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Revision 1.340 by root, Fri Dec 3 18:39:06 2010 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 + IO::Async? No go. Tk + Event? No go. Again: if
78	your module uses one of those, every user of your module has to use it,	91	your module uses one of those, every user of your module has to use it,
79	too. But if your module uses AnyEvent, it works transparently with all	92	too. But if your module uses AnyEvent, it works transparently with all
80	event models it supports (including stuff like IO::Async, as long as those	93	event models it supports (including stuff like IO::Async, as long as those
81	use one of the supported event loops. It is trivial to add new event loops	94	use one of the supported event loops. It is easy to add new event loops
82	to AnyEvent, too, so it is future-proof).	95	to AnyEvent, too, 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::Impl::Perl>,
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::Impl::Perl> 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
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
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
…		…
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 the latency and race problems
		488	mentioned in the description of signal watchers apply.
408		489
409	Example: fork a process and wait for it	490	Example: fork a process and wait for it
410		491
411	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
412		493
…		…
424	# do something else, then wait for process exit	505	# do something else, then wait for process exit
425	$done->recv;	506	$done->recv;
426		507
427	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
428		509
429	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
430	to do it instantly, but only when there is nothing better to do. This
431	"nothing better to do" is usually defined to be "no other events need
432	attention by the event loop".
433		511
434	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
435	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
436	events. Instead of blocking, the idle watcher is invoked.
437		514
438	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
439	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
440	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
441		527
442	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
443	program is otherwise idle:	529	program is otherwise idle:
…		…
459	});	545	});
460	});	546	});
461		547
462	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
463		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
464	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
465	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
466	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
467		558
468	AnyEvent is different, it expects somebody else to run the event loop and	559	AnyEvent is slightly different: it expects somebody else to run the event
469	will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
470		561
471	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
472	because they represent a condition that must become true.	563	they represent a condition that must become true.
		564
		565	Now is probably a good time to look at the examples further below.
473		566
474	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
475	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
476
477	C<cb>, which specifies a callback to be called when the condition variable	569	C<cb>, which specifies a callback to be called when the condition variable
478	becomes true, with the condition variable as the first argument (but not	570	becomes true, with the condition variable as the first argument (but not
479	the results).	571	the results).
480		572
481	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
482	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
483	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
484	->send >> method).	576	->send >> method).
485		577
486	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
487	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
488	in time where multiple outstanding events have been processed. And yet	580
489	another way to call them is transactions - each condition variable can be	581	=over 4
490	used to represent a transaction, which finishes at some point and delivers	582
491	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
492		601
493	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
494	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
495	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
496	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
509		618
510	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
511	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
512	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
513	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
514	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
515		624
516	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
517	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
518	for the send to occur.	627	for the send to occur.
519		628
520	Example: wait for a timer.	629	Example: wait for a timer.
521		630
522	# wait till the result is ready	631	# condition: "wait till the timer is fired"
523	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
524		633
525	# do something such as adding a timer	634	# create the timer - we could wait for, say
526	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
527	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
528	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
529	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
530	after => 1,	639	after => 1,
531	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
532	);	641	);
533		642
534	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
535	# calls send	644	# calls ->send
536	$result_ready->recv;	645	$timer_fired->recv;
537		646
538	Example: wait for a timer, but take advantage of the fact that	647	Example: wait for a timer, but take advantage of the fact that condition
539	condition variables are also code references.	648	variables are also callable directly.
540		649
541	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
542	my $delay = AnyEvent->timer (after => 5, cb => $done);	651	my $delay = AnyEvent->timer (after => 5, cb => $done);
543	$done->recv;	652	$done->recv;
544		653
…		…
550		659
551	...	660	...
552		661
553	my @info = $couchdb->info->recv;	662	my @info = $couchdb->info->recv;
554		663
555	And this is how you would just ste a callback to be called whenever the	664	And this is how you would just set a callback to be called whenever the
556	results are available:	665	results are available:
557		666
558	$couchdb->info->cb (sub {	667	$couchdb->info->cb (sub {
559	my @info = $_[0]->recv;	668	my @info = $_[0]->recv;
560	});	669	});
…		…
578	immediately from within send.	687	immediately from within send.
579		688
580	Any arguments passed to the C<send> call will be returned by all	689	Any arguments passed to the C<send> call will be returned by all
581	future C<< ->recv >> calls.	690	future C<< ->recv >> calls.
582		691
583	Condition variables are overloaded so one can call them directly	692	Condition variables are overloaded so one can call them directly (as if
584	(as a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
585	C<send>. Note, however, that many C-based event loops do not handle	694	C<send>.
586	overloading, so as tempting as it may be, passing a condition variable
587	instead of a callback does not work. Both the pure perl and EV loops
588	support overloading, however, as well as all functions that use perl to
589	invoke a callback (as in L<AnyEvent::Socket> and L<AnyEvent::DNS> for
590	example).
591		695
592	=item $cv->croak ($error)	696	=item $cv->croak ($error)
593		697
594	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
595	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
596		700
597	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
598	user/consumer.	702	user/consumer. Doing it this way instead of calling C<croak> directly
		703	delays the error detection, but has the overwhelming advantage that it
		704	diagnoses the error at the place where the result is expected, and not
		705	deep in some event callback with no connection to the actual code causing
		706	the problem.
599		707
600	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
601		709
602	=item $cv->end	710	=item $cv->end
603		711
…		…
605	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
606	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
607		715
608	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
609	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
610	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
611	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
612	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
613		722
614	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
615	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
616	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
617		726
…		…
639	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
640	sending.	749	sending.
641		750
642	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
643	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
644	begung can potentially be zero:	753	begun can potentially be zero:
645		754
646	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
647		756
648	my %result;	757	my %result;
649	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
650		759
651	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
652	$cv->begin;	761	$cv->begin;
653	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
654	$result{$host} = ...;	763	$result{$host} = ...;
…		…
670	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
671	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
672	doesn't execute once).	781	doesn't execute once).
673		782
674	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
675	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
676	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
677	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
678	call C<end>.	787	call C<end>.
679		788
680	=back	789	=back
…		…
687	=over 4	796	=over 4
688		797
689	=item $cv->recv	798	=item $cv->recv
690		799
691	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
692	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
693	normally.	802	normally.
694		803
695	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
696	will return immediately.	805	will return immediately.
697		806
…		…
699	function will call C<croak>.	808	function will call C<croak>.
700		809
701	In list context, all parameters passed to C<send> will be returned,	810	In list context, all parameters passed to C<send> will be returned,
702	in scalar context only the first one will be returned.	811	in scalar context only the first one will be returned.
703		812
		813	Note that doing a blocking wait in a callback is not supported by any
		814	event loop, that is, recursive invocation of a blocking C<< ->recv
		815	>> is not allowed, and the C<recv> call will C<croak> if such a
		816	condition is detected. This condition can be slightly loosened by using
		817	L<Coro::AnyEvent>, which allows you to do a blocking C<< ->recv >> from
		818	any thread that doesn't run the event loop itself.
		819
704	Not all event models support a blocking wait - some die in that case	820	Not all event models support a blocking wait - some die in that case
705	(programs might want to do that to stay interactive), so I<if you are	821	(programs might want to do that to stay interactive), so I<if you are
706	using this from a module, never require a blocking wait>, but let the	822	using this from a module, never require a blocking wait>. Instead, let the
707	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
708	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
709	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
710	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
711		827
712	Another reason I<never> to C<< ->recv >> in a module is that you cannot
713	sensibly have two C<< ->recv >>'s in parallel, as that would require
714	multiple interpreters or coroutines/threads, none of which C<AnyEvent>
715	can supply.
716
717	The L<Coro> module, however, I<can> and I<does> supply coroutines and, in
718	fact, L<Coro::AnyEvent> replaces AnyEvent's condvars by coroutine-safe
719	versions and also integrates coroutines into AnyEvent, making blocking
720	C<< ->recv >> calls perfectly safe as long as they are done from another
721	coroutine (one that doesn't run the event loop).
722
723	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
724	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
725	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
726	waits otherwise.	831	waits otherwise.
727		832
728	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
734		839
735	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
736	replaces it before doing so.	841	replaces it before doing so.
737		842
738	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
739	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
740	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
741	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
742		848
743	=back	849	=back
744		850
		851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
		852
		853	The available backend classes are (every class has its own manpage):
		854
		855	=over 4
		856
		857	=item Backends that are autoprobed when no other event loop can be found.
