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Revision 1.251 by root, Mon Jul 20 22:39:57 2009 UTC vs.
Revision 1.332 by root, Tue Aug 31 23:32:40 2010 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - events independent of event loop implementation	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
…		…
47		50
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	51	There is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	52	channel, too.
50		53
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	54	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Respository>, at L<http://anyevent.schmorp.de>, for more info.	55	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		56
54	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	57	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
55		58
56	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	59	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
57	nowadays. So what is different about AnyEvent?	60	nowadays. So what is different about AnyEvent?
…		…
73	module users into the same thing by forcing them to use the same event	76	module users into the same thing by forcing them to use the same event
74	model you use.	77	model you use.
75		78
76	For modules like POE or IO::Async (which is a total misnomer as it is	79	For modules like POE or IO::Async (which is a total misnomer as it is
77	actually doing all I/O I<synchronously>...), using them in your module is	80	actually doing all I/O I<synchronously>...), using them in your module is
78	like joining a cult: After you joined, you are dependent on them and you	81	like joining a cult: After you join, you are dependent on them and you
79	cannot use anything else, as they are simply incompatible to everything	82	cannot use anything else, as they are simply incompatible to everything
80	that isn't them. What's worse, all the potential users of your	83	that isn't them. What's worse, all the potential users of your
81	module are I<also> forced to use the same event loop you use.	84	module are I<also> forced to use the same event loop you use.
82		85
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	86	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	87	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
85	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	88	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if
86	your module uses one of those, every user of your module has to use it,	89	your module uses one of those, every user of your module has to use it,
87	too. But if your module uses AnyEvent, it works transparently with all	90	too. But if your module uses AnyEvent, it works transparently with all
88	event models it supports (including stuff like IO::Async, as long as those	91	event models it supports (including stuff like IO::Async, as long as those
89	use one of the supported event loops. It is trivial to add new event loops	92	use one of the supported event loops. It is easy to add new event loops
90	to AnyEvent, too, so it is future-proof).	93	to AnyEvent, too, so it is future-proof).
91		94
92	In addition to being free of having to use I<the one and only true event	95	In addition to being free of having to use I<the one and only true event
93	model>, AnyEvent also is free of bloat and policy: with POE or similar	96	model>, AnyEvent also is free of bloat and policy: with POE or similar
94	modules, you get an enormous amount of code and strict rules you have to	97	modules, you get an enormous amount of code and strict rules you have to
95	follow. AnyEvent, on the other hand, is lean and up to the point, by only	98	follow. AnyEvent, on the other hand, is lean and to the point, by only
96	offering the functionality that is necessary, in as thin as a wrapper as	99	offering the functionality that is necessary, in as thin as a wrapper as
97	technically possible.	100	technically possible.
98		101
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	102	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	103	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	useful) and you want to force your users to use the one and only event	109	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	110	model, you should I<not> use this module.
108		111
109	=head1 DESCRIPTION	112	=head1 DESCRIPTION
110		113
111	L<AnyEvent> provides an identical interface to multiple event loops. This	114	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	115	allows module authors to use event loop functionality without forcing
113	users to use the same event loop (as only a single event loop can coexist	116	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	117	than one event loop cannot coexist peacefully).
115		118
116	The interface itself is vaguely similar, but not identical to the L<Event>	119	The interface itself is vaguely similar, but not identical to the L<Event>
117	module.	120	module.
118		121
119	During the first call of any watcher-creation method, the module tries	122	During the first call of any watcher-creation method, the module tries
120	to detect the currently loaded event loop by probing whether one of the	123	to detect the currently loaded event loop by probing whether one of the
121	following modules is already loaded: L<EV>,	124	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	125	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123	L<POE>. The first one found is used. If none are found, the module tries	126	found is used. If none are detected, the module tries to load the first
124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	127	four modules in the order given; but note that if L<EV> is not
125	adaptor should always succeed) in the order given. The first one that can	128	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	129	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		130
130	Because AnyEvent first checks for modules that are already loaded, loading	131	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	132	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	133	that model the default. For example:
133		134
…		…
135	use AnyEvent;	136	use AnyEvent;
136		137
137	# .. AnyEvent will likely default to Tk	138	# .. AnyEvent will likely default to Tk
138		139
139	The I<likely> means that, if any module loads another event model and	140	The I<likely> means that, if any module loads another event model and
140	starts using it, all bets are off. Maybe you should tell their authors to	141	starts using it, all bets are off - this case should be very rare though,
141	use AnyEvent so their modules work together with others seamlessly...	142	as very few modules hardcode event loops without announcing this very
		143	loudly.
142		144
143	The pure-perl implementation of AnyEvent is called	145	The pure-perl implementation of AnyEvent is called
144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	146	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
145	explicitly and enjoy the high availability of that event loop :)	147	explicitly and enjoy the high availability of that event loop :)
146		148
…		…
155	callback when the event occurs (of course, only when the event model	157	callback when the event occurs (of course, only when the event model
156	is in control).	158	is in control).
157		159
158	Note that B<callbacks must not permanently change global variables>	160	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	161	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	162	callbacks must not C<die> >>. The former is good programming practice in
161	Perl and the latter stems from the fact that exception handling differs	163	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	164	widely between event loops.
163		165
164	To disable the watcher you have to destroy it (e.g. by setting the	166	To disable a watcher you have to destroy it (e.g. by setting the
165	variable you store it in to C<undef> or otherwise deleting all references	167	variable you store it in to C<undef> or otherwise deleting all references
166	to it).	168	to it).
167		169
168	All watchers are created by calling a method on the C<AnyEvent> class.	170	All watchers are created by calling a method on the C<AnyEvent> class.
169		171
170	Many watchers either are used with "recursion" (repeating timers for	172	Many watchers either are used with "recursion" (repeating timers for
171	example), or need to refer to their watcher object in other ways.	173	example), or need to refer to their watcher object in other ways.
172		174
173	An any way to achieve that is this pattern:	175	One way to achieve that is this pattern:
174		176
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	177	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	178	# you can use $w here, for example to undef it
177	undef $w;	179	undef $w;
178	});	180	});
…		…
180	Note that C<my $w; $w => combination. This is necessary because in Perl,	182	Note that C<my $w; $w => combination. This is necessary because in Perl,
181	my variables are only visible after the statement in which they are	183	my variables are only visible after the statement in which they are
182	declared.	184	declared.
183		185
184	=head2 I/O WATCHERS	186	=head2 I/O WATCHERS
		187
		188	$w = AnyEvent->io (
		189	fh => <filehandle_or_fileno>,
		190	poll => <"r" or "w">,
		191	cb => <callback>,
		192	);
185		193
186	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	194	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
187	with the following mandatory key-value pairs as arguments:	195	with the following mandatory key-value pairs as arguments:
188		196
189	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	197	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
204		212
205	The I/O watcher might use the underlying file descriptor or a copy of it.	213	The I/O watcher might use the underlying file descriptor or a copy of it.
206	You must not close a file handle as long as any watcher is active on the	214	You must not close a file handle as long as any watcher is active on the
207	underlying file descriptor.	215	underlying file descriptor.
208		216
209	Some event loops issue spurious readyness notifications, so you should	217	Some event loops issue spurious readiness notifications, so you should
210	always use non-blocking calls when reading/writing from/to your file	218	always use non-blocking calls when reading/writing from/to your file
211	handles.	219	handles.
212		220
213	Example: wait for readability of STDIN, then read a line and disable the	221	Example: wait for readability of STDIN, then read a line and disable the
214	watcher.	222	watcher.
…		…
219	undef $w;	227	undef $w;
220	});	228	});
221		229
222	=head2 TIME WATCHERS	230	=head2 TIME WATCHERS
223		231
		232	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		233
		234	$w = AnyEvent->timer (
		235	after => <fractional_seconds>,
		236	interval => <fractional_seconds>,
		237	cb => <callback>,
		238	);
		239
224	You can create a time watcher by calling the C<< AnyEvent->timer >>	240	You can create a time watcher by calling the C<< AnyEvent->timer >>
225	method with the following mandatory arguments:	241	method with the following mandatory arguments:
226		242
227	C<after> specifies after how many seconds (fractional values are	243	C<after> specifies after how many seconds (fractional values are
228	supported) the callback should be invoked. C<cb> is the callback to invoke	244	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
230		246
231	Although the callback might get passed parameters, their value and	247	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	248	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	249	callbacks cannot use arguments passed to time watcher callbacks.
234		250
235	The callback will normally be invoked once only. If you specify another	251	The callback will normally be invoked only once. If you specify another
236	parameter, C<interval>, as a strictly positive number (> 0), then the	252	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	253	callback will be invoked regularly at that interval (in fractional
238	seconds) after the first invocation. If C<interval> is specified with a	254	seconds) after the first invocation. If C<interval> is specified with a
239	false value, then it is treated as if it were missing.	255	false value, then it is treated as if it were not specified at all.
240		256
241	The callback will be rescheduled before invoking the callback, but no	257	The callback will be rescheduled before invoking the callback, but no
242	attempt is done to avoid timer drift in most backends, so the interval is	258	attempt is made to avoid timer drift in most backends, so the interval is
243	only approximate.	259	only approximate.
244		260
245	Example: fire an event after 7.7 seconds.	261	Example: fire an event after 7.7 seconds.
246		262
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	263	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		281
266	While most event loops expect timers to specified in a relative way, they	282	While most event loops expect timers to specified in a relative way, they
267	use absolute time internally. This makes a difference when your clock	283	use absolute time internally. This makes a difference when your clock
268	"jumps", for example, when ntp decides to set your clock backwards from	284	"jumps", for example, when ntp decides to set your clock backwards from
269	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	285	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
270	fire "after" a second might actually take six years to finally fire.	286	fire "after a second" might actually take six years to finally fire.
271		287
272	AnyEvent cannot compensate for this. The only event loop that is conscious	288	AnyEvent cannot compensate for this. The only event loop that is conscious
273	about these issues is L<EV>, which offers both relative (ev_timer, based	289	of these issues is L<EV>, which offers both relative (ev_timer, based
274	on true relative time) and absolute (ev_periodic, based on wallclock time)	290	on true relative time) and absolute (ev_periodic, based on wallclock time)
275	timers.	291	timers.
276		292
277	AnyEvent always prefers relative timers, if available, matching the	293	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	294	AnyEvent API.
