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Revision 1.354 by root, Thu Aug 11 21:26:39 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	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	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
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
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		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> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
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 slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
469	loop and 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.
473		564
474	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
475		566
476	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
477	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
482	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
483	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
484	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<<
485	->send >> method).	576	->send >> method).
486		577
487	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
488	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:
489	in time where multiple outstanding events have been processed. And yet	580
490	another way to call them is transactions - each condition variable can be	581	=over 4
491	used to represent a transaction, which finishes at some point and delivers	582
492	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
493		601
494	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
495	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,
496	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
497	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
…		…
510		618
511	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
512	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
513	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
514	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
515	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
516		624
517	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
518	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
519	for the send to occur.	627	for the send to occur.
520		628
521	Example: wait for a timer.	629	Example: wait for a timer.
522		630
523	# wait till the result is ready	631	# condition: "wait till the timer is fired"
524	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
525		633
526	# do something such as adding a timer	634	# create the timer - we could wait for, say
527	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
528	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
529	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
530	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
531	after => 1,	639	after => 1,
532	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
533	);	641	);
534		642
535	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
536	# calls -<send	644	# calls ->send
537	$result_ready->recv;	645	$timer_fired->recv;
538		646
539	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
540	variables are also callable directly.	648	variables are also callable directly.
541		649
542	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
585	they were 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
586	C<send>.	694	C<send>.
587		695
588	=item $cv->croak ($error)	696	=item $cv->croak ($error)
589		697
590	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
591	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
592		700
593	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
594	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
595	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
596	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
597	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
598	the problem.	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
…		…
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
…		…
714	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
715	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
716	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,
717	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
718		827
719	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
720	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
721	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
722	waits otherwise.	831	waits otherwise.
723		832
724	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
730		839
731	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
732	replaces it before doing so.	841	replaces it before doing so.
733		842
734	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
735	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
736	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
737	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.
738		848
739	=back	849	=back
740		850
741	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
742		852
…		…
745	=over 4	855	=over 4
746		856
747	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
748		858
749	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
750	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
751	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
752	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
753		863
754	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
755	AnyEvent::Impl::Event based on Event, very stable, few glitches.
756	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
757		866
758	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
759		868
760	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
761	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
762	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
763	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
764	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
765		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
766	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
767	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
768	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
769	AnyEvent::Impl::POE based on POE, very slow, some limitations.	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.
770		884
771	=item Backends with special needs.	885	=item Backends with special needs.
772		886
773	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
774	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
775	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
776	everything should just work.	890	everything should just work.
777		891
778	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
779		893
780	Support for IO::Async can only be partial, as it is too broken and
781	architecturally limited to even support the AnyEvent API. It also
782	is the only event loop that needs the loop to be set explicitly, so
783	it can only be used by a main program knowing about AnyEvent. See
784	L<AnyEvent::Impl::Async> for the gory details.
785
786	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
787
788	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
789		895
790	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
791		897
792	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
817	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
818	backend has been autodetected.	924	backend has been autodetected.
819		925
820	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
821	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
822	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
823	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
824	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
825		931
826	=item AnyEvent::detect	932	=item AnyEvent::detect
827		933
828	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
829	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
830	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
831	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
832		938
833	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
834	created, use C<post_detect>.	940	created, use C<post_detect>.
835		941
836	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
837		943
838	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
839	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
840		946
841	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
842	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
843	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
844	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
848	event module detection too early, for example, L<AnyEvent::AIO> creates	954	event module detection too early, for example, L<AnyEvent::AIO> creates
849	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	955	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
850	avoid autodetecting the event module at load time.	956	avoid autodetecting the event module at load time.
851		957
852	If called in scalar or list context, then it creates and returns an object	958	If called in scalar or list context, then it creates and returns an object
853	that automatically removes the callback again when it is destroyed. See	959	that automatically removes the callback again when it is destroyed (or
		960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
854	L<Coro::BDB> for a case where this is useful.	961	a case where this is useful.
		962
		963	Example: Create a watcher for the IO::AIO module and store it in
		964	C<$WATCHER>, but do so only do so after the event loop is initialised.
		965
		966	our WATCHER;
		967
		968	my $guard = AnyEvent::post_detect {
		969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		970	};
		971
		972	# the ||= is important in case post_detect immediately runs the block,
		973	# as to not clobber the newly-created watcher. assigning both watcher and
		974	# post_detect guard to the same variable has the advantage of users being
		975	# able to just C<undef $WATCHER> if the watcher causes them grief.
		976
		977	$WATCHER ||= $guard;
855		978
856	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
857		980
858	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
859	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
860	the event loop has been chosen.	983	after the event loop has been chosen.
861		984
862	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
863	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
864	array will be ignored.	987	array will be ignored.
865		988
866	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
867	it,as it takes care of these details.	990	it, as it takes care of these details.
868		991
869	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
870	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
871	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
872	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
873		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
		1049
874	=back	1050	=back
875		1051
876	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
877		1053
878	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1054	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
888	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
889	events is to stay interactive.	1065	events is to stay interactive.
890		1066
891	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
892	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
893	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
894	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
895		1071
896	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
897		1073
898	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
899	dictate which event model to use.	1075	dictate which event model to use.
900		1076
901	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
902	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
903	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
904		1082
905	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
906	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
907	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
908	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
909	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
910	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
911	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
912		1090
913	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
914	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
915	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
916		1094
917	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
918		1096
919	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
934	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
935		1113
936	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
937	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
938	modules and other event loops in the same program. Some of the modules	1116	modules and other event loops in the same program. Some of the modules
939	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
940		1118
941	=over 4	1119	=over 4
942		1120
943	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
944		1122
945	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
946	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
947		1125
948	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
949		1127
950	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
951	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
953		1131
954	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
955		1133
956	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
957	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
958	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
959		1137
960	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
961		1139
962	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
963		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
964	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
965		1166
966	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
967	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
968		1176
969	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
970		1178
971	Provides a simple web application server framework.	1179	A simple embedded webserver.
972		1180
973	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
974		1182
975	The fastest ping in the west.	1183	The fastest ping in the west.
976		1184
977	=item L<AnyEvent::DBI>
978
979	Executes L<DBI> requests asynchronously in a proxy process.
980
981	=item L<AnyEvent::AIO>
982
983	Truly asynchronous I/O, should be in the toolbox of every event
984	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
985	together.
