresses and name resolution. Also functions to create non-blocking tcp
736	connections or tcp servers, with IPv6 and SRV record support and more.	952	connections or tcp servers, with IPv6 and SRV record support and more.
737		953
		954	=item L<AnyEvent::Handle>
		955
		956	Provide read and write buffers, manages watchers for reads and writes,
		957	supports raw and formatted I/O, I/O queued and fully transparent and
		958	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
		959
738	=item L<AnyEvent::DNS>	960	=item L<AnyEvent::DNS>
739		961
740	Provides rich asynchronous DNS resolver capabilities.	962	Provides rich asynchronous DNS resolver capabilities.
741		963
		964	=item L<AnyEvent::HTTP>
		965
		966	A simple-to-use HTTP library that is capable of making a lot of concurrent
		967	HTTP requests.
		968
742	=item L<AnyEvent::HTTPD>	969	=item L<AnyEvent::HTTPD>
743		970
744	Provides a simple web application server framework.	971	Provides a simple web application server framework.
745		972
746	=item L<AnyEvent::FastPing>	973	=item L<AnyEvent::FastPing>
747		974
748	The fastest ping in the west.	975	The fastest ping in the west.
749		976
		977	=item L<AnyEvent::DBI>
		978
		979	Executes L<DBI> requests asynchronously in a proxy process.
		980
		981	=item L<AnyEvent::AIO>
		982
		983	Truly asynchronous I/O, should be in the toolbox of every event
		984	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		985	together.
		986
		987	=item L<AnyEvent::BDB>
		988
		989	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		990	L<BDB> and AnyEvent together.
		991
		992	=item L<AnyEvent::GPSD>
		993
		994	A non-blocking interface to gpsd, a daemon delivering GPS information.
		995
750	=item L<Net::IRC3>	996	=item L<AnyEvent::IRC>
751		997
752	AnyEvent based IRC client module family.	998	AnyEvent based IRC client module family (replacing the older Net::IRC3).
753		999
754	=item L<Net::XMPP2>	1000	=item L<AnyEvent::XMPP>
755		1001
756	AnyEvent based XMPP (Jabber protocol) module family.	1002	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1003	Net::XMPP2>.
		1004
		1005	=item L<AnyEvent::IGS>
		1006
		1007	A non-blocking interface to the Internet Go Server protocol (used by
		1008	L<App::IGS>).
757		1009
758	=item L<Net::FCP>	1010	=item L<Net::FCP>
759		1011
760	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1012	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
761	of AnyEvent.	1013	of AnyEvent.
…		…
766		1018
767	=item L<Coro>	1019	=item L<Coro>
768		1020
769	Has special support for AnyEvent via L<Coro::AnyEvent>.	1021	Has special support for AnyEvent via L<Coro::AnyEvent>.
770		1022
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>
783
784	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
785
786	=back	1023	=back
787		1024
788	=cut	1025	=cut
789		1026
790	package AnyEvent;	1027	package AnyEvent;
791		1028
792	no warnings;	1029	no warnings;
793	use strict;	1030	use strict qw(vars subs);
794		1031
795	use Carp;	1032	use Carp ();
796		1033
797	our $VERSION = '4.05';	1034	our $VERSION = 4.82;
798	our $MODEL;	1035	our $MODEL;
799		1036
800	our $AUTOLOAD;	1037	our $AUTOLOAD;
801	our @ISA;	1038	our @ISA;
802		1039
803	our @REGISTRY;	1040	our @REGISTRY;
804		1041
805	our $WIN32;	1042	our $WIN32;
806		1043
807	BEGIN {	1044	BEGIN {
808	my $win32 = ! ! ($^O =~ /mswin32/i);	1045	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
809	eval "sub WIN32(){ $win32 }";	1046	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1047
		1048	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1049	if ${^TAINT};
810	}	1050	}
811		1051
812	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1052	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
813		1053
814	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1054	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
…		…
825	[Event:: => AnyEvent::Impl::Event::],	1065	[Event:: => AnyEvent::Impl::Event::],
826	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1066	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
827	# everything below here will not be autoprobed	1067	# everything below here will not be autoprobed
828	# as the pureperl backend should work everywhere	1068	# as the pureperl backend should work everywhere
829	# and is usually faster	1069	# and is usually faster
830	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
831	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1070	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
832	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1071	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1072	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
833	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1073	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
834	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1074	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
835	[Wx:: => AnyEvent::Impl::POE::],	1075	[Wx:: => AnyEvent::Impl::POE::],
836	[Prima:: => AnyEvent::Impl::POE::],	1076	[Prima:: => AnyEvent::Impl::POE::],
		1077	# IO::Async is just too broken - we would need workarounds for its
		1078	# byzantine signal and broken child handling, among others.
