ViewVC Help

View File | Revision Log | Show Annotations | Download File

/cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.117 by root, Sun May 11 17:54:13 2008 UTC vs.
Revision 1.210 by root, Wed May 13 15:19:43 2009 UTC

…		…
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
		11	# file descriptor readable
11	my $w = AnyEvent->io (fh => $fh, poll => "r|w", cb => sub {	12	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
		13
		14	# one-shot or repeating timers
		15	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
		16	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...
		17
		18	print AnyEvent->now; # prints current event loop time
		19	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
		20
		21	# POSIX signal
		22	my $w = AnyEvent->signal (signal => "TERM", cb => sub { ... });
		23
		24	# child process exit
		25	my $w = AnyEvent->child (pid => $pid, cb => sub {
		26	my ($pid, $status) = @_;
12	...	27	...
13	});	28	});
14		29
15	my $w = AnyEvent->timer (after => $seconds, cb => sub {	30	# called when event loop idle (if applicable)
16	...	31	my $w = AnyEvent->idle (cb => sub { ... });
17	});
18		32
19	my $w = AnyEvent->condvar; # stores whether a condition was flagged	33	my $w = AnyEvent->condvar; # stores whether a condition was flagged
20	$w->send; # wake up current and all future recv's	34	$w->send; # wake up current and all future recv's
21	$w->recv; # enters "main loop" till $condvar gets ->send	35	$w->recv; # enters "main loop" till $condvar gets ->send
		36	# use a condvar in callback mode:
		37	$w->cb (sub { $_[0]->recv });
		38
		39	=head1 INTRODUCTION/TUTORIAL
		40
		41	This manpage is mainly a reference manual. If you are interested
		42	in a tutorial or some gentle introduction, have a look at the
		43	L<AnyEvent::Intro> manpage.
22		44
23	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	45	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
24		46
25	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	47	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
26	nowadays. So what is different about AnyEvent?	48	nowadays. So what is different about AnyEvent?
27		49
28	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of	50	Executive Summary: AnyEvent is I<compatible>, AnyEvent is I<free of
29	policy> and AnyEvent is I<small and efficient>.	51	policy> and AnyEvent is I<small and efficient>.
30		52
31	First and foremost, I<AnyEvent is not an event model> itself, it only	53	First and foremost, I<AnyEvent is not an event model> itself, it only
32	interfaces to whatever event model the main program happens to use in a	54	interfaces to whatever event model the main program happens to use, in a
33	pragmatic way. For event models and certain classes of immortals alike,	55	pragmatic way. For event models and certain classes of immortals alike,
34	the statement "there can only be one" is a bitter reality: In general,	56	the statement "there can only be one" is a bitter reality: In general,
35	only one event loop can be active at the same time in a process. AnyEvent	57	only one event loop can be active at the same time in a process. AnyEvent
36	helps hiding the differences between those event loops.	58	cannot change this, but it can hide the differences between those event
		59	loops.
37		60
38	The goal of AnyEvent is to offer module authors the ability to do event	61	The goal of AnyEvent is to offer module authors the ability to do event
39	programming (waiting for I/O or timer events) without subscribing to a	62	programming (waiting for I/O or timer events) without subscribing to a
40	religion, a way of living, and most importantly: without forcing your	63	religion, a way of living, and most importantly: without forcing your
41	module users into the same thing by forcing them to use the same event	64	module users into the same thing by forcing them to use the same event
42	model you use.	65	model you use.
43		66
44	For modules like POE or IO::Async (which is a total misnomer as it is	67	For modules like POE or IO::Async (which is a total misnomer as it is
45	actually doing all I/O I<synchronously>...), using them in your module is	68	actually doing all I/O I<synchronously>...), using them in your module is
46	like joining a cult: After you joined, you are dependent on them and you	69	like joining a cult: After you joined, you are dependent on them and you
47	cannot use anything else, as it is simply incompatible to everything that	70	cannot use anything else, as they are simply incompatible to everything
48	isn't itself. What's worse, all the potential users of your module are	71	that isn't them. What's worse, all the potential users of your
49	I<also> forced to use the same event loop you use.	72	module are I<also> forced to use the same event loop you use.
50		73
51	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	74	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
52	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	75	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
53	with the rest: POE + IO::Async? no go. Tk + Event? no go. Again: if	76	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
54	your module uses one of those, every user of your module has to use it,	77	your module uses one of those, every user of your module has to use it,
55	too. But if your module uses AnyEvent, it works transparently with all	78	too. But if your module uses AnyEvent, it works transparently with all
56	event models it supports (including stuff like POE and IO::Async, as long	79	event models it supports (including stuff like IO::Async, as long as those
57	as those use one of the supported event loops. It is trivial to add new	80	use one of the supported event loops. It is trivial to add new event loops
58	event loops to AnyEvent, too, so it is future-proof).	81	to AnyEvent, too, so it is future-proof).
59		82
60	In addition to being free of having to use I<the one and only true event	83	In addition to being free of having to use I<the one and only true event
61	model>, AnyEvent also is free of bloat and policy: with POE or similar	84	model>, AnyEvent also is free of bloat and policy: with POE or similar
62	modules, you get an enourmous amount of code and strict rules you have to	85	modules, you get an enormous amount of code and strict rules you have to
63	follow. AnyEvent, on the other hand, is lean and up to the point, by only	86	follow. AnyEvent, on the other hand, is lean and up to the point, by only
64	offering the functionality that is necessary, in as thin as a wrapper as	87	offering the functionality that is necessary, in as thin as a wrapper as
65	technically possible.	88	technically possible.
66		89
		90	Of course, AnyEvent comes with a big (and fully optional!) toolbox
		91	of useful functionality, such as an asynchronous DNS resolver, 100%
		92	non-blocking connects (even with TLS/SSL, IPv6 and on broken platforms
		93	such as Windows) and lots of real-world knowledge and workarounds for
		94	platform bugs and differences.
		95
67	Of course, if you want lots of policy (this can arguably be somewhat	96	Now, if you I<do want> lots of policy (this can arguably be somewhat
68	useful) and you want to force your users to use the one and only event	97	useful) and you want to force your users to use the one and only event
69	model, you should I<not> use this module.	98	model, you should I<not> use this module.
70		99
71	=head1 DESCRIPTION	100	=head1 DESCRIPTION
72		101
…		…
102	starts using it, all bets are off. Maybe you should tell their authors to	131	starts using it, all bets are off. Maybe you should tell their authors to
103	use AnyEvent so their modules work together with others seamlessly...	132	use AnyEvent so their modules work together with others seamlessly...
104		133
105	The pure-perl implementation of AnyEvent is called	134	The pure-perl implementation of AnyEvent is called
106	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	135	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
107	explicitly.	136	explicitly and enjoy the high availability of that event loop :)
108		137
109	=head1 WATCHERS	138	=head1 WATCHERS
110		139
111	AnyEvent has the central concept of a I<watcher>, which is an object that	140	AnyEvent has the central concept of a I<watcher>, which is an object that
112	stores relevant data for each kind of event you are waiting for, such as	141	stores relevant data for each kind of event you are waiting for, such as
113	the callback to call, the filehandle to watch, etc.	142	the callback to call, the file handle to watch, etc.
114		143
115	These watchers are normal Perl objects with normal Perl lifetime. After	144	These watchers are normal Perl objects with normal Perl lifetime. After
116	creating a watcher it will immediately "watch" for events and invoke the	145	creating a watcher it will immediately "watch" for events and invoke the
117	callback when the event occurs (of course, only when the event model	146	callback when the event occurs (of course, only when the event model
118	is in control).	147	is in control).
119		148
		149	Note that B<callbacks must not permanently change global variables>
		150	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
		151	callbacks must not C<die> >>. The former is good programming practise in
		152	Perl and the latter stems from the fact that exception handling differs
		153	widely between event loops.
		154
120	To disable the watcher you have to destroy it (e.g. by setting the	155	To disable the watcher you have to destroy it (e.g. by setting the
121	variable you store it in to C<undef> or otherwise deleting all references	156	variable you store it in to C<undef> or otherwise deleting all references
122	to it).	157	to it).
123		158
124	All watchers are created by calling a method on the C<AnyEvent> class.	159	All watchers are created by calling a method on the C<AnyEvent> class.
…		…
126	Many watchers either are used with "recursion" (repeating timers for	161	Many watchers either are used with "recursion" (repeating timers for
127	example), or need to refer to their watcher object in other ways.	162	example), or need to refer to their watcher object in other ways.
128		163
129	An any way to achieve that is this pattern:	164	An any way to achieve that is this pattern:
130		165
131	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	166	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
132	# you can use $w here, for example to undef it	167	# you can use $w here, for example to undef it
133	undef $w;	168	undef $w;
134	});	169	});
135		170
136	Note that C<my $w; $w => combination. This is necessary because in Perl,	171	Note that C<my $w; $w => combination. This is necessary because in Perl,
137	my variables are only visible after the statement in which they are	172	my variables are only visible after the statement in which they are
138	declared.	173	declared.
