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Revision 1.142 by root, Tue May 27 02:34:30 2008 UTC vs.
Revision 1.238 by root, Thu Jul 16 03:48:33 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
…		…
233	timers.	267	timers.
234		268
235	AnyEvent always prefers relative timers, if available, matching the	269	AnyEvent always prefers relative timers, if available, matching the
236	AnyEvent API.	270	AnyEvent API.
237		271
		272	AnyEvent has two additional methods that return the "current time":
		273
		274	=over 4
		275
		276	=item AnyEvent->time
		277
		278	This returns the "current wallclock time" as a fractional number of
		279	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		280	return, and the result is guaranteed to be compatible with those).
		281
		282	It progresses independently of any event loop processing, i.e. each call
		283	will check the system clock, which usually gets updated frequently.
		284
		285	=item AnyEvent->now
		286
		287	This also returns the "current wallclock time", but unlike C<time>, above,
		288	this value might change only once per event loop iteration, depending on
		289	the event loop (most return the same time as C<time>, above). This is the
		290	time that AnyEvent's timers get scheduled against.
		291
		292	I<In almost all cases (in all cases if you don't care), this is the
		293	function to call when you want to know the current time.>
		294
		295	This function is also often faster then C<< AnyEvent->time >>, and
		296	thus the preferred method if you want some timestamp (for example,
		297	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		298
		299	The rest of this section is only of relevance if you try to be very exact
		300	with your timing, you can skip it without bad conscience.
		301
		302	For a practical example of when these times differ, consider L<Event::Lib>
		303	and L<EV> and the following set-up:
		304
		305	The event loop is running and has just invoked one of your callback at
		306	time=500 (assume no other callbacks delay processing). In your callback,
		307	you wait a second by executing C<sleep 1> (blocking the process for a
		308	second) and then (at time=501) you create a relative timer that fires
		309	after three seconds.
		310
		311	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		312	both return C<501>, because that is the current time, and the timer will
		313	be scheduled to fire at time=504 (C<501> + C<3>).
		314
		315	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		316	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		317	last event processing phase started. With L<EV>, your timer gets scheduled
		318	to run at time=503 (C<500> + C<3>).
		319
		320	In one sense, L<Event::Lib> is more exact, as it uses the current time
		321	regardless of any delays introduced by event processing. However, most
		322	callbacks do not expect large delays in processing, so this causes a
		323	higher drift (and a lot more system calls to get the current time).
		324
		325	In another sense, L<EV> is more exact, as your timer will be scheduled at
		326	the same time, regardless of how long event processing actually took.
		327
		328	In either case, if you care (and in most cases, you don't), then you
		329	can get whatever behaviour you want with any event loop, by taking the
		330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		331	account.
		332
		333	=item AnyEvent->now_update
		334
		335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		336	the current time for each loop iteration (see the discussion of L<<
		337	AnyEvent->now >>, above).
		338
		339	When a callback runs for a long time (or when the process sleeps), then
		340	this "current" time will differ substantially from the real time, which
		341	might affect timers and time-outs.
		342
		343	When this is the case, you can call this method, which will update the
		344	event loop's idea of "current time".
		345
		346	Note that updating the time I<might> cause some events to be handled.
		347
		348	=back
		349
238	=head2 SIGNAL WATCHERS	350	=head2 SIGNAL WATCHERS
239		351
240	You can watch for signals using a signal watcher, C<signal> is the signal	352	You can watch for signals using a signal watcher, C<signal> is the signal
241	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
242	be invoked whenever a signal occurs.	354	callback to be invoked whenever a signal occurs.
243		355
244	Although the callback might get passed parameters, their value and	356	Although the callback might get passed parameters, their value and
245	presence is undefined and you cannot rely on them. Portable AnyEvent	357	presence is undefined and you cannot rely on them. Portable AnyEvent
246	callbacks cannot use arguments passed to signal watcher callbacks.	358	callbacks cannot use arguments passed to signal watcher callbacks.
247		359
…		…
263	=head2 CHILD PROCESS WATCHERS	375	=head2 CHILD PROCESS WATCHERS
264		376
265	You can also watch on a child process exit and catch its exit status.	377	You can also watch on a child process exit and catch its exit status.
266		378
267	The child process is specified by the C<pid> argument (if set to C<0>, it	379	The child process is specified by the C<pid> argument (if set to C<0>, it
268	watches for any child process exit). The watcher will trigger as often	380	watches for any child process exit). The watcher will triggered only when
269	as status change for the child are received. This works by installing a	381	the child process has finished and an exit status is available, not on
270	signal handler for C<SIGCHLD>. The callback will be called with the pid	382	any trace events (stopped/continued).
271	and exit status (as returned by waitpid), so unlike other watcher types,	383
272	you I<can> rely on child watcher callback arguments.	384	The callback will be called with the pid and exit status (as returned by
		385	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		386	callback arguments.
		387
		388	This watcher type works by installing a signal handler for C<SIGCHLD>,
		389	and since it cannot be shared, nothing else should use SIGCHLD or reap
		390	random child processes (waiting for specific child processes, e.g. inside
		391	C<system>, is just fine).
273		392
274	There is a slight catch to child watchers, however: you usually start them	393	There is a slight catch to child watchers, however: you usually start them
275	I<after> the child process was created, and this means the process could	394	I<after> the child process was created, and this means the process could
276	have exited already (and no SIGCHLD will be sent anymore).	395	have exited already (and no SIGCHLD will be sent anymore).
277		396
278	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
279	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
280	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.
281		403
282	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
283	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
284	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>).
285		408
286	Example: fork a process and wait for it	409	Example: fork a process and wait for it
287		410
288	my $done = AnyEvent->condvar;	411	my $done = AnyEvent->condvar;
289		412
290	my $pid = fork or exit 5;	413	my $pid = fork or exit 5;
291		414
292	my $w = AnyEvent->child (	415	my $w = AnyEvent->child (
293	pid => $pid,	416	pid => $pid,
294	cb => sub {	417	cb => sub {
295	my ($pid, $status) = @_;	418	my ($pid, $status) = @_;
296	warn "pid $pid exited with status $status";	419	warn "pid $pid exited with status $status";
297	$done->send;	420	$done->send;
298	},	421	},
299	);	422	);
300		423
301	# do something else, then wait for process exit	424	# do something else, then wait for process exit
302	$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	});
303		461
304	=head2 CONDITION VARIABLES	462	=head2 CONDITION VARIABLES
305		463
306	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
307	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
…		…
313	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
314	because they represent a condition that must become true.	472	because they represent a condition that must become true.