986
987	=item L<AnyEvent::BDB>
988
989	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
990	L<BDB> and AnyEvent together.
991
992	=item L<AnyEvent::GPSD>
993
994	A non-blocking interface to gpsd, a daemon delivering GPS information.
995
996	=item L<AnyEvent::IRC>
997
998	AnyEvent based IRC client module family (replacing the older Net::IRC3).
999
1000	=item L<AnyEvent::XMPP>
1001
1002	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1003	Net::XMPP2>.
1004
1005	=item L<AnyEvent::IGS>
1006
1007	A non-blocking interface to the Internet Go Server protocol (used by
1008	L<App::IGS>).
1009
1010	=item L<Net::FCP>
1011
1012	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1013	of AnyEvent.
1014
1015	=item L<Event::ExecFlow>
1016
1017	High level API for event-based execution flow control.
1018
1019	=item L<Coro>	1185	=item L<Coro>
1020		1186
1021	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1022		1188
1023	=back	1189	=back
1024		1190
1025	=cut	1191	=cut
1026		1192
1027	package AnyEvent;	1193	package AnyEvent;
1028		1194
1029	no warnings;	1195	# basically a tuned-down version of common::sense
1030	use strict qw(vars subs);	1196	sub common_sense {
		1197	# from common:.sense 3.4
		1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
		1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1200	$^H |= 0x00000600;
		1201	}
		1202
		1203	BEGIN { AnyEvent::common_sense }
1031		1204
1032	use Carp ();	1205	use Carp ();
1033		1206
1034	our $VERSION = 4.83;	1207	our $VERSION = '5.34';
1035	our $MODEL;	1208	our $MODEL;
1036		1209
1037	our $AUTOLOAD;	1210	our $AUTOLOAD;
1038	our @ISA;	1211	our @ISA;
1039		1212
1040	our @REGISTRY;	1213	our @REGISTRY;
1041		1214
1042	our $WIN32;	1215	our $VERBOSE;
1043		1216
1044	BEGIN {	1217	BEGIN {
1045	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1218	require "AnyEvent/constants.pl";
		1219
1046	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1220	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1047		1221
1048	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1222	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1049	if ${^TAINT};	1223	if ${^TAINT};
1050	}
1051		1224
1052	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1225	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1226
		1227	}
		1228
		1229	our $MAX_SIGNAL_LATENCY = 10;
1053		1230
1054	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1231	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1055		1232
1056	{	1233	{
1057	my $idx;	1234	my $idx;
…		…
1059	for reverse split /\s*,\s*/,	1236	for reverse split /\s*,\s*/,
1060	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1237	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1061	}	1238	}
1062		1239
1063	my @models = (	1240	my @models = (
1064	[EV:: => AnyEvent::Impl::EV::],	1241	[EV:: => AnyEvent::Impl::EV:: , 1],
1065	[Event:: => AnyEvent::Impl::Event::],	1242	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1066	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
1067	# everything below here will not be autoprobed	1243	# everything below here will not (normally) be autoprobed
1068	# as the pureperl backend should work everywhere	1244	# as the pure perl backend should work everywhere
1069	# and is usually faster	1245	# and is usually faster
		1246	[Event:: => AnyEvent::Impl::Event::, 1],
1070	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1247	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1071	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1248	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1249	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1072	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1250	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1073	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1251	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1074	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1252	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1075	[Wx:: => AnyEvent::Impl::POE::],	1253	[Wx:: => AnyEvent::Impl::POE::],
1076	[Prima:: => AnyEvent::Impl::POE::],	1254	[Prima:: => AnyEvent::Impl::POE::],
1077	# IO::Async is just too broken - we would need workarounds for its
1078	# byzantine signal and broken child handling, among others.
1079	# IO::Async is rather hard to detect, as it doesn't have any
1080	# obvious default class.
1081	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1082	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1255	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1083	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1256	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1257	[FLTK:: => AnyEvent::Impl::FLTK::],
1084	);	1258	);
1085		1259
1086	our %method = map +($_ => 1),	1260	our %method = map +($_ => 1),
1087	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1261	qw(io timer time now now_update signal child idle condvar DESTROY);
1088		1262
1089	our @post_detect;	1263	our @post_detect;
1090		1264
1091	sub post_detect(&) {	1265	sub post_detect(&) {
1092	my ($cb) = @_;	1266	my ($cb) = @_;
1093		1267
1094	if ($MODEL) {
1095	$cb->();
1096
1097	1
1098	} else {
1099	push @post_detect, $cb;	1268	push @post_detect, $cb;
1100		1269
1101	defined wantarray	1270	defined wantarray
1102	? bless \$cb, "AnyEvent::Util::postdetect"	1271	? bless \$cb, "AnyEvent::Util::postdetect"
1103	: ()	1272	: ()
1104	}
1105	}	1273	}
1106		1274
1107	sub AnyEvent::Util::postdetect::DESTROY {	1275	sub AnyEvent::Util::postdetect::DESTROY {
1108	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1276	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1109	}	1277	}
1110		1278
1111	sub detect() {	1279	sub detect() {
		1280	# free some memory
		1281	*detect = sub () { $MODEL };
		1282
		1283	local $!; # for good measure
		1284	local $SIG{__DIE__};
		1285
		1286	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1287	my $model = "AnyEvent::Impl::$1";
		1288	if (eval "require $model") {
		1289	$MODEL = $model;
		1290	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1291	} else {
		1292	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1293	}
		1294	}
		1295
		1296	# check for already loaded models
1112	unless ($MODEL) {	1297	unless ($MODEL) {
1113	no strict 'refs';	1298	for (@REGISTRY, @models) {
1114	local $SIG{__DIE__};	1299	my ($package, $model) = @$_;
1115		1300	if (${"$package\::VERSION"} > 0) {
1116	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1117	my $model = "AnyEvent::Impl::$1";
1118	if (eval "require $model") {	1301	if (eval "require $model") {
1119	$MODEL = $model;	1302	$MODEL = $model;
1120	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $verbose > 1;	1303	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1121	} else {	1304	last;
1122	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $verbose;	1305	}
1123	}	1306	}
1124	}	1307	}
1125		1308
1126	# check for already loaded models
1127	unless ($MODEL) {	1309	unless ($MODEL) {
		1310	# try to autoload a model
1128	for (@REGISTRY, @models) {	1311	for (@REGISTRY, @models) {
1129	my ($package, $model) = @$_;	1312	my ($package, $model, $autoload) = @$_;
		1313	if (
		1314	$autoload
		1315	and eval "require $package"
1130	if (${"$package\::VERSION"} > 0) {	1316	and ${"$package\::VERSION"} > 0
1131	if (eval "require $model") {	1317	and eval "require $model"
		1318	) {
1132	$MODEL = $model;	1319	$MODEL = $model;
1133	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1320	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1134	last;	1321	last;
1135	}
1136	}	1322	}
1137	}	1323	}
1138		1324
1139	unless ($MODEL) {
1140	# try to load a model
1141
1142	for (@REGISTRY, @models) {
1143	my ($package, $model) = @$_;
1144	if (eval "require $package"
1145	and ${"$package\::VERSION"} > 0
1146	and eval "require $model") {
1147	$MODEL = $model;
1148	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1149	last;
1150	}
1151	}
1152
1153	$MODEL	1325	$MODEL
1154	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1326	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1155	}
1156	}	1327	}
1157
1158	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1159
1160	unshift @ISA, $MODEL;
1161
1162	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1163
1164	(shift @post_detect)->() while @post_detect;
1165	}	1328	}
		1329
		1330	@models = (); # free probe data
		1331
		1332	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1333	unshift @ISA, $MODEL;
		1334
		1335	# now nuke some methods that are overridden by the backend.
