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Revision 1.384 by root, Mon Sep 5 07:21:54 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	event loops.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Loop>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Loop> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called C<AnyEvent::Loop>. Like
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
137	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
138		150
139	=head1 WATCHERS	151	=head1 WATCHERS
140		152
141	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
142	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
177		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (I<not> file descriptor) to watch	199	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	200	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	201	handle). Note that only file handles pointing to things for which
184	non-blocking operation makes sense are allowed. This includes sockets,	202	non-blocking operation makes sense are allowed. This includes sockets,
185	most character devices, pipes, fifos and so on, but not for example files	203	most character devices, pipes, fifos and so on, but not for example files
186	or block devices.	204	or block devices.
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	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	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	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.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	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.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	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	333	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	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
330	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
331	account.	357	account.
332		358
333	=item AnyEvent->now_update	359	=item AnyEvent->now_update
334		360
335	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
336	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
337	AnyEvent->now >>, above).	363	above).
338		364
339	When a callback runs for a long time (or when the process sleeps), then	365	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	366	this "current" time will differ substantially from the real time, which
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
361	invocation, and callback invocation will be synchronous. Synchronous means	396	invocation, and callback invocation will be synchronous. Synchronous means
362	that it might take a while until the signal gets handled by the process,	397	that it might take a while until the signal gets handled by the process,
363	but it is guaranteed not to interrupt any other callbacks.	398	but it is guaranteed not to interrupt any other callbacks.
364		399
365	The main advantage of using these watchers is that you can share a signal	400	The main advantage of using these watchers is that you can share a signal
366	between multiple watchers.	401	between multiple watchers, and AnyEvent will ensure that signals will not
		402	interrupt your program at bad times.
367		403
368	This watcher might use C<%SIG>, so programs overwriting those signals	404	This watcher might use C<%SIG> (depending on the event loop used),
369	directly will likely not work correctly.	405	so programs overwriting those signals directly will likely not work
		406	correctly.
370		407
371	Example: exit on SIGINT	408	Example: exit on SIGINT
372		409
373	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
374		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
		429	=head3 Signal Races, Delays and Workarounds
		430
		431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
		432	callbacks to signals in a generic way, which is a pity, as you cannot
		433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
		435	signals will be delayed. The maximum time a signal might be delayed is
		436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
		437	variable can be changed only before the first signal watcher is created,
		438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
		440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
		443	All these problems can be avoided by installing the optional
		444	L<Async::Interrupt> module, which works with most event loops. It will not
		445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
		446	(and not with L<POE> currently, as POE does its own workaround with
		447	one-second latency). For those, you just have to suffer the delays.
		448
375	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
376		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
377	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
378		454
379	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
380	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
381	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
382	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
383		460
384	The callback will be called with the pid and exit status (as returned by	461	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	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
386	callback arguments.	463	callback arguments.
387		464
…		…
403		480
404	This means you cannot create a child watcher as the very first	481	This means you cannot create a child watcher as the very first
405	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
406	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
407	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
		485
		486	As most event loops do not support waiting for child events, they will be
		487	emulated by AnyEvent in most cases, in which case the latency and race
		488	problems mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
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		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	576	->send >> method).
485		577
486	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
509		618
510	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
515		624
516	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
598	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603		711
…		…
605	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
613		722
614	You can think of C<< $cv->send >> giving you an OR condition (one call	723	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	724	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).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		726
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	749	sending.
641		750
642	The ping example mentioned above is slightly more complicated, as the	751	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	752	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	753	begun can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	781	doesn't execute once).
673		782
674	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	787	call C<end>.
679		788
680	=back	789	=back
…		…
687	=over 4	796	=over 4
688		797
689	=item $cv->recv	798	=item $cv->recv
690		799
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	802	normally.
694		803
695	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	805	will return immediately.
697		806
…		…
699	function will call C<croak>.	808	function will call C<croak>.
700		809
701	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
703		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
704	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
711		827
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
726	waits otherwise.	831	waits otherwise.
727		832
728	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
734		839
735	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	841	replaces it before doing so.
737		842
738	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
742		848
743	=back	849	=back
744		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK based on FLTK (fltk 2 binding).
		884
		885	=item Backends with special needs.
		886
		887	Qt requires the Qt::Application to be instantiated first, but will
		888	otherwise be picked up automatically. As long as the main program
		889	instantiates the application before any AnyEvent watchers are created,
		890	everything should just work.
		891
		892	AnyEvent::Impl::Qt based on Qt.
		893
		894	=item Event loops that are indirectly supported via other backends.
		895
		896	Some event loops can be supported via other modules:
		897
		898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		899
		900	B<WxWidgets> has no support for watching file handles. However, you can
		901	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		902	polls 20 times per second, which was considered to be too horrible to even
		903	consider for AnyEvent.
		904
		905	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		906	backend, so it can be supported through POE.
		907
		908	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		909	load L<POE> when detecting them, in the hope that POE will pick them up,
		910	in which case everything will be automatic.
		911
		912	=back
		913
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	914	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		915
		916	These are not normally required to use AnyEvent, but can be useful to
		917	write AnyEvent extension modules.
		918
747	=over 4	919	=over 4
748		920
749	=item $AnyEvent::MODEL	921	=item $AnyEvent::MODEL
750		922
751	Contains C<undef> until the first watcher is being created. Then it	923	Contains C<undef> until the first watcher is being created, before the
		924	backend has been autodetected.
		925
752	contains the event model that is being used, which is the name of the	926	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	927	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		930	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		931
782	=item AnyEvent::detect	932	=item AnyEvent::detect
783		933
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
		942
		943	If you need to do some initialisation before AnyEvent watchers are
		944	created, use C<post_detect>.
788		945
789	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
790		947
791	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
		950
		951	The block will be executed I<after> the actual backend has been detected
		952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		954	other initialisations - see the sources of L<AnyEvent::Strict> or
		955	L<AnyEvent::AIO> to see how this is used.
		956
		957	The most common usage is to create some global watchers, without forcing
		958	event module detection too early, for example, L<AnyEvent::AIO> creates
		959	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		960	avoid autodetecting the event module at load time.
793		961
794	If called in scalar or list context, then it creates and returns an object	962	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	963	that automatically removes the callback again when it is destroyed (or
		964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	965	a case where this is useful.
		966
		967	Example: Create a watcher for the IO::AIO module and store it in
		968	C<$WATCHER>, but do so only do so after the event loop is initialised.
		969
		970	our WATCHER;
		971
		972	my $guard = AnyEvent::post_detect {
		973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		974	};
		975
		976	# the ||= is important in case post_detect immediately runs the block,
		977	# as to not clobber the newly-created watcher. assigning both watcher and
		978	# post_detect guard to the same variable has the advantage of users being
		979	# able to just C<undef $WATCHER> if the watcher causes them grief.
		980
		981	$WATCHER ||= $guard;
797		982
798	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
799		984
800	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
802	the event loop has been chosen.	987	after the event loop has been chosen.
803		988
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	990	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	991	array will be ignored.
807		992
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		994	it, as it takes care of these details.
		995
		996	This variable is mainly useful for modules that can do something useful
		997	when AnyEvent is used and thus want to know when it is initialised, but do
		998	not need to even load it by default. This array provides the means to hook
		999	into AnyEvent passively, without loading it.
		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
		1054	=item AnyEvent::log $level, $msg[, @args]
		1055
		1056	Log the given C<$msg> at the given C<$level>.
		1057
		1058	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1059	to see whether the message will be logged. If the test succeeds it will
		1060	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1061	the L<AnyEvent::Log> documentation for details.
		1062
		1063	If the test fails it will simply return. Right now this happens when a
		1064	numerical loglevel is used and it is larger than the level specified via
		1065	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1066
		1067	If you want to sprinkle loads of logging calls around your code, consider
		1068	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1069	which can reduce typing, codesize and can reduce the logging overhead
		1070	enourmously.
809		1071
810	=back	1072	=back
811		1073
812	=head1 WHAT TO DO IN A MODULE	1074	=head1 WHAT TO DO IN A MODULE
813		1075
…		…
824	because it will stall the whole program, and the whole point of using	1086	because it will stall the whole program, and the whole point of using
825	events is to stay interactive.	1087	events is to stay interactive.
826		1088
827	It is fine, however, to call C<< ->recv >> when the user of your module	1089	It is fine, however, to call C<< ->recv >> when the user of your module
828	requests it (i.e. if you create a http request object ad have a method	1090	requests it (i.e. if you create a http request object ad have a method
829	called C<results> that returns the results, it should call C<< ->recv >>	1091	called C<results> that returns the results, it may call C<< ->recv >>
830	freely, as the user of your module knows what she is doing. always).	1092	freely, as the user of your module knows what she is doing. Always).