315		473
316	Condition variables can be created by calling the C<< AnyEvent->condvar	474	Condition variables can be created by calling the C<< AnyEvent->condvar
317	>> method, usually without arguments. The only argument pair allowed is	475	>> method, usually without arguments. The only argument pair allowed is
		476
318	C<cb>, which specifies a callback to be called when the condition variable	477	C<cb>, which specifies a callback to be called when the condition variable
319	becomes true.	478	becomes true, with the condition variable as the first argument (but not
		479	the results).
320		480
321	After creation, the condition variable is "false" until it becomes "true"	481	After creation, the condition variable is "false" until it becomes "true"
322	by calling the C<send> method (or calling the condition variable as if it	482	by calling the C<send> method (or calling the condition variable as if it
323	were a callback, read about the caveats in the description for the C<<	483	were a callback, read about the caveats in the description for the C<<
324	->send >> method).	484	->send >> method).
…		…
380		540
381	my $done = AnyEvent->condvar;	541	my $done = AnyEvent->condvar;
382	my $delay = AnyEvent->timer (after => 5, cb => $done);	542	my $delay = AnyEvent->timer (after => 5, cb => $done);
383	$done->recv;	543	$done->recv;
384		544
		545	Example: Imagine an API that returns a condvar and doesn't support
		546	callbacks. This is how you make a synchronous call, for example from
		547	the main program:
		548
		549	use AnyEvent::CouchDB;
		550
		551	...
		552
		553	my @info = $couchdb->info->recv;
		554
		555	And this is how you would just ste a callback to be called whenever the
		556	results are available:
		557
		558	$couchdb->info->cb (sub {
		559	my @info = $_[0]->recv;
		560	});
		561
385	=head3 METHODS FOR PRODUCERS	562	=head3 METHODS FOR PRODUCERS
386		563
387	These methods should only be used by the producing side, i.e. the	564	These methods should only be used by the producing side, i.e. the
388	code/module that eventually sends the signal. Note that it is also	565	code/module that eventually sends the signal. Note that it is also
389	the producer side which creates the condvar in most cases, but it isn't	566	the producer side which creates the condvar in most cases, but it isn't
…		…
422		599
423	=item $cv->begin ([group callback])	600	=item $cv->begin ([group callback])
424		601
425	=item $cv->end	602	=item $cv->end
426		603
427	These two methods are EXPERIMENTAL and MIGHT CHANGE.
428
429	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
430	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
431	to use a condition variable for the whole process.	606	to use a condition variable for the whole process.
432		607
433	Every call to C<< ->begin >> will increment a counter, and every call to	608	Every call to C<< ->begin >> will increment a counter, and every call to
434	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
435	>>, 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
436	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
437	callback was set, C<send> will be called without any arguments.	612	callback was set, C<send> will be called without any arguments.
438		613
439	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:
440		645
441	my $cv = AnyEvent->condvar;	646	my $cv = AnyEvent->condvar;
442		647
443	my %result;	648	my %result;
444	$cv->begin (sub { $cv->send (\%result) });	649	$cv->begin (sub { $cv->send (\%result) });
…		…
464	loop, which serves two important purposes: first, it sets the callback	669	loop, which serves two important purposes: first, it sets the callback
465	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
466	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
467	doesn't execute once).	672	doesn't execute once).
468		673
469	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
470	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
471	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
472	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>.
473		679
474	=back	680	=back
475		681
476	=head3 METHODS FOR CONSUMERS	682	=head3 METHODS FOR CONSUMERS
477		683
…		…
522	=item $bool = $cv->ready	728	=item $bool = $cv->ready
523		729
524	Returns true when the condition is "true", i.e. whether C<send> or	730	Returns true when the condition is "true", i.e. whether C<send> or
525	C<croak> have been called.	731	C<croak> have been called.
526		732
527	=item $cb = $cv->cb ([new callback])	733	=item $cb = $cv->cb ($cb->($cv))
528		734
529	This is a mutator function that returns the callback set and optionally	735	This is a mutator function that returns the callback set and optionally
530	replaces it before doing so.	736	replaces it before doing so.
531		737
532	The callback will be called when the condition becomes "true", i.e. when	738	The callback will be called when the condition becomes "true", i.e. when
533	C<send> or C<croak> are called. Calling C<recv> inside the callback	739	C<send> or C<croak> are called, with the only argument being the condition
534	or at any later time is guaranteed not to block.	740	variable itself. Calling C<recv> inside the callback or at any later time
		741	is guaranteed not to block.
535		742
536	=back	743	=back
537		744
		745	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		746
		747	The available backend classes are (every class has its own manpage):
		748
		749	=over 4
		750
		751	=item Backends that are autoprobed when no other event loop can be found.
		752
		753	EV is the preferred backend when no other event loop seems to be in
		754	use. If EV is not installed, then AnyEvent will try Event, and, failing
		755	that, will fall back to its own pure-perl implementation, which is
		756	available everywhere as it comes with AnyEvent itself.
		757
		758	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		759	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		760	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		761
		762	=item Backends that are transparently being picked up when they are used.
		763
		764	These will be used when they are currently loaded when the first watcher
		765	is created, in which case it is assumed that the application is using
		766	them. This means that AnyEvent will automatically pick the right backend
		767	when the main program loads an event module before anything starts to
		768	create watchers. Nothing special needs to be done by the main program.
		769
		770	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		771	AnyEvent::Impl::Tk based on Tk, very broken.
		772	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		773	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		774
		775	=item Backends with special needs.
		776
		777	Qt requires the Qt::Application to be instantiated first, but will
		778	otherwise be picked up automatically. As long as the main program
		779	instantiates the application before any AnyEvent watchers are created,
		780	everything should just work.
		781
		782	AnyEvent::Impl::Qt based on Qt.
		783
		784	Support for IO::Async can only be partial, as it is too broken and
		785	architecturally limited to even support the AnyEvent API. It also
		786	is the only event loop that needs the loop to be set explicitly, so
		787	it can only be used by a main program knowing about AnyEvent. See
		788	L<AnyEvent::Impl::Async> for the gory details.
		789
		790	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		791
		792	=item Event loops that are indirectly supported via other backends.
		793
		794	Some event loops can be supported via other modules:
		795
		796	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		797
		798	B<WxWidgets> has no support for watching file handles. However, you can
		799	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		800	polls 20 times per second, which was considered to be too horrible to even
		801	consider for AnyEvent.
		802
		803	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		804	backend, so it can be supported through POE.
		805
		806	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		807	load L<POE> when detecting them, in the hope that POE will pick them up,
		808	in which case everything will be automatic.