		1336	# SUPER is not allowed.
		1337	for (qw(time signal child idle)) {
		1338	undef &{"AnyEvent::Base::$_"}
		1339	if defined &{"$MODEL\::$_"};
		1340	}
		1341
		1342	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1343	eval { require AnyEvent::Strict };
		1344	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1345	if $@ && $VERBOSE;
		1346	}
		1347
		1348	(shift @post_detect)->() while @post_detect;
		1349
		1350	*post_detect = sub(&) {
		1351	shift->();
		1352
		1353	undef
		1354	};
1166		1355
1167	$MODEL	1356	$MODEL
1168	}	1357	}
1169		1358
1170	sub AUTOLOAD {	1359	sub AUTOLOAD {
1171	(my $func = $AUTOLOAD) =~ s/.*://;	1360	(my $func = $AUTOLOAD) =~ s/.*://;
1172		1361
1173	$method{$func}	1362	$method{$func}
1174	or Carp::croak "$func: not a valid method for AnyEvent objects";	1363	or Carp::croak "$func: not a valid AnyEvent class method";
1175		1364
1176	detect unless $MODEL;	1365	detect;
1177		1366
1178	my $class = shift;	1367	my $class = shift;
1179	$class->$func (@_);	1368	$class->$func (@_);
		1369	}
		1370
		1371	our $POSTPONE_W;
		1372	our @POSTPONE;
		1373
		1374	sub _postpone_exec {
		1375	undef $POSTPONE_W;
		1376	(pop @POSTPONE)->()
		1377	while @POSTPONE;
		1378	}
		1379
		1380	sub postpone(&) {
		1381	push @POSTPONE, shift;
		1382
		1383	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1384
		1385	()
1180	}	1386	}
1181		1387
1182	# utility function to dup a filehandle. this is used by many backends	1388	# utility function to dup a filehandle. this is used by many backends
1183	# to support binding more than one watcher per filehandle (they usually	1389	# to support binding more than one watcher per filehandle (they usually
1184	# allow only one watcher per fd, so we dup it to get a different one).	1390	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1194	# we assume CLOEXEC is already set by perl in all important cases	1400	# we assume CLOEXEC is already set by perl in all important cases
1195		1401
1196	($fh2, $rw)	1402	($fh2, $rw)
1197	}	1403	}
1198		1404
		1405	=head1 SIMPLIFIED AE API
		1406
		1407	Starting with version 5.0, AnyEvent officially supports a second, much
		1408	simpler, API that is designed to reduce the calling, typing and memory
		1409	overhead by using function call syntax and a fixed number of parameters.
		1410
		1411	See the L<AE> manpage for details.
		1412
		1413	=cut
		1414
		1415	package AE;
		1416
		1417	our $VERSION = $AnyEvent::VERSION;
		1418
		1419	# fall back to the main API by default - backends and AnyEvent::Base
		1420	# implementations can overwrite these.
		1421
		1422	sub io($$$) {
		1423	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1424	}
		1425
		1426	sub timer($$$) {
		1427	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1428	}
		1429
		1430	sub signal($$) {
		1431	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1432	}
		1433
		1434	sub child($$) {
		1435	AnyEvent->child (pid => $_[0], cb => $_[1])
		1436	}
		1437
		1438	sub idle($) {
		1439	AnyEvent->idle (cb => $_[0])
		1440	}
		1441
		1442	sub cv(;&) {
		1443	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1444	}
		1445
		1446	sub now() {
		1447	AnyEvent->now
		1448	}
		1449
		1450	sub now_update() {
		1451	AnyEvent->now_update
		1452	}
		1453
		1454	sub time() {
		1455	AnyEvent->time
		1456	}
		1457
		1458	*postpone = \&AnyEvent::postpone;
		1459
1199	package AnyEvent::Base;	1460	package AnyEvent::Base;
1200		1461
1201	# default implementations for many methods	1462	# default implementations for many methods
1202		1463
1203	BEGIN {	1464	sub time {
		1465	eval q{ # poor man's autoloading {}
		1466	# probe for availability of Time::HiRes
1204	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1467	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1468	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1205	*_time = \&Time::HiRes::time;	1469	*AE::time = \&Time::HiRes::time;
1206	# if (eval "use POSIX (); (POSIX::times())...	1470	# if (eval "use POSIX (); (POSIX::times())...