…		…
300	I<In almost all cases (in all cases if you don't care), this is the	316	I<In almost all cases (in all cases if you don't care), this is the
301	function to call when you want to know the current time.>	317	function to call when you want to know the current time.>
302		318
303	This function is also often faster then C<< AnyEvent->time >>, and	319	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	320	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	321	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		322
307	The rest of this section is only of relevance if you try to be very exact	323	The rest of this section is only of relevance if you try to be very exact
308	with your timing, you can skip it without bad conscience.	324	with your timing; you can skip it without a bad conscience.
309		325
310	For a practical example of when these times differ, consider L<Event::Lib>	326	For a practical example of when these times differ, consider L<Event::Lib>
311	and L<EV> and the following set-up:	327	and L<EV> and the following set-up:
312		328
313	The event loop is running and has just invoked one of your callback at	329	The event loop is running and has just invoked one of your callbacks at
314	time=500 (assume no other callbacks delay processing). In your callback,	330	time=500 (assume no other callbacks delay processing). In your callback,
315	you wait a second by executing C<sleep 1> (blocking the process for a	331	you wait a second by executing C<sleep 1> (blocking the process for a
316	second) and then (at time=501) you create a relative timer that fires	332	second) and then (at time=501) you create a relative timer that fires
317	after three seconds.	333	after three seconds.
318		334
…		…
349	might affect timers and time-outs.	365	might affect timers and time-outs.
350		366
351	When this is the case, you can call this method, which will update the	367	When this is the case, you can call this method, which will update the
352	event loop's idea of "current time".	368	event loop's idea of "current time".
353		369
		370	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		371	when mod_perl executes the script, then the event loop will have the wrong
		372	idea about the "current time" (being potentially far in the past, when the
		373	script ran the last time). In that case you should arrange a call to C<<
		374	AnyEvent->now_update >> each time the web server process wakes up again
		375	(e.g. at the start of your script, or in a handler).
		376
354	Note that updating the time I<might> cause some events to be handled.	377	Note that updating the time I<might> cause some events to be handled.
355		378
356	=back	379	=back
357		380
358	=head2 SIGNAL WATCHERS	381	=head2 SIGNAL WATCHERS
		382
		383	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		384
360	You can watch for signals using a signal watcher, C<signal> is the signal	385	You can watch for signals using a signal watcher, C<signal> is the signal
361	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	386	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
362	callback to be invoked whenever a signal occurs.	387	callback to be invoked whenever a signal occurs.
363		388
…		…
380		405
381	Example: exit on SIGINT	406	Example: exit on SIGINT
382		407
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	408	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		409
		410	=head3 Restart Behaviour
		411
		412	While restart behaviour is up to the event loop implementation, most will
		413	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		414	pure perl implementation).
		415
		416	=head3 Safe/Unsafe Signals
		417
		418	Perl signals can be either "safe" (synchronous to opcode handling) or
		419	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		420	latter might corrupt your memory.
		421
		422	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		423	i.e. they will not interrupt your running perl program but will only be
		424	called as part of the normal event handling (just like timer, I/O etc.
		425	callbacks, too).
		426
385	=head3 Signal Races, Delays and Workarounds	427	=head3 Signal Races, Delays and Workarounds
386		428
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	429	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388	callbacks to signals in a generic way, which is a pity, as you cannot do	430	callbacks to signals in a generic way, which is a pity, as you cannot
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	431	do race-free signal handling in perl, requiring C libraries for
		432	this. AnyEvent will try to do its best, which means in some cases,
390	in some cases, signals will be delayed. The maximum time a signal might	433	signals will be delayed. The maximum time a signal might be delayed is
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	434	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392	seconds). This variable can be changed only before the first signal	435	variable can be changed only before the first signal watcher is created,
393	watcher is created, and should be left alone otherwise. Higher values	436	and should be left alone otherwise. This variable determines how often
		437	AnyEvent polls for signals (in case a wake-up was missed). Higher values
394	will cause fewer spurious wake-ups, which is better for power and CPU	438	will cause fewer spurious wake-ups, which is better for power and CPU
		439	saving.
		440
395	saving. All these problems can be avoided by installing the optional	441	All these problems can be avoided by installing the optional
396	L<Async::Interrupt> module. This will not work with inherently broken	442	L<Async::Interrupt> module, which works with most event loops. It will not
397	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	443	work with inherently broken event loops such as L<Event> or L<Event::Lib>
398	currently, as POE does it's own workaround with one-second latency). With	444	(and not with L<POE> currently, as POE does its own workaround with
399	those, you just have to suffer the delays.	445	one-second latency). For those, you just have to suffer the delays.
400		446
401	=head2 CHILD PROCESS WATCHERS	447	=head2 CHILD PROCESS WATCHERS
402		448
		449	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		450
403	You can also watch on a child process exit and catch its exit status.	451	You can also watch for a child process exit and catch its exit status.
404		452
405	The child process is specified by the C<pid> argument (if set to C<0>, it	453	The child process is specified by the C<pid> argument (on some backends,
406	watches for any child process exit). The watcher will triggered only when	454	using C<0> watches for any child process exit, on others this will
407	the child process has finished and an exit status is available, not on	455	croak). The watcher will be triggered only when the child process has
408	any trace events (stopped/continued).	456	finished and an exit status is available, not on any trace events
		457	(stopped/continued).
409		458
410	The callback will be called with the pid and exit status (as returned by	459	The callback will be called with the pid and exit status (as returned by
411	waitpid), so unlike other watcher types, you I<can> rely on child watcher	460	waitpid), so unlike other watcher types, you I<can> rely on child watcher
412	callback arguments.	461	callback arguments.
413		462
…		…
454	# do something else, then wait for process exit	503	# do something else, then wait for process exit
455	$done->recv;	504	$done->recv;
456		505
457	=head2 IDLE WATCHERS	506	=head2 IDLE WATCHERS
458		507
459	Sometimes there is a need to do something, but it is not so important	508	$w = AnyEvent->idle (cb => <callback>);
460	to do it instantly, but only when there is nothing better to do. This
461	"nothing better to do" is usually defined to be "no other events need
462	attention by the event loop".
463		509
464	Idle watchers ideally get invoked when the event loop has nothing	510	This will repeatedly invoke the callback after the process becomes idle,
465	better to do, just before it would block the process to wait for new	511	until either the watcher is destroyed or new events have been detected.
466	events. Instead of blocking, the idle watcher is invoked.
467		512
468	Most event loops unfortunately do not really support idle watchers (only	513	Idle watchers are useful when there is a need to do something, but it
		514	is not so important (or wise) to do it instantly. The callback will be
		515	invoked only when there is "nothing better to do", which is usually
		516	defined as "all outstanding events have been handled and no new events
		517	have been detected". That means that idle watchers ideally get invoked
		518	when the event loop has just polled for new events but none have been
		519	detected. Instead of blocking to wait for more events, the idle watchers
		520	will be invoked.
		521
		522	Unfortunately, most event loops do not really support idle watchers (only
469	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	523	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
470	will simply call the callback "from time to time".	524	will simply call the callback "from time to time".
471		525
472	Example: read lines from STDIN, but only process them when the	526	Example: read lines from STDIN, but only process them when the
473	program is otherwise idle:	527	program is otherwise idle:
…		…
489	});	543	});
490	});	544	});
491		545
492	=head2 CONDITION VARIABLES	546	=head2 CONDITION VARIABLES
493		547
		548	$cv = AnyEvent->condvar;
		549
		550	$cv->send (<list>);
		551	my @res = $cv->recv;
		552
494	If you are familiar with some event loops you will know that all of them	553	If you are familiar with some event loops you will know that all of them
495	require you to run some blocking "loop", "run" or similar function that	554	require you to run some blocking "loop", "run" or similar function that
496	will actively watch for new events and call your callbacks.	555	will actively watch for new events and call your callbacks.
497		556
498	AnyEvent is slightly different: it expects somebody else to run the event	557	AnyEvent is slightly different: it expects somebody else to run the event
499	loop and will only block when necessary (usually when told by the user).	558	loop and will only block when necessary (usually when told by the user).
500		559
501	The instrument to do that is called a "condition variable", so called	560	The tool to do that is called a "condition variable", so called because
502	because they represent a condition that must become true.	561	they represent a condition that must become true.
503		562
504	Now is probably a good time to look at the examples further below.	563	Now is probably a good time to look at the examples further below.
505		564
506	Condition variables can be created by calling the C<< AnyEvent->condvar	565	Condition variables can be created by calling the C<< AnyEvent->condvar
507	>> method, usually without arguments. The only argument pair allowed is	566	>> method, usually without arguments. The only argument pair allowed is
…		…
512	After creation, the condition variable is "false" until it becomes "true"	571	After creation, the condition variable is "false" until it becomes "true"
513	by calling the C<send> method (or calling the condition variable as if it	572	by calling the C<send> method (or calling the condition variable as if it
514	were a callback, read about the caveats in the description for the C<<	573	were a callback, read about the caveats in the description for the C<<
515	->send >> method).	574	->send >> method).
516		575
517	Condition variables are similar to callbacks, except that you can	576	Since condition variables are the most complex part of the AnyEvent API, here are
518	optionally wait for them. They can also be called merge points - points	577	some different mental models of what they are - pick the ones you can connect to:
519	in time where multiple outstanding events have been processed. And yet	578
520	another way to call them is transactions - each condition variable can be	579	=over 4
521	used to represent a transaction, which finishes at some point and delivers	580
522	a result. And yet some people know them as "futures" - a promise to	581	=item * Condition variables are like callbacks - you can call them (and pass them instead
523	compute/deliver something that you can wait for.	582	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		583
		584	=item * Condition variables are signals - one side can emit or send them,
		585	the other side can wait for them, or install a handler that is called when
		586	the signal fires.
		587
		588	=item * Condition variables are like "Merge Points" - points in your program
		589	where you merge multiple independent results/control flows into one.
		590
		591	=item * Condition variables represent a transaction - functions that start
		592	some kind of transaction can return them, leaving the caller the choice
		593	between waiting in a blocking fashion, or setting a callback.
		594
		595	=item * Condition variables represent future values, or promises to deliver
		596	some result, long before the result is available.
		597
		598	=back
524		599
525	Condition variables are very useful to signal that something has finished,	600	Condition variables are very useful to signal that something has finished,
526	for example, if you write a module that does asynchronous http requests,	601	for example, if you write a module that does asynchronous http requests,
527	then a condition variable would be the ideal candidate to signal the	602	then a condition variable would be the ideal candidate to signal the
528	availability of results. The user can either act when the callback is	603	availability of results. The user can either act when the callback is
…		…
541		616
542	Condition variables are represented by hash refs in perl, and the keys	617	Condition variables are represented by hash refs in perl, and the keys
543	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	618	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
544	easy (it is often useful to build your own transaction class on top of	619	easy (it is often useful to build your own transaction class on top of
545	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	620	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
546	it's C<new> method in your own C<new> method.	621	its C<new> method in your own C<new> method.