		1079	# IO::Async is rather hard to detect, as it doesn't have any
		1080	# obvious default class.
		1081	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1082	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1083	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
837	);	1084	);
838		1085
839	our %method = map +($_ => 1), qw(io timer time now signal child condvar one_event DESTROY);	1086	our %method = map +($_ => 1),
		1087	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
840		1088
841	our @post_detect;	1089	our @post_detect;
842		1090
843	sub post_detect(&) {	1091	sub post_detect(&) {
844	my ($cb) = @_;	1092	my ($cb) = @_;
…		…
849	1	1097	1
850	} else {	1098	} else {
851	push @post_detect, $cb;	1099	push @post_detect, $cb;
852		1100
853	defined wantarray	1101	defined wantarray
854	? bless \$cb, "AnyEvent::Util::PostDetect"	1102	? bless \$cb, "AnyEvent::Util::postdetect"
855	: ()	1103	: ()
856	}	1104	}
857	}	1105	}
858		1106
859	sub AnyEvent::Util::PostDetect::DESTROY {	1107	sub AnyEvent::Util::postdetect::DESTROY {
860	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1108	@post_detect = grep $_ != ${$_[0]}, @post_detect;
861	}	1109	}
862		1110
863	sub detect() {	1111	sub detect() {
864	unless ($MODEL) {	1112	unless ($MODEL) {
…		…
867		1115
868	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1116	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
869	my $model = "AnyEvent::Impl::$1";	1117	my $model = "AnyEvent::Impl::$1";
870	if (eval "require $model") {	1118	if (eval "require $model") {
871	$MODEL = $model;	1119	$MODEL = $model;
872	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1120	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;
873	} else {	1121	} else {
874	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1122	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;
875	}	1123	}
876	}	1124	}
877		1125
878	# check for already loaded models	1126	# check for already loaded models
879	unless ($MODEL) {	1127	unless ($MODEL) {
…		…
901	last;	1149	last;
902	}	1150	}
903	}	1151	}
904		1152
905	$MODEL	1153	$MODEL
906	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1154	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
907	}	1155	}
908	}	1156	}
909		1157
		1158	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1159
910	unshift @ISA, $MODEL;	1160	unshift @ISA, $MODEL;
911	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1161
		1162	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
912		1163
913	(shift @post_detect)->() while @post_detect;	1164	(shift @post_detect)->() while @post_detect;
914	}	1165	}
915		1166
916	$MODEL	1167	$MODEL
…		…
918		1169
919	sub AUTOLOAD {	1170	sub AUTOLOAD {
920	(my $func = $AUTOLOAD) =~ s/.*://;	1171	(my $func = $AUTOLOAD) =~ s/.*://;
921		1172
922	$method{$func}	1173	$method{$func}
923	or croak "$func: not a valid method for AnyEvent objects";	1174	or Carp::croak "$func: not a valid method for AnyEvent objects";
924		1175
925	detect unless $MODEL;	1176	detect unless $MODEL;
926		1177
927	my $class = shift;	1178	my $class = shift;
928	$class->$func (@_);	1179	$class->$func (@_);
929	}	1180	}
930		1181
		1182	# utility function to dup a filehandle. this is used by many backends
		1183	# to support binding more than one watcher per filehandle (they usually
		1184	# allow only one watcher per fd, so we dup it to get a different one).