139		174
140	=head2 I/O WATCHERS	175	=head2 I/O WATCHERS
141		176
142	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	177	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
143	with the following mandatory key-value pairs as arguments:	178	with the following mandatory key-value pairs as arguments:
144		179
145	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch	180	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch
		181	for events (AnyEvent might or might not keep a reference to this file
		182	handle). Note that only file handles pointing to things for which
		183	non-blocking operation makes sense are allowed. This includes sockets,
		184	most character devices, pipes, fifos and so on, but not for example files
		185	or block devices.
		186
146	for events. C<poll> must be a string that is either C<r> or C<w>,	187	C<poll> must be a string that is either C<r> or C<w>, which creates a
147	which creates a watcher waiting for "r"eadable or "w"ritable events,	188	watcher waiting for "r"eadable or "w"ritable events, respectively.
		189
148	respectively. C<cb> is the callback to invoke each time the file handle	190	C<cb> is the callback to invoke each time the file handle becomes ready.
149	becomes ready.
150		191
151	Although the callback might get passed parameters, their value and	192	Although the callback might get passed parameters, their value and
152	presence is undefined and you cannot rely on them. Portable AnyEvent	193	presence is undefined and you cannot rely on them. Portable AnyEvent
153	callbacks cannot use arguments passed to I/O watcher callbacks.	194	callbacks cannot use arguments passed to I/O watcher callbacks.
154		195
…		…
158		199
159	Some event loops issue spurious readyness notifications, so you should	200	Some event loops issue spurious readyness notifications, so you should
160	always use non-blocking calls when reading/writing from/to your file	201	always use non-blocking calls when reading/writing from/to your file
161	handles.	202	handles.
162		203
163	Example:
164
165	# wait for readability of STDIN, then read a line and disable the watcher	204	Example: wait for readability of STDIN, then read a line and disable the
		205	watcher.
		206
166	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {	207	my $w; $w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
167	chomp (my $input = <STDIN>);	208	chomp (my $input = <STDIN>);
168	warn "read: $input\n";	209	warn "read: $input\n";
169	undef $w;	210	undef $w;
170	});	211	});
…		…
180		221
181	Although the callback might get passed parameters, their value and	222	Although the callback might get passed parameters, their value and
182	presence is undefined and you cannot rely on them. Portable AnyEvent	223	presence is undefined and you cannot rely on them. Portable AnyEvent
183	callbacks cannot use arguments passed to time watcher callbacks.	224	callbacks cannot use arguments passed to time watcher callbacks.
184		225
185	The timer callback will be invoked at most once: if you want a repeating	226	The callback will normally be invoked once only. If you specify another
186	timer you have to create a new watcher (this is a limitation by both Tk	227	parameter, C<interval>, as a strictly positive number (> 0), then the
187	and Glib).	228	callback will be invoked regularly at that interval (in fractional
		229	seconds) after the first invocation. If C<interval> is specified with a
		230	false value, then it is treated as if it were missing.
188		231
189	Example:	232	The callback will be rescheduled before invoking the callback, but no
		233	attempt is done to avoid timer drift in most backends, so the interval is
		234	only approximate.
190		235
191	# fire an event after 7.7 seconds	236	Example: fire an event after 7.7 seconds.
		237
192	my $w = AnyEvent->timer (after => 7.7, cb => sub {	238	my $w = AnyEvent->timer (after => 7.7, cb => sub {
193	warn "timeout\n";	239	warn "timeout\n";
194	});	240	});
195		241
196	# to cancel the timer:	242	# to cancel the timer:
197	undef $w;	243	undef $w;
198		244
199	Example 2:
200
201	# fire an event after 0.5 seconds, then roughly every second	245	Example 2: fire an event after 0.5 seconds, then roughly every second.
202	my $w;
203		246
204	my $cb = sub {
205	# cancel the old timer while creating a new one
206	$w = AnyEvent->timer (after => 1, cb => $cb);	247	my $w = AnyEvent->timer (after => 0.5, interval => 1, cb => sub {
		248	warn "timeout\n";
207	};	249	};
208
209	# start the "loop" by creating the first watcher
210	$w = AnyEvent->timer (after => 0.5, cb => $cb);
211		250
212	=head3 TIMING ISSUES	251	=head3 TIMING ISSUES
213		252
214	There are two ways to handle timers: based on real time (relative, "fire	253	There are two ways to handle timers: based on real time (relative, "fire
215	in 10 seconds") and based on wallclock time (absolute, "fire at 12	254	in 10 seconds") and based on wallclock time (absolute, "fire at 12
…		…
227	timers.	266	timers.
228		267
229	AnyEvent always prefers relative timers, if available, matching the	268	AnyEvent always prefers relative timers, if available, matching the
230	AnyEvent API.	269	AnyEvent API.
231		270
		271	AnyEvent has two additional methods that return the "current time":
		272
		273	=over 4
		274
		275	=item AnyEvent->time
		276
		277	This returns the "current wallclock time" as a fractional number of
		278	seconds since the Epoch (the same thing as C<time> or C<Time::HiRes::time>
		279	return, and the result is guaranteed to be compatible with those).
		280
		281	It progresses independently of any event loop processing, i.e. each call
		282	will check the system clock, which usually gets updated frequently.
		283
		284	=item AnyEvent->now
		285
		286	This also returns the "current wallclock time", but unlike C<time>, above,
		287	this value might change only once per event loop iteration, depending on
		288	the event loop (most return the same time as C<time>, above). This is the
		289	time that AnyEvent's timers get scheduled against.
		290
		291	I<In almost all cases (in all cases if you don't care), this is the
		292	function to call when you want to know the current time.>
		293
		294	This function is also often faster then C<< AnyEvent->time >>, and
		295	thus the preferred method if you want some timestamp (for example,
		296	L<AnyEvent::Handle> uses this to update it's activity timeouts).
		297
		298	The rest of this section is only of relevance if you try to be very exact
		299	with your timing, you can skip it without bad conscience.
		300
		301	For a practical example of when these times differ, consider L<Event::Lib>
		302	and L<EV> and the following set-up:
		303
		304	The event loop is running and has just invoked one of your callback at
		305	time=500 (assume no other callbacks delay processing). In your callback,
		306	you wait a second by executing C<sleep 1> (blocking the process for a
		307	second) and then (at time=501) you create a relative timer that fires
		308	after three seconds.
		309
		310	With L<Event::Lib>, C<< AnyEvent->time >> and C<< AnyEvent->now >> will
		311	both return C<501>, because that is the current time, and the timer will
		312	be scheduled to fire at time=504 (C<501> + C<3>).
		313
		314	With L<EV>, C<< AnyEvent->time >> returns C<501> (as that is the current
		315	time), but C<< AnyEvent->now >> returns C<500>, as that is the time the
		316	last event processing phase started. With L<EV>, your timer gets scheduled
		317	to run at time=503 (C<500> + C<3>).
		318
		319	In one sense, L<Event::Lib> is more exact, as it uses the current time
		320	regardless of any delays introduced by event processing. However, most
		321	callbacks do not expect large delays in processing, so this causes a
		322	higher drift (and a lot more system calls to get the current time).
		323
		324	In another sense, L<EV> is more exact, as your timer will be scheduled at
		325	the same time, regardless of how long event processing actually took.
		326
		327	In either case, if you care (and in most cases, you don't), then you
		328	can get whatever behaviour you want with any event loop, by taking the
		329	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
		330	account.
		331
		332	=item AnyEvent->now_update
		333
		334	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache
		335	the current time for each loop iteration (see the discussion of L<<
		336	AnyEvent->now >>, above).
		337
		338	When a callback runs for a long time (or when the process sleeps), then
		339	this "current" time will differ substantially from the real time, which
		340	might affect timers and time-outs.
		341
		342	When this is the case, you can call this method, which will update the
		343	event loop's idea of "current time".
		344
		345	Note that updating the time I<might> cause some events to be handled.
		346
		347	=back
		348
232	=head2 SIGNAL WATCHERS	349	=head2 SIGNAL WATCHERS
233		350
234	You can watch for signals using a signal watcher, C<signal> is the signal	351	You can watch for signals using a signal watcher, C<signal> is the signal
235	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	352	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
236	be invoked whenever a signal occurs.	353	callback to be invoked whenever a signal occurs.
237		354
238	Although the callback might get passed parameters, their value and	355	Although the callback might get passed parameters, their value and
239	presence is undefined and you cannot rely on them. Portable AnyEvent	356	presence is undefined and you cannot rely on them. Portable AnyEvent
240	callbacks cannot use arguments passed to signal watcher callbacks.	357	callbacks cannot use arguments passed to signal watcher callbacks.
241		358
242	Multiple signal occurances can be clumped together into one callback	359	Multiple signal occurrences can be clumped together into one callback
243	invocation, and callback invocation will be synchronous. synchronous means	360	invocation, and callback invocation will be synchronous. Synchronous means
244	that it might take a while until the signal gets handled by the process,	361	that it might take a while until the signal gets handled by the process,
245	but it is guarenteed not to interrupt any other callbacks.	362	but it is guaranteed not to interrupt any other callbacks.