831		1093
832	=head1 WHAT TO DO IN THE MAIN PROGRAM	1094	=head1 WHAT TO DO IN THE MAIN PROGRAM
833		1095
834	There will always be a single main program - the only place that should	1096	There will always be a single main program - the only place that should
835	dictate which event model to use.	1097	dictate which event model to use.
836		1098
837	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1099	If the program is not event-based, it need not do anything special, even
838	do anything special (it does not need to be event-based) and let AnyEvent	1100	when it depends on a module that uses an AnyEvent. If the program itself
839	decide which implementation to chose if some module relies on it.	1101	uses AnyEvent, but does not care which event loop is used, all it needs
		1102	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1103	available loop implementation.
840		1104
841	If the main program relies on a specific event model - for example, in	1105	If the main program relies on a specific event model - for example, in
842	Gtk2 programs you have to rely on the Glib module - you should load the	1106	Gtk2 programs you have to rely on the Glib module - you should load the
843	event module before loading AnyEvent or any module that uses it: generally	1107	event module before loading AnyEvent or any module that uses it: generally
844	speaking, you should load it as early as possible. The reason is that	1108	speaking, you should load it as early as possible. The reason is that
845	modules might create watchers when they are loaded, and AnyEvent will	1109	modules might create watchers when they are loaded, and AnyEvent will
846	decide on the event model to use as soon as it creates watchers, and it	1110	decide on the event model to use as soon as it creates watchers, and it
847	might chose the wrong one unless you load the correct one yourself.	1111	might choose the wrong one unless you load the correct one yourself.
848		1112
849	You can chose to use a pure-perl implementation by loading the	1113	You can chose to use a pure-perl implementation by loading the
850	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1114	C<AnyEvent::Loop> module, which gives you similar behaviour
851	everywhere, but letting AnyEvent chose the model is generally better.	1115	everywhere, but letting AnyEvent chose the model is generally better.
852		1116
853	=head2 MAINLOOP EMULATION	1117	=head2 MAINLOOP EMULATION
854		1118
855	Sometimes (often for short test scripts, or even standalone programs who	1119	Sometimes (often for short test scripts, or even standalone programs who
…		…
868		1132
869		1133
870	=head1 OTHER MODULES	1134	=head1 OTHER MODULES
871		1135
872	The following is a non-exhaustive list of additional modules that use	1136	The following is a non-exhaustive list of additional modules that use
873	AnyEvent and can therefore be mixed easily with other AnyEvent modules	1137	AnyEvent as a client and can therefore be mixed easily with other
874	in the same program. Some of the modules come with AnyEvent, some are	1138	AnyEvent modules and other event loops in the same program. Some of the
875	available via CPAN.	1139	modules come as part of AnyEvent, the others are available via CPAN (see
		1140	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1141	a longer non-exhaustive list), and the list is heavily biased towards
		1142	modules of the AnyEvent author himself :)
876		1143
877	=over 4	1144	=over 4
878		1145
879	=item L<AnyEvent::Util>	1146	=item L<AnyEvent::Util>
880		1147
881	Contains various utility functions that replace often-used but blocking	1148	Contains various utility functions that replace often-used blocking
882	functions such as C<inet_aton> by event-/callback-based versions.	1149	functions such as C<inet_aton> with event/callback-based versions.
883		1150
884	=item L<AnyEvent::Socket>	1151	=item L<AnyEvent::Socket>
885		1152
886	Provides various utility functions for (internet protocol) sockets,	1153	Provides various utility functions for (internet protocol) sockets,
887	addresses and name resolution. Also functions to create non-blocking tcp	1154	addresses and name resolution. Also functions to create non-blocking tcp
…		…
889		1156
890	=item L<AnyEvent::Handle>	1157	=item L<AnyEvent::Handle>
891		1158
892	Provide read and write buffers, manages watchers for reads and writes,	1159	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1160	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS.	1161	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
895		1162
896	=item L<AnyEvent::DNS>	1163	=item L<AnyEvent::DNS>
897		1164
898	Provides rich asynchronous DNS resolver capabilities.	1165	Provides rich asynchronous DNS resolver capabilities.
899		1166
		1167	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1168
		1169	Implement event-based interfaces to the protocols of the same name (for
		1170	the curious, IGS is the International Go Server and FCP is the Freenet
		1171	Client Protocol).
		1172
900	=item L<AnyEvent::HTTP>	1173	=item L<AnyEvent::AIO>
901		1174
902	A simple-to-use HTTP library that is capable of making a lot of concurrent	1175	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
903	HTTP requests.	1176	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1177	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1178	file I/O, and much more.
		1179
		1180	=item L<AnyEvent::Filesys::Notify>
		1181
		1182	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1183	path changes (e.g. "watch this directory for new files", "watch this
		1184	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1185	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1186	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1187	fall back to blocking scans at regular intervals transparently on other
		1188	platforms, so it's about as portable as it gets.
		1189
		1190	(I haven't used it myself, but I haven't heard anybody complaining about
		1191	it yet).
		1192
		1193	=item L<AnyEvent::DBI>
		1194
		1195	Executes L<DBI> requests asynchronously in a proxy process for you,
		1196	notifying you in an event-based way when the operation is finished.
904		1197
905	=item L<AnyEvent::HTTPD>	1198	=item L<AnyEvent::HTTPD>
906		1199
907	Provides a simple web application server framework.	1200	A simple embedded webserver.
908		1201
909	=item L<AnyEvent::FastPing>	1202	=item L<AnyEvent::FastPing>
910		1203
911	The fastest ping in the west.	1204	The fastest ping in the west.
912		1205
913	=item L<AnyEvent::DBI>
914
915	Executes L<DBI> requests asynchronously in a proxy process.
916
917	=item L<AnyEvent::AIO>
918
919	Truly asynchronous I/O, should be in the toolbox of every event
920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
921	together.
922
923	=item L<AnyEvent::BDB>
924
925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
926	L<BDB> and AnyEvent together.
927
928	=item L<AnyEvent::GPSD>
929
930	A non-blocking interface to gpsd, a daemon delivering GPS information.
931
932	=item L<AnyEvent::IGS>
933
934	A non-blocking interface to the Internet Go Server protocol (used by
935	L<App::IGS>).
936
937	=item L<AnyEvent::IRC>
938
939	AnyEvent based IRC client module family (replacing the older Net::IRC3).
940
941	=item L<Net::XMPP2>
942
943	AnyEvent based XMPP (Jabber protocol) module family.
944
945	=item L<Net::FCP>
946
947	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
948	of AnyEvent.