1207	} else {	1471	} else {
		1472	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1208	*_time = sub { time }; # epic fail	1473	*AE::time = sub (){ time }; # epic fail
		1474	}
		1475
		1476	*time = sub { AE::time }; # different prototypes
		1477	};
		1478	die if $@;
		1479
		1480	&time
		1481	}
		1482
		1483	*now = \&time;
		1484
		1485	sub now_update { }
		1486
		1487	sub _poll {
		1488	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1489	}
		1490
		1491	# default implementation for ->condvar
		1492	# in fact, the default should not be overwritten
		1493
		1494	sub condvar {
		1495	eval q{ # poor man's autoloading {}
		1496	*condvar = sub {
		1497	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1498	};
		1499
		1500	*AE::cv = sub (;&) {
		1501	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1502	};
		1503	};
		1504	die if $@;
		1505
		1506	&condvar
		1507	}
		1508
		1509	# default implementation for ->signal
		1510
		1511	our $HAVE_ASYNC_INTERRUPT;
		1512
		1513	sub _have_async_interrupt() {
		1514	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1515	&& eval "use Async::Interrupt 1.02 (); 1")
		1516	unless defined $HAVE_ASYNC_INTERRUPT;
		1517
		1518	$HAVE_ASYNC_INTERRUPT
		1519	}
		1520
		1521	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1522	our (%SIG_ASY, %SIG_ASY_W);
		1523	our ($SIG_COUNT, $SIG_TW);
		1524
		1525	# install a dummy wakeup watcher to reduce signal catching latency
		1526	# used by Impls
		1527	sub _sig_add() {
		1528	unless ($SIG_COUNT++) {
		1529	# try to align timer on a full-second boundary, if possible
		1530	my $NOW = AE::now;
		1531
		1532	$SIG_TW = AE::timer
		1533	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1534	$MAX_SIGNAL_LATENCY,
		1535	sub { } # just for the PERL_ASYNC_CHECK
		1536	;
1209	}	1537	}
1210	}	1538	}
1211		1539
1212	sub time { _time }	1540	sub _sig_del {
1213	sub now { _time }	1541	undef $SIG_TW
1214	sub now_update { }	1542	unless --$SIG_COUNT;
1215
1216	# default implementation for ->condvar
1217
1218	sub condvar {
1219	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1220	}	1543	}
1221		1544
1222	# default implementation for ->signal	1545	our $_sig_name_init; $_sig_name_init = sub {
		1546	eval q{ # poor man's autoloading {}
		1547	undef $_sig_name_init;
1223		1548
1224	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1549	if (_have_async_interrupt) {
		1550	*sig2num = \&Async::Interrupt::sig2num;
		1551	*sig2name = \&Async::Interrupt::sig2name;
		1552	} else {
		1553	require Config;
1225		1554
1226	sub _signal_exec {	1555	my %signame2num;
1227	sysread $SIGPIPE_R, my $dummy, 4;	1556	@signame2num{ split ' ', $Config::Config{sig_name} }
		1557	= split ' ', $Config::Config{sig_num};
1228		1558
1229	while (%SIG_EV) {	1559	my @signum2name;
1230	for (keys %SIG_EV) {	1560	@signum2name[values %signame2num] = keys %signame2num;
1231	delete $SIG_EV{$_};	1561
1232	$_->() for values %{ $SIG_CB{$_} || {} };	1562	*sig2num = sub($) {
		1563	$_[0] > 0 ? shift : $signame2num{+shift}
		1564	};
		1565	*sig2name = sub ($) {
		1566	$_[0] > 0 ? $signum2name[+shift] : shift
		1567	};
1233	}	1568	}
1234	}	1569	};
1235	}	1570	die if $@;
		1571	};
		1572
		1573	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1574	sub sig2name($) { &$_sig_name_init; &sig2name }
1236		1575
1237	sub signal {	1576	sub signal {
1238	my (undef, %arg) = @_;	1577	eval q{ # poor man's autoloading {}
		1578	# probe for availability of Async::Interrupt
		1579	if (_have_async_interrupt) {
		1580	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1239		1581
1240	unless ($SIGPIPE_R) {	1582	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1241	require Fcntl;	1583	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1242		1584
1243	if (AnyEvent::WIN32) {
1244	require AnyEvent::Util;
1245
1246	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1247	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1248	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1249	} else {	1585	} else {
		1586	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1587
		1588	if (AnyEvent::WIN32) {
		1589	require AnyEvent::Util;
		1590
		1591	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1592	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1593	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1594	} else {
1250	pipe $SIGPIPE_R, $SIGPIPE_W;	1595	pipe $SIGPIPE_R, $SIGPIPE_W;
1251	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1596	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1252	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1597	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1253		1598
1254	# not strictly required, as $^F is normally 2, but let's make sure...	1599	# not strictly required, as $^F is normally 2, but let's make sure...
1255	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1600	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1256	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1601	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1602	}
		1603
		1604	$SIGPIPE_R
		1605	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1606
		1607	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1257	}	1608	}
1258		1609
1259	$SIGPIPE_R	1610	*signal = $HAVE_ASYNC_INTERRUPT
1260	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1611	? sub {
		1612	my (undef, %arg) = @_;
1261		1613
1262	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1614	# async::interrupt
1263	}
1264
1265	my $signal = uc $arg{signal}	1615	my $signal = sig2num $arg{signal};
1266	or Carp::croak "required option 'signal' is missing";
1267
1268	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1616	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1617
		1618	$SIG_ASY{$signal} ||= new Async::Interrupt
		1619	cb => sub { undef $SIG_EV{$signal} },
		1620	signal => $signal,
		1621	pipe => [$SIGPIPE_R->filenos],
		1622	pipe_autodrain => 0,
		1623	;
		1624
		1625	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1626	}
		1627	: sub {
		1628	my (undef, %arg) = @_;
		1629
		1630	# pure perl
		1631	my $signal = sig2name $arg{signal};
		1632	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1633
1269	$SIG{$signal} ||= sub {	1634	$SIG{$signal} ||= sub {
1270	local $!;	1635	local $!;
1271	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1636	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1272	undef $SIG_EV{$signal};	1637	undef $SIG_EV{$signal};
		1638	};
		1639
		1640	# can't do signal processing without introducing races in pure perl,
		1641	# so limit the signal latency.
		1642	_sig_add;
		1643
		1644	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1645	}
		1646	;
		1647
		1648	*AnyEvent::Base::signal::DESTROY = sub {
		1649	my ($signal, $cb) = @{$_[0]};
		1650
		1651	_sig_del;
		1652
		1653	delete $SIG_CB{$signal}{$cb};
		1654
		1655	$HAVE_ASYNC_INTERRUPT
		1656	? delete $SIG_ASY{$signal}
		1657	: # delete doesn't work with older perls - they then
		1658	# print weird messages, or just unconditionally exit
		1659	# instead of getting the default action.