		858
		859	EV is the preferred backend when no other event loop seems to be in
		860	use. If EV is not installed, then AnyEvent will fall back to its own
		861	pure-perl implementation, which is available everywhere as it comes with
		862	AnyEvent itself.
		863
		864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
		865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
		866
		867	=item Backends that are transparently being picked up when they are used.
		868
		869	These will be used if they are already loaded when the first watcher
		870	is created, in which case it is assumed that the application is using
		871	them. This means that AnyEvent will automatically pick the right backend
		872	when the main program loads an event module before anything starts to
		873	create watchers. Nothing special needs to be done by the main program.
		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
		876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
		877	AnyEvent::Impl::Tk based on Tk, very broken.
		878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881
		882	=item Backends with special needs.
		883
		884	Qt requires the Qt::Application to be instantiated first, but will
		885	otherwise be picked up automatically. As long as the main program
		886	instantiates the application before any AnyEvent watchers are created,
		887	everything should just work.
		888
		889	AnyEvent::Impl::Qt based on Qt.
		890
		891	Support for IO::Async can only be partial, as it is too broken and
		892	architecturally limited to even support the AnyEvent API. It also
		893	is the only event loop that needs the loop to be set explicitly, so
		894	it can only be used by a main program knowing about AnyEvent. See
		895	L<AnyEvent::Impl::IOAsync> for the gory details.
		896
		897	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
		898
		899	=item Event loops that are indirectly supported via other backends.
		900
		901	Some event loops can be supported via other modules:
		902
		903	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
		904
		905	B<WxWidgets> has no support for watching file handles. However, you can
		906	use WxWidgets through the POE adaptor, as POE has a Wx backend that simply
		907	polls 20 times per second, which was considered to be too horrible to even
		908	consider for AnyEvent.
		909
		910	B<Prima> is not supported as nobody seems to be using it, but it has a POE
		911	backend, so it can be supported through POE.
		912
		913	AnyEvent knows about both L<Prima> and L<Wx>, however, and will try to
		914	load L<POE> when detecting them, in the hope that POE will pick them up,
		915	in which case everything will be automatic.
		916
		917	=back
		918
745	=head1 GLOBAL VARIABLES AND FUNCTIONS	919	=head1 GLOBAL VARIABLES AND FUNCTIONS
746		920
		921	These are not normally required to use AnyEvent, but can be useful to
		922	write AnyEvent extension modules.
		923
747	=over 4	924	=over 4
748		925
749	=item $AnyEvent::MODEL	926	=item $AnyEvent::MODEL
750		927
751	Contains C<undef> until the first watcher is being created. Then it	928	Contains C<undef> until the first watcher is being created, before the
		929	backend has been autodetected.
		930
752	contains the event model that is being used, which is the name of the	931	Afterwards it contains the event model that is being used, which is the
753	Perl class implementing the model. This class is usually one of the	932	name of the Perl class implementing the model. This class is usually one
754	C<AnyEvent::Impl:xxx> modules, but can be any other class in the case	933	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
755	AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode>).	934	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
756		935	will be C<urxvt::anyevent>).
757	The known classes so far are:
758
759	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
760	AnyEvent::Impl::Event based on Event, second best choice.
761	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
762	AnyEvent::Impl::Glib based on Glib, third-best choice.
763	AnyEvent::Impl::Tk based on Tk, very bad choice.
764	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
765	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
766	AnyEvent::Impl::POE based on POE, not generic enough for full support.
767
768	# warning, support for IO::Async is only partial, as it is too broken
769	# and limited toe ven support the AnyEvent API. See AnyEvent::Impl::Async.
770	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed (see its docs).
771
772	There is no support for WxWidgets, as WxWidgets has no support for
773	watching file handles. However, you can use WxWidgets through the
774	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
775	second, which was considered to be too horrible to even consider for
776	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
777	it's adaptor.
778
779	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
780	autodetecting them.
781		936
782	=item AnyEvent::detect	937	=item AnyEvent::detect
783		938
784	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	939	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
785	if necessary. You should only call this function right before you would	940	if necessary. You should only call this function right before you would
786	have created an AnyEvent watcher anyway, that is, as late as possible at	941	have created an AnyEvent watcher anyway, that is, as late as possible at
787	runtime.	942	runtime, and not e.g. during initialisation of your module.
		943
		944	If you need to do some initialisation before AnyEvent watchers are
		945	created, use C<post_detect>.
788		946
789	=item $guard = AnyEvent::post_detect { BLOCK }	947	=item $guard = AnyEvent::post_detect { BLOCK }
790		948
791	Arranges for the code block to be executed as soon as the event model is	949	Arranges for the code block to be executed as soon as the event model is
792	autodetected (or immediately if this has already happened).	950	autodetected (or immediately if that has already happened).
		951
		952	The block will be executed I<after> the actual backend has been detected
		953	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
		954	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
		955	other initialisations - see the sources of L<AnyEvent::Strict> or
		956	L<AnyEvent::AIO> to see how this is used.
		957
		958	The most common usage is to create some global watchers, without forcing
		959	event module detection too early, for example, L<AnyEvent::AIO> creates
		960	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
		961	avoid autodetecting the event module at load time.
793		962
794	If called in scalar or list context, then it creates and returns an object	963	If called in scalar or list context, then it creates and returns an object
795	that automatically removes the callback again when it is destroyed. See	964	that automatically removes the callback again when it is destroyed (or
		965	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
796	L<Coro::BDB> for a case where this is useful.	966	a case where this is useful.
		967
		968	Example: Create a watcher for the IO::AIO module and store it in
		969	C<$WATCHER>, but do so only do so after the event loop is initialised.
		970
		971	our WATCHER;
		972
		973	my $guard = AnyEvent::post_detect {
		974	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		975	};
		976
		977	# the ||= is important in case post_detect immediately runs the block,
		978	# as to not clobber the newly-created watcher. assigning both watcher and
		979	# post_detect guard to the same variable has the advantage of users being
		980	# able to just C<undef $WATCHER> if the watcher causes them grief.
		981
		982	$WATCHER ||= $guard;
797		983
798	=item @AnyEvent::post_detect	984	=item @AnyEvent::post_detect
799		985
800	If there are any code references in this array (you can C<push> to it	986	If there are any code references in this array (you can C<push> to it
801	before or after loading AnyEvent), then they will called directly after	987	before or after loading AnyEvent), then they will be called directly
802	the event loop has been chosen.	988	after the event loop has been chosen.
803		989
804	You should check C<$AnyEvent::MODEL> before adding to this array, though:	990	You should check C<$AnyEvent::MODEL> before adding to this array, though:
805	if it contains a true value then the event loop has already been detected,	991	if it is defined then the event loop has already been detected, and the
806	and the array will be ignored.	992	array will be ignored.
807		993
808	Best use C<AnyEvent::post_detect { BLOCK }> instead.	994	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
		995	it, as it takes care of these details.
		996
		997	This variable is mainly useful for modules that can do something useful
		998	when AnyEvent is used and thus want to know when it is initialised, but do
		999	not need to even load it by default. This array provides the means to hook
		1000	into AnyEvent passively, without loading it.
		1001
		1002	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1003	together, you could put this into Coro (this is the actual code used by
		1004	Coro to accomplish this):
		1005
		1006	if (defined $AnyEvent::MODEL) {
		1007	# AnyEvent already initialised, so load Coro::AnyEvent
		1008	require Coro::AnyEvent;
		1009	} else {
		1010	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1011	# as soon as it is
		1012	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1013	}
809		1014
810	=back	1015	=back
811		1016
812	=head1 WHAT TO DO IN A MODULE	1017	=head1 WHAT TO DO IN A MODULE
813		1018
…		…
824	because it will stall the whole program, and the whole point of using	1029	because it will stall the whole program, and the whole point of using
825	events is to stay interactive.	1030	events is to stay interactive.
826		1031
827	It is fine, however, to call C<< ->recv >> when the user of your module	1032	It is fine, however, to call C<< ->recv >> when the user of your module
828	requests it (i.e. if you create a http request object ad have a method	1033	requests it (i.e. if you create a http request object ad have a method
829	called C<results> that returns the results, it should call C<< ->recv >>	1034	called C<results> that returns the results, it may call C<< ->recv >>
830	freely, as the user of your module knows what she is doing. always).	1035	freely, as the user of your module knows what she is doing. Always).