949
950	=item L<Event::ExecFlow>
951
952	High level API for event-based execution flow control.
953
954	=item L<Coro>	1206	=item L<Coro>
955		1207
956	Has special support for AnyEvent via L<Coro::AnyEvent>.	1208	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1209	to simply invert the flow control - don't call us, we will call you:
957		1210
958	=item L<IO::Lambda>	1211	async {
		1212	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1213	print "5 seconds later!\n";
959		1214
960	The lambda approach to I/O - don't ask, look there. Can use AnyEvent.	1215	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1216	my $line = <STDIN>; # works for ttys
		1217
		1218	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1219	my ($body, $hdr) = Coro::rouse_wait;
		1220	};
961		1221
962	=back	1222	=back
963		1223
964	=cut	1224	=cut
965		1225
966	package AnyEvent;	1226	package AnyEvent;
967		1227
968	no warnings;	1228	# basically a tuned-down version of common::sense
969	use strict qw(vars subs);	1229	sub common_sense {
		1230	# from common:.sense 3.4
		1231	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1232	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1233	$^H |= 0x00000600;
		1234	}
970		1235
		1236	BEGIN { AnyEvent::common_sense }
		1237
971	use Carp;	1238	use Carp ();
972		1239
973	our $VERSION = 4.45;	1240	our $VERSION = '6.02';
974	our $MODEL;	1241	our $MODEL;
975
976	our $AUTOLOAD;
977	our @ISA;	1242	our @ISA;
978
979	our @REGISTRY;	1243	our @REGISTRY;
980		1244	our $VERBOSE;
981	our $WIN32;	1245	our $MAX_SIGNAL_LATENCY = 10;
		1246	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
982		1247
983	BEGIN {	1248	BEGIN {
984	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1249	require "AnyEvent/constants.pl";
		1250
985	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1251	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
986		1252
987	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1253	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
988	if ${^TAINT};	1254	if ${^TAINT};
989	}
990		1255
991	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1256	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1257	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
992		1258
993	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1259	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1260	if ${^TAINT};
994		1261
995	{	1262	# $ENV{PERL_ANYEVENT_xxx} now valid
		1263
		1264	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 4;
		1265
996	my $idx;	1266	my $idx;
997	$PROTOCOL{$_} = ++$idx	1267	$PROTOCOL{$_} = ++$idx
998	for reverse split /\s*,\s*/,	1268	for reverse split /\s*,\s*/,
999	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1269	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1000	}	1270	}
1001		1271
		1272	our @post_detect;
		1273
		1274	sub post_detect(&) {
		1275	my ($cb) = @_;
		1276
		1277	push @post_detect, $cb;
		1278
		1279	defined wantarray
		1280	? bless \$cb, "AnyEvent::Util::postdetect"
		1281	: ()
		1282	}
		1283
		1284	sub AnyEvent::Util::postdetect::DESTROY {
		1285	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1286	}
		1287
		1288	our $POSTPONE_W;
		1289	our @POSTPONE;
		1290
		1291	sub _postpone_exec {
		1292	undef $POSTPONE_W;
		1293
		1294	&{ shift @POSTPONE }
		1295	while @POSTPONE;
		1296	}
		1297
		1298	sub postpone(&) {
		1299	push @POSTPONE, shift;
		1300
		1301	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1302
		1303	()
		1304	}
		1305
		1306	sub log($$;@) {
		1307	# only load the big bloated module when we actually are about to log something
		1308	if ($_[0] <= ($VERBOSE || 1)) { # also catches non-numeric levels(!) and fatal
		1309	require AnyEvent::Log; # among other things, sets $VERBOSE to 9
		1310	# AnyEvent::Log overwrites this function
		1311	goto &log;
		1312	}
		1313
		1314	0 # not logged
		1315	}
		1316
		1317	sub logger($;$) {
		1318	package AnyEvent::Log;
		1319
		1320	my ($level, $renabled) = @_;
		1321
		1322	$$renabled = $level <= $VERBOSE;
		1323
		1324	my $pkg = (caller)[0];
		1325
		1326	my $logger = [$pkg, $level, $renabled];
		1327
		1328	our %LOGGER;
		1329	$LOGGER{$logger+0} = $logger;
		1330
		1331	require AnyEvent::Util;
		1332	my $guard = AnyEvent::Util::guard (sub {
		1333	# "clean up"
		1334	delete $LOGGER{$logger+0};
		1335	});
		1336
		1337	sub {
		1338	return 0 unless $$renabled;
		1339
		1340	$guard if 0; # keep guard alive, but don't cause runtime overhead
		1341	require AnyEvent::Log unless $AnyEvent::Log::VERSION;
		1342	package AnyEvent::Log;
		1343	_log ($logger->[0], $level, @_) # logger->[0] has been converted at load time
		1344	}
		1345	}
		1346
		1347	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1348	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1349	}
		1350
1002	my @models = (	1351	our @models = (
1003	[EV:: => AnyEvent::Impl::EV::],	1352	[EV:: => AnyEvent::Impl::EV:: , 1],
1004	[Event:: => AnyEvent::Impl::Event::],	1353	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1005	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1006	# everything below here will not be autoprobed	1354	# everything below here will not (normally) be autoprobed
1007	# as the pureperl backend should work everywhere	1355	# as the pure perl backend should work everywhere
1008	# and is usually faster	1356	# and is usually faster
		1357	[Event:: => AnyEvent::Impl::Event::, 1],
		1358	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1359	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1360	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1009	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1361	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1010	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1011	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1012	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1362	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1013	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1363	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1014	[Wx:: => AnyEvent::Impl::POE::],	1364	[Wx:: => AnyEvent::Impl::POE::],
1015	[Prima:: => AnyEvent::Impl::POE::],	1365	[Prima:: => AnyEvent::Impl::POE::],
1016	# IO::Async is just too broken - we would need workaorunds for its	1366	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1017	# byzantine signal and broken child handling, among others.	1367	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1018	# IO::Async is rather hard to detect, as it doesn't have any	1368	[FLTK:: => AnyEvent::Impl::FLTK::],
1019	# obvious default class.
1020	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1021	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1022	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1023	);	1369	);
1024		1370
1025	our %method = map +($_ => 1),	1371	our @isa_hook;
		1372
		1373	sub _isa_set {
		1374	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1375
		1376	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1377	for 1 .. $#pkg;
		1378
		1379	grep $_ && $_->[1], @isa_hook
		1380	and AE::_reset ();
		1381	}
		1382
		1383	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1384	sub _isa_hook($$;$) {
		1385	my ($i, $pkg, $reset_ae) = @_;
		1386
		1387	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1388
		1389	_isa_set;
		1390	}
		1391
		1392	# all autoloaded methods reserve the complete glob, not just the method slot.
		1393	# due to bugs in perls method cache implementation.
1026	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1394	our @methods = qw(io timer time now now_update signal child idle condvar);
1027		1395
1028	our @post_detect;
1029
1030	sub post_detect(&) {	1396	sub detect() {
1031	my ($cb) = @_;	1397	return $MODEL if $MODEL; # some programs keep references to detect
1032		1398
1033	if ($MODEL) {	1399	local $!; # for good measure
1034	$cb->();	1400	local $SIG{__DIE__}; # we use eval
1035		1401
1036	1	1402	# free some memory
		1403	*detect = sub () { $MODEL };
		1404	# undef &func doesn't correctly update the method cache. grmbl.
		1405	# so we delete the whole glob. grmbl.
		1406	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1407	# a glob with an active sub. hrm. i hope it works, but perl is
		1408	# usually buggy in this department. sigh.
		1409	delete @{"AnyEvent::"}{@methods};
		1410	undef @methods;
		1411
		1412	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1413	my $model = $1;
		1414	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1415	if (eval "require $model") {
		1416	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1417	$MODEL = $model;
1037	} else {	1418	} else {
1038	push @post_detect, $cb;	1419	AnyEvent::log 4 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1039		1420	}
1040	defined wantarray
1041	? bless \$cb, "AnyEvent::Util::postdetect"
1042	: ()
1043	}	1421	}
1044	}
1045		1422
1046	sub AnyEvent::Util::postdetect::DESTROY {	1423	# check for already loaded models
1047	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1048	}
1049
1050	sub detect() {
1051	unless ($MODEL) {	1424	unless ($MODEL) {
1052	no strict 'refs';	1425	for (@REGISTRY, @models) {
1053	local $SIG{__DIE__};	1426	my ($package, $model) = @$_;
1054		1427	if (${"$package\::VERSION"} > 0) {
1055	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1056	my $model = "AnyEvent::Impl::$1";
1057	if (eval "require $model") {	1428	if (eval "require $model") {
		1429	AnyEvent::log 7 => "autodetected model '$model', using it.";
1058	$MODEL = $model;	1430	$MODEL = $model;
1059	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1431	last;
1060	} else {	1432	}
1061	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
1062	}	1433	}
1063	}	1434	}
1064		1435
1065	# check for already loaded models
1066	unless ($MODEL) {	1436	unless ($MODEL) {
		1437	# try to autoload a model
1067	for (@REGISTRY, @models) {	1438	for (@REGISTRY, @models) {
1068	my ($package, $model) = @$_;	1439	my ($package, $model, $autoload) = @$_;
		1440	if (
		1441	$autoload
		1442	and eval "require $package"
1069	if (${"$package\::VERSION"} > 0) {	1443	and ${"$package\::VERSION"} > 0
1070	if (eval "require $model") {	1444	and eval "require $model"
		1445	) {
		1446	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1071	$MODEL = $model;	1447	$MODEL = $model;
1072	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
1073	last;	1448	last;
1074	}
1075	}	1449	}
1076	}	1450	}
1077		1451
1078	unless ($MODEL) {
1079	# try to load a model
1080
1081	for (@REGISTRY, @models) {
1082	my ($package, $model) = @$_;
1083	if (eval "require $package"
1084	and ${"$package\::VERSION"} > 0
1085	and eval "require $model") {
1086	$MODEL = $model;
1087	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1088	last;
1089	}
1090	}
1091
1092	$MODEL	1452	$MODEL
1093	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1453	or AnyEvent::log fatal => "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1094	}
1095	}	1454	}
1096
1097	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1098
1099	unshift @ISA, $MODEL;
1100
1101	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1102
1103	(shift @post_detect)->() while @post_detect;
1104	}	1455	}
1105		1456
		1457	# free memory only needed for probing
		1458	undef @models;
		1459	undef @REGISTRY;
		1460
		1461	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1462
		1463	# now nuke some methods that are overridden by the backend.
		1464	# SUPER usage is not allowed in these.
		1465	for (qw(time signal child idle)) {
		1466	undef &{"AnyEvent::Base::$_"}
		1467	if defined &{"$MODEL\::$_"};
		1468	}
		1469
		1470	_isa_set;
		1471
		1472	# we're officially open!