		1660	undef $SIG{$signal}
		1661	unless keys %{ $SIG_CB{$signal} };
		1662	};
		1663
		1664	*_signal_exec = sub {
		1665	$HAVE_ASYNC_INTERRUPT
		1666	? $SIGPIPE_R->drain
		1667	: sysread $SIGPIPE_R, (my $dummy), 9;
		1668
		1669	while (%SIG_EV) {
		1670	for (keys %SIG_EV) {
		1671	delete $SIG_EV{$_};
		1672	$_->() for values %{ $SIG_CB{$_} || {} };
		1673	}
		1674	}
		1675	};
1273	};	1676	};
		1677	die if $@;
1274		1678
1275	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1679	&signal
1276	}
1277
1278	sub AnyEvent::Base::signal::DESTROY {
1279	my ($signal, $cb) = @{$_[0]};
1280
1281	delete $SIG_CB{$signal}{$cb};
1282
1283	# delete doesn't work with older perls - they then
1284	# print weird messages, or just unconditionally exit
1285	# instead of getting the default action.
1286	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1287	}	1680	}
1288		1681
1289	# default implementation for ->child	1682	# default implementation for ->child
1290		1683
1291	our %PID_CB;	1684	our %PID_CB;
1292	our $CHLD_W;	1685	our $CHLD_W;
1293	our $CHLD_DELAY_W;	1686	our $CHLD_DELAY_W;
1294	our $WNOHANG;
1295		1687
1296	sub _sigchld {	1688	# used by many Impl's
1297	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1689	sub _emit_childstatus($$) {
		1690	my (undef, $rpid, $rstatus) = @_;
		1691
		1692	$_->($rpid, $rstatus)
1298	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1693	for values %{ $PID_CB{$rpid} || {} },
1299	(values %{ $PID_CB{0} || {} });	1694	values %{ $PID_CB{0} || {} };
1300	}
1301	}	1695	}
1302		1696
1303	sub child {	1697	sub child {
		1698	eval q{ # poor man's autoloading {}
		1699	*_sigchld = sub {
		1700	my $pid;
		1701
		1702	AnyEvent->_emit_childstatus ($pid, $?)
		1703	while ($pid = waitpid -1, WNOHANG) > 0;
		1704	};
		1705
		1706	*child = sub {
1304	my (undef, %arg) = @_;	1707	my (undef, %arg) = @_;
1305		1708
1306	defined (my $pid = $arg{pid} + 0)	1709	my $pid = $arg{pid};
1307	or Carp::croak "required option 'pid' is missing";	1710	my $cb = $arg{cb};
1308		1711
1309	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1712	$PID_CB{$pid}{$cb+0} = $cb;
1310		1713
1311	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1312
1313	unless ($CHLD_W) {	1714	unless ($CHLD_W) {
1314	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1715	$CHLD_W = AE::signal CHLD => \&_sigchld;
1315	# child could be a zombie already, so make at least one round	1716	# child could be a zombie already, so make at least one round
1316	&_sigchld;	1717	&_sigchld;
1317	}	1718	}
1318		1719
1319	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1720	bless [$pid, $cb+0], "AnyEvent::Base::child"
1320	}	1721	};
1321		1722
1322	sub AnyEvent::Base::child::DESTROY {	1723	*AnyEvent::Base::child::DESTROY = sub {
1323	my ($pid, $cb) = @{$_[0]};	1724	my ($pid, $icb) = @{$_[0]};
1324		1725
1325	delete $PID_CB{$pid}{$cb};	1726	delete $PID_CB{$pid}{$icb};
1326	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1727	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1327		1728
1328	undef $CHLD_W unless keys %PID_CB;	1729	undef $CHLD_W unless keys %PID_CB;
		1730	};
		1731	};
		1732	die if $@;
		1733
		1734	&child
1329	}	1735	}
1330		1736
1331	# idle emulation is done by simply using a timer, regardless	1737	# idle emulation is done by simply using a timer, regardless
1332	# of whether the process is idle or not, and not letting	1738	# of whether the process is idle or not, and not letting
1333	# the callback use more than 50% of the time.	1739	# the callback use more than 50% of the time.
1334	sub idle {	1740	sub idle {
		1741	eval q{ # poor man's autoloading {}
		1742	*idle = sub {
1335	my (undef, %arg) = @_;	1743	my (undef, %arg) = @_;
1336		1744
1337	my ($cb, $w, $rcb) = $arg{cb};	1745	my ($cb, $w, $rcb) = $arg{cb};
1338		1746
1339	$rcb = sub {	1747	$rcb = sub {
1340	if ($cb) {	1748	if ($cb) {
1341	$w = _time;	1749	$w = _time;
1342	&$cb;	1750	&$cb;
1343	$w = _time - $w;	1751	$w = _time - $w;
1344		1752
1345	# never use more then 50% of the time for the idle watcher,	1753	# never use more then 50% of the time for the idle watcher,
1346	# within some limits	1754	# within some limits
1347	$w = 0.0001 if $w < 0.0001;	1755	$w = 0.0001 if $w < 0.0001;
1348	$w = 5 if $w > 5;	1756	$w = 5 if $w > 5;
1349		1757
1350	$w = AnyEvent->timer (after => $w, cb => $rcb);	1758	$w = AE::timer $w, 0, $rcb;
1351	} else {	1759	} else {
1352	# clean up...	1760	# clean up...