		809
		810	=back
		811
538	=head1 GLOBAL VARIABLES AND FUNCTIONS	812	=head1 GLOBAL VARIABLES AND FUNCTIONS
539		813
		814	These are not normally required to use AnyEvent, but can be useful to
		815	write AnyEvent extension modules.
		816
540	=over 4	817	=over 4
541		818
542	=item $AnyEvent::MODEL	819	=item $AnyEvent::MODEL
543		820
544	Contains C<undef> until the first watcher is being created. Then it	821	Contains C<undef> until the first watcher is being created, before the
		822	backend has been autodetected.
		823
545	contains the event model that is being used, which is the name of the	824	Afterwards it contains the event model that is being used, which is the
546	Perl class implementing the model. This class is usually one of the	825	name of the Perl class implementing the model. This class is usually one
547	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	826	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the
548	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	827	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
549		828	will be C<urxvt::anyevent>).
550	The known classes so far are:
551
552	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
553	AnyEvent::Impl::Event based on Event, second best choice.
554	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
555	AnyEvent::Impl::Glib based on Glib, third-best choice.
556	AnyEvent::Impl::Tk based on Tk, very bad choice.
557	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
558	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
559	AnyEvent::Impl::POE based on POE, not generic enough for full support.
560
561	There is no support for WxWidgets, as WxWidgets has no support for
562	watching file handles. However, you can use WxWidgets through the
563	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
564	second, which was considered to be too horrible to even consider for
565	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
566	it's adaptor.
567
568	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
569	autodetecting them.
570		829
571	=item AnyEvent::detect	830	=item AnyEvent::detect
572		831
573	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	832	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
574	if necessary. You should only call this function right before you would	833	if necessary. You should only call this function right before you would
575	have created an AnyEvent watcher anyway, that is, as late as possible at	834	have created an AnyEvent watcher anyway, that is, as late as possible at
576	runtime.	835	runtime, and not e.g. while initialising of your module.
		836
		837	If you need to do some initialisation before AnyEvent watchers are
		838	created, use C<post_detect>.
577		839
578	=item $guard = AnyEvent::post_detect { BLOCK }	840	=item $guard = AnyEvent::post_detect { BLOCK }
579		841
580	Arranges for the code block to be executed as soon as the event model is	842	Arranges for the code block to be executed as soon as the event model is
581	autodetected (or immediately if this has already happened).	843	autodetected (or immediately if this has already happened).
		844
		845	The block will be executed I<after> the actual backend has been detected
		846	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		847	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		848	other initialisations - see the sources of L<AnyEvent::Strict> or
		849	L<AnyEvent::AIO> to see how this is used.
		850
		851	The most common usage is to create some global watchers, without forcing
		852	event module detection too early, for example, L<AnyEvent::AIO> creates
		853	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		854	avoid autodetecting the event module at load time.
582		855
583	If called in scalar or list context, then it creates and returns an object	856	If called in scalar or list context, then it creates and returns an object
584	that automatically removes the callback again when it is destroyed. See	857	that automatically removes the callback again when it is destroyed. See
585	L<Coro::BDB> for a case where this is useful.	858	L<Coro::BDB> for a case where this is useful.
586		859
…		…
589	If there are any code references in this array (you can C<push> to it	862	If there are any code references in this array (you can C<push> to it
590	before or after loading AnyEvent), then they will called directly after	863	before or after loading AnyEvent), then they will called directly after
591	the event loop has been chosen.	864	the event loop has been chosen.
592		865
593	You should check C<$AnyEvent::MODEL> before adding to this array, though:	866	You should check C<$AnyEvent::MODEL> before adding to this array, though:
594	if it contains a true value then the event loop has already been detected,	867	if it is defined then the event loop has already been detected, and the
595	and the array will be ignored.	868	array will be ignored.
596		869
597	Best use C<AnyEvent::post_detect { BLOCK }> instead.	870	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		871	it,as it takes care of these details.
		872
		873	This variable is mainly useful for modules that can do something useful
		874	when AnyEvent is used and thus want to know when it is initialised, but do
		875	not need to even load it by default. This array provides the means to hook
		876	into AnyEvent passively, without loading it.
598		877
599	=back	878	=back
600		879
601	=head1 WHAT TO DO IN A MODULE	880	=head1 WHAT TO DO IN A MODULE
602		881
…		…
657		936
658		937
659	=head1 OTHER MODULES	938	=head1 OTHER MODULES
660		939
661	The following is a non-exhaustive list of additional modules that use	940	The following is a non-exhaustive list of additional modules that use
662	AnyEvent and can therefore be mixed easily with other AnyEvent modules	941	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
663	in the same program. Some of the modules come with AnyEvent, some are	942	modules and other event loops in the same program. Some of the modules
664	available via CPAN.	943	come with AnyEvent, most are available via CPAN.
665		944
666	=over 4	945	=over 4
667		946
668	=item L<AnyEvent::Util>	947	=item L<AnyEvent::Util>
669		948
670	Contains various utility functions that replace often-used but blocking	949	Contains various utility functions that replace often-used but blocking
671	functions such as C<inet_aton> by event-/callback-based versions.	950	functions such as C<inet_aton> by event-/callback-based versions.
672
673	=item L<AnyEvent::Handle>
674
675	Provide read and write buffers and manages watchers for reads and writes.
676		951
677	=item L<AnyEvent::Socket>	952	=item L<AnyEvent::Socket>
678		953
679	Provides various utility functions for (internet protocol) sockets,	954	Provides various utility functions for (internet protocol) sockets,
680	addresses and name resolution. Also functions to create non-blocking tcp	955	addresses and name resolution. Also functions to create non-blocking tcp
681	connections or tcp servers, with IPv6 and SRV record support and more.	956	connections or tcp servers, with IPv6 and SRV record support and more.
682		957
		958	=item L<AnyEvent::Handle>
		959
		960	Provide read and write buffers, manages watchers for reads and writes,
		961	supports raw and formatted I/O, I/O queued and fully transparent and
		962	non-blocking SSL/TLS (via L<AnyEvent::TLS>.
		963
683	=item L<AnyEvent::DNS>	964	=item L<AnyEvent::DNS>
684		965
685	Provides rich asynchronous DNS resolver capabilities.	966	Provides rich asynchronous DNS resolver capabilities.
686		967
		968	=item L<AnyEvent::HTTP>
		969
		970	A simple-to-use HTTP library that is capable of making a lot of concurrent
		971	HTTP requests.
		972
687	=item L<AnyEvent::HTTPD>	973	=item L<AnyEvent::HTTPD>
688		974
689	Provides a simple web application server framework.	975	Provides a simple web application server framework.
690		976
691	=item L<AnyEvent::FastPing>	977	=item L<AnyEvent::FastPing>
692		978
693	The fastest ping in the west.	979	The fastest ping in the west.
694		980
		981	=item L<AnyEvent::DBI>
		982
		983	Executes L<DBI> requests asynchronously in a proxy process.
		984
		985	=item L<AnyEvent::AIO>
		986
		987	Truly asynchronous I/O, should be in the toolbox of every event
		988	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		989	together.