		1473
		1474	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1475	require AnyEvent::Strict;
		1476	}
		1477
		1478	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1479	require AnyEvent::Debug;
		1480	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1481	}
		1482
		1483	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1484	require AnyEvent::Socket;
		1485	require AnyEvent::Debug;
		1486
		1487	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1488	$shell =~ s/\$\$/$$/g;
		1489
		1490	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1491	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1492	}
		1493
		1494	# now the anyevent environment is set up as the user told us to, so
		1495	# call the actual user code - post detects
		1496
		1497	(shift @post_detect)->() while @post_detect;
		1498	undef @post_detect;
		1499
		1500	*post_detect = sub(&) {
		1501	shift->();
		1502
		1503	undef
		1504	};
		1505
1106	$MODEL	1506	$MODEL
1107	}	1507	}
1108		1508
1109	sub AUTOLOAD {	1509	for my $name (@methods) {
1110	(my $func = $AUTOLOAD) =~ s/.*://;	1510	*$name = sub {
1111		1511	detect;
1112	$method{$func}	1512	# we use goto because
1113	or croak "$func: not a valid method for AnyEvent objects";	1513	# a) it makes the thunk more transparent
1114		1514	# b) it allows us to delete the thunk later
1115	detect unless $MODEL;	1515	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1116		1516	};
1117	my $class = shift;
1118	$class->$func (@_);
1119	}	1517	}
1120		1518
1121	# utility function to dup a filehandle. this is used by many backends	1519	# utility function to dup a filehandle. this is used by many backends
1122	# to support binding more than one watcher per filehandle (they usually	1520	# to support binding more than one watcher per filehandle (they usually
1123	# allow only one watcher per fd, so we dup it to get a different one).	1521	# allow only one watcher per fd, so we dup it to get a different one).
1124	sub _dupfh($$;$$) {	1522	sub _dupfh($$;$$) {
1125	my ($poll, $fh, $r, $w) = @_;	1523	my ($poll, $fh, $r, $w) = @_;
1126		1524
1127	# cygwin requires the fh mode to be matching, unix doesn't	1525	# cygwin requires the fh mode to be matching, unix doesn't
1128	my ($rw, $mode) = $poll eq "r" ? ($r, "<")	1526	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1129	: $poll eq "w" ? ($w, ">")
1130	: Carp::croak "AnyEvent->io requires poll set to either 'r' or 'w'";
1131		1527
1132	open my $fh2, "$mode&" . fileno $fh	1528	open my $fh2, $mode, $fh
1133	or die "cannot dup() filehandle: $!,";	1529	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1134		1530
1135	# we assume CLOEXEC is already set by perl in all important cases	1531	# we assume CLOEXEC is already set by perl in all important cases
1136		1532
1137	($fh2, $rw)	1533	($fh2, $rw)
1138	}	1534	}
1139		1535
		1536	=head1 SIMPLIFIED AE API
		1537
		1538	Starting with version 5.0, AnyEvent officially supports a second, much
		1539	simpler, API that is designed to reduce the calling, typing and memory
		1540	overhead by using function call syntax and a fixed number of parameters.
		1541
		1542	See the L<AE> manpage for details.
		1543
		1544	=cut
		1545
		1546	package AE;
		1547
		1548	our $VERSION = $AnyEvent::VERSION;
		1549
		1550	sub _reset() {
		1551	eval q{
		1552	# fall back to the main API by default - backends and AnyEvent::Base
		1553	# implementations can overwrite these.
		1554
		1555	sub io($$$) {
		1556	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1557	}
		1558
		1559	sub timer($$$) {
		1560	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1561	}
		1562
		1563	sub signal($$) {
		1564	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1565	}
		1566
		1567	sub child($$) {
		1568	AnyEvent->child (pid => $_[0], cb => $_[1])
		1569	}
		1570
		1571	sub idle($) {
		1572	AnyEvent->idle (cb => $_[0]);
		1573	}
		1574
		1575	sub cv(;&) {
		1576	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1577	}
		1578
		1579	sub now() {
		1580	AnyEvent->now
		1581	}
		1582
		1583	sub now_update() {
		1584	AnyEvent->now_update
		1585	}
		1586
		1587	sub time() {
		1588	AnyEvent->time
		1589	}
		1590
		1591	*postpone = \&AnyEvent::postpone;
		1592	*log = \&AnyEvent::log;
		1593	};
		1594	die if $@;
		1595	}
		1596
		1597	BEGIN { _reset }
		1598
1140	package AnyEvent::Base;	1599	package AnyEvent::Base;
1141		1600
1142	# default implementations for many methods	1601	# default implementations for many methods
1143		1602
1144	BEGIN {	1603	sub time {
		1604	eval q{ # poor man's autoloading {}
		1605	# probe for availability of Time::HiRes
1145	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1606	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1607	*time = sub { Time::HiRes::time () };
1146	*_time = \&Time::HiRes::time;	1608	*AE::time = \& Time::HiRes::time ;
		1609	*now = \&time;
		1610	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1147	# if (eval "use POSIX (); (POSIX::times())...	1611	# if (eval "use POSIX (); (POSIX::times())...
1148	} else {	1612	} else {
1149	*_time = sub { time }; # epic fail	1613	*time = sub { CORE::time };
		1614	*AE::time = sub (){ CORE::time };
		1615	*now = \&time;
		1616	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
		1617	}
		1618	};
		1619	die if $@;
		1620
		1621	&time
		1622	}
		1623
		1624	*now = \&time;
		1625	sub now_update { }
		1626
		1627	sub _poll {
		1628	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1629	}
		1630
		1631	# default implementation for ->condvar
		1632	# in fact, the default should not be overwritten
		1633
		1634	sub condvar {
		1635	eval q{ # poor man's autoloading {}
		1636	*condvar = sub {
		1637	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1638	};
		1639
		1640	*AE::cv = sub (;&) {
		1641	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1642	};
		1643	};
		1644	die if $@;
		1645
		1646	&condvar
		1647	}
		1648
		1649	# default implementation for ->signal
		1650
		1651	our $HAVE_ASYNC_INTERRUPT;
		1652
		1653	sub _have_async_interrupt() {
		1654	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1655	&& eval "use Async::Interrupt 1.02 (); 1")
		1656	unless defined $HAVE_ASYNC_INTERRUPT;
		1657
		1658	$HAVE_ASYNC_INTERRUPT
		1659	}
		1660
		1661	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1662	our (%SIG_ASY, %SIG_ASY_W);
		1663	our ($SIG_COUNT, $SIG_TW);
		1664
		1665	# install a dummy wakeup watcher to reduce signal catching latency
		1666	# used by Impls
		1667	sub _sig_add() {
		1668	unless ($SIG_COUNT++) {
		1669	# try to align timer on a full-second boundary, if possible
		1670	my $NOW = AE::now;
		1671
		1672	$SIG_TW = AE::timer
		1673	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1674	$MAX_SIGNAL_LATENCY,
		1675	sub { } # just for the PERL_ASYNC_CHECK
		1676	;
1150	}	1677	}
1151	}	1678	}
1152		1679
1153	sub time { _time }	1680	sub _sig_del {
1154	sub now { _time }	1681	undef $SIG_TW
1155	sub now_update { }	1682	unless --$SIG_COUNT;
1156
1157	# default implementation for ->condvar
1158
1159	sub condvar {
1160	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1161	}	1683	}
1162		1684
1163	# default implementation for ->signal	1685	our $_sig_name_init; $_sig_name_init = sub {
		1686	eval q{ # poor man's autoloading {}
		1687	undef $_sig_name_init;
1164		1688
1165	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1689	if (_have_async_interrupt) {
		1690	*sig2num = \&Async::Interrupt::sig2num;
		1691	*sig2name = \&Async::Interrupt::sig2name;
		1692	} else {
		1693	require Config;
1166		1694
1167	sub _signal_exec {	1695	my %signame2num;
1168	sysread $SIGPIPE_R, my $dummy, 4;	1696	@signame2num{ split ' ', $Config::Config{sig_name} }
		1697	= split ' ', $Config::Config{sig_num};
1169		1698
1170	while (%SIG_EV) {	1699	my @signum2name;
1171	for (keys %SIG_EV) {	1700	@signum2name[values %signame2num] = keys %signame2num;
1172	delete $SIG_EV{$_};	1701
1173	$_->() for values %{ $SIG_CB{$_} || {} };	1702	*sig2num = sub($) {
		1703	$_[0] > 0 ? shift : $signame2num{+shift}
		1704	};
		1705	*sig2name = sub ($) {
		1706	$_[0] > 0 ? $signum2name[+shift] : shift
		1707	};
1174	}	1708	}
1175	}	1709	};
1176	}	1710	die if $@;
		1711	};
		1712
		1713	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1714	sub sig2name($) { &$_sig_name_init; &sig2name }
1177		1715
1178	sub signal {	1716	sub signal {
1179	my (undef, %arg) = @_;	1717	eval q{ # poor man's autoloading {}
		1718	# probe for availability of Async::Interrupt
		1719	if (_have_async_interrupt) {
		1720	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1180		1721
1181	unless ($SIGPIPE_R) {	1722	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1182	require Fcntl;	1723	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1183		1724
1184	if (AnyEvent::WIN32) {
1185	require AnyEvent::Util;
1186
1187	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1188	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1189	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1190	} else {	1725	} else {
		1726	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
		1727
		1728	if (AnyEvent::WIN32) {
		1729	require AnyEvent::Util;
		1730
		1731	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1732	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1733	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1734	} else {
1191	pipe $SIGPIPE_R, $SIGPIPE_W;	1735	pipe $SIGPIPE_R, $SIGPIPE_W;
1192	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1736	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1193	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1737	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1194		1738
1195	# not strictly required, as $^F is normally 2, but let's make sure...	1739	# not strictly required, as $^F is normally 2, but let's make sure...