1353	undef $w;	1761	undef $w;
1354	undef $rcb;	1762	undef $rcb;
		1763	}
		1764	};
		1765
		1766	$w = AE::timer 0.05, 0, $rcb;
		1767
		1768	bless \\$cb, "AnyEvent::Base::idle"
1355	}	1769	};
		1770
		1771	*AnyEvent::Base::idle::DESTROY = sub {
		1772	undef $${$_[0]};
		1773	};
1356	};	1774	};
		1775	die if $@;
1357		1776
1358	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1777	&idle
1359
1360	bless \\$cb, "AnyEvent::Base::idle"
1361	}
1362
1363	sub AnyEvent::Base::idle::DESTROY {
1364	undef $${$_[0]};
1365	}	1778	}
1366		1779
1367	package AnyEvent::CondVar;	1780	package AnyEvent::CondVar;
1368		1781
1369	our @ISA = AnyEvent::CondVar::Base::;	1782	our @ISA = AnyEvent::CondVar::Base::;
1370		1783
		1784	# only to be used for subclassing
		1785	sub new {
		1786	my $class = shift;
		1787	bless AnyEvent->condvar (@_), $class
		1788	}
		1789
1371	package AnyEvent::CondVar::Base;	1790	package AnyEvent::CondVar::Base;
1372		1791
1373	use overload	1792	#use overload
1374	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1793	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1375	fallback => 1;	1794	# fallback => 1;
		1795
		1796	# save 300+ kilobytes by dirtily hardcoding overloading
		1797	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1798	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1799	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1800	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
1376		1801
1377	our $WAITING;	1802	our $WAITING;
1378		1803
1379	sub _send {	1804	sub _send {
1380	# nop	1805	# nop
		1806	}
		1807
		1808	sub _wait {
		1809	AnyEvent->_poll until $_[0]{_ae_sent};
1381	}	1810	}
1382		1811
1383	sub send {	1812	sub send {
1384	my $cv = shift;	1813	my $cv = shift;
1385	$cv->{_ae_sent} = [@_];	1814	$cv->{_ae_sent} = [@_];
…		…
1394		1823
1395	sub ready {	1824	sub ready {
1396	$_[0]{_ae_sent}	1825	$_[0]{_ae_sent}
1397	}	1826	}
1398		1827
1399	sub _wait {
1400	$WAITING
1401	and !$_[0]{_ae_sent}
1402	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1403
1404	local $WAITING = 1;
1405	AnyEvent->one_event while !$_[0]{_ae_sent};
1406	}
1407
1408	sub recv {	1828	sub recv {
		1829	unless ($_[0]{_ae_sent}) {
		1830	$WAITING
		1831	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1832
		1833	local $WAITING = 1;
1409	$_[0]->_wait;	1834	$_[0]->_wait;
		1835	}
1410		1836
1411	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1837	$_[0]{_ae_croak}
1412	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1838	and Carp::croak $_[0]{_ae_croak};
		1839
		1840	wantarray
		1841	? @{ $_[0]{_ae_sent} }
		1842	: $_[0]{_ae_sent}[0]
1413	}	1843	}
1414		1844
1415	sub cb {	1845	sub cb {
1416	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1846	my $cv = shift;
		1847
		1848	@_
		1849	and $cv->{_ae_cb} = shift
		1850	and $cv->{_ae_sent}
		1851	and (delete $cv->{_ae_cb})->($cv);
		1852
1417	$_[0]{_ae_cb}	1853	$cv->{_ae_cb}
1418	}	1854	}
1419		1855
1420	sub begin {	1856	sub begin {
1421	++$_[0]{_ae_counter};	1857	++$_[0]{_ae_counter};
1422	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1858	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1427	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1863	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1428	}	1864	}
1429		1865
1430	# undocumented/compatibility with pre-3.4	1866	# undocumented/compatibility with pre-3.4
1431	*broadcast = \&send;	1867	*broadcast = \&send;
1432	*wait = \&_wait;	1868	*wait = \&recv;
1433		1869
1434	=head1 ERROR AND EXCEPTION HANDLING	1870	=head1 ERROR AND EXCEPTION HANDLING
1435		1871
1436	In general, AnyEvent does not do any error handling - it relies on the	1872	In general, AnyEvent does not do any error handling - it relies on the
1437	caller to do that if required. The L<AnyEvent::Strict> module (see also	1873	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1471	C<PERL_ANYEVENT_MODEL>.	1907	C<PERL_ANYEVENT_MODEL>.
1472		1908
1473	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1909	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1474	model it chooses.	1910	model it chooses.
1475		1911
		1912	When set to C<8> or higher, then AnyEvent will report extra information on
		1913	which optional modules it loads and how it implements certain features.
		1914
1476	=item C<PERL_ANYEVENT_STRICT>	1915	=item C<PERL_ANYEVENT_STRICT>
1477		1916
1478	AnyEvent does not do much argument checking by default, as thorough	1917	AnyEvent does not do much argument checking by default, as thorough
1479	argument checking is very costly. Setting this variable to a true value	1918	argument checking is very costly. Setting this variable to a true value
1480	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1919	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1481	check the arguments passed to most method calls. If it finds any problems,	1920	check the arguments passed to most method calls. If it finds any problems,
1482	it will croak.	1921	it will croak.
1483		1922
1484	In other words, enables "strict" mode.	1923	In other words, enables "strict" mode.
1485		1924
1486	Unlike C<use strict>, it is definitely recommended to keep it off in	1925	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1487	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1926	>>, it is definitely recommended to keep it off in production. Keeping
1488	developing programs can be very useful, however.	1927	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1928	can be very useful, however.
1489		1929
1490	=item C<PERL_ANYEVENT_MODEL>	1930	=item C<PERL_ANYEVENT_MODEL>
1491		1931
1492	This can be used to specify the event model to be used by AnyEvent, before	1932	This can be used to specify the event model to be used by AnyEvent, before
1493	auto detection and -probing kicks in. It must be a string consisting	1933	auto detection and -probing kicks in. It must be a string consisting
…		…
1496	used as event model. If it fails to load AnyEvent will proceed with	1936	used as event model. If it fails to load AnyEvent will proceed with
1497	auto detection and -probing.	1937	auto detection and -probing.
1498		1938
1499	This functionality might change in future versions.	1939	This functionality might change in future versions.
1500		1940
1501	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1941	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1502	could start your program like this:	1942	could start your program like this:
1503		1943
1504	PERL_ANYEVENT_MODEL=Perl perl ...	1944	PERL_ANYEVENT_MODEL=Perl perl ...
1505		1945
1506	=item C<PERL_ANYEVENT_PROTOCOLS>	1946	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1555		1995
1556	When neither C<ca_file> nor C<ca_path> was specified during	1996	When neither C<ca_file> nor C<ca_path> was specified during
1557	L<AnyEvent::TLS> context creation, and either of these environment	1997	L<AnyEvent::TLS> context creation, and either of these environment
1558	variables exist, they will be used to specify CA certificate locations	1998	variables exist, they will be used to specify CA certificate locations
1559	instead of a system-dependent default.	1999	instead of a system-dependent default.
		2000
		2001	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		2002
		2003	When these are set to C<1>, then the respective modules are not
		2004	loaded. Mostly good for testing AnyEvent itself.