547		622
548	There are two "sides" to a condition variable - the "producer side" which	623	There are two "sides" to a condition variable - the "producer side" which
549	eventually calls C<< -> send >>, and the "consumer side", which waits	624	eventually calls C<< -> send >>, and the "consumer side", which waits
550	for the send to occur.	625	for the send to occur.
551		626
552	Example: wait for a timer.	627	Example: wait for a timer.
553		628
554	# wait till the result is ready	629	# condition: "wait till the timer is fired"
555	my $result_ready = AnyEvent->condvar;	630	my $timer_fired = AnyEvent->condvar;
556		631
557	# do something such as adding a timer	632	# create the timer - we could wait for, say
558	# or socket watcher the calls $result_ready->send	633	# a handle becomign ready, or even an
559	# when the "result" is ready.	634	# AnyEvent::HTTP request to finish, but
560	# in this case, we simply use a timer:	635	# in this case, we simply use a timer:
561	my $w = AnyEvent->timer (	636	my $w = AnyEvent->timer (
562	after => 1,	637	after => 1,
563	cb => sub { $result_ready->send },	638	cb => sub { $timer_fired->send },
564	);	639	);
565		640
566	# this "blocks" (while handling events) till the callback	641	# this "blocks" (while handling events) till the callback
567	# calls -<send	642	# calls ->send
568	$result_ready->recv;	643	$timer_fired->recv;
569		644
570	Example: wait for a timer, but take advantage of the fact that condition	645	Example: wait for a timer, but take advantage of the fact that condition
571	variables are also callable directly.	646	variables are also callable directly.
572		647
573	my $done = AnyEvent->condvar;	648	my $done = AnyEvent->condvar;
…		…
616	they were a code reference). Calling them directly is the same as calling	691	they were a code reference). Calling them directly is the same as calling
617	C<send>.	692	C<send>.
618		693
619	=item $cv->croak ($error)	694	=item $cv->croak ($error)
620		695
621	Similar to send, but causes all call's to C<< ->recv >> to invoke	696	Similar to send, but causes all calls to C<< ->recv >> to invoke
622	C<Carp::croak> with the given error message/object/scalar.	697	C<Carp::croak> with the given error message/object/scalar.
623		698
624	This can be used to signal any errors to the condition variable	699	This can be used to signal any errors to the condition variable
625	user/consumer. Doing it this way instead of calling C<croak> directly	700	user/consumer. Doing it this way instead of calling C<croak> directly
626	delays the error detetcion, but has the overwhelmign advantage that it	701	delays the error detection, but has the overwhelming advantage that it
627	diagnoses the error at the place where the result is expected, and not	702	diagnoses the error at the place where the result is expected, and not
628	deep in some event clalback without connection to the actual code causing	703	deep in some event callback with no connection to the actual code causing
629	the problem.	704	the problem.
630		705
631	=item $cv->begin ([group callback])	706	=item $cv->begin ([group callback])
632		707
633	=item $cv->end	708	=item $cv->end
…		…
636	one. For example, a function that pings many hosts in parallel might want	711	one. For example, a function that pings many hosts in parallel might want
637	to use a condition variable for the whole process.	712	to use a condition variable for the whole process.
638		713
639	Every call to C<< ->begin >> will increment a counter, and every call to	714	Every call to C<< ->begin >> will increment a counter, and every call to
640	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	715	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
641	>>, the (last) callback passed to C<begin> will be executed. That callback	716	>>, the (last) callback passed to C<begin> will be executed, passing the
642	is I<supposed> to call C<< ->send >>, but that is not required. If no	717	condvar as first argument. That callback is I<supposed> to call C<< ->send
643	callback was set, C<send> will be called without any arguments.	718	>>, but that is not required. If no group callback was set, C<send> will
		719	be called without any arguments.
644		720
645	You can think of C<< $cv->send >> giving you an OR condition (one call	721	You can think of C<< $cv->send >> giving you an OR condition (one call
646	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	722	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
647	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	723	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
648		724
…		…
670	one call to C<begin>, so the condvar waits for all calls to C<end> before	746	one call to C<begin>, so the condvar waits for all calls to C<end> before
671	sending.	747	sending.
672		748
673	The ping example mentioned above is slightly more complicated, as the	749	The ping example mentioned above is slightly more complicated, as the
674	there are results to be passwd back, and the number of tasks that are	750	there are results to be passwd back, and the number of tasks that are
675	begung can potentially be zero:	751	begun can potentially be zero:
676		752
677	my $cv = AnyEvent->condvar;	753	my $cv = AnyEvent->condvar;
678		754
679	my %result;	755	my %result;
680	$cv->begin (sub { $cv->send (\%result) });	756	$cv->begin (sub { shift->send (\%result) });
681		757
682	for my $host (@list_of_hosts) {	758	for my $host (@list_of_hosts) {
683	$cv->begin;	759	$cv->begin;
684	ping_host_then_call_callback $host, sub {	760	ping_host_then_call_callback $host, sub {
685	$result{$host} = ...;	761	$result{$host} = ...;
…		…
701	to be called once the counter reaches C<0>, and second, it ensures that	777	to be called once the counter reaches C<0>, and second, it ensures that
702	C<send> is called even when C<no> hosts are being pinged (the loop	778	C<send> is called even when C<no> hosts are being pinged (the loop
703	doesn't execute once).	779	doesn't execute once).
704		780
705	This is the general pattern when you "fan out" into multiple (but	781	This is the general pattern when you "fan out" into multiple (but
706	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	782	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
707	the callback and ensure C<end> is called at least once, and then, for each	783	the callback and ensure C<end> is called at least once, and then, for each
708	subrequest you start, call C<begin> and for each subrequest you finish,	784	subrequest you start, call C<begin> and for each subrequest you finish,
709	call C<end>.	785	call C<end>.
710		786
711	=back	787	=back
…		…
718	=over 4	794	=over 4
719		795
720	=item $cv->recv	796	=item $cv->recv
721		797
722	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	798	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
723	>> methods have been called on c<$cv>, while servicing other watchers	799	>> methods have been called on C<$cv>, while servicing other watchers
724	normally.	800	normally.
725		801
726	You can only wait once on a condition - additional calls are valid but	802	You can only wait once on a condition - additional calls are valid but
727	will return immediately.	803	will return immediately.
728		804
…		…
745	caller decide whether the call will block or not (for example, by coupling	821	caller decide whether the call will block or not (for example, by coupling
746	condition variables with some kind of request results and supporting	822	condition variables with some kind of request results and supporting
747	callbacks so the caller knows that getting the result will not block,	823	callbacks so the caller knows that getting the result will not block,
748	while still supporting blocking waits if the caller so desires).	824	while still supporting blocking waits if the caller so desires).
749		825
750	You can ensure that C<< -recv >> never blocks by setting a callback and	826	You can ensure that C<< ->recv >> never blocks by setting a callback and
751	only calling C<< ->recv >> from within that callback (or at a later	827	only calling C<< ->recv >> from within that callback (or at a later
752	time). This will work even when the event loop does not support blocking	828	time). This will work even when the event loop does not support blocking
753	waits otherwise.	829	waits otherwise.
754		830
755	=item $bool = $cv->ready	831	=item $bool = $cv->ready
…		…
761		837
762	This is a mutator function that returns the callback set and optionally	838	This is a mutator function that returns the callback set and optionally
763	replaces it before doing so.	839	replaces it before doing so.
764		840
765	The callback will be called when the condition becomes "true", i.e. when	841	The callback will be called when the condition becomes "true", i.e. when
766	C<send> or C<croak> are called, with the only argument being the condition	842	C<send> or C<croak> are called, with the only argument being the
767	variable itself. Calling C<recv> inside the callback or at any later time	843	condition variable itself. If the condition is already true, the
768	is guaranteed not to block.	844	callback is called immediately when it is set. Calling C<recv> inside
		845	the callback or at any later time is guaranteed not to block.
769		846
770	=back	847	=back
771		848
772	=head1 SUPPORTED EVENT LOOPS/BACKENDS	849	=head1 SUPPORTED EVENT LOOPS/BACKENDS
773		850
…		…
776	=over 4	853	=over 4
777		854
778	=item Backends that are autoprobed when no other event loop can be found.	855	=item Backends that are autoprobed when no other event loop can be found.
779		856
780	EV is the preferred backend when no other event loop seems to be in	857	EV is the preferred backend when no other event loop seems to be in
781	use. If EV is not installed, then AnyEvent will try Event, and, failing	858	use. If EV is not installed, then AnyEvent will fall back to its own
782	that, will fall back to its own pure-perl implementation, which is	859	pure-perl implementation, which is available everywhere as it comes with
783	available everywhere as it comes with AnyEvent itself.	860	AnyEvent itself.
784		861
785	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	862	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
786	AnyEvent::Impl::Event based on Event, very stable, few glitches.
787	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	863	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
788		864
789	=item Backends that are transparently being picked up when they are used.	865	=item Backends that are transparently being picked up when they are used.
790		866
791	These will be used when they are currently loaded when the first watcher	867	These will be used if they are already loaded when the first watcher
792	is created, in which case it is assumed that the application is using	868	is created, in which case it is assumed that the application is using
793	them. This means that AnyEvent will automatically pick the right backend	869	them. This means that AnyEvent will automatically pick the right backend
794	when the main program loads an event module before anything starts to	870	when the main program loads an event module before anything starts to
795	create watchers. Nothing special needs to be done by the main program.	871	create watchers. Nothing special needs to be done by the main program.
796		872
		873	AnyEvent::Impl::Event based on Event, very stable, few glitches.
797	AnyEvent::Impl::Glib based on Glib, slow but very stable.	874	AnyEvent::Impl::Glib based on Glib, slow but very stable.
798	AnyEvent::Impl::Tk based on Tk, very broken.	875	AnyEvent::Impl::Tk based on Tk, very broken.
799	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	876	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
800	AnyEvent::Impl::POE based on POE, very slow, some limitations.	877	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		878	AnyEvent::Impl::Irssi used when running within irssi.
801		879
802	=item Backends with special needs.	880	=item Backends with special needs.