246		363
247	The main advantage of using these watchers is that you can share a signal	364	The main advantage of using these watchers is that you can share a signal
248	between multiple watchers.	365	between multiple watchers.
249		366
250	This watcher might use C<%SIG>, so programs overwriting those signals	367	This watcher might use C<%SIG>, so programs overwriting those signals
…		…
257	=head2 CHILD PROCESS WATCHERS	374	=head2 CHILD PROCESS WATCHERS
258		375
259	You can also watch on a child process exit and catch its exit status.	376	You can also watch on a child process exit and catch its exit status.
260		377
261	The child process is specified by the C<pid> argument (if set to C<0>, it	378	The child process is specified by the C<pid> argument (if set to C<0>, it
262	watches for any child process exit). The watcher will trigger as often	379	watches for any child process exit). The watcher will triggered only when
263	as status change for the child are received. This works by installing a	380	the child process has finished and an exit status is available, not on
264	signal handler for C<SIGCHLD>. The callback will be called with the pid	381	any trace events (stopped/continued).
265	and exit status (as returned by waitpid), so unlike other watcher types,	382
266	you I<can> rely on child watcher callback arguments.	383	The callback will be called with the pid and exit status (as returned by
		384	waitpid), so unlike other watcher types, you I<can> rely on child watcher
		385	callback arguments.
		386
		387	This watcher type works by installing a signal handler for C<SIGCHLD>,
		388	and since it cannot be shared, nothing else should use SIGCHLD or reap
		389	random child processes (waiting for specific child processes, e.g. inside
		390	C<system>, is just fine).
267		391
268	There is a slight catch to child watchers, however: you usually start them	392	There is a slight catch to child watchers, however: you usually start them
269	I<after> the child process was created, and this means the process could	393	I<after> the child process was created, and this means the process could
270	have exited already (and no SIGCHLD will be sent anymore).	394	have exited already (and no SIGCHLD will be sent anymore).
271		395
…		…
277	AnyEvent program, you I<have> to create at least one watcher before you	401	AnyEvent program, you I<have> to create at least one watcher before you
278	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).	402	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
279		403
280	Example: fork a process and wait for it	404	Example: fork a process and wait for it
281		405
282	my $done = AnyEvent->condvar;	406	my $done = AnyEvent->condvar;
283		407
284	my $pid = fork or exit 5;	408	my $pid = fork or exit 5;
285		409
286	my $w = AnyEvent->child (	410	my $w = AnyEvent->child (
287	pid => $pid,	411	pid => $pid,
288	cb => sub {	412	cb => sub {
289	my ($pid, $status) = @_;	413	my ($pid, $status) = @_;
290	warn "pid $pid exited with status $status";	414	warn "pid $pid exited with status $status";
291	$done->send;	415	$done->send;
292	},	416	},
293	);	417	);
294		418
295	# do something else, then wait for process exit	419	# do something else, then wait for process exit
296	$done->recv;	420	$done->recv;
		421
		422	=head2 IDLE WATCHERS
		423
		424	Sometimes there is a need to do something, but it is not so important
		425	to do it instantly, but only when there is nothing better to do. This
		426	"nothing better to do" is usually defined to be "no other events need
		427	attention by the event loop".
		428
		429	Idle watchers ideally get invoked when the event loop has nothing
		430	better to do, just before it would block the process to wait for new
		431	events. Instead of blocking, the idle watcher is invoked.
		432
		433	Most event loops unfortunately do not really support idle watchers (only
		434	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
		435	will simply call the callback "from time to time".
		436
		437	Example: read lines from STDIN, but only process them when the
		438	program is otherwise idle:
		439
		440	my @lines; # read data
		441	my $idle_w;
		442	my $io_w = AnyEvent->io (fh => \*STDIN, poll => 'r', cb => sub {
		443	push @lines, scalar <STDIN>;
		444
		445	# start an idle watcher, if not already done
		446	$idle_w ||= AnyEvent->idle (cb => sub {
		447	# handle only one line, when there are lines left
		448	if (my $line = shift @lines) {
		449	print "handled when idle: $line";
		450	} else {
		451	# otherwise disable the idle watcher again
		452	undef $idle_w;
		453	}
		454	});
		455	});
297		456
298	=head2 CONDITION VARIABLES	457	=head2 CONDITION VARIABLES
299		458
300	If you are familiar with some event loops you will know that all of them	459	If you are familiar with some event loops you will know that all of them
301	require you to run some blocking "loop", "run" or similar function that	460	require you to run some blocking "loop", "run" or similar function that
…		…
307	The instrument to do that is called a "condition variable", so called	466	The instrument to do that is called a "condition variable", so called
308	because they represent a condition that must become true.	467	because they represent a condition that must become true.
309		468
310	Condition variables can be created by calling the C<< AnyEvent->condvar	469	Condition variables can be created by calling the C<< AnyEvent->condvar
311	>> method, usually without arguments. The only argument pair allowed is	470	>> method, usually without arguments. The only argument pair allowed is
		471
312	C<cb>, which specifies a callback to be called when the condition variable	472	C<cb>, which specifies a callback to be called when the condition variable
313	becomes true.	473	becomes true, with the condition variable as the first argument (but not
		474	the results).
314		475
315	After creation, the conditon variable is "false" until it becomes "true"	476	After creation, the condition variable is "false" until it becomes "true"
316	by calling the C<send> method.	477	by calling the C<send> method (or calling the condition variable as if it
		478	were a callback, read about the caveats in the description for the C<<
		479	->send >> method).
317		480
318	Condition variables are similar to callbacks, except that you can	481	Condition variables are similar to callbacks, except that you can
319	optionally wait for them. They can also be called merge points - points	482	optionally wait for them. They can also be called merge points - points
320	in time where multiple outstandign events have been processed. And yet	483	in time where multiple outstanding events have been processed. And yet
321	another way to call them is transations - each condition variable can be	484	another way to call them is transactions - each condition variable can be
322	used to represent a transaction, which finishes at some point and delivers	485	used to represent a transaction, which finishes at some point and delivers
323	a result.	486	a result.
324		487
325	Condition variables are very useful to signal that something has finished,	488	Condition variables are very useful to signal that something has finished,
326	for example, if you write a module that does asynchronous http requests,	489	for example, if you write a module that does asynchronous http requests,
…		…
332	you can block your main program until an event occurs - for example, you	495	you can block your main program until an event occurs - for example, you
333	could C<< ->recv >> in your main program until the user clicks the Quit	496	could C<< ->recv >> in your main program until the user clicks the Quit
334	button of your app, which would C<< ->send >> the "quit" event.	497	button of your app, which would C<< ->send >> the "quit" event.
335		498
336	Note that condition variables recurse into the event loop - if you have	499	Note that condition variables recurse into the event loop - if you have
337	two pieces of code that call C<< ->recv >> in a round-robbin fashion, you	500	two pieces of code that call C<< ->recv >> in a round-robin fashion, you
338	lose. Therefore, condition variables are good to export to your caller, but	501	lose. Therefore, condition variables are good to export to your caller, but
339	you should avoid making a blocking wait yourself, at least in callbacks,	502	you should avoid making a blocking wait yourself, at least in callbacks,
340	as this asks for trouble.	503	as this asks for trouble.
341		504
342	Condition variables are represented by hash refs in perl, and the keys	505	Condition variables are represented by hash refs in perl, and the keys
…		…
347		510
348	There are two "sides" to a condition variable - the "producer side" which	511	There are two "sides" to a condition variable - the "producer side" which
349	eventually calls C<< -> send >>, and the "consumer side", which waits	512	eventually calls C<< -> send >>, and the "consumer side", which waits
350	for the send to occur.	513	for the send to occur.
351		514
352	Example:	515	Example: wait for a timer.
353		516
354	# wait till the result is ready	517	# wait till the result is ready
355	my $result_ready = AnyEvent->condvar;	518	my $result_ready = AnyEvent->condvar;
356		519
357	# do something such as adding a timer	520	# do something such as adding a timer
…		…
365		528
366	# this "blocks" (while handling events) till the callback	529	# this "blocks" (while handling events) till the callback
367	# calls send	530	# calls send
368	$result_ready->recv;	531	$result_ready->recv;
369		532
		533	Example: wait for a timer, but take advantage of the fact that
		534	condition variables are also code references.
		535
		536	my $done = AnyEvent->condvar;
		537	my $delay = AnyEvent->timer (after => 5, cb => $done);
		538	$done->recv;
		539
		540	Example: Imagine an API that returns a condvar and doesn't support
		541	callbacks. This is how you make a synchronous call, for example from
		542	the main program:
		543
		544	use AnyEvent::CouchDB;
		545
		546	...