1560		2005
1561	=back	2006	=back
1562		2007
1563	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	2008	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1564		2009
…		…
1622	warn "read: $input\n"; # output what has been read	2067	warn "read: $input\n"; # output what has been read
1623	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2068	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1624	},	2069	},
1625	);	2070	);
1626		2071
1627	my $time_watcher; # can only be used once
1628
1629	sub new_timer {
1630	$timer = AnyEvent->timer (after => 1, cb => sub {	2072	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1631	warn "timeout\n"; # print 'timeout' about every second	2073	warn "timeout\n"; # print 'timeout' at most every second
1632	&new_timer; # and restart the time
1633	});	2074	});
1634	}
1635
1636	new_timer; # create first timer
1637		2075
1638	$cv->recv; # wait until user enters /^q/i	2076	$cv->recv; # wait until user enters /^q/i
1639		2077
1640	=head1 REAL-WORLD EXAMPLE	2078	=head1 REAL-WORLD EXAMPLE
1641		2079
…		…
1714		2152
1715	The actual code goes further and collects all errors (C<die>s, exceptions)	2153	The actual code goes further and collects all errors (C<die>s, exceptions)
1716	that occurred during request processing. The C<result> method detects	2154	that occurred during request processing. The C<result> method detects
1717	whether an exception as thrown (it is stored inside the $txn object)	2155	whether an exception as thrown (it is stored inside the $txn object)
1718	and just throws the exception, which means connection errors and other	2156	and just throws the exception, which means connection errors and other
1719	problems get reported tot he code that tries to use the result, not in a	2157	problems get reported to the code that tries to use the result, not in a
1720	random callback.	2158	random callback.
1721		2159
1722	All of this enables the following usage styles:	2160	All of this enables the following usage styles:
1723		2161
1724	1. Blocking:	2162	1. Blocking:
…		…
1772	through AnyEvent. The benchmark creates a lot of timers (with a zero	2210	through AnyEvent. The benchmark creates a lot of timers (with a zero
1773	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2211	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1774	which it is), lets them fire exactly once and destroys them again.	2212	which it is), lets them fire exactly once and destroys them again.
1775		2213
1776	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2214	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1777	distribution.	2215	distribution. It uses the L<AE> interface, which makes a real difference
		2216	for the EV and Perl backends only.
1778		2217
1779	=head3 Explanation of the columns	2218	=head3 Explanation of the columns
1780		2219
1781	I<watcher> is the number of event watchers created/destroyed. Since	2220	I<watcher> is the number of event watchers created/destroyed. Since
1782	different event models feature vastly different performances, each event	2221	different event models feature vastly different performances, each event
…		…
1803	watcher.	2242	watcher.
1804		2243
1805	=head3 Results	2244	=head3 Results
1806		2245
1807	name watchers bytes create invoke destroy comment	2246	name watchers bytes create invoke destroy comment
1808	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2247	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1809	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2248	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1810	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2249	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1811	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2250	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1812	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2251	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1813	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2252	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1814	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2253	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1815	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2254	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1816	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2255	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1817	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2256	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1818	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2257	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1819	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2258	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1820		2259
1821	=head3 Discussion	2260	=head3 Discussion
1822		2261
1823	The benchmark does I<not> measure scalability of the event loop very	2262	The benchmark does I<not> measure scalability of the event loop very
1824	well. For example, a select-based event loop (such as the pure perl one)	2263	well. For example, a select-based event loop (such as the pure perl one)
…		…
1836	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2275	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1837	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2276	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1838	cycles with POE.	2277	cycles with POE.
1839		2278
1840	C<EV> is the sole leader regarding speed and memory use, which are both	2279	C<EV> is the sole leader regarding speed and memory use, which are both
1841	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2280	maximal/minimal, respectively. When using the L<AE> API there is zero
		2281	overhead (when going through the AnyEvent API create is about 5-6 times
		2282	slower, with other times being equal, so still uses far less memory than
1842	far less memory than any other event loop and is still faster than Event	2283	any other event loop and is still faster than Event natively).
1843	natively.
1844		2284
1845	The pure perl implementation is hit in a few sweet spots (both the	2285	The pure perl implementation is hit in a few sweet spots (both the
1846	constant timeout and the use of a single fd hit optimisations in the perl	2286	constant timeout and the use of a single fd hit optimisations in the perl
1847	interpreter and the backend itself). Nevertheless this shows that it	2287	interpreter and the backend itself). Nevertheless this shows that it
1848	adds very little overhead in itself. Like any select-based backend its	2288	adds very little overhead in itself. Like any select-based backend its
…		…
1922	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2362	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1923	(1%) are active. This mirrors the activity of large servers with many	2363	(1%) are active. This mirrors the activity of large servers with many
1924	connections, most of which are idle at any one point in time.	2364	connections, most of which are idle at any one point in time.
1925		2365
1926	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2366	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1927	distribution.	2367	distribution. It uses the L<AE> interface, which makes a real difference
		2368	for the EV and Perl backends only.
1928		2369
1929	=head3 Explanation of the columns	2370	=head3 Explanation of the columns
1930		2371
1931	I<sockets> is the number of sockets, and twice the number of "servers" (as	2372	I<sockets> is the number of sockets, and twice the number of "servers" (as
1932	each server has a read and write socket end).	2373	each server has a read and write socket end).
…		…
1940	a new one that moves the timeout into the future.	2381	a new one that moves the timeout into the future.
1941		2382
1942	=head3 Results	2383	=head3 Results
1943		2384
1944	name sockets create request	2385	name sockets create request
1945	EV 20000 69.01 11.16	2386	EV 20000 62.66 7.99
1946	Perl 20000 73.32 35.87	2387	Perl 20000 68.32 32.64
1947	IOAsync 20000 157.00 98.14 epoll	2388	IOAsync 20000 174.06 101.15 epoll
1948	IOAsync 20000 159.31 616.06 poll	2389	IOAsync 20000 174.67 610.84 poll
1949	Event 20000 212.62 257.32	2390	Event 20000 202.69 242.91
1950	Glib 20000 651.16 1896.30	2391	Glib 20000 557.01 1689.52
1951	POE 20000 349.67 12317.24 uses POE::Loop::Event	2392	POE 20000 341.54 12086.32 uses POE::Loop::Event
1952		2393
1953	=head3 Discussion	2394	=head3 Discussion
1954		2395
1955	This benchmark I<does> measure scalability and overall performance of the	2396	This benchmark I<does> measure scalability and overall performance of the
1956	particular event loop.	2397	particular event loop.
…		…
2082	As you can see, the AnyEvent + EV combination even beats the	2523	As you can see, the AnyEvent + EV combination even beats the
2083	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2524	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2084	backend easily beats IO::Lambda and POE.	2525	backend easily beats IO::Lambda and POE.