1196	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1740	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1197	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1741	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1742	}
		1743
		1744	$SIGPIPE_R
		1745	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1746
		1747	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1198	}	1748	}
1199		1749
1200	$SIGPIPE_R	1750	*signal = $HAVE_ASYNC_INTERRUPT
1201	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1751	? sub {
		1752	my (undef, %arg) = @_;
1202		1753
1203	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1754	# async::interrupt
1204	}
1205
1206	my $signal = uc $arg{signal}	1755	my $signal = sig2num $arg{signal};
1207	or Carp::croak "required option 'signal' is missing";
1208
1209	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1756	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1757
		1758	$SIG_ASY{$signal} ||= new Async::Interrupt
		1759	cb => sub { undef $SIG_EV{$signal} },
		1760	signal => $signal,
		1761	pipe => [$SIGPIPE_R->filenos],
		1762	pipe_autodrain => 0,
		1763	;
		1764
		1765	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1766	}
		1767	: sub {
		1768	my (undef, %arg) = @_;
		1769
		1770	# pure perl
		1771	my $signal = sig2name $arg{signal};
		1772	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1773
1210	$SIG{$signal} ||= sub {	1774	$SIG{$signal} ||= sub {
1211	local $!;	1775	local $!;
1212	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1776	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1213	undef $SIG_EV{$signal};	1777	undef $SIG_EV{$signal};
		1778	};
		1779
		1780	# can't do signal processing without introducing races in pure perl,
		1781	# so limit the signal latency.
		1782	_sig_add;
		1783
		1784	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1785	}
		1786	;
		1787
		1788	*AnyEvent::Base::signal::DESTROY = sub {
		1789	my ($signal, $cb) = @{$_[0]};
		1790
		1791	_sig_del;
		1792
		1793	delete $SIG_CB{$signal}{$cb};
		1794
		1795	$HAVE_ASYNC_INTERRUPT
		1796	? delete $SIG_ASY{$signal}
		1797	: # delete doesn't work with older perls - they then
		1798	# print weird messages, or just unconditionally exit
		1799	# instead of getting the default action.
		1800	undef $SIG{$signal}
		1801	unless keys %{ $SIG_CB{$signal} };
		1802	};
		1803
		1804	*_signal_exec = sub {
		1805	$HAVE_ASYNC_INTERRUPT
		1806	? $SIGPIPE_R->drain
		1807	: sysread $SIGPIPE_R, (my $dummy), 9;
		1808
		1809	while (%SIG_EV) {
		1810	for (keys %SIG_EV) {
		1811	delete $SIG_EV{$_};
		1812	&$_ for values %{ $SIG_CB{$_} || {} };
		1813	}
		1814	}
		1815	};
1214	};	1816	};
		1817	die if $@;
1215		1818
1216	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1819	&signal
1217	}
1218
1219	sub AnyEvent::Base::signal::DESTROY {
1220	my ($signal, $cb) = @{$_[0]};
1221
1222	delete $SIG_CB{$signal}{$cb};
1223
1224	# delete doesn't work with older perls - they then
1225	# print weird messages, or just unconditionally exit
1226	# instead of getting the default action.
1227	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1228	}	1820	}
1229		1821
1230	# default implementation for ->child	1822	# default implementation for ->child
1231		1823
1232	our %PID_CB;	1824	our %PID_CB;
1233	our $CHLD_W;	1825	our $CHLD_W;
1234	our $CHLD_DELAY_W;	1826	our $CHLD_DELAY_W;
1235	our $WNOHANG;
1236		1827
1237	sub _sigchld {	1828	# used by many Impl's
1238	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1829	sub _emit_childstatus($$) {
		1830	my (undef, $rpid, $rstatus) = @_;
		1831
		1832	$_->($rpid, $rstatus)
1239	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1833	for values %{ $PID_CB{$rpid} || {} },
1240	(values %{ $PID_CB{0} || {} });	1834	values %{ $PID_CB{0} || {} };
1241	}
1242	}	1835	}
1243		1836
1244	sub child {	1837	sub child {
		1838	eval q{ # poor man's autoloading {}
		1839	*_sigchld = sub {
		1840	my $pid;
		1841
		1842	AnyEvent->_emit_childstatus ($pid, $?)
		1843	while ($pid = waitpid -1, WNOHANG) > 0;
		1844	};
		1845
		1846	*child = sub {
1245	my (undef, %arg) = @_;	1847	my (undef, %arg) = @_;
1246		1848
1247	defined (my $pid = $arg{pid} + 0)	1849	my $pid = $arg{pid};
1248	or Carp::croak "required option 'pid' is missing";	1850	my $cb = $arg{cb};
1249		1851
1250	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1852	$PID_CB{$pid}{$cb+0} = $cb;
1251		1853
1252	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1253
1254	unless ($CHLD_W) {	1854	unless ($CHLD_W) {
1255	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1855	$CHLD_W = AE::signal CHLD => \&_sigchld;
1256	# child could be a zombie already, so make at least one round	1856	# child could be a zombie already, so make at least one round
1257	&_sigchld;	1857	&_sigchld;
1258	}	1858	}
1259		1859
1260	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1860	bless [$pid, $cb+0], "AnyEvent::Base::child"
1261	}	1861	};
1262		1862
1263	sub AnyEvent::Base::child::DESTROY {	1863	*AnyEvent::Base::child::DESTROY = sub {
1264	my ($pid, $cb) = @{$_[0]};	1864	my ($pid, $icb) = @{$_[0]};
1265		1865
1266	delete $PID_CB{$pid}{$cb};	1866	delete $PID_CB{$pid}{$icb};
1267	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1867	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1268		1868
1269	undef $CHLD_W unless keys %PID_CB;	1869	undef $CHLD_W unless keys %PID_CB;
		1870	};
		1871	};
		1872	die if $@;
		1873
		1874	&child
1270	}	1875	}
1271		1876
1272	# idle emulation is done by simply using a timer, regardless	1877	# idle emulation is done by simply using a timer, regardless
1273	# of whether the process is idle or not, and not letting	1878	# of whether the process is idle or not, and not letting
1274	# the callback use more than 50% of the time.	1879	# the callback use more than 50% of the time.
1275	sub idle {	1880	sub idle {
		1881	eval q{ # poor man's autoloading {}
		1882	*idle = sub {
1276	my (undef, %arg) = @_;	1883	my (undef, %arg) = @_;
1277		1884
1278	my ($cb, $w, $rcb) = $arg{cb};	1885	my ($cb, $w, $rcb) = $arg{cb};
1279		1886
1280	$rcb = sub {	1887	$rcb = sub {
1281	if ($cb) {	1888	if ($cb) {
1282	$w = _time;	1889	$w = AE::time;
1283	&$cb;	1890	&$cb;
1284	$w = _time - $w;	1891	$w = AE::time - $w;
1285		1892
1286	# never use more then 50% of the time for the idle watcher,	1893	# never use more then 50% of the time for the idle watcher,
1287	# within some limits	1894	# within some limits
1288	$w = 0.0001 if $w < 0.0001;	1895	$w = 0.0001 if $w < 0.0001;
1289	$w = 5 if $w > 5;	1896	$w = 5 if $w > 5;
1290		1897
1291	$w = AnyEvent->timer (after => $w, cb => $rcb);	1898	$w = AE::timer $w, 0, $rcb;
1292	} else {	1899	} else {
1293	# clean up...	1900	# clean up...