		547
		548	my @info = $couchdb->info->recv;
		549
		550	And this is how you would just ste a callback to be called whenever the
		551	results are available:
		552
		553	$couchdb->info->cb (sub {
		554	my @info = $_[0]->recv;
		555	});
		556
370	=head3 METHODS FOR PRODUCERS	557	=head3 METHODS FOR PRODUCERS
371		558
372	These methods should only be used by the producing side, i.e. the	559	These methods should only be used by the producing side, i.e. the
373	code/module that eventually sends the signal. Note that it is also	560	code/module that eventually sends the signal. Note that it is also
374	the producer side which creates the condvar in most cases, but it isn't	561	the producer side which creates the condvar in most cases, but it isn't
…		…
385	If a callback has been set on the condition variable, it is called	572	If a callback has been set on the condition variable, it is called
386	immediately from within send.	573	immediately from within send.
387		574
388	Any arguments passed to the C<send> call will be returned by all	575	Any arguments passed to the C<send> call will be returned by all
389	future C<< ->recv >> calls.	576	future C<< ->recv >> calls.
		577
		578	Condition variables are overloaded so one can call them directly
		579	(as a code reference). Calling them directly is the same as calling
		580	C<send>. Note, however, that many C-based event loops do not handle
		581	overloading, so as tempting as it may be, passing a condition variable
		582	instead of a callback does not work. Both the pure perl and EV loops
		583	support overloading, however, as well as all functions that use perl to
		584	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
		585	example).
390		586
391	=item $cv->croak ($error)	587	=item $cv->croak ($error)
392		588
393	Similar to send, but causes all call's to C<< ->recv >> to invoke	589	Similar to send, but causes all call's to C<< ->recv >> to invoke
394	C<Carp::croak> with the given error message/object/scalar.	590	C<Carp::croak> with the given error message/object/scalar.
…		…
443	doesn't execute once).	639	doesn't execute once).
444		640
445	This is the general pattern when you "fan out" into multiple subrequests:	641	This is the general pattern when you "fan out" into multiple subrequests:
446	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>	642	use an outer C<begin>/C<end> pair to set the callback and ensure C<end>
447	is called at least once, and then, for each subrequest you start, call	643	is called at least once, and then, for each subrequest you start, call
448	C<begin> and for eahc subrequest you finish, call C<end>.	644	C<begin> and for each subrequest you finish, call C<end>.
449		645
450	=back	646	=back
451		647
452	=head3 METHODS FOR CONSUMERS	648	=head3 METHODS FOR CONSUMERS
453		649
…		…
475	(programs might want to do that to stay interactive), so I<if you are	671	(programs might want to do that to stay interactive), so I<if you are
476	using this from a module, never require a blocking wait>, but let the	672	using this from a module, never require a blocking wait>, but let the
477	caller decide whether the call will block or not (for example, by coupling	673	caller decide whether the call will block or not (for example, by coupling
478	condition variables with some kind of request results and supporting	674	condition variables with some kind of request results and supporting
479	callbacks so the caller knows that getting the result will not block,	675	callbacks so the caller knows that getting the result will not block,
480	while still suppporting blocking waits if the caller so desires).	676	while still supporting blocking waits if the caller so desires).
481		677
482	Another reason I<never> to C<< ->recv >> in a module is that you cannot	678	Another reason I<never> to C<< ->recv >> in a module is that you cannot
483	sensibly have two C<< ->recv >>'s in parallel, as that would require	679	sensibly have two C<< ->recv >>'s in parallel, as that would require
484	multiple interpreters or coroutines/threads, none of which C<AnyEvent>	680	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
485	can supply.	681	can supply.
…		…
498	=item $bool = $cv->ready	694	=item $bool = $cv->ready
499		695
500	Returns true when the condition is "true", i.e. whether C<send> or	696	Returns true when the condition is "true", i.e. whether C<send> or
501	C<croak> have been called.	697	C<croak> have been called.
502		698
503	=item $cb = $cv->cb ([new callback])	699	=item $cb = $cv->cb ($cb->($cv))
504		700
505	This is a mutator function that returns the callback set and optionally	701	This is a mutator function that returns the callback set and optionally
506	replaces it before doing so.	702	replaces it before doing so.
507		703
508	The callback will be called when the condition becomes "true", i.e. when	704	The callback will be called when the condition becomes "true", i.e. when
509	C<send> or C<croak> are called. Calling C<recv> inside the callback	705	C<send> or C<croak> are called, with the only argument being the condition
510	or at any later time is guaranteed not to block.	706	variable itself. Calling C<recv> inside the callback or at any later time
		707	is guaranteed not to block.
511		708
512	=back	709	=back
513		710
514	=head1 GLOBAL VARIABLES AND FUNCTIONS	711	=head1 GLOBAL VARIABLES AND FUNCTIONS
515		712
…		…
601		798
602	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	799	If it doesn't care, it can just "use AnyEvent" and use it itself, or not
603	do anything special (it does not need to be event-based) and let AnyEvent	800	do anything special (it does not need to be event-based) and let AnyEvent
604	decide which implementation to chose if some module relies on it.	801	decide which implementation to chose if some module relies on it.
605		802
606	If the main program relies on a specific event model. For example, in	803	If the main program relies on a specific event model - for example, in
607	Gtk2 programs you have to rely on the Glib module. You should load the	804	Gtk2 programs you have to rely on the Glib module - you should load the
608	event module before loading AnyEvent or any module that uses it: generally	805	event module before loading AnyEvent or any module that uses it: generally
609	speaking, you should load it as early as possible. The reason is that	806	speaking, you should load it as early as possible. The reason is that
610	modules might create watchers when they are loaded, and AnyEvent will	807	modules might create watchers when they are loaded, and AnyEvent will
611	decide on the event model to use as soon as it creates watchers, and it	808	decide on the event model to use as soon as it creates watchers, and it
612	might chose the wrong one unless you load the correct one yourself.	809	might chose the wrong one unless you load the correct one yourself.
613		810
614	You can chose to use a rather inefficient pure-perl implementation by	811	You can chose to use a pure-perl implementation by loading the
615	loading the C<AnyEvent::Impl::Perl> module, which gives you similar	812	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
616	behaviour everywhere, but letting AnyEvent chose is generally better.	813	everywhere, but letting AnyEvent chose the model is generally better.
		814
		815	=head2 MAINLOOP EMULATION
		816
		817	Sometimes (often for short test scripts, or even standalone programs who
		818	only want to use AnyEvent), you do not want to run a specific event loop.
		819
		820	In that case, you can use a condition variable like this:
		821
		822	AnyEvent->condvar->recv;
		823
		824	This has the effect of entering the event loop and looping forever.
		825
		826	Note that usually your program has some exit condition, in which case
		827	it is better to use the "traditional" approach of storing a condition
		828	variable somewhere, waiting for it, and sending it when the program should
		829	exit cleanly.
		830
617		831
618	=head1 OTHER MODULES	832	=head1 OTHER MODULES
619		833
620	The following is a non-exhaustive list of additional modules that use	834	The following is a non-exhaustive list of additional modules that use
621	AnyEvent and can therefore be mixed easily with other AnyEvent modules	835	AnyEvent and can therefore be mixed easily with other AnyEvent modules
…		…
627	=item L<AnyEvent::Util>	841	=item L<AnyEvent::Util>
628		842
629	Contains various utility functions that replace often-used but blocking	843	Contains various utility functions that replace often-used but blocking
630	functions such as C<inet_aton> by event-/callback-based versions.	844	functions such as C<inet_aton> by event-/callback-based versions.
631		845
		846	=item L<AnyEvent::Socket>
		847
		848	Provides various utility functions for (internet protocol) sockets,
		849	addresses and name resolution. Also functions to create non-blocking tcp
		850	connections or tcp servers, with IPv6 and SRV record support and more.
		851
632	=item L<AnyEvent::Handle>	852	=item L<AnyEvent::Handle>
633		853
634	Provide read and write buffers and manages watchers for reads and writes.	854	Provide read and write buffers, manages watchers for reads and writes,
		855	supports raw and formatted I/O, I/O queued and fully transparent and
		856	non-blocking SSL/TLS.
		857
		858	=item L<AnyEvent::DNS>
		859
		860	Provides rich asynchronous DNS resolver capabilities.
		861
		862	=item L<AnyEvent::HTTP>
		863
		864	A simple-to-use HTTP library that is capable of making a lot of concurrent
		865	HTTP requests.
635		866
636	=item L<AnyEvent::HTTPD>	867	=item L<AnyEvent::HTTPD>
637		868
638	Provides a simple web application server framework.	869	Provides a simple web application server framework.
639		870
640	=item L<AnyEvent::DNS>
641
642	Provides asynchronous DNS resolver capabilities, beyond what
643	L<AnyEvent::Util> offers.
644
645	=item L<AnyEvent::FastPing>	871	=item L<AnyEvent::FastPing>
646		872
647	The fastest ping in the west.	873	The fastest ping in the west.
648		874
		875	=item L<AnyEvent::DBI>
		876
		877	Executes L<DBI> requests asynchronously in a proxy process.
		878
		879	=item L<AnyEvent::AIO>
		880
		881	Truly asynchronous I/O, should be in the toolbox of every event
		882	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
		883	together.