803		881
804	Qt requires the Qt::Application to be instantiated first, but will	882	Qt requires the Qt::Application to be instantiated first, but will
805	otherwise be picked up automatically. As long as the main program	883	otherwise be picked up automatically. As long as the main program
…		…
810		888
811	Support for IO::Async can only be partial, as it is too broken and	889	Support for IO::Async can only be partial, as it is too broken and
812	architecturally limited to even support the AnyEvent API. It also	890	architecturally limited to even support the AnyEvent API. It also
813	is the only event loop that needs the loop to be set explicitly, so	891	is the only event loop that needs the loop to be set explicitly, so
814	it can only be used by a main program knowing about AnyEvent. See	892	it can only be used by a main program knowing about AnyEvent. See
815	L<AnyEvent::Impl::Async> for the gory details.	893	L<AnyEvent::Impl::IOAsync> for the gory details.
816		894
817	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.	895	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
818		896
819	=item Event loops that are indirectly supported via other backends.	897	=item Event loops that are indirectly supported via other backends.
820		898
…		…
848	Contains C<undef> until the first watcher is being created, before the	926	Contains C<undef> until the first watcher is being created, before the
849	backend has been autodetected.	927	backend has been autodetected.
850		928
851	Afterwards it contains the event model that is being used, which is the	929	Afterwards it contains the event model that is being used, which is the
852	name of the Perl class implementing the model. This class is usually one	930	name of the Perl class implementing the model. This class is usually one
853	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	931	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
854	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	932	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
855	will be C<urxvt::anyevent>).	933	will be C<urxvt::anyevent>).
856		934
857	=item AnyEvent::detect	935	=item AnyEvent::detect
858		936
859	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	937	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
860	if necessary. You should only call this function right before you would	938	if necessary. You should only call this function right before you would
861	have created an AnyEvent watcher anyway, that is, as late as possible at	939	have created an AnyEvent watcher anyway, that is, as late as possible at
862	runtime, and not e.g. while initialising of your module.	940	runtime, and not e.g. during initialisation of your module.
863		941
864	If you need to do some initialisation before AnyEvent watchers are	942	If you need to do some initialisation before AnyEvent watchers are
865	created, use C<post_detect>.	943	created, use C<post_detect>.
866		944
867	=item $guard = AnyEvent::post_detect { BLOCK }	945	=item $guard = AnyEvent::post_detect { BLOCK }
868		946
869	Arranges for the code block to be executed as soon as the event model is	947	Arranges for the code block to be executed as soon as the event model is
870	autodetected (or immediately if this has already happened).	948	autodetected (or immediately if that has already happened).
871		949
872	The block will be executed I<after> the actual backend has been detected	950	The block will be executed I<after> the actual backend has been detected
873	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	951	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
874	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	952	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
875	other initialisations - see the sources of L<AnyEvent::Strict> or	953	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
879	event module detection too early, for example, L<AnyEvent::AIO> creates	957	event module detection too early, for example, L<AnyEvent::AIO> creates
880	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	958	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
881	avoid autodetecting the event module at load time.	959	avoid autodetecting the event module at load time.
882		960
883	If called in scalar or list context, then it creates and returns an object	961	If called in scalar or list context, then it creates and returns an object
884	that automatically removes the callback again when it is destroyed. See	962	that automatically removes the callback again when it is destroyed (or
		963	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
885	L<Coro::BDB> for a case where this is useful.	964	a case where this is useful.
		965
		966	Example: Create a watcher for the IO::AIO module and store it in
		967	C<$WATCHER>, but do so only do so after the event loop is initialised.
		968
		969	our WATCHER;
		970
		971	my $guard = AnyEvent::post_detect {
		972	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		973	};
		974
		975	# the ||= is important in case post_detect immediately runs the block,
		976	# as to not clobber the newly-created watcher. assigning both watcher and
		977	# post_detect guard to the same variable has the advantage of users being
		978	# able to just C<undef $WATCHER> if the watcher causes them grief.
		979
		980	$WATCHER ||= $guard;
886		981
887	=item @AnyEvent::post_detect	982	=item @AnyEvent::post_detect
888		983
889	If there are any code references in this array (you can C<push> to it	984	If there are any code references in this array (you can C<push> to it
890	before or after loading AnyEvent), then they will called directly after	985	before or after loading AnyEvent), then they will be called directly
891	the event loop has been chosen.	986	after the event loop has been chosen.
892		987
893	You should check C<$AnyEvent::MODEL> before adding to this array, though:	988	You should check C<$AnyEvent::MODEL> before adding to this array, though:
894	if it is defined then the event loop has already been detected, and the	989	if it is defined then the event loop has already been detected, and the
895	array will be ignored.	990	array will be ignored.
896		991
897	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	992	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
898	it,as it takes care of these details.	993	it, as it takes care of these details.
899		994
900	This variable is mainly useful for modules that can do something useful	995	This variable is mainly useful for modules that can do something useful
901	when AnyEvent is used and thus want to know when it is initialised, but do	996	when AnyEvent is used and thus want to know when it is initialised, but do
902	not need to even load it by default. This array provides the means to hook	997	not need to even load it by default. This array provides the means to hook
903	into AnyEvent passively, without loading it.	998	into AnyEvent passively, without loading it.
904		999
		1000	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1001	together, you could put this into Coro (this is the actual code used by
		1002	Coro to accomplish this):
		1003
		1004	if (defined $AnyEvent::MODEL) {
		1005	# AnyEvent already initialised, so load Coro::AnyEvent
		1006	require Coro::AnyEvent;
		1007	} else {
		1008	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1009	# as soon as it is
		1010	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1011	}
		1012
905	=back	1013	=back
906		1014
907	=head1 WHAT TO DO IN A MODULE	1015	=head1 WHAT TO DO IN A MODULE
908		1016
909	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1017	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
919	because it will stall the whole program, and the whole point of using	1027	because it will stall the whole program, and the whole point of using
920	events is to stay interactive.	1028	events is to stay interactive.
921		1029
922	It is fine, however, to call C<< ->recv >> when the user of your module	1030	It is fine, however, to call C<< ->recv >> when the user of your module
923	requests it (i.e. if you create a http request object ad have a method	1031	requests it (i.e. if you create a http request object ad have a method
924	called C<results> that returns the results, it should call C<< ->recv >>	1032	called C<results> that returns the results, it may call C<< ->recv >>
925	freely, as the user of your module knows what she is doing. always).	1033	freely, as the user of your module knows what she is doing. Always).
926		1034
927	=head1 WHAT TO DO IN THE MAIN PROGRAM	1035	=head1 WHAT TO DO IN THE MAIN PROGRAM
928		1036
929	There will always be a single main program - the only place that should	1037	There will always be a single main program - the only place that should
930	dictate which event model to use.	1038	dictate which event model to use.
931		1039
932	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1040	If the program is not event-based, it need not do anything special, even
933	do anything special (it does not need to be event-based) and let AnyEvent	1041	when it depends on a module that uses an AnyEvent. If the program itself
934	decide which implementation to chose if some module relies on it.	1042	uses AnyEvent, but does not care which event loop is used, all it needs
		1043	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1044	available loop implementation.
935		1045
936	If the main program relies on a specific event model - for example, in	1046	If the main program relies on a specific event model - for example, in
937	Gtk2 programs you have to rely on the Glib module - you should load the	1047	Gtk2 programs you have to rely on the Glib module - you should load the
938	event module before loading AnyEvent or any module that uses it: generally	1048	event module before loading AnyEvent or any module that uses it: generally
939	speaking, you should load it as early as possible. The reason is that	1049	speaking, you should load it as early as possible. The reason is that
940	modules might create watchers when they are loaded, and AnyEvent will	1050	modules might create watchers when they are loaded, and AnyEvent will
941	decide on the event model to use as soon as it creates watchers, and it	1051	decide on the event model to use as soon as it creates watchers, and it
942	might chose the wrong one unless you load the correct one yourself.	1052	might choose the wrong one unless you load the correct one yourself.
943		1053
944	You can chose to use a pure-perl implementation by loading the	1054	You can chose to use a pure-perl implementation by loading the
945	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1055	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
946	everywhere, but letting AnyEvent chose the model is generally better.	1056	everywhere, but letting AnyEvent chose the model is generally better.
947		1057
…		…
965	=head1 OTHER MODULES	1075	=head1 OTHER MODULES
966		1076
967	The following is a non-exhaustive list of additional modules that use	1077	The following is a non-exhaustive list of additional modules that use
968	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1078	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
969	modules and other event loops in the same program. Some of the modules	1079	modules and other event loops in the same program. Some of the modules
970	come with AnyEvent, most are available via CPAN.	1080	come as part of AnyEvent, the others are available via CPAN.
971		1081
972	=over 4	1082	=over 4
973		1083
974	=item L<AnyEvent::Util>	1084	=item L<AnyEvent::Util>
975		1085
976	Contains various utility functions that replace often-used but blocking	1086	Contains various utility functions that replace often-used blocking
977	functions such as C<inet_aton> by event-/callback-based versions.	1087	functions such as C<inet_aton> with event/callback-based versions.
978		1088
979	=item L<AnyEvent::Socket>	1089	=item L<AnyEvent::Socket>
980		1090
981	Provides various utility functions for (internet protocol) sockets,	1091	Provides various utility functions for (internet protocol) sockets,
982	addresses and name resolution. Also functions to create non-blocking tcp	1092	addresses and name resolution. Also functions to create non-blocking tcp
…		…
984		1094
985	=item L<AnyEvent::Handle>	1095	=item L<AnyEvent::Handle>
986		1096
987	Provide read and write buffers, manages watchers for reads and writes,	1097	Provide read and write buffers, manages watchers for reads and writes,
988	supports raw and formatted I/O, I/O queued and fully transparent and	1098	supports raw and formatted I/O, I/O queued and fully transparent and
989	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1099	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
990		1100
991	=item L<AnyEvent::DNS>	1101	=item L<AnyEvent::DNS>
992		1102
993	Provides rich asynchronous DNS resolver capabilities.	1103	Provides rich asynchronous DNS resolver capabilities.
994		1104
		1105	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1106
		1107	Implement event-based interfaces to the protocols of the same name (for
		1108	the curious, IGS is the International Go Server and FCP is the Freenet
		1109	Client Protocol).
		1110
		1111	=item L<AnyEvent::Handle::UDP>
		1112
		1113	Here be danger!
		1114
		1115	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1116	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1117	its use of a stream-based API with a protocol that isn't streamable, that
		1118	the only way to improve it is to delete it.
		1119
		1120	It features data corruption (but typically only under load) and general
		1121	confusion. On top, the author is not only clueless about UDP but also
		1122	fact-resistant - some gems of his understanding: "connect doesn't work
		1123	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1124	packets", "I don't need to implement proper error checking as UDP doesn't
		1125	support error checking" and so on - he doesn't even understand what's
		1126	wrong with his module when it is explained to him.