831		1036
832	=head1 WHAT TO DO IN THE MAIN PROGRAM	1037	=head1 WHAT TO DO IN THE MAIN PROGRAM
833		1038
834	There will always be a single main program - the only place that should	1039	There will always be a single main program - the only place that should
835	dictate which event model to use.	1040	dictate which event model to use.
836		1041
837	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1042	If the program is not event-based, it need not do anything special, even
838	do anything special (it does not need to be event-based) and let AnyEvent	1043	when it depends on a module that uses an AnyEvent. If the program itself
839	decide which implementation to chose if some module relies on it.	1044	uses AnyEvent, but does not care which event loop is used, all it needs
		1045	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1046	available loop implementation.
840		1047
841	If the main program relies on a specific event model - for example, in	1048	If the main program relies on a specific event model - for example, in
842	Gtk2 programs you have to rely on the Glib module - you should load the	1049	Gtk2 programs you have to rely on the Glib module - you should load the
843	event module before loading AnyEvent or any module that uses it: generally	1050	event module before loading AnyEvent or any module that uses it: generally
844	speaking, you should load it as early as possible. The reason is that	1051	speaking, you should load it as early as possible. The reason is that
845	modules might create watchers when they are loaded, and AnyEvent will	1052	modules might create watchers when they are loaded, and AnyEvent will
846	decide on the event model to use as soon as it creates watchers, and it	1053	decide on the event model to use as soon as it creates watchers, and it
847	might chose the wrong one unless you load the correct one yourself.	1054	might choose the wrong one unless you load the correct one yourself.
848		1055
849	You can chose to use a pure-perl implementation by loading the	1056	You can chose to use a pure-perl implementation by loading the
850	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1057	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
851	everywhere, but letting AnyEvent chose the model is generally better.	1058	everywhere, but letting AnyEvent chose the model is generally better.
852		1059
…		…
870	=head1 OTHER MODULES	1077	=head1 OTHER MODULES
871		1078
872	The following is a non-exhaustive list of additional modules that use	1079	The following is a non-exhaustive list of additional modules that use
873	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1080	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
874	modules and other event loops in the same program. Some of the modules	1081	modules and other event loops in the same program. Some of the modules
875	come with AnyEvent, most are available via CPAN.	1082	come as part of AnyEvent, the others are available via CPAN.
876		1083
877	=over 4	1084	=over 4
878		1085
879	=item L<AnyEvent::Util>	1086	=item L<AnyEvent::Util>
880		1087
881	Contains various utility functions that replace often-used but blocking	1088	Contains various utility functions that replace often-used blocking
882	functions such as C<inet_aton> by event-/callback-based versions.	1089	functions such as C<inet_aton> with event/callback-based versions.
883		1090
884	=item L<AnyEvent::Socket>	1091	=item L<AnyEvent::Socket>
885		1092
886	Provides various utility functions for (internet protocol) sockets,	1093	Provides various utility functions for (internet protocol) sockets,
887	addresses and name resolution. Also functions to create non-blocking tcp	1094	addresses and name resolution. Also functions to create non-blocking tcp
…		…
889		1096
890	=item L<AnyEvent::Handle>	1097	=item L<AnyEvent::Handle>
891		1098
892	Provide read and write buffers, manages watchers for reads and writes,	1099	Provide read and write buffers, manages watchers for reads and writes,
893	supports raw and formatted I/O, I/O queued and fully transparent and	1100	supports raw and formatted I/O, I/O queued and fully transparent and
894	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1101	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
895		1102
896	=item L<AnyEvent::DNS>	1103	=item L<AnyEvent::DNS>
897		1104
898	Provides rich asynchronous DNS resolver capabilities.	1105	Provides rich asynchronous DNS resolver capabilities.
899		1106
		1107	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1108
		1109	Implement event-based interfaces to the protocols of the same name (for
		1110	the curious, IGS is the International Go Server and FCP is the Freenet
		1111	Client Protocol).
		1112
		1113	=item L<AnyEvent::Handle::UDP>
		1114
		1115	Here be danger!
		1116
		1117	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1118	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1119	its use of a stream-based API with a protocol that isn't streamable, that
		1120	the only way to improve it is to delete it.
		1121
		1122	It features data corruption (but typically only under load) and general
		1123	confusion. On top, the author is not only clueless about UDP but also
		1124	fact-resistant - some gems of his understanding: "connect doesn't work
		1125	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1126	packets", "I don't need to implement proper error checking as UDP doesn't
		1127	support error checking" and so on - he doesn't even understand what's
		1128	wrong with his module when it is explained to him.
		1129
900	=item L<AnyEvent::HTTP>	1130	=item L<AnyEvent::DBI>
901		1131
902	A simple-to-use HTTP library that is capable of making a lot of concurrent	1132	Executes L<DBI> requests asynchronously in a proxy process for you,
903	HTTP requests.	1133	notifying you in an event-based way when the operation is finished.
		1134
		1135	=item L<AnyEvent::AIO>
		1136
		1137	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1138	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1139	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1140	file I/O, and much more.
904		1141
905	=item L<AnyEvent::HTTPD>	1142	=item L<AnyEvent::HTTPD>
906		1143
907	Provides a simple web application server framework.	1144	A simple embedded webserver.
908		1145
909	=item L<AnyEvent::FastPing>	1146	=item L<AnyEvent::FastPing>
910		1147
911	The fastest ping in the west.	1148	The fastest ping in the west.
912		1149
913	=item L<AnyEvent::DBI>
914
915	Executes L<DBI> requests asynchronously in a proxy process.
916
917	=item L<AnyEvent::AIO>
918
919	Truly asynchronous I/O, should be in the toolbox of every event
920	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
921	together.
922
923	=item L<AnyEvent::BDB>
924
925	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
926	L<BDB> and AnyEvent together.
927
928	=item L<AnyEvent::GPSD>
929
930	A non-blocking interface to gpsd, a daemon delivering GPS information.
931
932	=item L<AnyEvent::IRC>
933
934	AnyEvent based IRC client module family (replacing the older Net::IRC3).
935
936	=item L<AnyEvent::XMPP>
937
938	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
939	Net::XMPP2>.
940
941	=item L<AnyEvent::IGS>
942
943	A non-blocking interface to the Internet Go Server protocol (used by
944	L<App::IGS>).
945
946	=item L<Net::FCP>
947
948	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
949	of AnyEvent.
950
951	=item L<Event::ExecFlow>
952
953	High level API for event-based execution flow control.
954
955	=item L<Coro>	1150	=item L<Coro>
956		1151
957	Has special support for AnyEvent via L<Coro::AnyEvent>.	1152	Has special support for AnyEvent via L<Coro::AnyEvent>.
958		1153
959	=back	1154	=back
960		1155
961	=cut	1156	=cut
962		1157
963	package AnyEvent;	1158	package AnyEvent;
964		1159
965	no warnings;	1160	# basically a tuned-down version of common::sense
966	use strict qw(vars subs);	1161	sub common_sense {
		1162	# from common:.sense 3.3
		1163	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
		1164	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
		1165	$^H |= 0x00000600;
		1166	}
967		1167
		1168	BEGIN { AnyEvent::common_sense }
		1169
968	use Carp;	1170	use Carp ();
969		1171
970	our $VERSION = 4.801;	1172	our $VERSION = '5.29';
971	our $MODEL;	1173	our $MODEL;
972		1174
973	our $AUTOLOAD;	1175	our $AUTOLOAD;
974	our @ISA;	1176	our @ISA;
975		1177
976	our @REGISTRY;	1178	our @REGISTRY;
977		1179
978	our $WIN32;	1180	our $VERBOSE;
979		1181
980	BEGIN {	1182	BEGIN {
981	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1183	require "AnyEvent/constants.pl";
		1184
982	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1185	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
983		1186
984	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1187	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
985	if ${^TAINT};	1188	if ${^TAINT};
986	}
987		1189
988	our $verbose = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1190	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
		1191
		1192	}
		1193
		1194	our $MAX_SIGNAL_LATENCY = 10;
989		1195
990	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1196	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
991		1197
992	{	1198	{
993	my $idx;	1199	my $idx;
…		…
995	for reverse split /\s*,\s*/,	1201	for reverse split /\s*,\s*/,
996	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1202	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
997	}	1203	}
998		1204
999	my @models = (	1205	my @models = (
1000	[EV:: => AnyEvent::Impl::EV::],	1206	[EV:: => AnyEvent::Impl::EV:: , 1],
1001	[Event:: => AnyEvent::Impl::Event::],
1002	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1207	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1003	# everything below here will not be autoprobed	1208	# everything below here will not (normally) be autoprobed
1004	# as the pureperl backend should work everywhere	1209	# as the pureperl backend should work everywhere
1005	# and is usually faster	1210	# and is usually faster
		1211	[Event:: => AnyEvent::Impl::Event::, 1],
		1212	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
		1213	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1214	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1006	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1215	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1007	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers
1008	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1009	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1216	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1010	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1217	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1011	[Wx:: => AnyEvent::Impl::POE::],	1218	[Wx:: => AnyEvent::Impl::POE::],
1012	[Prima:: => AnyEvent::Impl::POE::],	1219	[Prima:: => AnyEvent::Impl::POE::],
1013	# IO::Async is just too broken - we would need workaorunds for its	1220	# IO::Async is just too broken - we would need workarounds for its
1014	# byzantine signal and broken child handling, among others.	1221	# byzantine signal and broken child handling, among others.