		884
		885	=item L<AnyEvent::BDB>
		886
		887	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
		888	L<BDB> and AnyEvent together.
		889
		890	=item L<AnyEvent::GPSD>
		891
		892	A non-blocking interface to gpsd, a daemon delivering GPS information.
		893
		894	=item L<AnyEvent::IGS>
		895
		896	A non-blocking interface to the Internet Go Server protocol (used by
		897	L<App::IGS>).
		898
649	=item L<Net::IRC3>	899	=item L<AnyEvent::IRC>
650		900
651	AnyEvent based IRC client module family.	901	AnyEvent based IRC client module family (replacing the older Net::IRC3).
652		902
653	=item L<Net::XMPP2>	903	=item L<Net::XMPP2>
654		904
655	AnyEvent based XMPP (Jabber protocol) module family.	905	AnyEvent based XMPP (Jabber protocol) module family.
656		906
…		…
665		915
666	=item L<Coro>	916	=item L<Coro>
667		917
668	Has special support for AnyEvent via L<Coro::AnyEvent>.	918	Has special support for AnyEvent via L<Coro::AnyEvent>.
669		919
670	=item L<AnyEvent::AIO>, L<IO::AIO>
671
672	Truly asynchronous I/O, should be in the toolbox of every event
673	programmer. AnyEvent::AIO transparently fuses IO::AIO and AnyEvent
674	together.
675
676	=item L<AnyEvent::BDB>, L<BDB>
677
678	Truly asynchronous Berkeley DB access. AnyEvent::AIO transparently fuses
679	IO::AIO and AnyEvent together.
680
681	=item L<IO::Lambda>	920	=item L<IO::Lambda>
682		921
683	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	922	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.
684		923
685	=back	924	=back
…		…
687	=cut	926	=cut
688		927
689	package AnyEvent;	928	package AnyEvent;
690		929
691	no warnings;	930	no warnings;
692	use strict;	931	use strict qw(vars subs);
693		932
694	use Carp;	933	use Carp;
695		934
696	our $VERSION = '3.41';	935	our $VERSION = 4.41;
697	our $MODEL;	936	our $MODEL;
698		937
699	our $AUTOLOAD;	938	our $AUTOLOAD;
700	our @ISA;	939	our @ISA;
701		940
		941	our @REGISTRY;
		942
		943	our $WIN32;
		944
		945	BEGIN {
		946	my $win32 = ! ! ($^O =~ /mswin32/i);
		947	eval "sub WIN32(){ $win32 }";
		948	}
		949
702	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	950	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;
703		951
704	our @REGISTRY;	952	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
		953
		954	{
		955	my $idx;
		956	$PROTOCOL{$_} = ++$idx
		957	for reverse split /\s*,\s*/,
		958	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
		959	}
705		960
706	my @models = (	961	my @models = (
707	[EV:: => AnyEvent::Impl::EV::],	962	[EV:: => AnyEvent::Impl::EV::],
708	[Event:: => AnyEvent::Impl::Event::],	963	[Event:: => AnyEvent::Impl::Event::],
709	[Tk:: => AnyEvent::Impl::Tk::],
710	[Wx:: => AnyEvent::Impl::POE::],
711	[Prima:: => AnyEvent::Impl::POE::],
712	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	964	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
713	# everything below here will not be autoprobed as the pureperl backend should work everywhere	965	# everything below here will not be autoprobed
714	[Glib:: => AnyEvent::Impl::Glib::],	966	# as the pureperl backend should work everywhere
		967	# and is usually faster
		968	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
		969	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
715	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	970	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
716	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	971	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
717	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	972	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
		973	[Wx:: => AnyEvent::Impl::POE::],
		974	[Prima:: => AnyEvent::Impl::POE::],
718	);	975	);
719		976
720	our %method = map +($_ => 1), qw(io timer signal child condvar one_event DESTROY);	977	our %method = map +($_ => 1),
		978	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
721		979
722	our @post_detect;	980	our @post_detect;
723		981
724	sub post_detect(&) {	982	sub post_detect(&) {
725	my ($cb) = @_;	983	my ($cb) = @_;
…		…
730	1	988	1
731	} else {	989	} else {
732	push @post_detect, $cb;	990	push @post_detect, $cb;
733		991
734	defined wantarray	992	defined wantarray
735	? bless \$cb, "AnyEvent::Util::Guard"	993	? bless \$cb, "AnyEvent::Util::postdetect"
736	: ()	994	: ()
737	}	995	}
738	}	996	}
739		997
740	sub AnyEvent::Util::Guard::DESTROY {	998	sub AnyEvent::Util::postdetect::DESTROY {
741	@post_detect = grep $_ != ${$_[0]}, @post_detect;	999	@post_detect = grep $_ != ${$_[0]}, @post_detect;
742	}	1000	}
743		1001
744	sub detect() {	1002	sub detect() {
745	unless ($MODEL) {	1003	unless ($MODEL) {
746	no strict 'refs';	1004	no strict 'refs';
		1005	local $SIG{__DIE__};
747		1006
748	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1007	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
749	my $model = "AnyEvent::Impl::$1";	1008	my $model = "AnyEvent::Impl::$1";
750	if (eval "require $model") {	1009	if (eval "require $model") {
751	$MODEL = $model;	1010	$MODEL = $model;
…		…
781	last;	1040	last;
782	}	1041	}
783	}	1042	}
784		1043
785	$MODEL	1044	$MODEL
786	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.";	1045	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
787	}	1046	}
788	}	1047	}
789		1048
		1049	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1050
790	unshift @ISA, $MODEL;	1051	unshift @ISA, $MODEL;
791	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	1052
		1053	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
792		1054
793	(shift @post_detect)->() while @post_detect;	1055	(shift @post_detect)->() while @post_detect;
794	}	1056	}
795		1057
796	$MODEL	1058	$MODEL
…		…
806		1068
807	my $class = shift;	1069	my $class = shift;
808	$class->$func (@_);	1070	$class->$func (@_);
809	}	1071	}
810		1072
		1073	# utility function to dup a filehandle. this is used by many backends
		1074	# to support binding more than one watcher per filehandle (they usually
		1075	# allow only one watcher per fd, so we dup it to get a different one).
		1076	sub _dupfh($$$$) {
		1077	my ($poll, $fh, $r, $w) = @_;
		1078
		1079	# cygwin requires the fh mode to be matching, unix doesn't
		1080	my ($rw, $mode) = $poll eq "r" ? ($r, "<")
		1081	: $poll eq "w" ? ($w, ">")
		1082	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
		1083
		1084	open my $fh2, "$mode&" . fileno $fh
		1085	or die "cannot dup() filehandle: $!,";
		1086
		1087	# we assume CLOEXEC is already set by perl in all important cases
		1088
		1089	($fh2, $rw)
		1090	}
		1091
811	package AnyEvent::Base;	1092	package AnyEvent::Base;
812		1093
		1094	# default implementations for many methods
		1095
		1096	BEGIN {
		1097	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1098	*_time = \&Time::HiRes::time;
		1099	# if (eval "use POSIX (); (POSIX::times())...
		1100	} else {
		1101	*_time = sub { time }; # epic fail
		1102	}
		1103	}
		1104
		1105	sub time { _time }
		1106	sub now { _time }
		1107	sub now_update { }
		1108
813	# default implementation for ->condvar	1109	# default implementation for ->condvar
814		1110
815	sub condvar {	1111	sub condvar {
816	bless {}, AnyEvent::CondVar::	1112	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
817	}	1113	}
818		1114
819	# default implementation for ->signal	1115	# default implementation for ->signal
820		1116
821	our %SIG_CB;	1117	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1118
		1119	sub _signal_exec {
		1120	sysread $SIGPIPE_R, my $dummy, 4;
		1121
		1122	while (%SIG_EV) {
		1123	for (keys %SIG_EV) {
		1124	delete $SIG_EV{$_};
		1125	$_->() for values %{ $SIG_CB{$_} || {} };
		1126	}
		1127	}
		1128	}
822		1129
823	sub signal {	1130	sub signal {
824	my (undef, %arg) = @_;	1131	my (undef, %arg) = @_;
825		1132
		1133	unless ($SIGPIPE_R) {
		1134	require Fcntl;
		1135
		1136	if (AnyEvent::WIN32) {
		1137	require AnyEvent::Util;
		1138
		1139	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1140	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
		1141	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
		1142	} else {
		1143	pipe $SIGPIPE_R, $SIGPIPE_W;
		1144	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
		1145	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
		1146	}
		1147
		1148	$SIGPIPE_R
		1149	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1150
		1151	# not strictly required, as $^F is normally 2, but let's make sure...