		1127
995	=item L<AnyEvent::HTTP>	1128	=item L<AnyEvent::DBI>
996		1129
997	A simple-to-use HTTP library that is capable of making a lot of concurrent	1130	Executes L<DBI> requests asynchronously in a proxy process for you,
998	HTTP requests.	1131	notifying you in an event-based way when the operation is finished.
		1132
		1133	=item L<AnyEvent::AIO>
		1134
		1135	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1136	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1137	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1138	file I/O, and much more.
999		1139
1000	=item L<AnyEvent::HTTPD>	1140	=item L<AnyEvent::HTTPD>
1001		1141
1002	Provides a simple web application server framework.	1142	A simple embedded webserver.
1003		1143
1004	=item L<AnyEvent::FastPing>	1144	=item L<AnyEvent::FastPing>
1005		1145
1006	The fastest ping in the west.	1146	The fastest ping in the west.
1007
1008	=item L<AnyEvent::DBI>
1009
1010	Executes L<DBI> requests asynchronously in a proxy process.
1011
1012	=item L<AnyEvent::AIO>
1013
1014	Truly asynchronous I/O, should be in the toolbox of every event
1015	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1016	together.
1017
1018	=item L<AnyEvent::BDB>
1019
1020	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1021	L<BDB> and AnyEvent together.
1022
1023	=item L<AnyEvent::GPSD>
1024
1025	A non-blocking interface to gpsd, a daemon delivering GPS information.
1026
1027	=item L<AnyEvent::IRC>
1028
1029	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1030
1031	=item L<AnyEvent::XMPP>
1032
1033	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1034	Net::XMPP2>.
1035
1036	=item L<AnyEvent::IGS>
1037
1038	A non-blocking interface to the Internet Go Server protocol (used by
1039	L<App::IGS>).
1040
1041	=item L<Net::FCP>
1042
1043	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1044	of AnyEvent.
1045
1046	=item L<Event::ExecFlow>
1047
1048	High level API for event-based execution flow control.
1049		1147
1050	=item L<Coro>	1148	=item L<Coro>
1051		1149
1052	Has special support for AnyEvent via L<Coro::AnyEvent>.	1150	Has special support for AnyEvent via L<Coro::AnyEvent>.
1053		1151
…		…
1057		1155
1058	package AnyEvent;	1156	package AnyEvent;
1059		1157
1060	# basically a tuned-down version of common::sense	1158	# basically a tuned-down version of common::sense
1061	sub common_sense {	1159	sub common_sense {
1062	# no warnings	1160	# from common:.sense 3.3
1063	${^WARNING_BITS} ^= ${^WARNING_BITS};	1161	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
1064	# use strict vars subs	1162	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1065	$^H |= 0x00000600;	1163	$^H |= 0x00000600;
1066	}	1164	}
1067		1165
1068	BEGIN { AnyEvent::common_sense }	1166	BEGIN { AnyEvent::common_sense }
1069		1167
1070	use Carp ();	1168	use Carp ();
1071		1169
1072	our $VERSION = 4.86;	1170	our $VERSION = '5.271';
1073	our $MODEL;	1171	our $MODEL;
1074		1172
1075	our $AUTOLOAD;	1173	our $AUTOLOAD;
1076	our @ISA;	1174	our @ISA;
1077		1175
1078	our @REGISTRY;	1176	our @REGISTRY;
1079		1177
1080	our $WIN32;
1081
1082	our $VERBOSE;	1178	our $VERBOSE;
1083		1179
1084	BEGIN {	1180	BEGIN {
1085	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1181	require "AnyEvent/constants.pl";
		1182
1086	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1183	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1087		1184
1088	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1185	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1089	if ${^TAINT};	1186	if ${^TAINT};
1090		1187
1091	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1188	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1102	for reverse split /\s*,\s*/,	1199	for reverse split /\s*,\s*/,
1103	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1200	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1104	}	1201	}
1105		1202
1106	my @models = (	1203	my @models = (
1107	[EV:: => AnyEvent::Impl::EV::],	1204	[EV:: => AnyEvent::Impl::EV:: , 1],
1108	[Event:: => AnyEvent::Impl::Event::],
1109	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1205	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1110	# everything below here will not be autoprobed	1206	# everything below here will not (normally) be autoprobed
1111	# as the pureperl backend should work everywhere	1207	# as the pureperl backend should work everywhere
1112	# and is usually faster	1208	# and is usually faster
		1209	[Event:: => AnyEvent::Impl::Event::, 1],
1113	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1210	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1114	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1211	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1212	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1115	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1213	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1116	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1214	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1117	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1215	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1118	[Wx:: => AnyEvent::Impl::POE::],	1216	[Wx:: => AnyEvent::Impl::POE::],
1119	[Prima:: => AnyEvent::Impl::POE::],	1217	[Prima:: => AnyEvent::Impl::POE::],
1120	# IO::Async is just too broken - we would need workarounds for its	1218	# IO::Async is just too broken - we would need workarounds for its
1121	# byzantine signal and broken child handling, among others.	1219	# byzantine signal and broken child handling, among others.
1122	# IO::Async is rather hard to detect, as it doesn't have any	1220	# IO::Async is rather hard to detect, as it doesn't have any
1123	# obvious default class.	1221	# obvious default class.
1124	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program	1222	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1125	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1223	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1126	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1224	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
		1225	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1127	);	1226	);
1128		1227
1129	our %method = map +($_ => 1),	1228	our %method = map +($_ => 1),
1130	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1229	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1131		1230
1132	our @post_detect;	1231	our @post_detect;
1133		1232
1134	sub post_detect(&) {	1233	sub post_detect(&) {
1135	my ($cb) = @_;	1234	my ($cb) = @_;
1136		1235
1137	if ($MODEL) {
1138	$cb->();
1139
1140	1
1141	} else {
1142	push @post_detect, $cb;	1236	push @post_detect, $cb;
1143		1237
1144	defined wantarray	1238	defined wantarray
1145	? bless \$cb, "AnyEvent::Util::postdetect"	1239	? bless \$cb, "AnyEvent::Util::postdetect"
1146	: ()	1240	: ()
1147	}
1148	}	1241	}
1149		1242
1150	sub AnyEvent::Util::postdetect::DESTROY {	1243	sub AnyEvent::Util::postdetect::DESTROY {
1151	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1244	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1152	}	1245	}
1153		1246
1154	sub detect() {	1247	sub detect() {
		1248	# free some memory
		1249	*detect = sub () { $MODEL };
		1250
		1251	local $!; # for good measure
		1252	local $SIG{__DIE__};
		1253
		1254	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1255	my $model = "AnyEvent::Impl::$1";
		1256	if (eval "require $model") {
		1257	$MODEL = $model;
		1258	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1259	} else {
		1260	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1261	}
		1262	}
		1263
		1264	# check for already loaded models
1155	unless ($MODEL) {	1265	unless ($MODEL) {
1156	local $SIG{__DIE__};	1266	for (@REGISTRY, @models) {
1157		1267	my ($package, $model) = @$_;
1158	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1268	if (${"$package\::VERSION"} > 0) {
1159	my $model = "AnyEvent::Impl::$1";
1160	if (eval "require $model") {	1269	if (eval "require $model") {
1161	$MODEL = $model;	1270	$MODEL = $model;
1162	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1271	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1163	} else {	1272	last;
1164	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1273	}
1165	}	1274	}
1166	}	1275	}
1167		1276
1168	# check for already loaded models
1169	unless ($MODEL) {	1277	unless ($MODEL) {
		1278	# try to autoload a model
1170	for (@REGISTRY, @models) {	1279	for (@REGISTRY, @models) {
1171	my ($package, $model) = @$_;	1280	my ($package, $model, $autoload) = @$_;
		1281	if (
		1282	$autoload
		1283	and eval "require $package"
1172	if (${"$package\::VERSION"} > 0) {	1284	and ${"$package\::VERSION"} > 0
1173	if (eval "require $model") {	1285	and eval "require $model"
		1286	) {
1174	$MODEL = $model;	1287	$MODEL = $model;
1175	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1288	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1176	last;	1289	last;
1177	}
1178	}	1290	}
1179	}	1291	}
1180		1292
1181	unless ($MODEL) {
1182	# try to load a model
1183
1184	for (@REGISTRY, @models) {
1185	my ($package, $model) = @$_;
1186	if (eval "require $package"
1187	and ${"$package\::VERSION"} > 0
1188	and eval "require $model") {
1189	$MODEL = $model;
1190	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1191	last;
1192	}
1193	}
1194
1195	$MODEL	1293	$MODEL
1196	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1294	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";
1197	}
1198	}	1295	}
1199
1200	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1201
1202	unshift @ISA, $MODEL;
1203
1204	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1205
1206	(shift @post_detect)->() while @post_detect;
1207	}	1296	}
		1297
		1298	@models = (); # free probe data
		1299
		1300	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1301	unshift @ISA, $MODEL;
		1302
		1303	# now nuke some methods that are overriden by the backend.
		1304	# SUPER is not allowed.
		1305	for (qw(time signal child idle)) {
		1306	undef &{"AnyEvent::Base::$_"}
		1307	if defined &{"$MODEL\::$_"};
		1308	}
		1309
		1310	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
		1311
		1312	(shift @post_detect)->() while @post_detect;
		1313
		1314	*post_detect = sub(&) {
		1315	shift->();
		1316
		1317	undef
		1318	};
1208		1319
1209	$MODEL	1320	$MODEL
1210	}	1321	}
1211		1322
1212	sub AUTOLOAD {	1323	sub AUTOLOAD {
1213	(my $func = $AUTOLOAD) =~ s/.*://;	1324	(my $func = $AUTOLOAD) =~ s/.*://;
1214		1325
1215	$method{$func}	1326	$method{$func}
1216	or Carp::croak "$func: not a valid method for AnyEvent objects";	1327	or Carp::croak "$func: not a valid AnyEvent class method";
1217		1328
1218	detect unless $MODEL;	1329	detect;
1219		1330
1220	my $class = shift;	1331	my $class = shift;
1221	$class->$func (@_);	1332	$class->$func (@_);
1222	}	1333	}
1223		1334
…		…
1236	# we assume CLOEXEC is already set by perl in all important cases	1347	# we assume CLOEXEC is already set by perl in all important cases
1237		1348
1238	($fh2, $rw)	1349	($fh2, $rw)
1239	}	1350	}
1240		1351
		1352	=head1 SIMPLIFIED AE API
		1353
		1354	Starting with version 5.0, AnyEvent officially supports a second, much
		1355	simpler, API that is designed to reduce the calling, typing and memory
		1356	overhead by using function call syntax and a fixed number of parameters.