		1185	sub _dupfh($$;$$) {
		1186	my ($poll, $fh, $r, $w) = @_;
		1187
		1188	# cygwin requires the fh mode to be matching, unix doesn't
		1189	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
		1190
		1191	open my $fh2, "$mode&", $fh
		1192	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
		1193
		1194	# we assume CLOEXEC is already set by perl in all important cases
		1195
		1196	($fh2, $rw)
		1197	}
		1198
931	package AnyEvent::Base;	1199	package AnyEvent::Base;
932		1200
933	# default implementation for now and time	1201	# default implementations for many methods
934		1202
935	use Time::HiRes ();	1203	BEGIN {
		1204	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1205	*_time = \&Time::HiRes::time;
		1206	# if (eval "use POSIX (); (POSIX::times())...
		1207	} else {
		1208	*_time = sub { time }; # epic fail
		1209	}
		1210	}
936		1211
937	sub time { Time::HiRes::time }	1212	sub time { _time }
938	sub now { Time::HiRes::time }	1213	sub now { _time }
		1214	sub now_update { }
939		1215
940	# default implementation for ->condvar	1216	# default implementation for ->condvar
941		1217
942	sub condvar {	1218	sub condvar {
943	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1219	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
944	}	1220	}
945		1221
946	# default implementation for ->signal	1222	# default implementation for ->signal
947		1223
948	our %SIG_CB;	1224	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1225
		1226	sub _signal_exec {
		1227	sysread $SIGPIPE_R, my $dummy, 4;
		1228
		1229	while (%SIG_EV) {
		1230	for (keys %SIG_EV) {
		1231	delete $SIG_EV{$_};
		1232	$_->() for values %{ $SIG_CB{$_} || {} };
		1233	}
		1234	}
		1235	}
949		1236
950	sub signal {	1237	sub signal {
951	my (undef, %arg) = @_;	1238	my (undef, %arg) = @_;
952		1239
		1240	unless ($SIGPIPE_R) {
		1241	require Fcntl;
		1242
		1243	if (AnyEvent::WIN32) {
		1244	require AnyEvent::Util;
		1245
		1246	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1247	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1248	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1249	} else {
		1250	pipe $SIGPIPE_R, $SIGPIPE_W;
		1251	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1252	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1253
		1254	# not strictly required, as $^F is normally 2, but let's make sure...
		1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1257	}
		1258
		1259	$SIGPIPE_R
		1260	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1261
		1262	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1263	}
		1264
953	my $signal = uc $arg{signal}	1265	my $signal = uc $arg{signal}
954	or Carp::croak "required option 'signal' is missing";	1266	or Carp::croak "required option 'signal' is missing";
955		1267
956	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1268	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
957	$SIG{$signal} ||= sub {	1269	$SIG{$signal} ||= sub {
958	$_->() for values %{ $SIG_CB{$signal} || {} };	1270	local $!;
		1271	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1272	undef $SIG_EV{$signal};
959	};	1273	};
960		1274
961	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1275	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
962	}	1276	}
963		1277
964	sub AnyEvent::Base::Signal::DESTROY {	1278	sub AnyEvent::Base::signal::DESTROY {
965	my ($signal, $cb) = @{$_[0]};	1279	my ($signal, $cb) = @{$_[0]};
966		1280
967	delete $SIG_CB{$signal}{$cb};	1281	delete $SIG_CB{$signal}{$cb};
968		1282
		1283	# delete doesn't work with older perls - they then
		1284	# print weird messages, or just unconditionally exit
		1285	# instead of getting the default action.