		1152	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1153	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
		1154
		1155	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
		1156	}
		1157
826	my $signal = uc $arg{signal}	1158	my $signal = uc $arg{signal}
827	or Carp::croak "required option 'signal' is missing";	1159	or Carp::croak "required option 'signal' is missing";
828		1160
829	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1161	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
830	$SIG{$signal} ||= sub {	1162	$SIG{$signal} ||= sub {
831	$_->() for values %{ $SIG_CB{$signal} || {} };	1163	local $!;
		1164	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1165	undef $SIG_EV{$signal};
832	};	1166	};
833		1167
834	bless [$signal, $arg{cb}], "AnyEvent::Base::Signal"	1168	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
835	}	1169	}
836		1170
837	sub AnyEvent::Base::Signal::DESTROY {	1171	sub AnyEvent::Base::signal::DESTROY {
838	my ($signal, $cb) = @{$_[0]};	1172	my ($signal, $cb) = @{$_[0]};
839		1173
840	delete $SIG_CB{$signal}{$cb};	1174	delete $SIG_CB{$signal}{$cb};
841		1175
		1176	# delete doesn't work with older perls - they then
		1177	# print weird messages, or just unconditionally exit
		1178	# instead of getting the default action.
842	$SIG{$signal} = 'DEFAULT' unless keys %{ $SIG_CB{$signal} };	1179	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
843	}	1180	}
844		1181
845	# default implementation for ->child	1182	# default implementation for ->child
846		1183
847	our %PID_CB;	1184	our %PID_CB;
848	our $CHLD_W;	1185	our $CHLD_W;
849	our $CHLD_DELAY_W;	1186	our $CHLD_DELAY_W;
850	our $PID_IDLE;
851	our $WNOHANG;	1187	our $WNOHANG;
852		1188
853	sub _child_wait {	1189	sub _sigchld {
854	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1190	while (0 < (my $pid = waitpid -1, $WNOHANG)) {
855	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1191	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),
856	(values %{ $PID_CB{0} || {} });	1192	(values %{ $PID_CB{0} || {} });
857	}	1193	}
858
859	undef $PID_IDLE;
860	}
861
862	sub _sigchld {
863	# make sure we deliver these changes "synchronous" with the event loop.
864	$CHLD_DELAY_W ||= AnyEvent->timer (after => 0, cb => sub {
865	undef $CHLD_DELAY_W;
866	&_child_wait;
867	});
868	}	1194	}
869		1195
870	sub child {	1196	sub child {
871	my (undef, %arg) = @_;	1197	my (undef, %arg) = @_;
872		1198
873	defined (my $pid = $arg{pid} + 0)	1199	defined (my $pid = $arg{pid} + 0)
874	or Carp::croak "required option 'pid' is missing";	1200	or Carp::croak "required option 'pid' is missing";
875		1201
876	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1202	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
877		1203
878	unless ($WNOHANG) {
879	$WNOHANG = eval { require POSIX; &POSIX::WNOHANG } || 1;	1204	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
880	}
881		1205
882	unless ($CHLD_W) {	1206	unless ($CHLD_W) {
883	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1207	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);
884	# child could be a zombie already, so make at least one round	1208	# child could be a zombie already, so make at least one round
885	&_sigchld;	1209	&_sigchld;
886	}	1210	}
887		1211
888	bless [$pid, $arg{cb}], "AnyEvent::Base::Child"	1212	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
889	}	1213	}
890		1214
891	sub AnyEvent::Base::Child::DESTROY {	1215	sub AnyEvent::Base::child::DESTROY {
892	my ($pid, $cb) = @{$_[0]};	1216	my ($pid, $cb) = @{$_[0]};
893		1217
894	delete $PID_CB{$pid}{$cb};	1218	delete $PID_CB{$pid}{$cb};
895	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1219	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
896		1220
897	undef $CHLD_W unless keys %PID_CB;	1221	undef $CHLD_W unless keys %PID_CB;
898	}	1222	}
899		1223
		1224	# idle emulation is done by simply using a timer, regardless
		1225	# of whether the process is idle or not, and not letting
		1226	# the callback use more than 50% of the time.
		1227	sub idle {
		1228	my (undef, %arg) = @_;
		1229
		1230	my ($cb, $w, $rcb) = $arg{cb};
		1231
		1232	$rcb = sub {
		1233	if ($cb) {
		1234	$w = _time;
		1235	&$cb;
		1236	$w = _time - $w;
		1237
		1238	# never use more then 50% of the time for the idle watcher,
		1239	# within some limits
		1240	$w = 0.0001 if $w < 0.0001;
		1241	$w = 5 if $w > 5;
		1242
		1243	$w = AnyEvent->timer (after => $w, cb => $rcb);
		1244	} else {
		1245	# clean up...
		1246	undef $w;
		1247	undef $rcb;
		1248	}
		1249	};
		1250
		1251	$w = AnyEvent->timer (after => 0.05, cb => $rcb);
		1252
		1253	bless \\$cb, "AnyEvent::Base::idle"
		1254	}
		1255
		1256	sub AnyEvent::Base::idle::DESTROY {
		1257	undef $${$_[0]};
		1258	}
		1259
900	package AnyEvent::CondVar;	1260	package AnyEvent::CondVar;
901		1261
902	our @ISA = AnyEvent::CondVar::Base::;	1262	our @ISA = AnyEvent::CondVar::Base::;
903		1263
904	package AnyEvent::CondVar::Base;	1264	package AnyEvent::CondVar::Base;
		1265
		1266	use overload
		1267	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },
		1268	fallback => 1;
905		1269
906	sub _send {	1270	sub _send {
907	# nop	1271	# nop
908	}	1272	}
909		1273
…		…
944	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1308	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
945	}	1309	}
946		1310
947	sub end {	1311	sub end {
948	return if --$_[0]{_ae_counter};	1312	return if --$_[0]{_ae_counter};
949	&{ $_[0]{_ae_end_cb} } if $_[0]{_ae_end_cb};	1313	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
950	}	1314	}
951		1315
952	# undocumented/compatibility with pre-3.4	1316	# undocumented/compatibility with pre-3.4
953	*broadcast = \&send;	1317	*broadcast = \&send;
954	*wait = \&_wait;	1318	*wait = \&_wait;
		1319
		1320	=head1 ERROR AND EXCEPTION HANDLING
		1321
		1322	In general, AnyEvent does not do any error handling - it relies on the
		1323	caller to do that if required. The L<AnyEvent::Strict> module (see also
		1324	the C<PERL_ANYEVENT_STRICT> environment variable, below) provides strict
		1325	checking of all AnyEvent methods, however, which is highly useful during
		1326	development.
		1327
		1328	As for exception handling (i.e. runtime errors and exceptions thrown while
		1329	executing a callback), this is not only highly event-loop specific, but
		1330	also not in any way wrapped by this module, as this is the job of the main
		1331	program.
		1332
		1333	The pure perl event loop simply re-throws the exception (usually
		1334	within C<< condvar->recv >>), the L<Event> and L<EV> modules call C<<
		1335	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
		1336	so on.
		1337
		1338	=head1 ENVIRONMENT VARIABLES
		1339
		1340	The following environment variables are used by this module or its
		1341	submodules:
		1342
		1343	=over 4
		1344
		1345	=item C<PERL_ANYEVENT_VERBOSE>
		1346
		1347	By default, AnyEvent will be completely silent except in fatal
		1348	conditions. You can set this environment variable to make AnyEvent more
		1349	talkative.
		1350
		1351	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		1352	conditions, such as not being able to load the event model specified by
		1353	C<PERL_ANYEVENT_MODEL>.
		1354
		1355	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		1356	model it chooses.
		1357
		1358	=item C<PERL_ANYEVENT_STRICT>
		1359
		1360	AnyEvent does not do much argument checking by default, as thorough
		1361	argument checking is very costly. Setting this variable to a true value
		1362	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
		1363	check the arguments passed to most method calls. If it finds any problems
		1364	it will croak.
		1365
		1366	In other words, enables "strict" mode.
		1367
		1368	Unlike C<use strict>, it is definitely recommended ot keep it off in
		1369	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while
		1370	developing programs can be very useful, however.
		1371
		1372	=item C<PERL_ANYEVENT_MODEL>
		1373
		1374	This can be used to specify the event model to be used by AnyEvent, before
		1375	auto detection and -probing kicks in. It must be a string consisting
		1376	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		1377	and the resulting module name is loaded and if the load was successful,
		1378	used as event model. If it fails to load AnyEvent will proceed with
		1379	auto detection and -probing.
		1380
		1381	This functionality might change in future versions.
		1382
		1383	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		1384	could start your program like this:
		1385
		1386	PERL_ANYEVENT_MODEL=Perl perl ...
		1387
		1388	=item C<PERL_ANYEVENT_PROTOCOLS>
		1389
		1390	Used by both L<AnyEvent::DNS> and L<AnyEvent::Socket> to determine preferences
		1391	for IPv4 or IPv6. The default is unspecified (and might change, or be the result
		1392	of auto probing).
		1393
		1394	Must be set to a comma-separated list of protocols or address families,
		1395	current supported: C<ipv4> and C<ipv6>. Only protocols mentioned will be
		1396	used, and preference will be given to protocols mentioned earlier in the
		1397	list.
		1398
		1399	This variable can effectively be used for denial-of-service attacks
		1400	against local programs (e.g. when setuid), although the impact is likely
		1401	small, as the program has to handle conenction and other failures anyways.