		990
		991	=item L<AnyEvent::BDB>
		992
		993	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		994	L<BDB> and AnyEvent together.
		995
		996	=item L<AnyEvent::GPSD>
		997
		998	A non-blocking interface to gpsd, a daemon delivering GPS information.
		999
695	=item L<Net::IRC3>	1000	=item L<AnyEvent::IRC>
696		1001
697	AnyEvent based IRC client module family.	1002	AnyEvent based IRC client module family (replacing the older Net::IRC3).
698		1003
699	=item L<Net::XMPP2>	1004	=item L<AnyEvent::XMPP>
700		1005
701	AnyEvent based XMPP (Jabber protocol) module family.	1006	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
		1007	Net::XMPP2>.
		1008
		1009	=item L<AnyEvent::IGS>
		1010
		1011	A non-blocking interface to the Internet Go Server protocol (used by
		1012	L<App::IGS>).
702		1013
703	=item L<Net::FCP>	1014	=item L<Net::FCP>
704		1015
705	AnyEvent-based implementation of the Freenet Client Protocol, birthplace	1016	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
706	of AnyEvent.	1017	of AnyEvent.
…		…
711		1022
712	=item L<Coro>	1023	=item L<Coro>
713		1024
714	Has special support for AnyEvent via L<Coro::AnyEvent>.	1025	Has special support for AnyEvent via L<Coro::AnyEvent>.
715		1026
716	=item L<AnyEvent::AIO>, L<IO::AIO>
717
718	Truly asynchronous I/O, should be in the toolbox of every event
719	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
720	together.
721
722	=item L<AnyEvent::BDB>, L<BDB>
723
724	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
725	IO::AIO and AnyEvent together.
726
727	=item L<IO::Lambda>
728
729	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
730
731	=back	1027	=back
732		1028
733	=cut	1029	=cut
734		1030
735	package AnyEvent;	1031	package AnyEvent;
736		1032
737	no warnings;	1033	no warnings;
738	use strict;	1034	use strict qw(vars subs);
739		1035
740	use Carp;	1036	use Carp;
741		1037
742	our $VERSION = '4.05';	1038	our $VERSION = 4.82;
743	our $MODEL;	1039	our $MODEL;
744		1040
745	our $AUTOLOAD;	1041	our $AUTOLOAD;
746	our @ISA;	1042	our @ISA;
747		1043
748	our @REGISTRY;	1044	our @REGISTRY;
749		1045
750	our $WIN32;	1046	our $WIN32;
751		1047
752	BEGIN {	1048	BEGIN {
753	my $win32 = ! ! ($^O =~ /mswin32/i);	1049	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";
754	eval "sub WIN32(){ $win32 }";	1050	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";
		1051
		1052	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
		1053	if ${^TAINT};
755	}	1054	}
756		1055
757	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1056	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
758		1057
759	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1058	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
…		…
770	[Event:: => AnyEvent::Impl::Event::],	1069	[Event:: => AnyEvent::Impl::Event::],
771	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1070	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
772	# everything below here will not be autoprobed	1071	# everything below here will not be autoprobed
773	# as the pureperl backend should work everywhere	1072	# as the pureperl backend should work everywhere
774	# and is usually faster	1073	# and is usually faster
775	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
776	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1074	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
777	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1075	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1076	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
778	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1077	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
779	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1078	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
780	[Wx:: => AnyEvent::Impl::POE::],	1079	[Wx:: => AnyEvent::Impl::POE::],
781	[Prima:: => AnyEvent::Impl::POE::],	1080	[Prima:: => AnyEvent::Impl::POE::],
		1081	# IO::Async is just too broken - we would need workarounds for its
		1082	# byzantine signal and broken child handling, among others.
		1083	# IO::Async is rather hard to detect, as it doesn't have any
		1084	# obvious default class.
		1085	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1086	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1087	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
782	);	1088	);
783		1089
784	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	1090	our %method = map +($_ => 1),
		1091	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
785		1092
786	our @post_detect;	1093	our @post_detect;
787		1094
788	sub post_detect(&) {	1095	sub post_detect(&) {
789	my ($cb) = @_;	1096	my ($cb) = @_;
…		…
794	1	1101	1
795	} else {	1102	} else {
796	push @post_detect, $cb;	1103	push @post_detect, $cb;
797		1104
798	defined wantarray	1105	defined wantarray
799	? bless \$cb, "AnyEvent::Util::PostDetect"	1106	? bless \$cb, "AnyEvent::Util::postdetect"
800	: ()	1107	: ()
801	}	1108	}
802	}	1109	}
803		1110
804	sub AnyEvent::Util::PostDetect::DESTROY {	1111	sub AnyEvent::Util::postdetect::DESTROY {
805	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1112	@post_detect = grep $_ != ${$_[0]}, @post_detect;
806	}	1113	}
807		1114
808	sub detect() {	1115	sub detect() {
809	unless ($MODEL) {	1116	unless ($MODEL) {
…		…
812		1119
813	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1120	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
814	my $model = "AnyEvent::Impl::$1";	1121	my $model = "AnyEvent::Impl::$1";
815	if (eval "require $model") {	1122	if (eval "require $model") {
816	$MODEL = $model;	1123	$MODEL = $model;
817	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1124	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;
818	} else {	1125	} else {
819	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1126	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;
820	}	1127	}
821	}	1128	}
822		1129
823	# check for already loaded models	1130	# check for already loaded models
824	unless ($MODEL) {	1131	unless ($MODEL) {
…		…
846	last;	1153	last;
847	}	1154	}
848	}	1155	}
849		1156
850	$MODEL	1157	$MODEL
851	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1158	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
852	}	1159	}
853	}	1160	}
854		1161
		1162	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1163
855	unshift @ISA, $MODEL;	1164	unshift @ISA, $MODEL;
856	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1165
		1166	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
857		1167
858	(shift @post_detect)->() while @post_detect;	1168	(shift @post_detect)->() while @post_detect;
859	}	1169	}
860		1170
861	$MODEL	1171	$MODEL
…		…
871		1181
872	my $class = shift;	1182	my $class = shift;
873	$class->$func (@_);	1183	$class->$func (@_);
874	}	1184	}
875		1185
		1186	# utility function to dup a filehandle. this is used by many backends
		1187	# to support binding more than one watcher per filehandle (they usually
		1188	# allow only one watcher per fd, so we dup it to get a different one).