969	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1286	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
970	}	1287	}
971		1288
972	# default implementation for ->child	1289	# default implementation for ->child
973		1290
974	our %PID_CB;	1291	our %PID_CB;
975	our $CHLD_W;	1292	our $CHLD_W;
976	our $CHLD_DELAY_W;	1293	our $CHLD_DELAY_W;
977	our $PID_IDLE;
978	our $WNOHANG;	1294	our $WNOHANG;
979		1295
980	sub _child_wait {	1296	sub _sigchld {
981	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1297	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
982	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1298	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
983	(values %{ $PID_CB{0} || {} });	1299	(values %{ $PID_CB{0} || {} });
984	}	1300	}
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	}	1301	}
996		1302
997	sub child {	1303	sub child {
998	my (undef, %arg) = @_;	1304	my (undef, %arg) = @_;
999		1305
1000	defined (my $pid = $arg{pid} + 0)	1306	defined (my $pid = $arg{pid} + 0)
1001	or Carp::croak "required option 'pid' is missing";	1307	or Carp::croak "required option 'pid' is missing";
1002		1308
1003	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1309	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1004		1310
1005	unless ($WNOHANG) {
1006	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1311	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1007	}
1008		1312
1009	unless ($CHLD_W) {	1313	unless ($CHLD_W) {
1010	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1314	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
1011	# child could be a zombie already, so make at least one round	1315	# child could be a zombie already, so make at least one round
1012	&_sigchld;	1316	&_sigchld;
1013	}	1317	}
1014		1318
1015	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1319	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1016	}	1320	}
1017		1321
1018	sub AnyEvent::Base::Child::DESTROY {	1322	sub AnyEvent::Base::child::DESTROY {
1019	my ($pid, $cb) = @{$_[0]};	1323	my ($pid, $cb) = @{$_[0]};
1020		1324
1021	delete $PID_CB{$pid}{$cb};	1325	delete $PID_CB{$pid}{$cb};
1022	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1326	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1023		1327
1024	undef $CHLD_W unless keys %PID_CB;	1328	undef $CHLD_W unless keys %PID_CB;
		1329	}
		1330
		1331	# idle emulation is done by simply using a timer, regardless
		1332	# of whether the process is idle or not, and not letting
		1333	# the callback use more than 50% of the time.
		1334	sub idle {
		1335	my (undef, %arg) = @_;
		1336
		1337	my ($cb, $w, $rcb) = $arg{cb};
		1338
		1339	$rcb = sub {
		1340	if ($cb) {
		1341	$w = _time;
		1342	&$cb;
		1343	$w = _time - $w;
		1344
		1345	# never use more then 50% of the time for the idle watcher,
		1346	# within some limits
		1347	$w = 0.0001 if $w < 0.0001;
		1348	$w = 5 if $w > 5;
		1349
		1350	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1351	} else {
		1352	# clean up...