1294	undef $w;	1901	undef $w;
1295	undef $rcb;	1902	undef $rcb;
		1903	}
		1904	};
		1905
		1906	$w = AE::timer 0.05, 0, $rcb;
		1907
		1908	bless \\$cb, "AnyEvent::Base::idle"
1296	}	1909	};
		1910
		1911	*AnyEvent::Base::idle::DESTROY = sub {
		1912	undef $${$_[0]};
		1913	};
1297	};	1914	};
		1915	die if $@;
1298		1916
1299	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1917	&idle
1300
1301	bless \\$cb, "AnyEvent::Base::idle"
1302	}
1303
1304	sub AnyEvent::Base::idle::DESTROY {
1305	undef $${$_[0]};
1306	}	1918	}
1307		1919
1308	package AnyEvent::CondVar;	1920	package AnyEvent::CondVar;
1309		1921
1310	our @ISA = AnyEvent::CondVar::Base::;	1922	our @ISA = AnyEvent::CondVar::Base::;
1311		1923
		1924	# only to be used for subclassing
		1925	sub new {
		1926	my $class = shift;
		1927	bless AnyEvent->condvar (@_), $class
		1928	}
		1929
1312	package AnyEvent::CondVar::Base;	1930	package AnyEvent::CondVar::Base;
1313		1931
1314	use overload	1932	#use overload
1315	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1933	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1316	fallback => 1;	1934	# fallback => 1;
		1935
		1936	# save 300+ kilobytes by dirtily hardcoding overloading
		1937	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1938	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1939	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1940	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1941
		1942	our $WAITING;
1317		1943
1318	sub _send {	1944	sub _send {
1319	# nop	1945	# nop
		1946	}
		1947
		1948	sub _wait {
		1949	AnyEvent->_poll until $_[0]{_ae_sent};
1320	}	1950	}
1321		1951
1322	sub send {	1952	sub send {
1323	my $cv = shift;	1953	my $cv = shift;
1324	$cv->{_ae_sent} = [@_];	1954	$cv->{_ae_sent} = [@_];
…		…
1333		1963
1334	sub ready {	1964	sub ready {
1335	$_[0]{_ae_sent}	1965	$_[0]{_ae_sent}
1336	}	1966	}
1337		1967
1338	sub _wait {
1339	AnyEvent->one_event while !$_[0]{_ae_sent};
1340	}
1341
1342	sub recv {	1968	sub recv {
		1969	unless ($_[0]{_ae_sent}) {
		1970	$WAITING
		1971	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1972
		1973	local $WAITING = 1;
1343	$_[0]->_wait;	1974	$_[0]->_wait;
		1975	}
1344		1976
1345	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1977	$_[0]{_ae_croak}
1346	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1978	and Carp::croak $_[0]{_ae_croak};
		1979
		1980	wantarray
		1981	? @{ $_[0]{_ae_sent} }
		1982	: $_[0]{_ae_sent}[0]
1347	}	1983	}
1348		1984
1349	sub cb {	1985	sub cb {
1350	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1986	my $cv = shift;
		1987
		1988	@_
		1989	and $cv->{_ae_cb} = shift
		1990	and $cv->{_ae_sent}
		1991	and (delete $cv->{_ae_cb})->($cv);
		1992
1351	$_[0]{_ae_cb}	1993	$cv->{_ae_cb}
1352	}	1994	}
1353		1995
1354	sub begin {	1996	sub begin {
1355	++$_[0]{_ae_counter};	1997	++$_[0]{_ae_counter};
1356	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1998	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1361	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	2003	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1362	}	2004	}
1363		2005
1364	# undocumented/compatibility with pre-3.4	2006	# undocumented/compatibility with pre-3.4
1365	*broadcast = \&send;	2007	*broadcast = \&send;
1366	*wait = \&_wait;	2008	*wait = \&recv;
1367		2009
1368	=head1 ERROR AND EXCEPTION HANDLING	2010	=head1 ERROR AND EXCEPTION HANDLING
1369		2011
1370	In general, AnyEvent does not do any error handling - it relies on the	2012	In general, AnyEvent does not do any error handling - it relies on the
1371	caller to do that if required. The L<AnyEvent::Strict> module (see also	2013	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1383	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	2025	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1384	so on.	2026	so on.
1385		2027
1386	=head1 ENVIRONMENT VARIABLES	2028	=head1 ENVIRONMENT VARIABLES
1387		2029
1388	The following environment variables are used by this module or its	2030	AnyEvent supports a number of environment variables that tune the
1389	submodules.	2031	runtime behaviour. They are usually evaluated when AnyEvent is
		2032	loaded, initialised, or a submodule that uses them is loaded. Many of
		2033	them also cause AnyEvent to load additional modules - for example,
		2034	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2035	loaded.
1390		2036
1391	Note that AnyEvent will remove I<all> environment variables starting with	2037	All the environment variables documented here start with
1392	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2038	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1393	enabled.	2039	namespace. Other modules are encouraged (but by no means required) to use
		2040	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2041	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2042	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2043	variables starting with C<AE_>, see below).
		2044
		2045	All variables can also be set via the C<AE_> prefix, that is, instead
		2046	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2047	case there is a clash btween anyevent and another program that uses
		2048	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2049	variable to the empty string, as those variables take precedence.
		2050
		2051	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2052	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2053	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2054	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2055	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2056	is set).
		2057
		2058	The exact algorithm is currently:
		2059
		2060	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2061	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2062	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2063
		2064	This ensures that child processes will not see the C<AE_> variables.
		2065
		2066	The following environment variables are currently known to AnyEvent:
1394		2067
1395	=over 4	2068	=over 4
1396		2069
1397	=item C<PERL_ANYEVENT_VERBOSE>	2070	=item C<PERL_ANYEVENT_VERBOSE>
1398		2071
1399	By default, AnyEvent will be completely silent except in fatal	2072	By default, AnyEvent will only log messages with loglevel C<3>
1400	conditions. You can set this environment variable to make AnyEvent more	2073	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2074	environment variable to a numerical loglevel to make AnyEvent more (or
1401	talkative.	2075	less) talkative.
1402		2076
		2077	If you want to do more than just set the global logging level
		2078	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2079	complex specifications.
		2080
		2081	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2082	the default logging settings.
		2083
1403	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2084	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1404	conditions, such as not being able to load the event model specified by	2085	unexpected conditions, such as not being able to load the event model
1405	C<PERL_ANYEVENT_MODEL>.	2086	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2087	exception - this is the minimum recommended level.
1406		2088
1407	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2089	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1408	model it chooses.	2090	chooses.
		2091
		2092	When set to C<8> or higher (debug), then AnyEvent will report extra information on
		2093	which optional modules it loads and how it implements certain features.
		2094
		2095	=item C<PERL_ANYEVENT_LOG>
		2096
		2097	Accepts rather complex logging specifications. For example, you could log
		2098	all C<debug> messages of some module to stderr, warnings and above to
		2099	stderr, and errors and above to syslog, with:
		2100
		2101	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2102
		2103	For the rather extensive details, see L<AnyEvent::Log>.
		2104
		2105	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2106	so will take effect even before AnyEvent has initialised itself.
		2107
		2108	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2109	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2110	using the latter saves a few hundred kB of memory until the first message
		2111	is being logged.
1409		2112
1410	=item C<PERL_ANYEVENT_STRICT>	2113	=item C<PERL_ANYEVENT_STRICT>
1411		2114
1412	AnyEvent does not do much argument checking by default, as thorough	2115	AnyEvent does not do much argument checking by default, as thorough
1413	argument checking is very costly. Setting this variable to a true value	2116	argument checking is very costly. Setting this variable to a true value
…		…
1415	check the arguments passed to most method calls. If it finds any problems,	2118	check the arguments passed to most method calls. If it finds any problems,
1416	it will croak.	2119	it will croak.
1417		2120
1418	In other words, enables "strict" mode.	2121	In other words, enables "strict" mode.
1419		2122
1420	Unlike C<use strict>, it is definitely recommended to keep it off in	2123	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1421	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	2124	>>, it is definitely recommended to keep it off in production. Keeping
1422	developing programs can be very useful, however.	2125	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		2126	can be very useful, however.
		2127
		2128	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2129
		2130	If this env variable is nonempty, then its contents will be interpreted by
		2131	C<AnyEvent::Socket::parse_hostport> and C<AnyEvent::Debug::shell> (after
		2132	replacing every occurance of C<$$> by the process pid). The shell object
		2133	is saved in C<$AnyEvent::Debug::SHELL>.
		2134
		2135	This happens when the first watcher is created.
		2136
		2137	For example, to bind a debug shell on a unix domain socket in
		2138	F<< /tmp/debug<pid>.sock >>, you could use this:
		2139
		2140	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2141	# connect with e.g.: socat readline /tmp/debug123.sock
		2142
		2143	Or to bind to tcp port 4545 on localhost:
		2144
		2145	PERL_ANYEVENT_DEBUG_SHELL=127.0.0.1:4545 perlprog
		2146	# connect with e.g.: telnet localhost 4545
		2147
		2148	Note that creating sockets in F</tmp> or on localhost is very unsafe on
		2149	multiuser systems.
		2150
		2151	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2152
		2153	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2154	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
1423		2155
1424	=item C<PERL_ANYEVENT_MODEL>	2156	=item C<PERL_ANYEVENT_MODEL>
1425		2157
1426	This can be used to specify the event model to be used by AnyEvent, before	2158	This can be used to specify the event model to be used by AnyEvent, before
1427	auto detection and -probing kicks in. It must be a string consisting	2159	auto detection and -probing kicks in.
1428	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2160
		2161	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2162	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1429	and the resulting module name is loaded and if the load was successful,	2163	resulting module name is loaded and - if the load was successful - used as
1430	used as event model. If it fails to load AnyEvent will proceed with	2164	event model backend. If it fails to load then AnyEvent will proceed with
1431	auto detection and -probing.	2165	auto detection and -probing.