		1357
		1358	See the L<AE> manpage for details.
		1359
		1360	=cut
		1361
		1362	package AE;
		1363
		1364	our $VERSION = $AnyEvent::VERSION;
		1365
		1366	# fall back to the main API by default - backends and AnyEvent::Base
		1367	# implementations can overwrite these.
		1368
		1369	sub io($$$) {
		1370	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1371	}
		1372
		1373	sub timer($$$) {
		1374	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1375	}
		1376
		1377	sub signal($$) {
		1378	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub child($$) {
		1382	AnyEvent->child (pid => $_[0], cb => $_[1])
		1383	}
		1384
		1385	sub idle($) {
		1386	AnyEvent->idle (cb => $_[0])
		1387	}
		1388
		1389	sub cv(;&) {
		1390	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1391	}
		1392
		1393	sub now() {
		1394	AnyEvent->now
		1395	}
		1396
		1397	sub now_update() {
		1398	AnyEvent->now_update
		1399	}
		1400
		1401	sub time() {
		1402	AnyEvent->time
		1403	}
		1404
1241	package AnyEvent::Base;	1405	package AnyEvent::Base;
1242		1406
1243	# default implementations for many methods	1407	# default implementations for many methods
1244		1408
1245	sub _time {	1409	sub time {
		1410	eval q{ # poor man's autoloading {}
1246	# probe for availability of Time::HiRes	1411	# probe for availability of Time::HiRes
1247	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1412	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1248	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1413	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1249	*_time = \&Time::HiRes::time;	1414	*AE::time = \&Time::HiRes::time;
1250	# if (eval "use POSIX (); (POSIX::times())...	1415	# if (eval "use POSIX (); (POSIX::times())...
1251	} else {	1416	} else {
1252	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1417	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1253	*_time = sub { time }; # epic fail	1418	*AE::time = sub (){ time }; # epic fail
		1419	}
		1420
		1421	*time = sub { AE::time }; # different prototypes
1254	}	1422	};
		1423	die if $@;
1255		1424
1256	&_time	1425	&time
1257	}	1426	}
1258		1427
1259	sub time { _time }	1428	*now = \&time;
1260	sub now { _time }	1429
1261	sub now_update { }	1430	sub now_update { }
1262		1431
1263	# default implementation for ->condvar	1432	# default implementation for ->condvar
1264		1433
1265	sub condvar {	1434	sub condvar {
		1435	eval q{ # poor man's autoloading {}
		1436	*condvar = sub {
1266	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1437	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1438	};
		1439
		1440	*AE::cv = sub (;&) {
		1441	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1442	};
		1443	};
		1444	die if $@;
		1445
		1446	&condvar
1267	}	1447	}
1268		1448
1269	# default implementation for ->signal	1449	# default implementation for ->signal
1270		1450
1271	our $HAVE_ASYNC_INTERRUPT;	1451	our $HAVE_ASYNC_INTERRUPT;
		1452
		1453	sub _have_async_interrupt() {
		1454	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1455	&& eval "use Async::Interrupt 1.02 (); 1")
		1456	unless defined $HAVE_ASYNC_INTERRUPT;
		1457
		1458	$HAVE_ASYNC_INTERRUPT
		1459	}
		1460
1272	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1461	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1273	our (%SIG_ASY, %SIG_ASY_W);	1462	our (%SIG_ASY, %SIG_ASY_W);
1274	our ($SIG_COUNT, $SIG_TW);	1463	our ($SIG_COUNT, $SIG_TW);
1275		1464
1276	sub _signal_exec {
1277	$HAVE_ASYNC_INTERRUPT
1278	? $SIGPIPE_R->drain
1279	: sysread $SIGPIPE_R, my $dummy, 9;
1280
1281	while (%SIG_EV) {
1282	for (keys %SIG_EV) {
1283	delete $SIG_EV{$_};
1284	$_->() for values %{ $SIG_CB{$_} || {} };
1285	}
1286	}
1287	}
1288
1289	# install a dumym wakeupw atcher to reduce signal catching latency	1465	# install a dummy wakeup watcher to reduce signal catching latency
		1466	# used by Impls
1290	sub _sig_add() {	1467	sub _sig_add() {
1291	unless ($SIG_COUNT++) {	1468	unless ($SIG_COUNT++) {
1292	# try to align timer on a full-second boundary, if possible	1469	# try to align timer on a full-second boundary, if possible
1293	my $NOW = AnyEvent->now;	1470	my $NOW = AE::now;
1294		1471
1295	$SIG_TW = AnyEvent->timer (	1472	$SIG_TW = AE::timer
1296	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1473	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1297	interval => $MAX_SIGNAL_LATENCY,	1474	$MAX_SIGNAL_LATENCY,
1298	cb => sub { }, # just for the PERL_ASYNC_CHECK	1475	sub { } # just for the PERL_ASYNC_CHECK
1299	);	1476	;
1300	}	1477	}
1301	}	1478	}
1302		1479
1303	sub _sig_del {	1480	sub _sig_del {
1304	undef $SIG_TW	1481	undef $SIG_TW
1305	unless --$SIG_COUNT;	1482	unless --$SIG_COUNT;
1306	}	1483	}
1307		1484
		1485	our $_sig_name_init; $_sig_name_init = sub {
		1486	eval q{ # poor man's autoloading {}
		1487	undef $_sig_name_init;
		1488
		1489	if (_have_async_interrupt) {
		1490	*sig2num = \&Async::Interrupt::sig2num;
		1491	*sig2name = \&Async::Interrupt::sig2name;
		1492	} else {
		1493	require Config;
		1494
		1495	my %signame2num;
		1496	@signame2num{ split ' ', $Config::Config{sig_name} }
		1497	= split ' ', $Config::Config{sig_num};
		1498
		1499	my @signum2name;
		1500	@signum2name[values %signame2num] = keys %signame2num;
		1501
		1502	*sig2num = sub($) {
		1503	$_[0] > 0 ? shift : $signame2num{+shift}
		1504	};
		1505	*sig2name = sub ($) {
		1506	$_[0] > 0 ? $signum2name[+shift] : shift
		1507	};
		1508	}
		1509	};
		1510	die if $@;
		1511	};
		1512
		1513	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1514	sub sig2name($) { &$_sig_name_init; &sig2name }
		1515
1308	sub _signal {	1516	sub signal {
1309	my (undef, %arg) = @_;	1517	eval q{ # poor man's autoloading {}
		1518	# probe for availability of Async::Interrupt
		1519	if (_have_async_interrupt) {
		1520	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1310		1521
1311	my $signal = uc $arg{signal}	1522	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1312	or Carp::croak "required option 'signal' is missing";	1523	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1313		1524
1314	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1525	} else {
		1526	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1315		1527
1316	if ($HAVE_ASYNC_INTERRUPT) {	1528	if (AnyEvent::WIN32) {
1317	# async::interrupt	1529	require AnyEvent::Util;
1318		1530
1319	$SIG_ASY{$signal} ||= do {	1531	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1320	my $asy = new Async::Interrupt	1532	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1321	cb => sub { undef $SIG_EV{$signal} },	1533	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1322	signal => $signal,	1534	} else {
1323	pipe => [$SIGPIPE_R->filenos],	1535	pipe $SIGPIPE_R, $SIGPIPE_W;
		1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1538
		1539	# not strictly required, as $^F is normally 2, but let's make sure...
		1540	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1541	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1324	;	1542	}
1325	$asy->pipe_autodrain (0);
1326		1543
1327	$asy	1544	$SIGPIPE_R
		1545	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1546
		1547	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1548	}
		1549
		1550	*signal = $HAVE_ASYNC_INTERRUPT
		1551	? sub {
		1552	my (undef, %arg) = @_;
		1553
		1554	# async::interrupt
		1555	my $signal = sig2num $arg{signal};
		1556	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1557
		1558	$SIG_ASY{$signal} ||= new Async::Interrupt
		1559	cb => sub { undef $SIG_EV{$signal} },
		1560	signal => $signal,
		1561	pipe => [$SIGPIPE_R->filenos],
		1562	pipe_autodrain => 0,
		1563	;
		1564
		1565	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1566	}
		1567	: sub {
		1568	my (undef, %arg) = @_;
		1569
		1570	# pure perl
		1571	my $signal = sig2name $arg{signal};
		1572	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1573
		1574	$SIG{$signal} ||= sub {
		1575	local $!;
		1576	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1577	undef $SIG_EV{$signal};
		1578	};
		1579
		1580	# can't do signal processing without introducing races in pure perl,
		1581	# so limit the signal latency.
		1582	_sig_add;
		1583
		1584	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1585	}
		1586	;
		1587
		1588	*AnyEvent::Base::signal::DESTROY = sub {
		1589	my ($signal, $cb) = @{$_[0]};
		1590
		1591	_sig_del;
		1592
		1593	delete $SIG_CB{$signal}{$cb};
		1594
		1595	$HAVE_ASYNC_INTERRUPT
		1596	? delete $SIG_ASY{$signal}
		1597	: # delete doesn't work with older perls - they then
		1598	# print weird messages, or just unconditionally exit
		1599	# instead of getting the default action.
		1600	undef $SIG{$signal}
		1601	unless keys %{ $SIG_CB{$signal} };
1328	};	1602	};
1329		1603
1330	} else {	1604	*_signal_exec = sub {
1331	# pure perl	1605	$HAVE_ASYNC_INTERRUPT
		1606	? $SIGPIPE_R->drain
		1607	: sysread $SIGPIPE_R, (my $dummy), 9;
1332		1608
1333	$SIG{$signal} ||= sub {	1609	while (%SIG_EV) {
1334	local $!;	1610	for (keys %SIG_EV) {
1335	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1611	delete $SIG_EV{$_};
1336	undef $SIG_EV{$signal};	1612	$_->() for values %{ $SIG_CB{$_} || {} };
		1613	}
		1614	}
1337	};	1615	};
1338
1339	# can't do signal processing without introducing races in pure perl,
1340	# so limit the signal latency.
1341	_sig_add;
1342	}	1616	};
		1617	die if $@;
1343		1618
1344	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1345	}
1346
1347	sub signal {
1348	# probe for availability of Async::Interrupt
1349	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1350	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1351
1352	$HAVE_ASYNC_INTERRUPT = 1;
1353	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1354	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1355
1356	} else {
1357	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1358
1359	require Fcntl;
1360
1361	if (AnyEvent::WIN32) {
1362	require AnyEvent::Util;
1363
1364	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1365	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1366	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1367	} else {
1368	pipe $SIGPIPE_R, $SIGPIPE_W;
1369	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1370	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1371
1372	# not strictly required, as $^F is normally 2, but let's make sure...