		1353	undef $w;
		1354	undef $rcb;
		1355	}
		1356	};
		1357
		1358	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1359
		1360	bless \\$cb, "AnyEvent::Base::idle"
		1361	}
		1362
		1363	sub AnyEvent::Base::idle::DESTROY {
		1364	undef $${$_[0]};
1025	}	1365	}
1026		1366
1027	package AnyEvent::CondVar;	1367	package AnyEvent::CondVar;
1028		1368
1029	our @ISA = AnyEvent::CondVar::Base::;	1369	our @ISA = AnyEvent::CondVar::Base::;
…		…
1031	package AnyEvent::CondVar::Base;	1371	package AnyEvent::CondVar::Base;
1032		1372
1033	use overload	1373	use overload
1034	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1374	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1035	fallback => 1;	1375	fallback => 1;
		1376
		1377	our $WAITING;
1036		1378
1037	sub _send {	1379	sub _send {
1038	# nop	1380	# nop
1039	}	1381	}
1040		1382
…		…
1053	sub ready {	1395	sub ready {
1054	$_[0]{_ae_sent}	1396	$_[0]{_ae_sent}
1055	}	1397	}
1056		1398
1057	sub _wait {	1399	sub _wait {
		1400	$WAITING
		1401	and !$_[0]{_ae_sent}
		1402	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1403
		1404	local $WAITING = 1;
1058	AnyEvent->one_event while !$_[0]{_ae_sent};	1405	AnyEvent->one_event while !$_[0]{_ae_sent};
1059	}	1406	}
1060		1407
1061	sub recv {	1408	sub recv {
1062	$_[0]->_wait;	1409	$_[0]->_wait;
…		…
1081	}	1428	}
1082		1429
1083	# undocumented/compatibility with pre-3.4	1430	# undocumented/compatibility with pre-3.4
1084	*broadcast = \&send;	1431	*broadcast = \&send;
1085	*wait = \&_wait;	1432	*wait = \&_wait;
		1433
		1434	=head1 ERROR AND EXCEPTION HANDLING
		1435
		1436	In general, AnyEvent does not do any error handling - it relies on the
		1437	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1438	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1439	checking of all AnyEvent methods, however, which is highly useful during
		1440	development.
		1441
		1442	As for exception handling (i.e. runtime errors and exceptions thrown while
		1443	executing a callback), this is not only highly event-loop specific, but
		1444	also not in any way wrapped by this module, as this is the job of the main
		1445	program.
		1446
		1447	The pure perl event loop simply re-throws the exception (usually
		1448	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1449	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1450	so on.
		1451
		1452	=head1 ENVIRONMENT VARIABLES
		1453
		1454	The following environment variables are used by this module or its
		1455	submodules.
		1456
		1457	Note that AnyEvent will remove I<all> environment variables starting with
		1458	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1459	enabled.
		1460
		1461	=over 4
		1462
		1463	=item C<PERL_ANYEVENT_VERBOSE>
		1464
		1465	By default, AnyEvent will be completely silent except in fatal
		1466	conditions. You can set this environment variable to make AnyEvent more
		1467	talkative.
		1468
		1469	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1470	conditions, such as not being able to load the event model specified by
		1471	C<PERL_ANYEVENT_MODEL>.
		1472
		1473	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1474	model it chooses.
		1475
		1476	=item C<PERL_ANYEVENT_STRICT>
		1477
		1478	AnyEvent does not do much argument checking by default, as thorough
		1479	argument checking is very costly. Setting this variable to a true value
		1480	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1481	check the arguments passed to most method calls. If it finds any problems,
		1482	it will croak.
		1483
		1484	In other words, enables "strict" mode.
		1485
		1486	Unlike C<use strict>, it is definitely recommended to keep it off in
		1487	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1488	developing programs can be very useful, however.
		1489
		1490	=item C<PERL_ANYEVENT_MODEL>
		1491
		1492	This can be used to specify the event model to be used by AnyEvent, before
		1493	auto detection and -probing kicks in. It must be a string consisting
		1494	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1495	and the resulting module name is loaded and if the load was successful,
		1496	used as event model. If it fails to load AnyEvent will proceed with
		1497	auto detection and -probing.
		1498
		1499	This functionality might change in future versions.
		1500
		1501	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1502	could start your program like this:
		1503
		1504	PERL_ANYEVENT_MODEL=Perl perl ...
		1505
		1506	=item C<PERL_ANYEVENT_PROTOCOLS>
		1507
		1508	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1509	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1510	of auto probing).
		1511
		1512	Must be set to a comma-separated list of protocols or address families,
		1513	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1514	used, and preference will be given to protocols mentioned earlier in the
		1515	list.
		1516
		1517	This variable can effectively be used for denial-of-service attacks
		1518	against local programs (e.g. when setuid), although the impact is likely
		1519	small, as the program has to handle conenction and other failures anyways.