1015	# IO::Async is rather hard to detect, as it doesn't have any	1222	# IO::Async is rather hard to detect, as it doesn't have any
1016	# obvious default class.	1223	# obvious default class.
1017	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1018	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1225	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1019	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1226	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1227	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1020	);	1228	);
1021		1229
1022	our %method = map +($_ => 1),	1230	our %method = map +($_ => 1),
1023	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1231	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1024		1232
1025	our @post_detect;	1233	our @post_detect;
1026		1234
1027	sub post_detect(&) {	1235	sub post_detect(&) {
1028	my ($cb) = @_;	1236	my ($cb) = @_;
1029		1237
1030	if ($MODEL) {
1031	$cb->();
1032
1033	1
1034	} else {
1035	push @post_detect, $cb;	1238	push @post_detect, $cb;
1036		1239
1037	defined wantarray	1240	defined wantarray
1038	? bless \$cb, "AnyEvent::Util::postdetect"	1241	? bless \$cb, "AnyEvent::Util::postdetect"
1039	: ()	1242	: ()
1040	}
1041	}	1243	}
1042		1244
1043	sub AnyEvent::Util::postdetect::DESTROY {	1245	sub AnyEvent::Util::postdetect::DESTROY {
1044	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1246	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1045	}	1247	}
1046		1248
1047	sub detect() {	1249	sub detect() {
		1250	# free some memory
		1251	*detect = sub () { $MODEL };
		1252
		1253	local $!; # for good measure
		1254	local $SIG{__DIE__};
		1255
		1256	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1257	my $model = "AnyEvent::Impl::$1";
		1258	if (eval "require $model") {
		1259	$MODEL = $model;
		1260	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1261	} else {
		1262	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1263	}
		1264	}
		1265
		1266	# check for already loaded models
1048	unless ($MODEL) {	1267	unless ($MODEL) {
1049	no strict 'refs';	1268	for (@REGISTRY, @models) {
1050	local $SIG{__DIE__};	1269	my ($package, $model) = @$_;
1051		1270	if (${"$package\::VERSION"} > 0) {
1052	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
1053	my $model = "AnyEvent::Impl::$1";
1054	if (eval "require $model") {	1271	if (eval "require $model") {
1055	$MODEL = $model;	1272	$MODEL = $model;
1056	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;	1273	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1057	} else {	1274	last;
1058	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;	1275	}
1059	}	1276	}
1060	}	1277	}
1061		1278
1062	# check for already loaded models
1063	unless ($MODEL) {	1279	unless ($MODEL) {
		1280	# try to autoload a model
1064	for (@REGISTRY, @models) {	1281	for (@REGISTRY, @models) {
1065	my ($package, $model) = @$_;	1282	my ($package, $model, $autoload) = @$_;
		1283	if (
		1284	$autoload
		1285	and eval "require $package"
1066	if (${"$package\::VERSION"} > 0) {	1286	and ${"$package\::VERSION"} > 0
1067	if (eval "require $model") {	1287	and eval "require $model"
		1288	) {
1068	$MODEL = $model;	1289	$MODEL = $model;
1069	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;	1290	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1070	last;	1291	last;
1071	}
1072	}	1292	}
1073	}	1293	}
1074		1294
1075	unless ($MODEL) {
1076	# try to load a model
1077
1078	for (@REGISTRY, @models) {
1079	my ($package, $model) = @$_;
1080	if (eval "require $package"
1081	and ${"$package\::VERSION"} > 0
1082	and eval "require $model") {
1083	$MODEL = $model;
1084	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
1085	last;
1086	}
1087	}
1088
1089	$MODEL	1295	$MODEL
1090	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1296	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1091	}
1092	}	1297	}
1093
1094	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1095
1096	unshift @ISA, $MODEL;
1097
1098	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1099
1100	(shift @post_detect)->() while @post_detect;
1101	}	1298	}
		1299
		1300	@models = (); # free probe data
		1301
		1302	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1303	unshift @ISA, $MODEL;
		1304
		1305	# now nuke some methods that are overridden by the backend.
		1306	# SUPER is not allowed.
		1307	for (qw(time signal child idle)) {
		1308	undef &{"AnyEvent::Base::$_"}
		1309	if defined &{"$MODEL\::$_"};
		1310	}
		1311
		1312	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1313	eval { require AnyEvent::Strict };
		1314	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1315	if $@ && $VERBOSE;
		1316	}
		1317
		1318	(shift @post_detect)->() while @post_detect;
		1319
		1320	*post_detect = sub(&) {
		1321	shift->();
		1322
		1323	undef
		1324	};
1102		1325
1103	$MODEL	1326	$MODEL
1104	}	1327	}
1105		1328
1106	sub AUTOLOAD {	1329	sub AUTOLOAD {
1107	(my $func = $AUTOLOAD) =~ s/.*://;	1330	(my $func = $AUTOLOAD) =~ s/.*://;
1108		1331
1109	$method{$func}	1332	$method{$func}
1110	or croak "$func: not a valid method for AnyEvent objects";	1333	or Carp::croak "$func: not a valid AnyEvent class method";
1111		1334
1112	detect unless $MODEL;	1335	detect;
1113		1336
1114	my $class = shift;	1337	my $class = shift;
1115	$class->$func (@_);	1338	$class->$func (@_);
1116	}	1339	}
1117		1340
…		…
1120	# allow only one watcher per fd, so we dup it to get a different one).	1343	# allow only one watcher per fd, so we dup it to get a different one).
1121	sub _dupfh($$;$$) {	1344	sub _dupfh($$;$$) {
1122	my ($poll, $fh, $r, $w) = @_;	1345	my ($poll, $fh, $r, $w) = @_;
1123		1346
1124	# cygwin requires the fh mode to be matching, unix doesn't	1347	# cygwin requires the fh mode to be matching, unix doesn't
1125	my ($rw, $mode) = $poll eq "r" ? ($r, "<") : ($w, ">");	1348	my ($rw, $mode) = $poll eq "r" ? ($r, "<&") : ($w, ">&");
1126		1349
1127	open my $fh2, "$mode&", $fh	1350	open my $fh2, $mode, $fh
1128	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";	1351	or die "AnyEvent->io: cannot dup() filehandle in mode '$poll': $!,";
1129		1352
1130	# we assume CLOEXEC is already set by perl in all important cases	1353	# we assume CLOEXEC is already set by perl in all important cases
1131		1354
1132	($fh2, $rw)	1355	($fh2, $rw)
1133	}	1356	}
1134		1357
		1358	=head1 SIMPLIFIED AE API
		1359
		1360	Starting with version 5.0, AnyEvent officially supports a second, much
		1361	simpler, API that is designed to reduce the calling, typing and memory
		1362	overhead by using function call syntax and a fixed number of parameters.
		1363
		1364	See the L<AE> manpage for details.
		1365
		1366	=cut
		1367
		1368	package AE;
		1369
		1370	our $VERSION = $AnyEvent::VERSION;
		1371
		1372	# fall back to the main API by default - backends and AnyEvent::Base
		1373	# implementations can overwrite these.