1373	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1374	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1375	}
1376
1377	$SIGPIPE_R
1378	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1379
1380	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1381	}
1382
1383	*signal = \&_signal;
1384	&signal	1619	&signal
1385	}
1386
1387	sub AnyEvent::Base::signal::DESTROY {
1388	my ($signal, $cb) = @{$_[0]};
1389
1390	_sig_del;
1391
1392	delete $SIG_CB{$signal}{$cb};
1393
1394	$HAVE_ASYNC_INTERRUPT
1395	? delete $SIG_ASY{$signal}
1396	: # delete doesn't work with older perls - they then
1397	# print weird messages, or just unconditionally exit
1398	# instead of getting the default action.
1399	undef $SIG{$signal}
1400	unless keys %{ $SIG_CB{$signal} };
1401	}	1620	}
1402		1621
1403	# default implementation for ->child	1622	# default implementation for ->child
1404		1623
1405	our %PID_CB;	1624	our %PID_CB;
1406	our $CHLD_W;	1625	our $CHLD_W;
1407	our $CHLD_DELAY_W;	1626	our $CHLD_DELAY_W;
1408	our $WNOHANG;	1627	our $WNOHANG;
1409		1628
1410	sub _sigchld {	1629	# used by many Impl's
1411	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1630	sub _emit_childstatus($$) {
1412	$_->($pid, $?)	1631	my (undef, $rpid, $rstatus) = @_;
		1632
		1633	$_->($rpid, $rstatus)
1413	for values %{ $PID_CB{$pid} || {} },	1634	for values %{ $PID_CB{$rpid} || {} },
1414	values %{ $PID_CB{0} || {} };	1635	values %{ $PID_CB{0} || {} };
1415	}
1416	}	1636	}
1417		1637
1418	sub child {	1638	sub child {
		1639	eval q{ # poor man's autoloading {}
		1640	*_sigchld = sub {
		1641	my $pid;
		1642
		1643	AnyEvent->_emit_childstatus ($pid, $?)
		1644	while ($pid = waitpid -1, $WNOHANG) > 0;
		1645	};
		1646
		1647	*child = sub {
1419	my (undef, %arg) = @_;	1648	my (undef, %arg) = @_;
1420		1649
1421	defined (my $pid = $arg{pid} + 0)	1650	defined (my $pid = $arg{pid} + 0)
1422	or Carp::croak "required option 'pid' is missing";	1651	or Carp::croak "required option 'pid' is missing";
1423		1652
1424	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1653	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1425		1654
1426	# WNOHANG is almost cetrainly 1 everywhere	1655	# WNOHANG is almost cetrainly 1 everywhere
1427	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/	1656	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1428	? 1	1657	? 1
1429	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;	1658	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1430		1659
1431	unless ($CHLD_W) {	1660	unless ($CHLD_W) {
1432	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1661	$CHLD_W = AE::signal CHLD => \&_sigchld;
1433	# child could be a zombie already, so make at least one round	1662	# child could be a zombie already, so make at least one round
1434	&_sigchld;	1663	&_sigchld;
1435	}	1664	}
1436		1665
1437	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1666	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1438	}	1667	};
1439		1668
1440	sub AnyEvent::Base::child::DESTROY {	1669	*AnyEvent::Base::child::DESTROY = sub {
1441	my ($pid, $cb) = @{$_[0]};	1670	my ($pid, $cb) = @{$_[0]};
1442		1671
1443	delete $PID_CB{$pid}{$cb};	1672	delete $PID_CB{$pid}{$cb};
1444	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1673	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1445		1674
1446	undef $CHLD_W unless keys %PID_CB;	1675	undef $CHLD_W unless keys %PID_CB;
		1676	};
		1677	};
		1678	die if $@;
		1679
		1680	&child
1447	}	1681	}
1448		1682
1449	# idle emulation is done by simply using a timer, regardless	1683	# idle emulation is done by simply using a timer, regardless
1450	# of whether the process is idle or not, and not letting	1684	# of whether the process is idle or not, and not letting
1451	# the callback use more than 50% of the time.	1685	# the callback use more than 50% of the time.
1452	sub idle {	1686	sub idle {
		1687	eval q{ # poor man's autoloading {}
		1688	*idle = sub {
1453	my (undef, %arg) = @_;	1689	my (undef, %arg) = @_;
1454		1690
1455	my ($cb, $w, $rcb) = $arg{cb};	1691	my ($cb, $w, $rcb) = $arg{cb};
1456		1692
1457	$rcb = sub {	1693	$rcb = sub {
1458	if ($cb) {	1694	if ($cb) {
1459	$w = _time;	1695	$w = _time;
1460	&$cb;	1696	&$cb;
1461	$w = _time - $w;	1697	$w = _time - $w;
1462		1698
1463	# never use more then 50% of the time for the idle watcher,	1699	# never use more then 50% of the time for the idle watcher,
1464	# within some limits	1700	# within some limits
1465	$w = 0.0001 if $w < 0.0001;	1701	$w = 0.0001 if $w < 0.0001;
1466	$w = 5 if $w > 5;	1702	$w = 5 if $w > 5;
1467		1703
1468	$w = AnyEvent->timer (after => $w, cb => $rcb);	1704	$w = AE::timer $w, 0, $rcb;
1469	} else {	1705	} else {
1470	# clean up...	1706	# clean up...
1471	undef $w;	1707	undef $w;
1472	undef $rcb;	1708	undef $rcb;
		1709	}
		1710	};
		1711
		1712	$w = AE::timer 0.05, 0, $rcb;
		1713
		1714	bless \\$cb, "AnyEvent::Base::idle"
1473	}	1715	};
		1716
		1717	*AnyEvent::Base::idle::DESTROY = sub {
		1718	undef $${$_[0]};
		1719	};
1474	};	1720	};
		1721	die if $@;
1475		1722
1476	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1723	&idle
1477
1478	bless \\$cb, "AnyEvent::Base::idle"
1479	}
1480
1481	sub AnyEvent::Base::idle::DESTROY {
1482	undef $${$_[0]};
1483	}	1724	}
1484		1725
1485	package AnyEvent::CondVar;	1726	package AnyEvent::CondVar;
1486		1727
1487	our @ISA = AnyEvent::CondVar::Base::;	1728	our @ISA = AnyEvent::CondVar::Base::;
…		…
1535	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1776	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1536	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1777	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1537	}	1778	}
1538		1779
1539	sub cb {	1780	sub cb {
1540	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1781	my $cv = shift;
		1782
		1783	@_
		1784	and $cv->{_ae_cb} = shift
		1785	and $cv->{_ae_sent}
		1786	and (delete $cv->{_ae_cb})->($cv);
		1787
1541	$_[0]{_ae_cb}	1788	$cv->{_ae_cb}
1542	}	1789	}
1543		1790
1544	sub begin {	1791	sub begin {
1545	++$_[0]{_ae_counter};	1792	++$_[0]{_ae_counter};
1546	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1793	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1608	check the arguments passed to most method calls. If it finds any problems,	1855	check the arguments passed to most method calls. If it finds any problems,
1609	it will croak.	1856	it will croak.
1610		1857
1611	In other words, enables "strict" mode.	1858	In other words, enables "strict" mode.
1612		1859
1613	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1860	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1614	>>, it is definitely recommended to keep it off in production. Keeping	1861	>>, it is definitely recommended to keep it off in production. Keeping
1615	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1862	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1616	can be very useful, however.	1863	can be very useful, however.
1617		1864
1618	=item C<PERL_ANYEVENT_MODEL>	1865	=item C<PERL_ANYEVENT_MODEL>
…		…
1755	warn "read: $input\n"; # output what has been read	2002	warn "read: $input\n"; # output what has been read
1756	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2003	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1757	},	2004	},
1758	);	2005	);
1759		2006
1760	my $time_watcher; # can only be used once
1761
1762	sub new_timer {
1763	$timer = AnyEvent->timer (after => 1, cb => sub {	2007	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1764	warn "timeout\n"; # print 'timeout' about every second	2008	warn "timeout\n"; # print 'timeout' at most every second
1765	&new_timer; # and restart the time
1766	});	2009	});
1767	}
1768
1769	new_timer; # create first timer
1770		2010
1771	$cv->recv; # wait until user enters /^q/i	2011	$cv->recv; # wait until user enters /^q/i
1772		2012
1773	=head1 REAL-WORLD EXAMPLE	2013	=head1 REAL-WORLD EXAMPLE
1774		2014
…		…
1847		2087
1848	The actual code goes further and collects all errors (C<die>s, exceptions)	2088	The actual code goes further and collects all errors (C<die>s, exceptions)
1849	that occurred during request processing. The C<result> method detects	2089	that occurred during request processing. The C<result> method detects
1850	whether an exception as thrown (it is stored inside the $txn object)	2090	whether an exception as thrown (it is stored inside the $txn object)
1851	and just throws the exception, which means connection errors and other	2091	and just throws the exception, which means connection errors and other
1852	problems get reported tot he code that tries to use the result, not in a	2092	problems get reported to the code that tries to use the result, not in a
1853	random callback.	2093	random callback.
1854		2094
1855	All of this enables the following usage styles:	2095	All of this enables the following usage styles:
1856		2096
1857	1. Blocking:	2097	1. Blocking:
…		…
1905	through AnyEvent. The benchmark creates a lot of timers (with a zero	2145	through AnyEvent. The benchmark creates a lot of timers (with a zero
1906	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2146	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1907	which it is), lets them fire exactly once and destroys them again.	2147	which it is), lets them fire exactly once and destroys them again.
1908		2148
1909	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2149	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1910	distribution.	2150	distribution. It uses the L<AE> interface, which makes a real difference
		2151	for the EV and Perl backends only.
1911		2152
1912	=head3 Explanation of the columns	2153	=head3 Explanation of the columns
1913		2154
1914	I<watcher> is the number of event watchers created/destroyed. Since	2155	I<watcher> is the number of event watchers created/destroyed. Since
1915	different event models feature vastly different performances, each event	2156	different event models feature vastly different performances, each event
…		…
1936	watcher.	2177	watcher.