		1520
		1521	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1522	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1523	- only support IPv4, never try to resolve or contact IPv6
		1524	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1525	IPv6, but prefer IPv6 over IPv4.
		1526
		1527	=item C<PERL_ANYEVENT_EDNS0>
		1528
		1529	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1530	for DNS. This extension is generally useful to reduce DNS traffic, but
		1531	some (broken) firewalls drop such DNS packets, which is why it is off by
		1532	default.
		1533
		1534	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1535	EDNS0 in its DNS requests.
		1536
		1537	=item C<PERL_ANYEVENT_MAX_FORKS>
		1538
		1539	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1540	will create in parallel.
		1541
		1542	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1543
		1544	The default value for the C<max_outstanding> parameter for the default DNS
		1545	resolver - this is the maximum number of parallel DNS requests that are
		1546	sent to the DNS server.
		1547
		1548	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1549
		1550	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1551	configuration) in the default resolver. When set to the empty string, no
		1552	default config will be used.
		1553
		1554	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1555
		1556	When neither C<ca_file> nor C<ca_path> was specified during
		1557	L<AnyEvent::TLS> context creation, and either of these environment
		1558	variables exist, they will be used to specify CA certificate locations
		1559	instead of a system-dependent default.
		1560
		1561	=back
1086		1562
1087	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1563	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1088		1564
1089	This is an advanced topic that you do not normally need to use AnyEvent in	1565	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	1566	a module. This section is only of use to event loop authors who want to
…		…
1124		1600
1125	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1601	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1126	condition variables: code blocking while waiting for a condition will	1602	condition variables: code blocking while waiting for a condition will
1127	C<die>. This still works with most modules/usages, and blocking calls must	1603	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.	1604	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		1605
1203	=head1 EXAMPLE PROGRAM	1606	=head1 EXAMPLE PROGRAM
1204		1607
1205	The following program uses an I/O watcher to read data from STDIN, a timer	1608	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	1609	to display a message once per second, and a condition variable to quit the
…		…
1400	watcher.	1803	watcher.
1401		1804
1402	=head3 Results	1805	=head3 Results
1403		1806
1404	name watchers bytes create invoke destroy comment	1807	name watchers bytes create invoke destroy comment
1405	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1808	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	1809	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	1810	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	1811	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	1812	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	1813	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1814	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1815	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1411	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1816	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	1817	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	1818	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	1819	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1415		1820
1416	=head3 Discussion	1821	=head3 Discussion
1417		1822
1418	The benchmark does I<not> measure scalability of the event loop very	1823	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)	1824	well. For example, a select-based event loop (such as the pure perl one)
…		…
1444	performance becomes really bad with lots of file descriptors (and few of	1849	performance becomes really bad with lots of file descriptors (and few of
1445	them active), of course, but this was not subject of this benchmark.	1850	them active), of course, but this was not subject of this benchmark.
1446		1851
1447	The C<Event> module has a relatively high setup and callback invocation	1852	The C<Event> module has a relatively high setup and callback invocation
1448	cost, but overall scores in on the third place.	1853	cost, but overall scores in on the third place.
		1854
		1855	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1856	when using its pure perl backend.
1449		1857
1450	C<Glib>'s memory usage is quite a bit higher, but it features a	1858	C<Glib>'s memory usage is quite a bit higher, but it features a
1451	faster callback invocation and overall ends up in the same class as	1859	faster callback invocation and overall ends up in the same class as
1452	C<Event>. However, Glib scales extremely badly, doubling the number of	1860	C<Event>. However, Glib scales extremely badly, doubling the number of
1453	watchers increases the processing time by more than a factor of four,	1861	watchers increases the processing time by more than a factor of four,
…		…
1531	it to another server. This includes deleting the old timeout and creating	1939	it to another server. This includes deleting the old timeout and creating
1532	a new one that moves the timeout into the future.	1940	a new one that moves the timeout into the future.