		1402
		1403	Examples: C<PERL_ANYEVENT_PROTOCOLS=ipv4,ipv6> - prefer IPv4 over IPv6,
		1404	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
		1405	- only support IPv4, never try to resolve or contact IPv6
		1406	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
		1407	IPv6, but prefer IPv6 over IPv4.
		1408
		1409	=item C<PERL_ANYEVENT_EDNS0>
		1410
		1411	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension
		1412	for DNS. This extension is generally useful to reduce DNS traffic, but
		1413	some (broken) firewalls drop such DNS packets, which is why it is off by
		1414	default.
		1415
		1416	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
		1417	EDNS0 in its DNS requests.
		1418
		1419	=item C<PERL_ANYEVENT_MAX_FORKS>
		1420
		1421	The maximum number of child processes that C<AnyEvent::Util::fork_call>
		1422	will create in parallel.
		1423
		1424	=back
955		1425
956	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1426	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
957		1427
958	This is an advanced topic that you do not normally need to use AnyEvent in	1428	This is an advanced topic that you do not normally need to use AnyEvent in
959	a module. This section is only of use to event loop authors who want to	1429	a module. This section is only of use to event loop authors who want to
…		…
993		1463
994	I<rxvt-unicode> also cheats a bit by not providing blocking access to	1464	I<rxvt-unicode> also cheats a bit by not providing blocking access to
995	condition variables: code blocking while waiting for a condition will	1465	condition variables: code blocking while waiting for a condition will
996	C<die>. This still works with most modules/usages, and blocking calls must	1466	C<die>. This still works with most modules/usages, and blocking calls must
997	not be done in an interactive application, so it makes sense.	1467	not be done in an interactive application, so it makes sense.
998
999	=head1 ENVIRONMENT VARIABLES
1000
1001	The following environment variables are used by this module:
1002
1003	=over 4
1004
1005	=item C<PERL_ANYEVENT_VERBOSE>
1006
1007	By default, AnyEvent will be completely silent except in fatal
1008	conditions. You can set this environment variable to make AnyEvent more
1009	talkative.
1010
1011	When set to C<1> or higher, causes AnyEvent to warn about unexpected
1012	conditions, such as not being able to load the event model specified by
1013	C<PERL_ANYEVENT_MODEL>.
1014
1015	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1016	model it chooses.
1017
1018	=item C<PERL_ANYEVENT_MODEL>
1019
1020	This can be used to specify the event model to be used by AnyEvent, before
1021	autodetection and -probing kicks in. It must be a string consisting
1022	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
1023	and the resulting module name is loaded and if the load was successful,
1024	used as event model. If it fails to load AnyEvent will proceed with
1025	autodetection and -probing.
1026
1027	This functionality might change in future versions.
1028
1029	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
1030	could start your program like this:
1031
1032	PERL_ANYEVENT_MODEL=Perl perl ...
1033
1034	=back
1035		1468
1036	=head1 EXAMPLE PROGRAM	1469	=head1 EXAMPLE PROGRAM
1037		1470
1038	The following program uses an I/O watcher to read data from STDIN, a timer	1471	The following program uses an I/O watcher to read data from STDIN, a timer
1039	to display a message once per second, and a condition variable to quit the	1472	to display a message once per second, and a condition variable to quit the
…		…
1048	poll => 'r',	1481	poll => 'r',
1049	cb => sub {	1482	cb => sub {
1050	warn "io event <$_[0]>\n"; # will always output <r>	1483	warn "io event <$_[0]>\n"; # will always output <r>
1051	chomp (my $input = <STDIN>); # read a line	1484	chomp (my $input = <STDIN>); # read a line
1052	warn "read: $input\n"; # output what has been read	1485	warn "read: $input\n"; # output what has been read
1053	$cv->broadcast if $input =~ /^q/i; # quit program if /^q/i	1486	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1054	},	1487	},
1055	);	1488	);
1056		1489
1057	my $time_watcher; # can only be used once	1490	my $time_watcher; # can only be used once
1058		1491
…		…
1063	});	1496	});
1064	}	1497	}
1065		1498
1066	new_timer; # create first timer	1499	new_timer; # create first timer
1067		1500
1068	$cv->wait; # wait until user enters /^q/i	1501	$cv->recv; # wait until user enters /^q/i
1069		1502
1070	=head1 REAL-WORLD EXAMPLE	1503	=head1 REAL-WORLD EXAMPLE
1071		1504
1072	Consider the L<Net::FCP> module. It features (among others) the following	1505	Consider the L<Net::FCP> module. It features (among others) the following
1073	API calls, which are to freenet what HTTP GET requests are to http:	1506	API calls, which are to freenet what HTTP GET requests are to http:
…		…
1123	syswrite $txn->{fh}, $txn->{request}	1556	syswrite $txn->{fh}, $txn->{request}
1124	or die "connection or write error";	1557	or die "connection or write error";
1125	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });	1558	$txn->{w} = AnyEvent->io (fh => $txn->{fh}, poll => 'r', cb => sub { $txn->fh_ready_r });
1126		1559
1127	Again, C<fh_ready_r> waits till all data has arrived, and then stores the	1560	Again, C<fh_ready_r> waits till all data has arrived, and then stores the
1128	result and signals any possible waiters that the request ahs finished:	1561	result and signals any possible waiters that the request has finished:
1129		1562
1130	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};	1563	sysread $txn->{fh}, $txn->{buf}, length $txn->{$buf};
1131		1564
1132	if (end-of-file or data complete) {	1565	if (end-of-file or data complete) {
1133	$txn->{result} = $txn->{buf};	1566	$txn->{result} = $txn->{buf};
1134	$txn->{finished}->broadcast;	1567	$txn->{finished}->send;
1135	$txb->{cb}->($txn) of $txn->{cb}; # also call callback	1568	$txb->{cb}->($txn) of $txn->{cb}; # also call callback
1136	}	1569	}
1137		1570
1138	The C<result> method, finally, just waits for the finished signal (if the	1571	The C<result> method, finally, just waits for the finished signal (if the
1139	request was already finished, it doesn't wait, of course, and returns the	1572	request was already finished, it doesn't wait, of course, and returns the
1140	data:	1573	data:
1141		1574
1142	$txn->{finished}->wait;	1575	$txn->{finished}->recv;
1143	return $txn->{result};	1576	return $txn->{result};
1144		1577
1145	The actual code goes further and collects all errors (C<die>s, exceptions)	1578	The actual code goes further and collects all errors (C<die>s, exceptions)
1146	that occured during request processing. The C<result> method detects	1579	that occurred during request processing. The C<result> method detects
1147	whether an exception as thrown (it is stored inside the $txn object)	1580	whether an exception as thrown (it is stored inside the $txn object)
1148	and just throws the exception, which means connection errors and other	1581	and just throws the exception, which means connection errors and other
1149	problems get reported tot he code that tries to use the result, not in a	1582	problems get reported tot he code that tries to use the result, not in a
1150	random callback.	1583	random callback.
1151		1584
…		…
1182		1615
1183	my $quit = AnyEvent->condvar;	1616	my $quit = AnyEvent->condvar;
1184		1617
1185	$fcp->txn_client_get ($url)->cb (sub {	1618	$fcp->txn_client_get ($url)->cb (sub {
1186	...	1619	...
1187	$quit->broadcast;	1620	$quit->send;
1188	});	1621	});
1189		1622
1190	$quit->wait;	1623	$quit->recv;
1191		1624
1192		1625
1193	=head1 BENCHMARKS	1626	=head1 BENCHMARKS
1194		1627
1195	To give you an idea of the performance and overheads that AnyEvent adds	1628	To give you an idea of the performance and overheads that AnyEvent adds
…		…
1197	of various event loops I prepared some benchmarks.	1630	of various event loops I prepared some benchmarks.
1198		1631
1199	=head2 BENCHMARKING ANYEVENT OVERHEAD	1632	=head2 BENCHMARKING ANYEVENT OVERHEAD
1200		1633
1201	Here is a benchmark of various supported event models used natively and	1634	Here is a benchmark of various supported event models used natively and
1202	through anyevent. The benchmark creates a lot of timers (with a zero	1635	through AnyEvent. The benchmark creates a lot of timers (with a zero
1203	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	1636	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1204	which it is), lets them fire exactly once and destroys them again.	1637	which it is), lets them fire exactly once and destroys them again.
1205		1638
1206	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	1639	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1207	distribution.	1640	distribution.
…		…
1224	all watchers, to avoid adding memory overhead. That means closure creation	1657	all watchers, to avoid adding memory overhead. That means closure creation
1225	and memory usage is not included in the figures.	1658	and memory usage is not included in the figures.
1226		1659
1227	I<invoke> is the time, in microseconds, used to invoke a simple	1660	I<invoke> is the time, in microseconds, used to invoke a simple
1228	callback. The callback simply counts down a Perl variable and after it was	1661	callback. The callback simply counts down a Perl variable and after it was
1229	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to	1662	invoked "watcher" times, it would C<< ->send >> a condvar once to
1230	signal the end of this phase.	1663	signal the end of this phase.