		1189	sub _dupfh($$;$$) {
		1190	my ($poll, $fh, $r, $w) = @_;
		1191
		1192	# cygwin requires the fh mode to be matching, unix doesn't
		1193	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");
		1194
		1195	open my $fh2, "$mode&", $fh
		1196	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
		1197
		1198	# we assume CLOEXEC is already set by perl in all important cases
		1199
		1200	($fh2, $rw)
		1201	}
		1202
876	package AnyEvent::Base;	1203	package AnyEvent::Base;
877		1204
		1205	# default implementations for many methods
		1206
		1207	BEGIN {
		1208	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1209	*_time = \&Time::HiRes::time;
		1210	# if (eval "use POSIX (); (POSIX::times())...
		1211	} else {
		1212	*_time = sub { time }; # epic fail
		1213	}
		1214	}
		1215
		1216	sub time { _time }
		1217	sub now { _time }
		1218	sub now_update { }
		1219
878	# default implementation for ->condvar	1220	# default implementation for ->condvar
879		1221
880	sub condvar {	1222	sub condvar {
881	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, AnyEvent::CondVar::	1223	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
882	}	1224	}
883		1225
884	# default implementation for ->signal	1226	# default implementation for ->signal
885		1227
886	our %SIG_CB;	1228	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1229
		1230	sub _signal_exec {
		1231	sysread $SIGPIPE_R, my $dummy, 4;
		1232
		1233	while (%SIG_EV) {
		1234	for (keys %SIG_EV) {
		1235	delete $SIG_EV{$_};
		1236	$_->() for values %{ $SIG_CB{$_} || {} };
		1237	}
		1238	}
		1239	}
887		1240
888	sub signal {	1241	sub signal {
889	my (undef, %arg) = @_;	1242	my (undef, %arg) = @_;
890		1243
		1244	unless ($SIGPIPE_R) {
		1245	require Fcntl;
		1246
		1247	if (AnyEvent::WIN32) {
		1248	require AnyEvent::Util;
		1249
		1250	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1251	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1252	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1253	} else {
		1254	pipe $SIGPIPE_R, $SIGPIPE_W;
		1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1257
		1258	# not strictly required, as $^F is normally 2, but let's make sure...
		1259	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1260	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1261	}
		1262
		1263	$SIGPIPE_R
		1264	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1265
		1266	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1267	}
		1268
891	my $signal = uc $arg{signal}	1269	my $signal = uc $arg{signal}
892	or Carp::croak "required option 'signal' is missing";	1270	or Carp::croak "required option 'signal' is missing";
893		1271
894	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1272	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
895	$SIG{$signal} ||= sub {	1273	$SIG{$signal} ||= sub {
896	$_->() for values %{ $SIG_CB{$signal} || {} };	1274	local $!;
		1275	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1276	undef $SIG_EV{$signal};
897	};	1277	};
898		1278
899	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1279	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
900	}	1280	}
901		1281
902	sub AnyEvent::Base::Signal::DESTROY {	1282	sub AnyEvent::Base::signal::DESTROY {
903	my ($signal, $cb) = @{$_[0]};	1283	my ($signal, $cb) = @{$_[0]};
904		1284
905	delete $SIG_CB{$signal}{$cb};	1285	delete $SIG_CB{$signal}{$cb};
906		1286
		1287	# delete doesn't work with older perls - they then
		1288	# print weird messages, or just unconditionally exit
		1289	# instead of getting the default action.
907	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1290	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
908	}	1291	}
909		1292
910	# default implementation for ->child	1293	# default implementation for ->child
911		1294
912	our %PID_CB;	1295	our %PID_CB;
913	our $CHLD_W;	1296	our $CHLD_W;
914	our $CHLD_DELAY_W;	1297	our $CHLD_DELAY_W;
915	our $PID_IDLE;
916	our $WNOHANG;	1298	our $WNOHANG;
917		1299
918	sub _child_wait {	1300	sub _sigchld {
919	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1301	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
920	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1302	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
921	(values %{ $PID_CB{0} || {} });	1303	(values %{ $PID_CB{0} || {} });
922	}	1304	}
923
924	undef $PID_IDLE;
925	}
926
927	sub _sigchld {
928	# make sure we deliver these changes "synchronous" with the event loop.
929	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
930	undef $CHLD_DELAY_W;
931	&_child_wait;
932	});
933	}	1305	}
934		1306
935	sub child {	1307	sub child {
936	my (undef, %arg) = @_;	1308	my (undef, %arg) = @_;
937		1309
938	defined (my $pid = $arg{pid} + 0)	1310	defined (my $pid = $arg{pid} + 0)
939	or Carp::croak "required option 'pid' is missing";	1311	or Carp::croak "required option 'pid' is missing";
940		1312
941	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1313	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
942		1314
943	unless ($WNOHANG) {
944	$WNOHANG = eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1315	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
945	}
946		1316
947	unless ($CHLD_W) {	1317	unless ($CHLD_W) {
948	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1318	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
949	# child could be a zombie already, so make at least one round	1319	# child could be a zombie already, so make at least one round
950	&_sigchld;	1320	&_sigchld;
951	}	1321	}
952		1322
953	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1323	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
954	}	1324	}
955		1325
956	sub AnyEvent::Base::Child::DESTROY {	1326	sub AnyEvent::Base::child::DESTROY {
957	my ($pid, $cb) = @{$_[0]};	1327	my ($pid, $cb) = @{$_[0]};
958		1328
959	delete $PID_CB{$pid}{$cb};	1329	delete $PID_CB{$pid}{$cb};
960	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1330	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
961		1331
962	undef $CHLD_W unless keys %PID_CB;	1332	undef $CHLD_W unless keys %PID_CB;
		1333	}
		1334
		1335	# idle emulation is done by simply using a timer, regardless
		1336	# of whether the process is idle or not, and not letting
		1337	# the callback use more than 50% of the time.
		1338	sub idle {
		1339	my (undef, %arg) = @_;
		1340
		1341	my ($cb, $w, $rcb) = $arg{cb};
		1342
		1343	$rcb = sub {
		1344	if ($cb) {
		1345	$w = _time;
		1346	&$cb;
		1347	$w = _time - $w;
		1348
		1349	# never use more then 50% of the time for the idle watcher,
		1350	# within some limits
		1351	$w = 0.0001 if $w < 0.0001;
		1352	$w = 5 if $w > 5;
		1353
		1354	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1355	} else {
		1356	# clean up...