1533		1941
1534	=head3 Results	1942	=head3 Results
1535		1943
1536	name sockets create request	1944	name sockets create request
1537	EV 20000 69.01 11.16	1945	EV 20000 69.01 11.16
1538	Perl 20000 73.32 35.87	1946	Perl 20000 73.32 35.87
		1947	IOAsync 20000 157.00 98.14 epoll
		1948	IOAsync 20000 159.31 616.06 poll
1539	Event 20000 212.62 257.32	1949	Event 20000 212.62 257.32
1540	Glib 20000 651.16 1896.30	1950	Glib 20000 651.16 1896.30
1541	POE 20000 349.67 12317.24 uses POE::Loop::Event	1951	POE 20000 349.67 12317.24 uses POE::Loop::Event
1542		1952
1543	=head3 Discussion	1953	=head3 Discussion
1544		1954
1545	This benchmark I<does> measure scalability and overall performance of the	1955	This benchmark I<does> measure scalability and overall performance of the
1546	particular event loop.	1956	particular event loop.
…		…
1548	EV is again fastest. Since it is using epoll on my system, the setup time	1958	EV is again fastest. Since it is using epoll on my system, the setup time
1549	is relatively high, though.	1959	is relatively high, though.
1550		1960
1551	Perl surprisingly comes second. It is much faster than the C-based event	1961	Perl surprisingly comes second. It is much faster than the C-based event
1552	loops Event and Glib.	1962	loops Event and Glib.
		1963
		1964	IO::Async performs very well when using its epoll backend, and still quite
		1965	good compared to Glib when using its pure perl backend.
1553		1966
1554	Event suffers from high setup time as well (look at its code and you will	1967	Event suffers from high setup time as well (look at its code and you will
1555	understand why). Callback invocation also has a high overhead compared to	1968	understand why). Callback invocation also has a high overhead compared to
1556	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1969	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1557	uses select or poll in basically all documented configurations.	1970	uses select or poll in basically all documented configurations.
…		…
1620	=item * C-based event loops perform very well with small number of	2033	=item * C-based event loops perform very well with small number of
1621	watchers, as the management overhead dominates.	2034	watchers, as the management overhead dominates.
1622		2035
1623	=back	2036	=back
1624		2037
		2038	=head2 THE IO::Lambda BENCHMARK
		2039
		2040	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2041	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2042	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2043	shouldn't come as a surprise to anybody). As such, the benchmark is
		2044	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2045	very optimal. But how would AnyEvent compare when used without the extra
		2046	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2047
		2048	The benchmark itself creates an echo-server, and then, for 500 times,
		2049	connects to the echo server, sends a line, waits for the reply, and then
		2050	creates the next connection. This is a rather bad benchmark, as it doesn't
		2051	test the efficiency of the framework or much non-blocking I/O, but it is a
		2052	benchmark nevertheless.
		2053
		2054	name runtime
		2055	Lambda/select 0.330 sec
		2056	+ optimized 0.122 sec
		2057	Lambda/AnyEvent 0.327 sec
		2058	+ optimized 0.138 sec
		2059	Raw sockets/select 0.077 sec
		2060	POE/select, components 0.662 sec
		2061	POE/select, raw sockets 0.226 sec
		2062	POE/select, optimized 0.404 sec
		2063
		2064	AnyEvent/select/nb 0.085 sec
		2065	AnyEvent/EV/nb 0.068 sec
		2066	+state machine 0.134 sec
		2067
		2068	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2069	benchmarks actually make blocking connects and use 100% blocking I/O,
		2070	defeating the purpose of an event-based solution. All of the newly
		2071	written AnyEvent benchmarks use 100% non-blocking connects (using
		2072	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2073	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2074	generally require a lot more bookkeeping and event handling than blocking
		2075	connects (which involve a single syscall only).