		1374
		1375	sub io($$$) {
		1376	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1377	}
		1378
		1379	sub timer($$$) {
		1380	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1381	}
		1382
		1383	sub signal($$) {
		1384	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1385	}
		1386
		1387	sub child($$) {
		1388	AnyEvent->child (pid => $_[0], cb => $_[1])
		1389	}
		1390
		1391	sub idle($) {
		1392	AnyEvent->idle (cb => $_[0])
		1393	}
		1394
		1395	sub cv(;&) {
		1396	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1397	}
		1398
		1399	sub now() {
		1400	AnyEvent->now
		1401	}
		1402
		1403	sub now_update() {
		1404	AnyEvent->now_update
		1405	}
		1406
		1407	sub time() {
		1408	AnyEvent->time
		1409	}
		1410
1135	package AnyEvent::Base;	1411	package AnyEvent::Base;
1136		1412
1137	# default implementations for many methods	1413	# default implementations for many methods
1138		1414
1139	BEGIN {	1415	sub time {
		1416	eval q{ # poor man's autoloading {}
		1417	# probe for availability of Time::HiRes
1140	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1418	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
		1419	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1141	*_time = \&Time::HiRes::time;	1420	*AE::time = \&Time::HiRes::time;
1142	# if (eval "use POSIX (); (POSIX::times())...	1421	# if (eval "use POSIX (); (POSIX::times())...
1143	} else {	1422	} else {
		1423	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1144	*_time = sub { time }; # epic fail	1424	*AE::time = sub (){ time }; # epic fail
		1425	}
		1426
		1427	*time = sub { AE::time }; # different prototypes
		1428	};
		1429	die if $@;
		1430
		1431	&time
		1432	}
		1433
		1434	*now = \&time;
		1435
		1436	sub now_update { }
		1437
		1438	# default implementation for ->condvar
		1439
		1440	sub condvar {
		1441	eval q{ # poor man's autoloading {}
		1442	*condvar = sub {
		1443	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1444	};
		1445
		1446	*AE::cv = sub (;&) {
		1447	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1448	};
		1449	};
		1450	die if $@;
		1451
		1452	&condvar
		1453	}
		1454
		1455	# default implementation for ->signal
		1456
		1457	our $HAVE_ASYNC_INTERRUPT;
		1458
		1459	sub _have_async_interrupt() {
		1460	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1461	&& eval "use Async::Interrupt 1.02 (); 1")
		1462	unless defined $HAVE_ASYNC_INTERRUPT;
		1463
		1464	$HAVE_ASYNC_INTERRUPT
		1465	}
		1466
		1467	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
		1468	our (%SIG_ASY, %SIG_ASY_W);
		1469	our ($SIG_COUNT, $SIG_TW);
		1470
		1471	# install a dummy wakeup watcher to reduce signal catching latency
		1472	# used by Impls
		1473	sub _sig_add() {
		1474	unless ($SIG_COUNT++) {
		1475	# try to align timer on a full-second boundary, if possible
		1476	my $NOW = AE::now;
		1477
		1478	$SIG_TW = AE::timer
		1479	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
		1480	$MAX_SIGNAL_LATENCY,
		1481	sub { } # just for the PERL_ASYNC_CHECK
		1482	;
1145	}	1483	}
1146	}	1484	}
1147		1485
1148	sub time { _time }	1486	sub _sig_del {
1149	sub now { _time }	1487	undef $SIG_TW
1150	sub now_update { }	1488	unless --$SIG_COUNT;
1151
1152	# default implementation for ->condvar
1153
1154	sub condvar {
1155	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
1156	}	1489	}
1157		1490
1158	# default implementation for ->signal	1491	our $_sig_name_init; $_sig_name_init = sub {
		1492	eval q{ # poor man's autoloading {}
		1493	undef $_sig_name_init;
1159		1494
1160	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1495	if (_have_async_interrupt) {
		1496	*sig2num = \&Async::Interrupt::sig2num;
		1497	*sig2name = \&Async::Interrupt::sig2name;
		1498	} else {
		1499	require Config;
1161		1500
1162	sub _signal_exec {	1501	my %signame2num;
1163	sysread $SIGPIPE_R, my $dummy, 4;	1502	@signame2num{ split ' ', $Config::Config{sig_name} }
		1503	= split ' ', $Config::Config{sig_num};
1164		1504
1165	while (%SIG_EV) {	1505	my @signum2name;
1166	for (keys %SIG_EV) {	1506	@signum2name[values %signame2num] = keys %signame2num;
1167	delete $SIG_EV{$_};	1507
1168	$_->() for values %{ $SIG_CB{$_} || {} };	1508	*sig2num = sub($) {
		1509	$_[0] > 0 ? shift : $signame2num{+shift}
		1510	};
		1511	*sig2name = sub ($) {
		1512	$_[0] > 0 ? $signum2name[+shift] : shift
		1513	};
1169	}	1514	}
1170	}	1515	};
1171	}	1516	die if $@;
		1517	};
		1518
		1519	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1520	sub sig2name($) { &$_sig_name_init; &sig2name }
1172		1521
1173	sub signal {	1522	sub signal {
1174	my (undef, %arg) = @_;	1523	eval q{ # poor man's autoloading {}
		1524	# probe for availability of Async::Interrupt
		1525	if (_have_async_interrupt) {
		1526	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1175		1527
1176	unless ($SIGPIPE_R) {	1528	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1177	require Fcntl;	1529	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1178		1530
1179	if (AnyEvent::WIN32) {
1180	require AnyEvent::Util;
1181
1182	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1183	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1184	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1185	} else {	1531	} else {
		1532	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
		1533
		1534	if (AnyEvent::WIN32) {
		1535	require AnyEvent::Util;
		1536
		1537	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
		1538	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
		1539	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
		1540	} else {
1186	pipe $SIGPIPE_R, $SIGPIPE_W;	1541	pipe $SIGPIPE_R, $SIGPIPE_W;
1187	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1542	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1188	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1543	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1189		1544
1190	# not strictly required, as $^F is normally 2, but let's make sure...	1545	# not strictly required, as $^F is normally 2, but let's make sure...
1191	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1546	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1192	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1547	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1548	}
		1549
		1550	$SIGPIPE_R
		1551	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1552
		1553	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1193	}	1554	}
1194		1555
1195	$SIGPIPE_R	1556	*signal = $HAVE_ASYNC_INTERRUPT
1196	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1557	? sub {
		1558	my (undef, %arg) = @_;
1197		1559
1198	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1560	# async::interrupt
1199	}
1200
1201	my $signal = uc $arg{signal}	1561	my $signal = sig2num $arg{signal};
1202	or Carp::croak "required option 'signal' is missing";
1203
1204	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1562	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1563
		1564	$SIG_ASY{$signal} ||= new Async::Interrupt
		1565	cb => sub { undef $SIG_EV{$signal} },
		1566	signal => $signal,
		1567	pipe => [$SIGPIPE_R->filenos],
		1568	pipe_autodrain => 0,
		1569	;
		1570
		1571	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1572	}
		1573	: sub {
		1574	my (undef, %arg) = @_;
		1575
		1576	# pure perl
		1577	my $signal = sig2name $arg{signal};
		1578	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1579
1205	$SIG{$signal} ||= sub {	1580	$SIG{$signal} ||= sub {
1206	local $!;	1581	local $!;
1207	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1582	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1208	undef $SIG_EV{$signal};	1583	undef $SIG_EV{$signal};
		1584	};
		1585
		1586	# can't do signal processing without introducing races in pure perl,
		1587	# so limit the signal latency.
		1588	_sig_add;
		1589
		1590	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1591	}
		1592	;
		1593
		1594	*AnyEvent::Base::signal::DESTROY = sub {
		1595	my ($signal, $cb) = @{$_[0]};
		1596
		1597	_sig_del;
		1598
		1599	delete $SIG_CB{$signal}{$cb};
		1600
		1601	$HAVE_ASYNC_INTERRUPT
		1602	? delete $SIG_ASY{$signal}
		1603	: # delete doesn't work with older perls - they then
		1604	# print weird messages, or just unconditionally exit
		1605	# instead of getting the default action.
		1606	undef $SIG{$signal}
		1607	unless keys %{ $SIG_CB{$signal} };
		1608	};
		1609
		1610	*_signal_exec = sub {
		1611	$HAVE_ASYNC_INTERRUPT
		1612	? $SIGPIPE_R->drain
		1613	: sysread $SIGPIPE_R, (my $dummy), 9;
		1614
		1615	while (%SIG_EV) {
		1616	for (keys %SIG_EV) {
		1617	delete $SIG_EV{$_};
		1618	$_->() for values %{ $SIG_CB{$_} || {} };
		1619	}
		1620	}
		1621	};
1209	};	1622	};
		1623	die if $@;
1210		1624
1211	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1625	&signal
1212	}
1213
1214	sub AnyEvent::Base::signal::DESTROY {
1215	my ($signal, $cb) = @{$_[0]};
1216
1217	delete $SIG_CB{$signal}{$cb};
1218
1219	# delete doesn't work with older perls - they then
1220	# print weird messages, or just unconditionally exit
1221	# instead of getting the default action.