		1357	undef $w;
		1358	undef $rcb;
		1359	}
		1360	};
		1361
		1362	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1363
		1364	bless \\$cb, "AnyEvent::Base::idle"
		1365	}
		1366
		1367	sub AnyEvent::Base::idle::DESTROY {
		1368	undef $${$_[0]};
963	}	1369	}
964		1370
965	package AnyEvent::CondVar;	1371	package AnyEvent::CondVar;
966		1372
967	our @ISA = AnyEvent::CondVar::Base::;	1373	our @ISA = AnyEvent::CondVar::Base::;
…		…
1019	}	1425	}
1020		1426
1021	# undocumented/compatibility with pre-3.4	1427	# undocumented/compatibility with pre-3.4
1022	*broadcast = \&send;	1428	*broadcast = \&send;
1023	*wait = \&_wait;	1429	*wait = \&_wait;
		1430
		1431	=head1 ERROR AND EXCEPTION HANDLING
		1432
		1433	In general, AnyEvent does not do any error handling - it relies on the
		1434	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1435	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1436	checking of all AnyEvent methods, however, which is highly useful during
		1437	development.
		1438
		1439	As for exception handling (i.e. runtime errors and exceptions thrown while
		1440	executing a callback), this is not only highly event-loop specific, but
		1441	also not in any way wrapped by this module, as this is the job of the main
		1442	program.
		1443
		1444	The pure perl event loop simply re-throws the exception (usually
		1445	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1446	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1447	so on.
		1448
		1449	=head1 ENVIRONMENT VARIABLES
		1450
		1451	The following environment variables are used by this module or its
		1452	submodules.
		1453
		1454	Note that AnyEvent will remove I<all> environment variables starting with
		1455	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		1456	enabled.
		1457
		1458	=over 4
		1459
		1460	=item C<PERL_ANYEVENT_VERBOSE>
		1461
		1462	By default, AnyEvent will be completely silent except in fatal
		1463	conditions. You can set this environment variable to make AnyEvent more
		1464	talkative.
		1465
		1466	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1467	conditions, such as not being able to load the event model specified by
		1468	C<PERL_ANYEVENT_MODEL>.
		1469
		1470	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1471	model it chooses.
		1472
		1473	=item C<PERL_ANYEVENT_STRICT>
		1474
		1475	AnyEvent does not do much argument checking by default, as thorough
		1476	argument checking is very costly. Setting this variable to a true value
		1477	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1478	check the arguments passed to most method calls. If it finds any problems,
		1479	it will croak.
		1480
		1481	In other words, enables "strict" mode.
		1482
		1483	Unlike C<use strict>, it is definitely recommended to keep it off in
		1484	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1485	developing programs can be very useful, however.
		1486
		1487	=item C<PERL_ANYEVENT_MODEL>
		1488
		1489	This can be used to specify the event model to be used by AnyEvent, before
		1490	auto detection and -probing kicks in. It must be a string consisting
		1491	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1492	and the resulting module name is loaded and if the load was successful,
		1493	used as event model. If it fails to load AnyEvent will proceed with
		1494	auto detection and -probing.
		1495
		1496	This functionality might change in future versions.
		1497
		1498	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1499	could start your program like this:
		1500
		1501	PERL_ANYEVENT_MODEL=Perl perl ...
		1502
		1503	=item C<PERL_ANYEVENT_PROTOCOLS>
		1504
		1505	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1506	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1507	of auto probing).
		1508
		1509	Must be set to a comma-separated list of protocols or address families,
		1510	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1511	used, and preference will be given to protocols mentioned earlier in the
		1512	list.
		1513
		1514	This variable can effectively be used for denial-of-service attacks
		1515	against local programs (e.g. when setuid), although the impact is likely
		1516	small, as the program has to handle conenction and other failures anyways.
		1517
		1518	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1519	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1520	- only support IPv4, never try to resolve or contact IPv6
		1521	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1522	IPv6, but prefer IPv6 over IPv4.
		1523
		1524	=item C<PERL_ANYEVENT_EDNS0>
		1525
		1526	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1527	for DNS. This extension is generally useful to reduce DNS traffic, but
		1528	some (broken) firewalls drop such DNS packets, which is why it is off by
		1529	default.
		1530
		1531	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1532	EDNS0 in its DNS requests.
		1533
		1534	=item C<PERL_ANYEVENT_MAX_FORKS>
		1535
		1536	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1537	will create in parallel.
		1538
		1539	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		1540
		1541	The default value for the C<max_outstanding> parameter for the default DNS
		1542	resolver - this is the maximum number of parallel DNS requests that are
		1543	sent to the DNS server.
		1544
		1545	=item C<PERL_ANYEVENT_RESOLV_CONF>
		1546
		1547	The file to use instead of F</etc/resolv.conf> (or OS-specific
		1548	configuration) in the default resolver. When set to the empty string, no
		1549	default config will be used.
		1550
		1551	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		1552
		1553	When neither C<ca_file> nor C<ca_path> was specified during
		1554	L<AnyEvent::TLS> context creation, and either of these environment
		1555	variables exist, they will be used to specify CA certificate locations
		1556	instead of a system-dependent default.
		1557
		1558	=back
1024		1559
1025	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1560	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1026		1561
1027	This is an advanced topic that you do not normally need to use AnyEvent in	1562	This is an advanced topic that you do not normally need to use AnyEvent in
1028	a module. This section is only of use to event loop authors who want to	1563	a module. This section is only of use to event loop authors who want to
…		…
1062		1597
1063	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1598	I<rxvt-unicode> also cheats a bit by not providing blocking access to
1064	condition variables: code blocking while waiting for a condition will	1599	condition variables: code blocking while waiting for a condition will
1065	C<die>. This still works with most modules/usages, and blocking calls must	1600	C<die>. This still works with most modules/usages, and blocking calls must
1066	not be done in an interactive application, so it makes sense.	1601	not be done in an interactive application, so it makes sense.
1067
1068	=head1 ENVIRONMENT VARIABLES
1069
1070	The following environment variables are used by this module:
1071
1072	=over 4
1073
1074	=item C<PERL_ANYEVENT_VERBOSE>
1075
1076	By default, AnyEvent will be completely silent except in fatal
1077	conditions. You can set this environment variable to make AnyEvent more
1078	talkative.
1079
1080	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1081	conditions, such as not being able to load the event model specified by
1082	C<PERL_ANYEVENT_MODEL>.
1083
1084	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1085	model it chooses.