1432		2166
1433	This functionality might change in future versions.	2167	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2168	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2169	the end of a string designates a module name and quotes it appropriately).
1434		2170
1435	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2171	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1436	could start your program like this:	2172	could start your program like this:
1437		2173
1438	PERL_ANYEVENT_MODEL=Perl perl ...	2174	PERL_ANYEVENT_MODEL=Perl perl ...
1439		2175
1440	=item C<PERL_ANYEVENT_PROTOCOLS>	2176	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1456	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2192	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1457	- only support IPv4, never try to resolve or contact IPv6	2193	- only support IPv4, never try to resolve or contact IPv6
1458	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2194	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1459	IPv6, but prefer IPv6 over IPv4.	2195	IPv6, but prefer IPv6 over IPv4.
1460		2196
		2197	=item C<PERL_ANYEVENT_HOSTS>
		2198
		2199	This variable, if specified, overrides the F</etc/hosts> file used by
		2200	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2201	from that file instead.
		2202
1461	=item C<PERL_ANYEVENT_EDNS0>	2203	=item C<PERL_ANYEVENT_EDNS0>
1462		2204
1463	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2205	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1464	for DNS. This extension is generally useful to reduce DNS traffic, but	2206	DNS. This extension is generally useful to reduce DNS traffic, especially
1465	some (broken) firewalls drop such DNS packets, which is why it is off by	2207	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1466	default.	2208	packets, which is why it is off by default.
1467		2209
1468	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2210	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1469	EDNS0 in its DNS requests.	2211	EDNS0 in its DNS requests.
1470		2212
1471	=item C<PERL_ANYEVENT_MAX_FORKS>	2213	=item C<PERL_ANYEVENT_MAX_FORKS>
1472		2214
1473	The maximum number of child processes that C<AnyEvent::Util::fork_call>	2215	The maximum number of child processes that C<AnyEvent::Util::fork_call>
1474	will create in parallel.	2216	will create in parallel.
		2217
		2218	=item C<PERL_ANYEVENT_MAX_OUTSTANDING_DNS>
		2219
		2220	The default value for the C<max_outstanding> parameter for the default DNS
		2221	resolver - this is the maximum number of parallel DNS requests that are
		2222	sent to the DNS server.
		2223
		2224	=item C<PERL_ANYEVENT_RESOLV_CONF>
		2225
		2226	The absolute path to a F<resolv.conf>-style file to use instead of
		2227	F</etc/resolv.conf> (or the OS-specific configuration) in the default
		2228	resolver, or the empty string to select the default configuration.
		2229
		2230	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
		2231
		2232	When neither C<ca_file> nor C<ca_path> was specified during
		2233	L<AnyEvent::TLS> context creation, and either of these environment
		2234	variables are nonempty, they will be used to specify CA certificate
		2235	locations instead of a system-dependent default.
		2236
		2237	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2238
		2239	When these are set to C<1>, then the respective modules are not
		2240	loaded. Mostly good for testing AnyEvent itself.
1475		2241
1476	=back	2242	=back
1477		2243
1478	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2244	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1479		2245
…		…
1537	warn "read: $input\n"; # output what has been read	2303	warn "read: $input\n"; # output what has been read
1538	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2304	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1539	},	2305	},
1540	);	2306	);
1541		2307
1542	my $time_watcher; # can only be used once
1543
1544	sub new_timer {
1545	$timer = AnyEvent->timer (after => 1, cb => sub {	2308	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1546	warn "timeout\n"; # print 'timeout' about every second	2309	warn "timeout\n"; # print 'timeout' at most every second
1547	&new_timer; # and restart the time
1548	});	2310	});
1549	}
1550
1551	new_timer; # create first timer
1552		2311
1553	$cv->recv; # wait until user enters /^q/i	2312	$cv->recv; # wait until user enters /^q/i
1554		2313
1555	=head1 REAL-WORLD EXAMPLE	2314	=head1 REAL-WORLD EXAMPLE
1556		2315
…		…
1629		2388
1630	The actual code goes further and collects all errors (C<die>s, exceptions)	2389	The actual code goes further and collects all errors (C<die>s, exceptions)
1631	that occurred during request processing. The C<result> method detects	2390	that occurred during request processing. The C<result> method detects
1632	whether an exception as thrown (it is stored inside the $txn object)	2391	whether an exception as thrown (it is stored inside the $txn object)
1633	and just throws the exception, which means connection errors and other	2392	and just throws the exception, which means connection errors and other
1634	problems get reported tot he code that tries to use the result, not in a	2393	problems get reported to the code that tries to use the result, not in a
1635	random callback.	2394	random callback.
1636		2395
1637	All of this enables the following usage styles:	2396	All of this enables the following usage styles:
1638		2397
1639	1. Blocking:	2398	1. Blocking:
…		…
1687	through AnyEvent. The benchmark creates a lot of timers (with a zero	2446	through AnyEvent. The benchmark creates a lot of timers (with a zero
1688	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2447	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1689	which it is), lets them fire exactly once and destroys them again.	2448	which it is), lets them fire exactly once and destroys them again.
1690		2449
1691	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2450	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1692	distribution.	2451	distribution. It uses the L<AE> interface, which makes a real difference
		2452	for the EV and Perl backends only.
1693		2453
1694	=head3 Explanation of the columns	2454	=head3 Explanation of the columns
1695		2455
1696	I<watcher> is the number of event watchers created/destroyed. Since	2456	I<watcher> is the number of event watchers created/destroyed. Since
1697	different event models feature vastly different performances, each event	2457	different event models feature vastly different performances, each event
…		…
1718	watcher.	2478	watcher.
1719		2479
1720	=head3 Results	2480	=head3 Results
1721		2481
1722	name watchers bytes create invoke destroy comment	2482	name watchers bytes create invoke destroy comment
1723	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2483	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1724	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2484	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1725	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2485	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1726	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2486	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1727	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2487	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1728	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2488	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1729	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2489	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1730	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2490	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1731	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2491	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1732	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2492	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1733	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2493	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1734	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2494	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1735		2495
1736	=head3 Discussion	2496	=head3 Discussion
1737		2497
1738	The benchmark does I<not> measure scalability of the event loop very	2498	The benchmark does I<not> measure scalability of the event loop very
1739	well. For example, a select-based event loop (such as the pure perl one)	2499	well. For example, a select-based event loop (such as the pure perl one)
…		…
1751	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2511	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1752	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2512	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1753	cycles with POE.	2513	cycles with POE.
1754		2514
1755	C<EV> is the sole leader regarding speed and memory use, which are both	2515	C<EV> is the sole leader regarding speed and memory use, which are both
1756	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2516	maximal/minimal, respectively. When using the L<AE> API there is zero
		2517	overhead (when going through the AnyEvent API create is about 5-6 times
		2518	slower, with other times being equal, so still uses far less memory than
1757	far less memory than any other event loop and is still faster than Event	2519	any other event loop and is still faster than Event natively).
1758	natively.
1759		2520
1760	The pure perl implementation is hit in a few sweet spots (both the	2521	The pure perl implementation is hit in a few sweet spots (both the
1761	constant timeout and the use of a single fd hit optimisations in the perl	2522	constant timeout and the use of a single fd hit optimisations in the perl
1762	interpreter and the backend itself). Nevertheless this shows that it	2523	interpreter and the backend itself). Nevertheless this shows that it
1763	adds very little overhead in itself. Like any select-based backend its	2524	adds very little overhead in itself. Like any select-based backend its
…		…
1811	(even when used without AnyEvent), but most event loops have acceptable	2572	(even when used without AnyEvent), but most event loops have acceptable
1812	performance with or without AnyEvent.	2573	performance with or without AnyEvent.
1813		2574
1814	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2575	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
1815	the actual event loop, only with extremely fast event loops such as EV	2576	the actual event loop, only with extremely fast event loops such as EV
1816	adds AnyEvent significant overhead.	2577	does AnyEvent add significant overhead.
1817		2578
1818	=item * You should avoid POE like the plague if you want performance or	2579	=item * You should avoid POE like the plague if you want performance or
1819	reasonable memory usage.	2580	reasonable memory usage.
1820		2581
1821	=back	2582	=back
…		…
1837	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2598	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1838	(1%) are active. This mirrors the activity of large servers with many	2599	(1%) are active. This mirrors the activity of large servers with many
1839	connections, most of which are idle at any one point in time.	2600	connections, most of which are idle at any one point in time.
1840		2601
1841	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2602	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1842	distribution.	2603	distribution. It uses the L<AE> interface, which makes a real difference
		2604	for the EV and Perl backends only.
1843		2605
1844	=head3 Explanation of the columns	2606	=head3 Explanation of the columns
1845		2607
1846	I<sockets> is the number of sockets, and twice the number of "servers" (as	2608	I<sockets> is the number of sockets, and twice the number of "servers" (as
1847	each server has a read and write socket end).	2609	each server has a read and write socket end).