1222	undef $SIG{$signal} unless keys %{ $SIG_CB{$signal} };
1223	}	1626	}
1224		1627
1225	# default implementation for ->child	1628	# default implementation for ->child
1226		1629
1227	our %PID_CB;	1630	our %PID_CB;
1228	our $CHLD_W;	1631	our $CHLD_W;
1229	our $CHLD_DELAY_W;	1632	our $CHLD_DELAY_W;
1230	our $WNOHANG;	1633	our $WNOHANG;
1231		1634
1232	sub _sigchld {	1635	# used by many Impl's
1233	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1636	sub _emit_childstatus($$) {
		1637	my (undef, $rpid, $rstatus) = @_;
		1638
		1639	$_->($rpid, $rstatus)
1234	$_->($pid, $?) for (values %{ $PID_CB{$pid} || {} }),	1640	for values %{ $PID_CB{$rpid} || {} },
1235	(values %{ $PID_CB{0} || {} });	1641	values %{ $PID_CB{0} || {} };
1236	}
1237	}	1642	}
1238		1643
1239	sub child {	1644	sub child {
		1645	eval q{ # poor man's autoloading {}
		1646	*_sigchld = sub {
		1647	my $pid;
		1648
		1649	AnyEvent->_emit_childstatus ($pid, $?)
		1650	while ($pid = waitpid -1, $WNOHANG) > 0;
		1651	};
		1652
		1653	*child = sub {
1240	my (undef, %arg) = @_;	1654	my (undef, %arg) = @_;
1241		1655
1242	defined (my $pid = $arg{pid} + 0)	1656	defined (my $pid = $arg{pid} + 0)
1243	or Carp::croak "required option 'pid' is missing";	1657	or Carp::croak "required option 'pid' is missing";
1244		1658
1245	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1659	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1246		1660
		1661	# WNOHANG is almost cetrainly 1 everywhere
		1662	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
		1663	? 1
1247	$WNOHANG ||= eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1664	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1248		1665
1249	unless ($CHLD_W) {	1666	unless ($CHLD_W) {
1250	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1667	$CHLD_W = AE::signal CHLD => \&_sigchld;
1251	# child could be a zombie already, so make at least one round	1668	# child could be a zombie already, so make at least one round
1252	&_sigchld;	1669	&_sigchld;
1253	}	1670	}
1254		1671
1255	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1672	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1256	}	1673	};
1257		1674
1258	sub AnyEvent::Base::child::DESTROY {	1675	*AnyEvent::Base::child::DESTROY = sub {
1259	my ($pid, $cb) = @{$_[0]};	1676	my ($pid, $cb) = @{$_[0]};
1260		1677
1261	delete $PID_CB{$pid}{$cb};	1678	delete $PID_CB{$pid}{$cb};
1262	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1679	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1263		1680
1264	undef $CHLD_W unless keys %PID_CB;	1681	undef $CHLD_W unless keys %PID_CB;
		1682	};
		1683	};
		1684	die if $@;
		1685
		1686	&child
1265	}	1687	}
1266		1688
1267	# idle emulation is done by simply using a timer, regardless	1689	# idle emulation is done by simply using a timer, regardless
1268	# of whether the process is idle or not, and not letting	1690	# of whether the process is idle or not, and not letting
1269	# the callback use more than 50% of the time.	1691	# the callback use more than 50% of the time.
1270	sub idle {	1692	sub idle {
		1693	eval q{ # poor man's autoloading {}
		1694	*idle = sub {
1271	my (undef, %arg) = @_;	1695	my (undef, %arg) = @_;
1272		1696
1273	my ($cb, $w, $rcb) = $arg{cb};	1697	my ($cb, $w, $rcb) = $arg{cb};
1274		1698
1275	$rcb = sub {	1699	$rcb = sub {
1276	if ($cb) {	1700	if ($cb) {
1277	$w = _time;	1701	$w = _time;
1278	&$cb;	1702	&$cb;
1279	$w = _time - $w;	1703	$w = _time - $w;
1280		1704
1281	# never use more then 50% of the time for the idle watcher,	1705	# never use more then 50% of the time for the idle watcher,
1282	# within some limits	1706	# within some limits
1283	$w = 0.0001 if $w < 0.0001;	1707	$w = 0.0001 if $w < 0.0001;
1284	$w = 5 if $w > 5;	1708	$w = 5 if $w > 5;
1285		1709
1286	$w = AnyEvent->timer (after => $w, cb => $rcb);	1710	$w = AE::timer $w, 0, $rcb;
1287	} else {	1711	} else {
1288	# clean up...	1712	# clean up...
1289	undef $w;	1713	undef $w;
1290	undef $rcb;	1714	undef $rcb;
		1715	}
		1716	};
		1717
		1718	$w = AE::timer 0.05, 0, $rcb;
		1719
		1720	bless \\$cb, "AnyEvent::Base::idle"
1291	}	1721	};
		1722
		1723	*AnyEvent::Base::idle::DESTROY = sub {
		1724	undef $${$_[0]};
		1725	};
1292	};	1726	};
		1727	die if $@;
1293		1728
1294	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1729	&idle
1295
1296	bless \\$cb, "AnyEvent::Base::idle"
1297	}
1298
1299	sub AnyEvent::Base::idle::DESTROY {
1300	undef $${$_[0]};
1301	}	1730	}
1302		1731
1303	package AnyEvent::CondVar;	1732	package AnyEvent::CondVar;
1304		1733
1305	our @ISA = AnyEvent::CondVar::Base::;	1734	our @ISA = AnyEvent::CondVar::Base::;
1306		1735
		1736	# only to be used for subclassing
		1737	sub new {
		1738	my $class = shift;
		1739	bless AnyEvent->condvar (@_), $class
		1740	}
		1741
1307	package AnyEvent::CondVar::Base;	1742	package AnyEvent::CondVar::Base;
1308		1743
1309	use overload	1744	#use overload
1310	'&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1745	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
1311	fallback => 1;	1746	# fallback => 1;
		1747
		1748	# save 300+ kilobytes by dirtily hardcoding overloading
		1749	${"AnyEvent::CondVar::Base::OVERLOAD"}{dummy}++; # Register with magic by touching.
		1750	*{'AnyEvent::CondVar::Base::()'} = sub { }; # "Make it findable via fetchmethod."
		1751	*{'AnyEvent::CondVar::Base::(&{}'} = sub { my $self = shift; sub { $self->send (@_) } }; # &{}
		1752	${'AnyEvent::CondVar::Base::()'} = 1; # fallback
		1753
		1754	our $WAITING;
1312		1755
1313	sub _send {	1756	sub _send {
1314	# nop	1757	# nop
1315	}	1758	}
1316		1759
…		…
1329	sub ready {	1772	sub ready {
1330	$_[0]{_ae_sent}	1773	$_[0]{_ae_sent}
1331	}	1774	}
1332		1775
1333	sub _wait {	1776	sub _wait {
		1777	$WAITING
		1778	and !$_[0]{_ae_sent}
		1779	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1780
		1781	local $WAITING = 1;
1334	AnyEvent->one_event while !$_[0]{_ae_sent};	1782	AnyEvent->one_event while !$_[0]{_ae_sent};
1335	}	1783	}
1336		1784
1337	sub recv {	1785	sub recv {
1338	$_[0]->_wait;	1786	$_[0]->_wait;
…		…
1340	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1788	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1341	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1789	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1342	}	1790	}
1343		1791
1344	sub cb {	1792	sub cb {
1345	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1793	my $cv = shift;
		1794
		1795	@_
		1796	and $cv->{_ae_cb} = shift
		1797	and $cv->{_ae_sent}
		1798	and (delete $cv->{_ae_cb})->($cv);
		1799
1346	$_[0]{_ae_cb}	1800	$cv->{_ae_cb}
1347	}	1801	}
1348		1802
1349	sub begin {	1803	sub begin {
1350	++$_[0]{_ae_counter};	1804	++$_[0]{_ae_counter};
1351	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1805	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1400	C<PERL_ANYEVENT_MODEL>.	1854	C<PERL_ANYEVENT_MODEL>.
1401		1855
1402	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	1856	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
1403	model it chooses.	1857	model it chooses.
1404		1858
		1859	When set to C<8> or higher, then AnyEvent will report extra information on
		1860	which optional modules it loads and how it implements certain features.