1937		2178
1938	=head3 Results	2179	=head3 Results
1939		2180
1940	name watchers bytes create invoke destroy comment	2181	name watchers bytes create invoke destroy comment
1941	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2182	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1942	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2183	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1943	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2184	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1944	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2185	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1945	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2186	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1946	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2187	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1947	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2188	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1948	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2189	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1949	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2190	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1950	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2191	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1951	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2192	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1952	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2193	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1953		2194
1954	=head3 Discussion	2195	=head3 Discussion
1955		2196
1956	The benchmark does I<not> measure scalability of the event loop very	2197	The benchmark does I<not> measure scalability of the event loop very
1957	well. For example, a select-based event loop (such as the pure perl one)	2198	well. For example, a select-based event loop (such as the pure perl one)
…		…
1969	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2210	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1970	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2211	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1971	cycles with POE.	2212	cycles with POE.
1972		2213
1973	C<EV> is the sole leader regarding speed and memory use, which are both	2214	C<EV> is the sole leader regarding speed and memory use, which are both
1974	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2215	maximal/minimal, respectively. When using the L<AE> API there is zero
		2216	overhead (when going through the AnyEvent API create is about 5-6 times
		2217	slower, with other times being equal, so still uses far less memory than
1975	far less memory than any other event loop and is still faster than Event	2218	any other event loop and is still faster than Event natively).
1976	natively.
1977		2219
1978	The pure perl implementation is hit in a few sweet spots (both the	2220	The pure perl implementation is hit in a few sweet spots (both the
1979	constant timeout and the use of a single fd hit optimisations in the perl	2221	constant timeout and the use of a single fd hit optimisations in the perl
1980	interpreter and the backend itself). Nevertheless this shows that it	2222	interpreter and the backend itself). Nevertheless this shows that it
1981	adds very little overhead in itself. Like any select-based backend its	2223	adds very little overhead in itself. Like any select-based backend its
…		…
2055	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2297	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2056	(1%) are active. This mirrors the activity of large servers with many	2298	(1%) are active. This mirrors the activity of large servers with many
2057	connections, most of which are idle at any one point in time.	2299	connections, most of which are idle at any one point in time.
2058		2300
2059	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2301	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2060	distribution.	2302	distribution. It uses the L<AE> interface, which makes a real difference
		2303	for the EV and Perl backends only.
2061		2304
2062	=head3 Explanation of the columns	2305	=head3 Explanation of the columns
2063		2306
2064	I<sockets> is the number of sockets, and twice the number of "servers" (as	2307	I<sockets> is the number of sockets, and twice the number of "servers" (as
2065	each server has a read and write socket end).	2308	each server has a read and write socket end).
…		…
2073	a new one that moves the timeout into the future.	2316	a new one that moves the timeout into the future.
2074		2317
2075	=head3 Results	2318	=head3 Results
2076		2319
2077	name sockets create request	2320	name sockets create request
2078	EV 20000 69.01 11.16	2321	EV 20000 62.66 7.99
2079	Perl 20000 73.32 35.87	2322	Perl 20000 68.32 32.64
2080	IOAsync 20000 157.00 98.14 epoll	2323	IOAsync 20000 174.06 101.15 epoll
2081	IOAsync 20000 159.31 616.06 poll	2324	IOAsync 20000 174.67 610.84 poll
2082	Event 20000 212.62 257.32	2325	Event 20000 202.69 242.91
2083	Glib 20000 651.16 1896.30	2326	Glib 20000 557.01 1689.52
2084	POE 20000 349.67 12317.24 uses POE::Loop::Event	2327	POE 20000 341.54 12086.32 uses POE::Loop::Event
2085		2328
2086	=head3 Discussion	2329	=head3 Discussion
2087		2330
2088	This benchmark I<does> measure scalability and overall performance of the	2331	This benchmark I<does> measure scalability and overall performance of the
2089	particular event loop.	2332	particular event loop.
…		…
2215	As you can see, the AnyEvent + EV combination even beats the	2458	As you can see, the AnyEvent + EV combination even beats the
2216	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2459	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2217	backend easily beats IO::Lambda and POE.	2460	backend easily beats IO::Lambda and POE.
2218		2461
2219	And even the 100% non-blocking version written using the high-level (and	2462	And even the 100% non-blocking version written using the high-level (and
2220	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2463	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2221	large margin, even though it does all of DNS, tcp-connect and socket I/O	2464	higher level ("unoptimised") abstractions by a large margin, even though
2222	in a non-blocking way.	2465	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2223		2466
2224	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2467	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2225	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2468	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2226	part of the IO::lambda distribution and were used without any changes.	2469	part of the IO::Lambda distribution and were used without any changes.
2227		2470
2228		2471
2229	=head1 SIGNALS	2472	=head1 SIGNALS
2230		2473
2231	AnyEvent currently installs handlers for these signals:	2474	AnyEvent currently installs handlers for these signals:
…		…
2268	unless defined $SIG{PIPE};	2511	unless defined $SIG{PIPE};
2269		2512
2270	=head1 RECOMMENDED/OPTIONAL MODULES	2513	=head1 RECOMMENDED/OPTIONAL MODULES
2271		2514
2272	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2515	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2273	it's built-in modules) are required to use it.	2516	its built-in modules) are required to use it.
2274		2517
2275	That does not mean that AnyEvent won't take advantage of some additional	2518	That does not mean that AnyEvent won't take advantage of some additional
2276	modules if they are installed.	2519	modules if they are installed.
2277		2520
2278	This section epxlains which additional modules will be used, and how they	2521	This section explains which additional modules will be used, and how they
2279	affect AnyEvent's operetion.	2522	affect AnyEvent's operation.
2280		2523
2281	=over 4	2524	=over 4
2282		2525
2283	=item L<Async::Interrupt>	2526	=item L<Async::Interrupt>
2284		2527
…		…
2289	catch the signals) with some delay (default is 10 seconds, look for	2532	catch the signals) with some delay (default is 10 seconds, look for
2290	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2533	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2291		2534
2292	If this module is available, then it will be used to implement signal	2535	If this module is available, then it will be used to implement signal
2293	catching, which means that signals will not be delayed, and the event loop	2536	catching, which means that signals will not be delayed, and the event loop
2294	will not be interrupted regularly, which is more efficient (And good for	2537	will not be interrupted regularly, which is more efficient (and good for
2295	battery life on laptops).	2538	battery life on laptops).
2296		2539
2297	This affects not just the pure-perl event loop, but also other event loops	2540	This affects not just the pure-perl event loop, but also other event loops
2298	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2541	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2299		2542
…		…
2311	automatic timer adjustments even when no monotonic clock is available,	2554	automatic timer adjustments even when no monotonic clock is available,
2312	can take avdantage of advanced kernel interfaces such as C<epoll> and	2555	can take avdantage of advanced kernel interfaces such as C<epoll> and
2313	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2556	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2314	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2557	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2315		2558
		2559	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2560	then this module will do nothing for you.
		2561
2316	=item L<Guard>	2562	=item L<Guard>
2317		2563
2318	The guard module, when used, will be used to implement	2564	The guard module, when used, will be used to implement
2319	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2565	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2320	lot less memory), but otherwise doesn't affect guard operation much. It is	2566	lot less memory), but otherwise doesn't affect guard operation much. It is
2321	purely used for performance.	2567	purely used for performance.
2322		2568
2323	=item L<JSON> and L<JSON::XS>	2569	=item L<JSON> and L<JSON::XS>
2324		2570
2325	This module is required when you want to read or write JSON data via	2571	One of these modules is required when you want to read or write JSON data
2326	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2572	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2327	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2573	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2328
2329	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2330	installed.
2331		2574
2332	=item L<Net::SSLeay>	2575	=item L<Net::SSLeay>
2333		2576
2334	Implementing TLS/SSL in Perl is certainly interesting, but not very	2577	Implementing TLS/SSL in Perl is certainly interesting, but not very
2335	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2578	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2336	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2579	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2337		2580
2338	=item L<Time::HiRes>	2581	=item L<Time::HiRes>
2339		2582
2340	This module is part of perl since release 5.008. It will be used when the	2583	This module is part of perl since release 5.008. It will be used when the
2341	chosen event library does not come with a timing source on it's own. The	2584	chosen event library does not come with a timing source of its own. The
2342	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2585	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2343	try to use a monotonic clock for timing stability.	2586	try to use a monotonic clock for timing stability.
2344		2587
2345	=back	2588	=back
2346		2589
2347		2590
2348	=head1 FORK	2591	=head1 FORK
2349		2592
2350	Most event libraries are not fork-safe. The ones who are usually are	2593	Most event libraries are not fork-safe. The ones who are usually are
2351	because they rely on inefficient but fork-safe C<select> or C<poll>	2594	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2352	calls. Only L<EV> is fully fork-aware.	2595	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2596	are usually badly thought-out hacks that are incompatible with fork in
		2597	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2598	continue event-processing in both parent and child (or both, if you know
		2599	what you are doing).
		2600
		2601	This means that, in general, you cannot fork and do event processing in
		2602	the child if the event library was initialised before the fork (which
		2603	usually happens when the first AnyEvent watcher is created, or the library
		2604	is loaded).
2353		2605
2354	If you have to fork, you must either do so I<before> creating your first	2606	If you have to fork, you must either do so I<before> creating your first
2355	watcher OR you must not use AnyEvent at all in the child OR you must do	2607	watcher OR you must not use AnyEvent at all in the child OR you must do
2356	something completely out of the scope of AnyEvent.	2608	something completely out of the scope of AnyEvent.
		2609
		2610	The problem of doing event processing in the parent I<and> the child
		2611	is much more complicated: even for backends that I<are> fork-aware or
		2612	fork-safe, their behaviour is not usually what you want: fork clones all
		2613	watchers, that means all timers, I/O watchers etc. are active in both
		2614	parent and child, which is almost never what you want. USing C<exec>
		2615	to start worker children from some kind of manage rprocess is usually
		2616	preferred, because it is much easier and cleaner, at the expense of having
		2617	to have another binary.
2357		2618
2358		2619
2359	=head1 SECURITY CONSIDERATIONS	2620	=head1 SECURITY CONSIDERATIONS
2360		2621
2361	AnyEvent can be forced to load any event model via	2622	AnyEvent can be forced to load any event model via
…		…
2399	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2660	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2400		2661
2401	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2662	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2402	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2663	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2403	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2664	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2404	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2665	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2405		2666
2406	Non-blocking file handles, sockets, TCP clients and	2667	Non-blocking file handles, sockets, TCP clients and
2407	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2668	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2408		2669
2409	Asynchronous DNS: L<AnyEvent::DNS>.	2670	Asynchronous DNS: L<AnyEvent::DNS>.

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