1086
1087	=item C<PERL_ANYEVENT_MODEL>
1088
1089	This can be used to specify the event model to be used by AnyEvent, before
1090	auto detection and -probing kicks in. It must be a string consisting
1091	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1092	and the resulting module name is loaded and if the load was successful,
1093	used as event model. If it fails to load AnyEvent will proceed with
1094	auto detection and -probing.
1095
1096	This functionality might change in future versions.
1097
1098	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1099	could start your program like this:
1100
1101	PERL_ANYEVENT_MODEL=Perl perl ...
1102
1103	=item C<PERL_ANYEVENT_PROTOCOLS>
1104
1105	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
1106	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
1107	of auto probing).
1108
1109	Must be set to a comma-separated list of protocols or address families,
1110	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
1111	used, and preference will be given to protocols mentioned earlier in the
1112	list.
1113
1114	This variable can effectively be used for denial-of-service attacks
1115	against local programs (e.g. when setuid), although the impact is likely
1116	small, as the program has to handle connection errors already-
1117
1118	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
1119	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1120	- only support IPv4, never try to resolve or contact IPv6
1121	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1122	IPv6, but prefer IPv6 over IPv4.
1123
1124	=item C<PERL_ANYEVENT_EDNS0>
1125
1126	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
1127	for DNS. This extension is generally useful to reduce DNS traffic, but
1128	some (broken) firewalls drop such DNS packets, which is why it is off by
1129	default.
1130
1131	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1132	EDNS0 in its DNS requests.
1133
1134	=item C<PERL_ANYEVENT_MAX_FORKS>
1135
1136	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1137	will create in parallel.
1138
1139	=back
1140		1602
1141	=head1 EXAMPLE PROGRAM	1603	=head1 EXAMPLE PROGRAM
1142		1604
1143	The following program uses an I/O watcher to read data from STDIN, a timer	1605	The following program uses an I/O watcher to read data from STDIN, a timer
1144	to display a message once per second, and a condition variable to quit the	1606	to display a message once per second, and a condition variable to quit the
…		…
1338	watcher.	1800	watcher.
1339		1801
1340	=head3 Results	1802	=head3 Results
1341		1803
1342	name watchers bytes create invoke destroy comment	1804	name watchers bytes create invoke destroy comment
1343	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1805	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1344	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1806	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1345	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1807	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1346	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1808	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1347	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1809	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1348	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1810	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
		1811	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll
		1812	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll
1349	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1813	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1350	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1814	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1351	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1815	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1352	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1816	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1353		1817
1354	=head3 Discussion	1818	=head3 Discussion
1355		1819
1356	The benchmark does I<not> measure scalability of the event loop very	1820	The benchmark does I<not> measure scalability of the event loop very
1357	well. For example, a select-based event loop (such as the pure perl one)	1821	well. For example, a select-based event loop (such as the pure perl one)
…		…
1382	performance becomes really bad with lots of file descriptors (and few of	1846	performance becomes really bad with lots of file descriptors (and few of
1383	them active), of course, but this was not subject of this benchmark.	1847	them active), of course, but this was not subject of this benchmark.
1384		1848
1385	The C<Event> module has a relatively high setup and callback invocation	1849	The C<Event> module has a relatively high setup and callback invocation
1386	cost, but overall scores in on the third place.	1850	cost, but overall scores in on the third place.
		1851
		1852	C<IO::Async> performs admirably well, about on par with C<Event>, even
		1853	when using its pure perl backend.
1387		1854
1388	C<Glib>'s memory usage is quite a bit higher, but it features a	1855	C<Glib>'s memory usage is quite a bit higher, but it features a
1389	faster callback invocation and overall ends up in the same class as	1856	faster callback invocation and overall ends up in the same class as
1390	C<Event>. However, Glib scales extremely badly, doubling the number of	1857	C<Event>. However, Glib scales extremely badly, doubling the number of
1391	watchers increases the processing time by more than a factor of four,	1858	watchers increases the processing time by more than a factor of four,
…		…
1469	it to another server. This includes deleting the old timeout and creating	1936	it to another server. This includes deleting the old timeout and creating
1470	a new one that moves the timeout into the future.	1937	a new one that moves the timeout into the future.
1471		1938
1472	=head3 Results	1939	=head3 Results
1473		1940
1474	name sockets create request	1941	name sockets create request
1475	EV 20000 69.01 11.16	1942	EV 20000 69.01 11.16
1476	Perl 20000 73.32 35.87	1943	Perl 20000 73.32 35.87
		1944	IOAsync 20000 157.00 98.14 epoll
		1945	IOAsync 20000 159.31 616.06 poll
1477	Event 20000 212.62 257.32	1946	Event 20000 212.62 257.32
1478	Glib 20000 651.16 1896.30	1947	Glib 20000 651.16 1896.30
1479	POE 20000 349.67 12317.24 uses POE::Loop::Event	1948	POE 20000 349.67 12317.24 uses POE::Loop::Event
1480		1949
1481	=head3 Discussion	1950	=head3 Discussion
1482		1951
1483	This benchmark I<does> measure scalability and overall performance of the	1952	This benchmark I<does> measure scalability and overall performance of the
1484	particular event loop.	1953	particular event loop.
…		…
1486	EV is again fastest. Since it is using epoll on my system, the setup time	1955	EV is again fastest. Since it is using epoll on my system, the setup time
1487	is relatively high, though.	1956	is relatively high, though.
1488		1957
1489	Perl surprisingly comes second. It is much faster than the C-based event	1958	Perl surprisingly comes second. It is much faster than the C-based event
1490	loops Event and Glib.	1959	loops Event and Glib.
		1960
		1961	IO::Async performs very well when using its epoll backend, and still quite
		1962	good compared to Glib when using its pure perl backend.
1491		1963
1492	Event suffers from high setup time as well (look at its code and you will	1964	Event suffers from high setup time as well (look at its code and you will
1493	understand why). Callback invocation also has a high overhead compared to	1965	understand why). Callback invocation also has a high overhead compared to
1494	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event	1966	the C<< $_->() for .. >>-style loop that the Perl event loop uses. Event
1495	uses select or poll in basically all documented configurations.	1967	uses select or poll in basically all documented configurations.
…		…
1558	=item * C-based event loops perform very well with small number of	2030	=item * C-based event loops perform very well with small number of
1559	watchers, as the management overhead dominates.	2031	watchers, as the management overhead dominates.