		1861
1405	=item C<PERL_ANYEVENT_STRICT>	1862	=item C<PERL_ANYEVENT_STRICT>
1406		1863
1407	AnyEvent does not do much argument checking by default, as thorough	1864	AnyEvent does not do much argument checking by default, as thorough
1408	argument checking is very costly. Setting this variable to a true value	1865	argument checking is very costly. Setting this variable to a true value
1409	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly	1866	will cause AnyEvent to load C<AnyEvent::Strict> and then to thoroughly
1410	check the arguments passed to most method calls. If it finds any problems,	1867	check the arguments passed to most method calls. If it finds any problems,
1411	it will croak.	1868	it will croak.
1412		1869
1413	In other words, enables "strict" mode.	1870	In other words, enables "strict" mode.
1414		1871
1415	Unlike C<use strict>, it is definitely recommended to keep it off in	1872	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1416	production. Keeping C<PERL_ANYEVENT_STRICT=1> in your environment while	1873	>>, it is definitely recommended to keep it off in production. Keeping
1417	developing programs can be very useful, however.	1874	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
		1875	can be very useful, however.
1418		1876
1419	=item C<PERL_ANYEVENT_MODEL>	1877	=item C<PERL_ANYEVENT_MODEL>
1420		1878
1421	This can be used to specify the event model to be used by AnyEvent, before	1879	This can be used to specify the event model to be used by AnyEvent, before
1422	auto detection and -probing kicks in. It must be a string consisting	1880	auto detection and -probing kicks in. It must be a string consisting
…		…
1484		1942
1485	When neither C<ca_file> nor C<ca_path> was specified during	1943	When neither C<ca_file> nor C<ca_path> was specified during
1486	L<AnyEvent::TLS> context creation, and either of these environment	1944	L<AnyEvent::TLS> context creation, and either of these environment
1487	variables exist, they will be used to specify CA certificate locations	1945	variables exist, they will be used to specify CA certificate locations
1488	instead of a system-dependent default.	1946	instead of a system-dependent default.
		1947
		1948	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
		1949
		1950	When these are set to C<1>, then the respective modules are not
		1951	loaded. Mostly good for testing AnyEvent itself.
1489		1952
1490	=back	1953	=back
1491		1954
1492	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE	1955	=head1 SUPPLYING YOUR OWN EVENT MODEL INTERFACE
1493		1956
…		…
1551	warn "read: $input\n"; # output what has been read	2014	warn "read: $input\n"; # output what has been read
1552	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2015	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1553	},	2016	},
1554	);	2017	);
1555		2018
1556	my $time_watcher; # can only be used once
1557
1558	sub new_timer {
1559	$timer = AnyEvent->timer (after => 1, cb => sub {	2019	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1560	warn "timeout\n"; # print 'timeout' about every second	2020	warn "timeout\n"; # print 'timeout' at most every second
1561	&new_timer; # and restart the time
1562	});	2021	});
1563	}
1564
1565	new_timer; # create first timer
1566		2022
1567	$cv->recv; # wait until user enters /^q/i	2023	$cv->recv; # wait until user enters /^q/i
1568		2024
1569	=head1 REAL-WORLD EXAMPLE	2025	=head1 REAL-WORLD EXAMPLE
1570		2026
…		…
1643		2099
1644	The actual code goes further and collects all errors (C<die>s, exceptions)	2100	The actual code goes further and collects all errors (C<die>s, exceptions)
1645	that occurred during request processing. The C<result> method detects	2101	that occurred during request processing. The C<result> method detects
1646	whether an exception as thrown (it is stored inside the $txn object)	2102	whether an exception as thrown (it is stored inside the $txn object)
1647	and just throws the exception, which means connection errors and other	2103	and just throws the exception, which means connection errors and other
1648	problems get reported tot he code that tries to use the result, not in a	2104	problems get reported to the code that tries to use the result, not in a
1649	random callback.	2105	random callback.
1650		2106
1651	All of this enables the following usage styles:	2107	All of this enables the following usage styles:
1652		2108
1653	1. Blocking:	2109	1. Blocking:
…		…
1701	through AnyEvent. The benchmark creates a lot of timers (with a zero	2157	through AnyEvent. The benchmark creates a lot of timers (with a zero
1702	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2158	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1703	which it is), lets them fire exactly once and destroys them again.	2159	which it is), lets them fire exactly once and destroys them again.
1704		2160
1705	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2161	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1706	distribution.	2162	distribution. It uses the L<AE> interface, which makes a real difference
		2163	for the EV and Perl backends only.
1707		2164
1708	=head3 Explanation of the columns	2165	=head3 Explanation of the columns
1709		2166
1710	I<watcher> is the number of event watchers created/destroyed. Since	2167	I<watcher> is the number of event watchers created/destroyed. Since
1711	different event models feature vastly different performances, each event	2168	different event models feature vastly different performances, each event
…		…
1732	watcher.	2189	watcher.
1733		2190
1734	=head3 Results	2191	=head3 Results
1735		2192
1736	name watchers bytes create invoke destroy comment	2193	name watchers bytes create invoke destroy comment
1737	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2194	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1738	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2195	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1739	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2196	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1740	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2197	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1741	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2198	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1742	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2199	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1743	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2200	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1744	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2201	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1745	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2202	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1746	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2203	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1747	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2204	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1748	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2205	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1749		2206
1750	=head3 Discussion	2207	=head3 Discussion
1751		2208
1752	The benchmark does I<not> measure scalability of the event loop very	2209	The benchmark does I<not> measure scalability of the event loop very
1753	well. For example, a select-based event loop (such as the pure perl one)	2210	well. For example, a select-based event loop (such as the pure perl one)
…		…
1765	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2222	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1766	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2223	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1767	cycles with POE.	2224	cycles with POE.
1768		2225
1769	C<EV> is the sole leader regarding speed and memory use, which are both	2226	C<EV> is the sole leader regarding speed and memory use, which are both
1770	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2227	maximal/minimal, respectively. When using the L<AE> API there is zero
		2228	overhead (when going through the AnyEvent API create is about 5-6 times
		2229	slower, with other times being equal, so still uses far less memory than
1771	far less memory than any other event loop and is still faster than Event	2230	any other event loop and is still faster than Event natively).
1772	natively.
1773		2231
1774	The pure perl implementation is hit in a few sweet spots (both the	2232	The pure perl implementation is hit in a few sweet spots (both the
1775	constant timeout and the use of a single fd hit optimisations in the perl	2233	constant timeout and the use of a single fd hit optimisations in the perl
1776	interpreter and the backend itself). Nevertheless this shows that it	2234	interpreter and the backend itself). Nevertheless this shows that it
1777	adds very little overhead in itself. Like any select-based backend its	2235	adds very little overhead in itself. Like any select-based backend its
…		…
1851	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2309	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
1852	(1%) are active. This mirrors the activity of large servers with many	2310	(1%) are active. This mirrors the activity of large servers with many
1853	connections, most of which are idle at any one point in time.	2311	connections, most of which are idle at any one point in time.
1854		2312
1855	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2313	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
1856	distribution.	2314	distribution. It uses the L<AE> interface, which makes a real difference
		2315	for the EV and Perl backends only.
1857		2316
1858	=head3 Explanation of the columns	2317	=head3 Explanation of the columns
1859		2318
1860	I<sockets> is the number of sockets, and twice the number of "servers" (as	2319	I<sockets> is the number of sockets, and twice the number of "servers" (as
1861	each server has a read and write socket end).	2320	each server has a read and write socket end).
…		…
1869	a new one that moves the timeout into the future.	2328	a new one that moves the timeout into the future.
1870		2329
1871	=head3 Results	2330	=head3 Results
1872		2331
1873	name sockets create request	2332	name sockets create request
1874	EV 20000 69.01 11.16	2333	EV 20000 62.66 7.99
1875	Perl 20000 73.32 35.87	2334	Perl 20000 68.32 32.64
1876	IOAsync 20000 157.00 98.14 epoll	2335	IOAsync 20000 174.06 101.15 epoll
1877	IOAsync 20000 159.31 616.06 poll	2336	IOAsync 20000 174.67 610.84 poll
1878	Event 20000 212.62 257.32	2337	Event 20000 202.69 242.91
1879	Glib 20000 651.16 1896.30	2338	Glib 20000 557.01 1689.52
1880	POE 20000 349.67 12317.24 uses POE::Loop::Event	2339	POE 20000 341.54 12086.32 uses POE::Loop::Event
1881		2340
1882	=head3 Discussion	2341	=head3 Discussion
1883		2342
1884	This benchmark I<does> measure scalability and overall performance of the	2343	This benchmark I<does> measure scalability and overall performance of the
1885	particular event loop.	2344	particular event loop.