2085		2526
2086	And even the 100% non-blocking version written using the high-level (and	2527	And even the 100% non-blocking version written using the high-level (and
2087	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2528	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2088	large margin, even though it does all of DNS, tcp-connect and socket I/O	2529	higher level ("unoptimised") abstractions by a large margin, even though
2089	in a non-blocking way.	2530	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2090		2531
2091	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2532	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2092	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2533	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2093	part of the IO::lambda distribution and were used without any changes.	2534	part of the IO::Lambda distribution and were used without any changes.
2094		2535
2095		2536
2096	=head1 SIGNALS	2537	=head1 SIGNALS
2097		2538
2098	AnyEvent currently installs handlers for these signals:	2539	AnyEvent currently installs handlers for these signals:
…		…
2132	if $SIG{CHLD} eq 'IGNORE';	2573	if $SIG{CHLD} eq 'IGNORE';
2133		2574
2134	$SIG{PIPE} = sub { }	2575	$SIG{PIPE} = sub { }
2135	unless defined $SIG{PIPE};	2576	unless defined $SIG{PIPE};
2136		2577
		2578	=head1 RECOMMENDED/OPTIONAL MODULES
		2579
		2580	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2581	its built-in modules) are required to use it.
		2582
		2583	That does not mean that AnyEvent won't take advantage of some additional
		2584	modules if they are installed.
		2585
		2586	This section explains which additional modules will be used, and how they
		2587	affect AnyEvent's operation.
		2588
		2589	=over 4
		2590
		2591	=item L<Async::Interrupt>
		2592
		2593	This slightly arcane module is used to implement fast signal handling: To
		2594	my knowledge, there is no way to do completely race-free and quick
		2595	signal handling in pure perl. To ensure that signals still get
		2596	delivered, AnyEvent will start an interval timer to wake up perl (and
		2597	catch the signals) with some delay (default is 10 seconds, look for
		2598	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2599
		2600	If this module is available, then it will be used to implement signal
		2601	catching, which means that signals will not be delayed, and the event loop
		2602	will not be interrupted regularly, which is more efficient (and good for
		2603	battery life on laptops).
		2604
		2605	This affects not just the pure-perl event loop, but also other event loops
		2606	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2607
		2608	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2609	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2610	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2611	does nothing for those backends.
		2612
		2613	=item L<EV>
		2614
		2615	This module isn't really "optional", as it is simply one of the backend
		2616	event loops that AnyEvent can use. However, it is simply the best event
		2617	loop available in terms of features, speed and stability: It supports
		2618	the AnyEvent API optimally, implements all the watcher types in XS, does
		2619	automatic timer adjustments even when no monotonic clock is available,
		2620	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2621	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2622	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2623
		2624	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2625	then this module will do nothing for you.
		2626
		2627	=item L<Guard>
		2628
		2629	The guard module, when used, will be used to implement
		2630	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2631	lot less memory), but otherwise doesn't affect guard operation much. It is
		2632	purely used for performance.
		2633
		2634	=item L<JSON> and L<JSON::XS>
		2635
		2636	One of these modules is required when you want to read or write JSON data
		2637	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2638	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2639
		2640	=item L<Net::SSLeay>
		2641
		2642	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2643	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2644	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2645
		2646	=item L<Time::HiRes>
		2647
		2648	This module is part of perl since release 5.008. It will be used when the
		2649	chosen event library does not come with a timing source of its own. The
		2650	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
		2651	try to use a monotonic clock for timing stability.
		2652
		2653	=back
		2654
		2655
2137	=head1 FORK	2656	=head1 FORK
2138		2657
2139	Most event libraries are not fork-safe. The ones who are usually are	2658	Most event libraries are not fork-safe. The ones who are usually are
2140	because they rely on inefficient but fork-safe C<select> or C<poll>	2659	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2141	calls. Only L<EV> is fully fork-aware.	2660	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2661	are usually badly thought-out hacks that are incompatible with fork in
		2662	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2663	continue event-processing in both parent and child (or both, if you know
		2664	what you are doing).
		2665
		2666	This means that, in general, you cannot fork and do event processing in
		2667	the child if the event library was initialised before the fork (which
		2668	usually happens when the first AnyEvent watcher is created, or the library
		2669	is loaded).
2142		2670
2143	If you have to fork, you must either do so I<before> creating your first	2671	If you have to fork, you must either do so I<before> creating your first
2144	watcher OR you must not use AnyEvent at all in the child.	2672	watcher OR you must not use AnyEvent at all in the child OR you must do
		2673	something completely out of the scope of AnyEvent.
		2674
		2675	The problem of doing event processing in the parent I<and> the child
		2676	is much more complicated: even for backends that I<are> fork-aware or
		2677	fork-safe, their behaviour is not usually what you want: fork clones all
		2678	watchers, that means all timers, I/O watchers etc. are active in both
		2679	parent and child, which is almost never what you want. USing C<exec>
		2680	to start worker children from some kind of manage rprocess is usually
		2681	preferred, because it is much easier and cleaner, at the expense of having
		2682	to have another binary.
2145		2683
2146		2684
2147	=head1 SECURITY CONSIDERATIONS	2685	=head1 SECURITY CONSIDERATIONS
2148		2686
2149	AnyEvent can be forced to load any event model via	2687	AnyEvent can be forced to load any event model via
…		…
2179	pronounced).	2717	pronounced).
2180		2718
2181		2719
2182	=head1 SEE ALSO	2720	=head1 SEE ALSO
2183		2721
		2722	Tutorial/Introduction: L<AnyEvent::Intro>.
		2723
		2724	FAQ: L<AnyEvent::FAQ>.
		2725
2184	Utility functions: L<AnyEvent::Util>.	2726	Utility functions: L<AnyEvent::Util>.
2185		2727
2186	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2728	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2187	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2729	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2188		2730
2189	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2731	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2190	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2732	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2191	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2733	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2192	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2734	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2193		2735
2194	Non-blocking file handles, sockets, TCP clients and	2736	Non-blocking file handles, sockets, TCP clients and
2195	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2737	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2196		2738
2197	Asynchronous DNS: L<AnyEvent::DNS>.	2739	Asynchronous DNS: L<AnyEvent::DNS>.
2198		2740
2199	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2741	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2200	L<Coro::Event>,
2201		2742
2202	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2743	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2203	L<AnyEvent::HTTP>.	2744	L<AnyEvent::HTTP>.
2204		2745
2205		2746
2206	=head1 AUTHOR	2747	=head1 AUTHOR
2207		2748

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