		2076
		2077	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2078	offers similar expressive power as POE and IO::Lambda, using conventional
		2079	Perl syntax. This means that both the echo server and the client are 100%
		2080	non-blocking, further placing it at a disadvantage.
		2081
		2082	As you can see, the AnyEvent + EV combination even beats the
		2083	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2084	backend easily beats IO::Lambda and POE.
		2085
		2086	And even the 100% non-blocking version written using the high-level (and
		2087	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2088	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2089	in a non-blocking way.
		2090
		2091	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2092	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2093	part of the IO::lambda distribution and were used without any changes.
		2094
		2095
		2096	=head1 SIGNALS
		2097
		2098	AnyEvent currently installs handlers for these signals:
		2099
		2100	=over 4
		2101
		2102	=item SIGCHLD
		2103
		2104	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2105	emulation for event loops that do not support them natively. Also, some
		2106	event loops install a similar handler.
		2107
		2108	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2109	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2110
		2111	=item SIGPIPE
		2112
		2113	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2114	when AnyEvent gets loaded.
		2115
		2116	The rationale for this is that AnyEvent users usually do not really depend
		2117	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2118	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2119	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2120	some random socket.
		2121
		2122	The rationale for installing a no-op handler as opposed to ignoring it is
		2123	that this way, the handler will be restored to defaults on exec.
		2124
		2125	Feel free to install your own handler, or reset it to defaults.
		2126
		2127	=back
		2128
		2129	=cut
		2130
		2131	undef $SIG{CHLD}
		2132	if $SIG{CHLD} eq 'IGNORE';
		2133
		2134	$SIG{PIPE} = sub { }
		2135	unless defined $SIG{PIPE};
1625		2136
1626	=head1 FORK	2137	=head1 FORK
1627		2138
1628	Most event libraries are not fork-safe. The ones who are usually are	2139	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>	2140	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1643	specified in the variable.	2154	specified in the variable.
1644		2155
1645	You can make AnyEvent completely ignore this variable by deleting it	2156	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:	2157	before the first watcher gets created, e.g. with a C<BEGIN> block:
1647		2158
1648	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	2159	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1649		2160
1650	use AnyEvent;	2161	use AnyEvent;
1651		2162
1652	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2163	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	2164	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).	2165	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2166	$ENV{PERL_ANYEVENT_STRICT}.
		2167
		2168	Note that AnyEvent will remove I<all> environment variables starting with
		2169	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2170	enabled.
		2171
		2172
		2173	=head1 BUGS
		2174
		2175	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		2176	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		2177	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		2178	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		2179	pronounced).
1655		2180
1656		2181
1657	=head1 SEE ALSO	2182	=head1 SEE ALSO
1658		2183
1659	Utility functions: L<AnyEvent::Util>.	2184	Utility functions: L<AnyEvent::Util>.
…		…
1662	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2187	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1663		2188
1664	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2189	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1665	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2190	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1666	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2191	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1667	L<AnyEvent::Impl::POE>.	2192	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1668		2193
1669	Non-blocking file handles, sockets, TCP clients and	2194	Non-blocking file handles, sockets, TCP clients and
1670	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2195	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1671		2196
1672	Asynchronous DNS: L<AnyEvent::DNS>.	2197	Asynchronous DNS: L<AnyEvent::DNS>.
1673		2198
1674	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2199	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2200	L<Coro::Event>,
1675		2201
1676	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2202	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2203	L<AnyEvent::HTTP>.
1677		2204
1678		2205
1679	=head1 AUTHOR	2206	=head1 AUTHOR
1680		2207
1681	Marc Lehmann <schmorp@schmorp.de>	2208	Marc Lehmann <schmorp@schmorp.de>
1682	http://home.schmorp.de/	2209	http://home.schmorp.de/
1683		2210
1684	=cut	2211	=cut
1685		2212
1686	1	2213	1
1687		2214

Diff Legend

–	Removed lines
+	Added lines
<	Changed lines
>	Changed lines