…		…
2011	As you can see, the AnyEvent + EV combination even beats the	2470	As you can see, the AnyEvent + EV combination even beats the
2012	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2471	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2013	backend easily beats IO::Lambda and POE.	2472	backend easily beats IO::Lambda and POE.
2014		2473
2015	And even the 100% non-blocking version written using the high-level (and	2474	And even the 100% non-blocking version written using the high-level (and
2016	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2475	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2017	large margin, even though it does all of DNS, tcp-connect and socket I/O	2476	higher level ("unoptimised") abstractions by a large margin, even though
2018	in a non-blocking way.	2477	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2019		2478
2020	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2479	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2021	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2480	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2022	part of the IO::lambda distribution and were used without any changes.	2481	part of the IO::Lambda distribution and were used without any changes.
2023		2482
2024		2483
2025	=head1 SIGNALS	2484	=head1 SIGNALS
2026		2485
2027	AnyEvent currently installs handlers for these signals:	2486	AnyEvent currently installs handlers for these signals:
…		…
2032		2491
2033	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher	2492	A handler for C<SIGCHLD> is installed by AnyEvent's child watcher
2034	emulation for event loops that do not support them natively. Also, some	2493	emulation for event loops that do not support them natively. Also, some
2035	event loops install a similar handler.	2494	event loops install a similar handler.
2036		2495
2037	If, when AnyEvent is loaded, SIGCHLD is set to IGNORE, then AnyEvent will	2496	Additionally, when AnyEvent is loaded and SIGCHLD is set to IGNORE, then
2038	reset it to default, to avoid losing child exit statuses.	2497	AnyEvent will reset it to default, to avoid losing child exit statuses.
2039		2498
2040	=item SIGPIPE	2499	=item SIGPIPE
2041		2500
2042	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>	2501	A no-op handler is installed for C<SIGPIPE> when C<$SIG{PIPE}> is C<undef>
2043	when AnyEvent gets loaded.	2502	when AnyEvent gets loaded.
…		…
2061	if $SIG{CHLD} eq 'IGNORE';	2520	if $SIG{CHLD} eq 'IGNORE';
2062		2521
2063	$SIG{PIPE} = sub { }	2522	$SIG{PIPE} = sub { }
2064	unless defined $SIG{PIPE};	2523	unless defined $SIG{PIPE};
2065		2524
		2525	=head1 RECOMMENDED/OPTIONAL MODULES
		2526
		2527	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
		2528	its built-in modules) are required to use it.
		2529
		2530	That does not mean that AnyEvent won't take advantage of some additional
		2531	modules if they are installed.
		2532
		2533	This section explains which additional modules will be used, and how they
		2534	affect AnyEvent's operation.
		2535
		2536	=over 4
		2537
		2538	=item L<Async::Interrupt>
		2539
		2540	This slightly arcane module is used to implement fast signal handling: To
		2541	my knowledge, there is no way to do completely race-free and quick
		2542	signal handling in pure perl. To ensure that signals still get
		2543	delivered, AnyEvent will start an interval timer to wake up perl (and
		2544	catch the signals) with some delay (default is 10 seconds, look for
		2545	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
		2546
		2547	If this module is available, then it will be used to implement signal
		2548	catching, which means that signals will not be delayed, and the event loop
		2549	will not be interrupted regularly, which is more efficient (and good for
		2550	battery life on laptops).
		2551
		2552	This affects not just the pure-perl event loop, but also other event loops
		2553	that have no signal handling on their own (e.g. Glib, Tk, Qt).
		2554
		2555	Some event loops (POE, Event, Event::Lib) offer signal watchers natively,
		2556	and either employ their own workarounds (POE) or use AnyEvent's workaround
		2557	(using C<$AnyEvent::MAX_SIGNAL_LATENCY>). Installing L<Async::Interrupt>
		2558	does nothing for those backends.
		2559
		2560	=item L<EV>
		2561
		2562	This module isn't really "optional", as it is simply one of the backend
		2563	event loops that AnyEvent can use. However, it is simply the best event
		2564	loop available in terms of features, speed and stability: It supports
		2565	the AnyEvent API optimally, implements all the watcher types in XS, does
		2566	automatic timer adjustments even when no monotonic clock is available,
		2567	can take avdantage of advanced kernel interfaces such as C<epoll> and
		2568	C<kqueue>, and is the fastest backend I<by far>. You can even embed
		2569	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
		2570
		2571	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2572	then this module will do nothing for you.
		2573
		2574	=item L<Guard>
		2575
		2576	The guard module, when used, will be used to implement
		2577	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
		2578	lot less memory), but otherwise doesn't affect guard operation much. It is
		2579	purely used for performance.
		2580
		2581	=item L<JSON> and L<JSON::XS>
		2582
		2583	One of these modules is required when you want to read or write JSON data
		2584	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
		2585	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
		2586
		2587	=item L<Net::SSLeay>
		2588
		2589	Implementing TLS/SSL in Perl is certainly interesting, but not very
		2590	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
		2591	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
		2592
		2593	=item L<Time::HiRes>
		2594
		2595	This module is part of perl since release 5.008. It will be used when the
		2596	chosen event library does not come with a timing source of its own. The
		2597	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
		2598	try to use a monotonic clock for timing stability.
		2599
		2600	=back
		2601
		2602
2066	=head1 FORK	2603	=head1 FORK
2067		2604
2068	Most event libraries are not fork-safe. The ones who are usually are	2605	Most event libraries are not fork-safe. The ones who are usually are
2069	because they rely on inefficient but fork-safe C<select> or C<poll>	2606	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2070	calls. Only L<EV> is fully fork-aware.	2607	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2608	are usually badly thought-out hacks that are incompatible with fork in
		2609	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2610	continue event-processing in both parent and child (or both, if you know
		2611	what you are doing).
		2612
		2613	This means that, in general, you cannot fork and do event processing in
		2614	the child if the event library was initialised before the fork (which
		2615	usually happens when the first AnyEvent watcher is created, or the library
		2616	is loaded).
2071		2617
2072	If you have to fork, you must either do so I<before> creating your first	2618	If you have to fork, you must either do so I<before> creating your first
2073	watcher OR you must not use AnyEvent at all in the child.	2619	watcher OR you must not use AnyEvent at all in the child OR you must do
		2620	something completely out of the scope of AnyEvent.
		2621
		2622	The problem of doing event processing in the parent I<and> the child
		2623	is much more complicated: even for backends that I<are> fork-aware or
		2624	fork-safe, their behaviour is not usually what you want: fork clones all
		2625	watchers, that means all timers, I/O watchers etc. are active in both
		2626	parent and child, which is almost never what you want. USing C<exec>
		2627	to start worker children from some kind of manage rprocess is usually
		2628	preferred, because it is much easier and cleaner, at the expense of having
		2629	to have another binary.
2074		2630
2075		2631
2076	=head1 SECURITY CONSIDERATIONS	2632	=head1 SECURITY CONSIDERATIONS
2077		2633
2078	AnyEvent can be forced to load any event model via	2634	AnyEvent can be forced to load any event model via
…		…
2108	pronounced).	2664	pronounced).
2109		2665
2110		2666
2111	=head1 SEE ALSO	2667	=head1 SEE ALSO
2112		2668
		2669	Tutorial/Introduction: L<AnyEvent::Intro>.
		2670
		2671	FAQ: L<AnyEvent::FAQ>.
		2672
2113	Utility functions: L<AnyEvent::Util>.	2673	Utility functions: L<AnyEvent::Util>.
2114		2674
2115	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2675	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2116	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2676	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2117		2677
2118	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2678	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2119	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2679	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2120	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2680	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2121	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2681	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2122		2682
2123	Non-blocking file handles, sockets, TCP clients and	2683	Non-blocking file handles, sockets, TCP clients and
2124	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2684	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2125		2685
2126	Asynchronous DNS: L<AnyEvent::DNS>.	2686	Asynchronous DNS: L<AnyEvent::DNS>.
2127		2687
2128	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2688	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2129	L<Coro::Event>,
2130		2689
2131	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2690	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2132	L<AnyEvent::HTTP>.	2691	L<AnyEvent::HTTP>.
2133		2692
2134		2693
2135	=head1 AUTHOR	2694	=head1 AUTHOR
2136		2695

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