1560		2032
1561	=back	2033	=back
1562		2034
		2035	=head2 THE IO::Lambda BENCHMARK
		2036
		2037	Recently I was told about the benchmark in the IO::Lambda manpage, which
		2038	could be misinterpreted to make AnyEvent look bad. In fact, the benchmark
		2039	simply compares IO::Lambda with POE, and IO::Lambda looks better (which
		2040	shouldn't come as a surprise to anybody). As such, the benchmark is
		2041	fine, and mostly shows that the AnyEvent backend from IO::Lambda isn't
		2042	very optimal. But how would AnyEvent compare when used without the extra
		2043	baggage? To explore this, I wrote the equivalent benchmark for AnyEvent.
		2044
		2045	The benchmark itself creates an echo-server, and then, for 500 times,
		2046	connects to the echo server, sends a line, waits for the reply, and then
		2047	creates the next connection. This is a rather bad benchmark, as it doesn't
		2048	test the efficiency of the framework or much non-blocking I/O, but it is a
		2049	benchmark nevertheless.
		2050
		2051	name runtime
		2052	Lambda/select 0.330 sec
		2053	+ optimized 0.122 sec
		2054	Lambda/AnyEvent 0.327 sec
		2055	+ optimized 0.138 sec
		2056	Raw sockets/select 0.077 sec
		2057	POE/select, components 0.662 sec
		2058	POE/select, raw sockets 0.226 sec
		2059	POE/select, optimized 0.404 sec
		2060
		2061	AnyEvent/select/nb 0.085 sec
		2062	AnyEvent/EV/nb 0.068 sec
		2063	+state machine 0.134 sec
		2064
		2065	The benchmark is also a bit unfair (my fault): the IO::Lambda/POE
		2066	benchmarks actually make blocking connects and use 100% blocking I/O,
		2067	defeating the purpose of an event-based solution. All of the newly
		2068	written AnyEvent benchmarks use 100% non-blocking connects (using
		2069	AnyEvent::Socket::tcp_connect and the asynchronous pure perl DNS
		2070	resolver), so AnyEvent is at a disadvantage here, as non-blocking connects
		2071	generally require a lot more bookkeeping and event handling than blocking
		2072	connects (which involve a single syscall only).
		2073
		2074	The last AnyEvent benchmark additionally uses L<AnyEvent::Handle>, which
		2075	offers similar expressive power as POE and IO::Lambda, using conventional
		2076	Perl syntax. This means that both the echo server and the client are 100%
		2077	non-blocking, further placing it at a disadvantage.
		2078
		2079	As you can see, the AnyEvent + EV combination even beats the
		2080	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
		2081	backend easily beats IO::Lambda and POE.
		2082
		2083	And even the 100% non-blocking version written using the high-level (and
		2084	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a
		2085	large margin, even though it does all of DNS, tcp-connect and socket I/O
		2086	in a non-blocking way.
		2087
		2088	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
		2089	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
		2090	part of the IO::lambda distribution and were used without any changes.
		2091
		2092
		2093	=head1 SIGNALS
		2094
		2095	AnyEvent currently installs handlers for these signals:
		2096
		2097	=over 4
		2098
		2099	=item SIGCHLD
		2100
		2101	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		2102	emulation for event loops that do not support them natively. Also, some
		2103	event loops install a similar handler.
		2104
		2105	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
		2106	AnyEvent will reset it to default, to avoid losing child exit statuses.
		2107
		2108	=item SIGPIPE
		2109
		2110	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		2111	when AnyEvent gets loaded.
		2112
		2113	The rationale for this is that AnyEvent users usually do not really depend
		2114	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		2115	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		2116	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		2117	some random socket.
		2118
		2119	The rationale for installing a no-op handler as opposed to ignoring it is
		2120	that this way, the handler will be restored to defaults on exec.
		2121
		2122	Feel free to install your own handler, or reset it to defaults.
		2123
		2124	=back
		2125
		2126	=cut
		2127
		2128	undef $SIG{CHLD}
		2129	if $SIG{CHLD} eq 'IGNORE';
		2130
		2131	$SIG{PIPE} = sub { }
		2132	unless defined $SIG{PIPE};
1563		2133
1564	=head1 FORK	2134	=head1 FORK
1565		2135
1566	Most event libraries are not fork-safe. The ones who are usually are	2136	Most event libraries are not fork-safe. The ones who are usually are
1567	because they rely on inefficient but fork-safe C<select> or C<poll>	2137	because they rely on inefficient but fork-safe C<select> or C<poll>
…		…
1581	specified in the variable.	2151	specified in the variable.
1582		2152
1583	You can make AnyEvent completely ignore this variable by deleting it	2153	You can make AnyEvent completely ignore this variable by deleting it
1584	before the first watcher gets created, e.g. with a C<BEGIN> block:	2154	before the first watcher gets created, e.g. with a C<BEGIN> block:
1585		2155
1586	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	2156	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1587		2157
1588	use AnyEvent;	2158	use AnyEvent;
1589		2159
1590	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	2160	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1591	be used to probe what backend is used and gain other information (which is	2161	be used to probe what backend is used and gain other information (which is
1592	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	2162	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		2163	$ENV{PERL_ANYEVENT_STRICT}.
		2164
		2165	Note that AnyEvent will remove I<all> environment variables starting with
		2166	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is
		2167	enabled.
		2168
		2169
		2170	=head1 BUGS
		2171
		2172	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		2173	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		2174	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		2175	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		2176	pronounced).
1593		2177
1594		2178
1595	=head1 SEE ALSO	2179	=head1 SEE ALSO
1596		2180
1597	Utility functions: L<AnyEvent::Util>.	2181	Utility functions: L<AnyEvent::Util>.
…		…
1600	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2184	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1601		2185
1602	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2186	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1603	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2187	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1604	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2188	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1605	L<AnyEvent::Impl::POE>.	2189	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.
1606		2190
1607	Non-blocking file handles, sockets, TCP clients and	2191	Non-blocking file handles, sockets, TCP clients and
1608	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2192	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
1609		2193
1610	Asynchronous DNS: L<AnyEvent::DNS>.	2194	Asynchronous DNS: L<AnyEvent::DNS>.
1611		2195
1612	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2196	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,
		2197	L<Coro::Event>,
1613		2198
1614	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2199	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,
		2200	L<AnyEvent::HTTP>.
1615		2201
1616		2202
1617	=head1 AUTHOR	2203	=head1 AUTHOR
1618		2204
1619	Marc Lehmann <schmorp@schmorp.de>	2205	Marc Lehmann <schmorp@schmorp.de>
1620	http://home.schmorp.de/	2206	http://home.schmorp.de/
1621		2207
1622	=cut	2208	=cut
1623		2209
1624	1	2210	1
1625		2211

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