…		…
1855	a new one that moves the timeout into the future.	2617	a new one that moves the timeout into the future.
1856		2618
1857	=head3 Results	2619	=head3 Results
1858		2620
1859	name sockets create request	2621	name sockets create request
1860	EV 20000 69.01 11.16	2622	EV 20000 62.66 7.99
1861	Perl 20000 73.32 35.87	2623	Perl 20000 68.32 32.64
1862	IOAsync 20000 157.00 98.14 epoll	2624	IOAsync 20000 174.06 101.15 epoll
1863	IOAsync 20000 159.31 616.06 poll	2625	IOAsync 20000 174.67 610.84 poll
1864	Event 20000 212.62 257.32	2626	Event 20000 202.69 242.91
1865	Glib 20000 651.16 1896.30	2627	Glib 20000 557.01 1689.52
1866	POE 20000 349.67 12317.24 uses POE::Loop::Event	2628	POE 20000 341.54 12086.32 uses POE::Loop::Event
1867		2629
1868	=head3 Discussion	2630	=head3 Discussion
1869		2631
1870	This benchmark I<does> measure scalability and overall performance of the	2632	This benchmark I<does> measure scalability and overall performance of the
1871	particular event loop.	2633	particular event loop.
…		…
1997	As you can see, the AnyEvent + EV combination even beats the	2759	As you can see, the AnyEvent + EV combination even beats the
1998	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2760	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
1999	backend easily beats IO::Lambda and POE.	2761	backend easily beats IO::Lambda and POE.
2000		2762
2001	And even the 100% non-blocking version written using the high-level (and	2763	And even the 100% non-blocking version written using the high-level (and
2002	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2764	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2003	large margin, even though it does all of DNS, tcp-connect and socket I/O	2765	higher level ("unoptimised") abstractions by a large margin, even though
2004	in a non-blocking way.	2766	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2005		2767
2006	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2768	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2007	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2769	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2008	part of the IO::lambda distribution and were used without any changes.	2770	part of the IO::Lambda distribution and were used without any changes.
2009		2771
2010		2772
2011	=head1 SIGNALS	2773	=head1 SIGNALS
2012		2774
2013	AnyEvent currently installs handlers for these signals:	2775	AnyEvent currently installs handlers for these signals:
…		…
2018		2780
2019	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2781	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2020	emulation for event loops that do not support them natively. Also, some	2782	emulation for event loops that do not support them natively. Also, some
2021	event loops install a similar handler.	2783	event loops install a similar handler.
2022		2784
2023	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2785	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2024	reset it to default, to avoid losing child exit statuses.	2786	AnyEvent will reset it to default, to avoid losing child exit statuses.
2025		2787
2026	=item SIGPIPE	2788	=item SIGPIPE
2027		2789
2028	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2790	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2029	when AnyEvent gets loaded.	2791	when AnyEvent gets loaded.
…		…
2047	if $SIG{CHLD} eq 'IGNORE';	2809	if $SIG{CHLD} eq 'IGNORE';
2048		2810
2049	$SIG{PIPE} = sub { }	2811	$SIG{PIPE} = sub { }
2050	unless defined $SIG{PIPE};	2812	unless defined $SIG{PIPE};
2051		2813
		2814	=head1 RECOMMENDED/OPTIONAL MODULES
		2815
		2816	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2817	its built-in modules) are required to use it.
		2818
		2819	That does not mean that AnyEvent won't take advantage of some additional
		2820	modules if they are installed.
		2821
		2822	This section explains which additional modules will be used, and how they
		2823	affect AnyEvent's operation.
		2824
		2825	=over 4
		2826
		2827	=item L<Async::Interrupt>
		2828
		2829	This slightly arcane module is used to implement fast signal handling: To
		2830	my knowledge, there is no way to do completely race-free and quick
		2831	signal handling in pure perl. To ensure that signals still get
		2832	delivered, AnyEvent will start an interval timer to wake up perl (and
		2833	catch the signals) with some delay (default is 10 seconds, look for
		2834	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2835
		2836	If this module is available, then it will be used to implement signal
		2837	catching, which means that signals will not be delayed, and the event loop
		2838	will not be interrupted regularly, which is more efficient (and good for
		2839	battery life on laptops).
		2840
		2841	This affects not just the pure-perl event loop, but also other event loops
		2842	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2843
		2844	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2845	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2846	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2847	does nothing for those backends.
		2848
		2849	=item L<EV>
		2850
		2851	This module isn't really "optional", as it is simply one of the backend
		2852	event loops that AnyEvent can use. However, it is simply the best event
		2853	loop available in terms of features, speed and stability: It supports
		2854	the AnyEvent API optimally, implements all the watcher types in XS, does
		2855	automatic timer adjustments even when no monotonic clock is available,
		2856	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2857	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2858	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2859
		2860	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2861	then this module will do nothing for you.
		2862
		2863	=item L<Guard>
		2864
		2865	The guard module, when used, will be used to implement
		2866	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2867	lot less memory), but otherwise doesn't affect guard operation much. It is
		2868	purely used for performance.
		2869
		2870	=item L<JSON> and L<JSON::XS>
		2871
		2872	One of these modules is required when you want to read or write JSON data
		2873	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2874	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2875
		2876	=item L<Net::SSLeay>
		2877
		2878	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2879	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2880	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2881
		2882	=item L<Time::HiRes>
		2883
		2884	This module is part of perl since release 5.008. It will be used when the
		2885	chosen event library does not come with a timing source of its own. The
		2886	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2887	try to use a monotonic clock for timing stability.
		2888
		2889	=back
		2890
		2891
2052	=head1 FORK	2892	=head1 FORK
2053		2893
2054	Most event libraries are not fork-safe. The ones who are usually are	2894	Most event libraries are not fork-safe. The ones who are usually are
2055	because they rely on inefficient but fork-safe C<select> or C<poll>	2895	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2056	calls. Only L<EV> is fully fork-aware.	2896	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2897	are usually badly thought-out hacks that are incompatible with fork in
		2898	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2899	continue event-processing in both parent and child (or both, if you know
		2900	what you are doing).
		2901
		2902	This means that, in general, you cannot fork and do event processing in
		2903	the child if the event library was initialised before the fork (which
		2904	usually happens when the first AnyEvent watcher is created, or the library
		2905	is loaded).
2057		2906
2058	If you have to fork, you must either do so I<before> creating your first	2907	If you have to fork, you must either do so I<before> creating your first
2059	watcher OR you must not use AnyEvent at all in the child.	2908	watcher OR you must not use AnyEvent at all in the child OR you must do
		2909	something completely out of the scope of AnyEvent.
		2910
		2911	The problem of doing event processing in the parent I<and> the child
		2912	is much more complicated: even for backends that I<are> fork-aware or
		2913	fork-safe, their behaviour is not usually what you want: fork clones all
		2914	watchers, that means all timers, I/O watchers etc. are active in both
		2915	parent and child, which is almost never what you want. USing C<exec>
		2916	to start worker children from some kind of manage rprocess is usually
		2917	preferred, because it is much easier and cleaner, at the expense of having
		2918	to have another binary.
2060		2919
2061		2920
2062	=head1 SECURITY CONSIDERATIONS	2921	=head1 SECURITY CONSIDERATIONS
2063		2922
2064	AnyEvent can be forced to load any event model via	2923	AnyEvent can be forced to load any event model via
…		…
2094	pronounced).	2953	pronounced).
2095		2954
2096		2955
2097	=head1 SEE ALSO	2956	=head1 SEE ALSO
2098		2957
2099	Utility functions: L<AnyEvent::Util>.	2958	Tutorial/Introduction: L<AnyEvent::Intro>.
2100		2959
2101	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2960	FAQ: L<AnyEvent::FAQ>.
2102	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2961
		2962	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2963	(simply logging).
		2964
		2965	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2966	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2967
		2968	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2969	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2970	L<Qt>, L<POE>, L<FLTK>.
2103		2971
2104	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2972	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2105	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2973	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2106	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2974	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
		2975	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
2107	L<AnyEvent::Impl::POE>.	2976	L<AnyEvent::Impl::FLTK>.
2108		2977
2109	Non-blocking file handles, sockets, TCP clients and	2978	Non-blocking handles, pipes, stream sockets, TCP clients and
2110	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>.	2979	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2111		2980
2112	Asynchronous DNS: L<AnyEvent::DNS>.	2981	Asynchronous DNS: L<AnyEvent::DNS>.
2113		2982
2114	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>,	2983	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2115		2984
2116	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>, L<AnyEvent::DNS>.	2985	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
		2986	L<AnyEvent::HTTP>.
2117		2987
2118		2988
2119	=head1 AUTHOR	2989	=head1 AUTHOR
2120		2990
2121	Marc Lehmann <schmorp@schmorp.de>	2991	Marc Lehmann <schmorp@schmorp.de>

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