1231		1664
1232	I<destroy> is the time, in microseconds, that it takes to destroy a single	1665	I<destroy> is the time, in microseconds, that it takes to destroy a single
1233	watcher.	1666	watcher.
1234		1667
1235	=head3 Results	1668	=head3 Results
1236		1669
1237	name watchers bytes create invoke destroy comment	1670	name watchers bytes create invoke destroy comment
1238	EV/EV 400000 244 0.56 0.46 0.31 EV native interface	1671	EV/EV 400000 224 0.47 0.35 0.27 EV native interface
1239	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers	1672	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers
1240	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal	1673	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal
1241	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation	1674	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation
1242	Event/Event 16000 516 31.88 31.30 0.85 Event native interface	1675	Event/Event 16000 517 32.20 31.80 0.81 Event native interface
1243	Event/Any 16000 590 35.75 31.42 1.08 Event + AnyEvent watchers	1676	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers
1244	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour	1677	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour
1245	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers	1678	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers
1246	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event	1679	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event
1247	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select	1680	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select
1248		1681
1249	=head3 Discussion	1682	=head3 Discussion
1250		1683
1251	The benchmark does I<not> measure scalability of the event loop very	1684	The benchmark does I<not> measure scalability of the event loop very
1252	well. For example, a select-based event loop (such as the pure perl one)	1685	well. For example, a select-based event loop (such as the pure perl one)
…		…
1330		1763
1331	=back	1764	=back
1332		1765
1333	=head2 BENCHMARKING THE LARGE SERVER CASE	1766	=head2 BENCHMARKING THE LARGE SERVER CASE
1334		1767
1335	This benchmark atcually benchmarks the event loop itself. It works by	1768	This benchmark actually benchmarks the event loop itself. It works by
1336	creating a number of "servers": each server consists of a socketpair, a	1769	creating a number of "servers": each server consists of a socket pair, a
1337	timeout watcher that gets reset on activity (but never fires), and an I/O	1770	timeout watcher that gets reset on activity (but never fires), and an I/O
1338	watcher waiting for input on one side of the socket. Each time the socket	1771	watcher waiting for input on one side of the socket. Each time the socket
1339	watcher reads a byte it will write that byte to a random other "server".	1772	watcher reads a byte it will write that byte to a random other "server".
1340		1773
1341	The effect is that there will be a lot of I/O watchers, only part of which	1774	The effect is that there will be a lot of I/O watchers, only part of which
1342	are active at any one point (so there is a constant number of active	1775	are active at any one point (so there is a constant number of active
1343	fds for each loop iterstaion, but which fds these are is random). The	1776	fds for each loop iteration, but which fds these are is random). The
1344	timeout is reset each time something is read because that reflects how	1777	timeout is reset each time something is read because that reflects how
1345	most timeouts work (and puts extra pressure on the event loops).	1778	most timeouts work (and puts extra pressure on the event loops).
1346		1779
1347	In this benchmark, we use 10000 socketpairs (20000 sockets), of which 100	1780	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1348	(1%) are active. This mirrors the activity of large servers with many	1781	(1%) are active. This mirrors the activity of large servers with many
1349	connections, most of which are idle at any one point in time.	1782	connections, most of which are idle at any one point in time.
1350		1783
1351	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	1784	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1352	distribution.	1785	distribution.
…		…
1354	=head3 Explanation of the columns	1787	=head3 Explanation of the columns
1355		1788
1356	I<sockets> is the number of sockets, and twice the number of "servers" (as	1789	I<sockets> is the number of sockets, and twice the number of "servers" (as
1357	each server has a read and write socket end).	1790	each server has a read and write socket end).
1358		1791
1359	I<create> is the time it takes to create a socketpair (which is	1792	I<create> is the time it takes to create a socket pair (which is
1360	nontrivial) and two watchers: an I/O watcher and a timeout watcher.	1793	nontrivial) and two watchers: an I/O watcher and a timeout watcher.
1361		1794
1362	I<request>, the most important value, is the time it takes to handle a	1795	I<request>, the most important value, is the time it takes to handle a
1363	single "request", that is, reading the token from the pipe and forwarding	1796	single "request", that is, reading the token from the pipe and forwarding
1364	it to another server. This includes deleting the old timeout and creating	1797	it to another server. This includes deleting the old timeout and creating
…		…
1437	speed most when you have lots of watchers, not when you only have a few of	1870	speed most when you have lots of watchers, not when you only have a few of
1438	them).	1871	them).
1439		1872
1440	EV is again fastest.	1873	EV is again fastest.
1441		1874
1442	Perl again comes second. It is noticably faster than the C-based event	1875	Perl again comes second. It is noticeably faster than the C-based event
1443	loops Event and Glib, although the difference is too small to really	1876	loops Event and Glib, although the difference is too small to really
1444	matter.	1877	matter.
1445		1878
1446	POE also performs much better in this case, but is is still far behind the	1879	POE also performs much better in this case, but is is still far behind the
1447	others.	1880	others.
…		…
1452		1885
1453	=item * C-based event loops perform very well with small number of	1886	=item * C-based event loops perform very well with small number of
1454	watchers, as the management overhead dominates.	1887	watchers, as the management overhead dominates.
1455		1888
1456	=back	1889	=back
		1890
		1891
		1892	=head1 SIGNALS
		1893
		1894	AnyEvent currently installs handlers for these signals:
		1895
		1896	=over 4
		1897
		1898	=item SIGCHLD
		1899
		1900	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
		1901	emulation for event loops that do not support them natively. Also, some
		1902	event loops install a similar handler.
		1903
		1904	=item SIGPIPE
		1905
		1906	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
		1907	when AnyEvent gets loaded.
		1908
		1909	The rationale for this is that AnyEvent users usually do not really depend
		1910	on SIGPIPE delivery (which is purely an optimisation for shell use, or
		1911	badly-written programs), but C<SIGPIPE> can cause spurious and rare
		1912	program exits as a lot of people do not expect C<SIGPIPE> when writing to
		1913	some random socket.
		1914
		1915	The rationale for installing a no-op handler as opposed to ignoring it is
		1916	that this way, the handler will be restored to defaults on exec.
		1917
		1918	Feel free to install your own handler, or reset it to defaults.
		1919
		1920	=back
		1921
		1922	=cut
		1923
		1924	$SIG{PIPE} = sub { }
		1925	unless defined $SIG{PIPE};
1457		1926
1458		1927
1459	=head1 FORK	1928	=head1 FORK
1460		1929
1461	Most event libraries are not fork-safe. The ones who are usually are	1930	Most event libraries are not fork-safe. The ones who are usually are
…		…
1476	specified in the variable.	1945	specified in the variable.
1477		1946
1478	You can make AnyEvent completely ignore this variable by deleting it	1947	You can make AnyEvent completely ignore this variable by deleting it
1479	before the first watcher gets created, e.g. with a C<BEGIN> block:	1948	before the first watcher gets created, e.g. with a C<BEGIN> block:
1480		1949
1481	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }	1950	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
1482		1951
1483	use AnyEvent;	1952	use AnyEvent;
1484		1953
1485	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can	1954	Similar considerations apply to $ENV{PERL_ANYEVENT_VERBOSE}, as that can
1486	be used to probe what backend is used and gain other information (which is	1955	be used to probe what backend is used and gain other information (which is
1487	probably even less useful to an attacker than PERL_ANYEVENT_MODEL).	1956	probably even less useful to an attacker than PERL_ANYEVENT_MODEL), and
		1957	$ENV{PERL_ANYEGENT_STRICT}.
		1958
		1959
		1960	=head1 BUGS
		1961
		1962	Perl 5.8 has numerous memleaks that sometimes hit this module and are hard
		1963	to work around. If you suffer from memleaks, first upgrade to Perl 5.10
		1964	and check wether the leaks still show up. (Perl 5.10.0 has other annoying
		1965	memleaks, such as leaking on C<map> and C<grep> but it is usually not as
		1966	pronounced).
1488		1967
1489		1968
1490	=head1 SEE ALSO	1969	=head1 SEE ALSO
		1970
		1971	Utility functions: L<AnyEvent::Util>.
1491		1972
1492	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	1973	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
1493	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	1974	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
1494		1975
1495	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	1976	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
1496	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	1977	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
1497	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	1978	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
1498	L<AnyEvent::Impl::POE>.	1979	L<AnyEvent::Impl::POE>.
1499		1980
		1981	Non-blocking file handles, sockets, TCP clients and
		1982	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.
		1983
		1984	Asynchronous DNS: L<AnyEvent::DNS>.
		1985
1500	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	1986	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,
1501		1987
1502	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1988	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.
1503		1989
1504		1990
1505	=head1 AUTHOR	1991	=head1 AUTHOR
1506		1992
1507	Marc Lehmann <schmorp@schmorp.de>	1993	Marc Lehmann <schmorp@schmorp.de>
1508	http://home.schmorp.de/	1994	http://home.schmorp.de/
1509		1995
1510	=cut	1996	=cut
1511		1997
1512	1	1998	1
1513		1999

Diff Legend

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