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Revision 1.350 by root, Tue Aug 2 20:02:44 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Qt and POE are various supported	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt
6	event loops.	6	and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
40	=head1 INTRODUCTION/TUTORIAL	43	=head1 INTRODUCTION/TUTORIAL
41		44
42	This manpage is mainly a reference manual. If you are interested	45	This manpage is mainly a reference manual. If you are interested
43	in a tutorial or some gentle introduction, have a look at the	46	in a tutorial or some gentle introduction, have a look at the
44	L<AnyEvent::Intro> manpage.	47	L<AnyEvent::Intro> manpage.
		48
		49	=head1 SUPPORT
		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
		53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
		54	channel, too.
		55
		56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
		57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
45		58
46	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)	59	=head1 WHY YOU SHOULD USE THIS MODULE (OR NOT)
47		60
48	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen	61	Glib, POE, IO::Async, Event... CPAN offers event models by the dozen
49	nowadays. So what is different about AnyEvent?	62	nowadays. So what is different about AnyEvent?
…		…
65	module users into the same thing by forcing them to use the same event	78	module users into the same thing by forcing them to use the same event
66	model you use.	79	model you use.
67		80
68	For modules like POE or IO::Async (which is a total misnomer as it is	81	For modules like POE or IO::Async (which is a total misnomer as it is
69	actually doing all I/O I<synchronously>...), using them in your module is	82	actually doing all I/O I<synchronously>...), using them in your module is
70	like joining a cult: After you joined, you are dependent on them and you	83	like joining a cult: After you join, you are dependent on them and you
71	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
72	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
73	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
74		87
75	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
76	fine. AnyEvent + Tk works fine etc. etc. but none of these work together	89	fine. AnyEvent + Tk works fine etc. etc. but none of these work together
77	with the rest: POE + IO::Async? No go. Tk + Event? No go. Again: if	90	with the rest: POE + EV? No go. Tk + Event? No go. Again: if your module
78	your module uses one of those, every user of your module has to use it,	91	uses one of those, every user of your module has to use it, too. But if
79	too. But if your module uses AnyEvent, it works transparently with all	92	your module uses AnyEvent, it works transparently with all event models it
80	event models it supports (including stuff like IO::Async, as long as those	93	supports (including stuff like IO::Async, as long as those use one of the
81	use one of the supported event loops. It is trivial to add new event loops	94	supported event loops. It is easy to add new event loops to AnyEvent, too,
82	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
83		96
84	In addition to being free of having to use I<the one and only true event	97	In addition to being free of having to use I<the one and only true event
85	model>, AnyEvent also is free of bloat and policy: with POE or similar	98	model>, AnyEvent also is free of bloat and policy: with POE or similar
86	modules, you get an enormous amount of code and strict rules you have to	99	modules, you get an enormous amount of code and strict rules you have to
87	follow. AnyEvent, on the other hand, is lean and up to the point, by only	100	follow. AnyEvent, on the other hand, is lean and to the point, by only
88	offering the functionality that is necessary, in as thin as a wrapper as	101	offering the functionality that is necessary, in as thin as a wrapper as
89	technically possible.	102	technically possible.
90		103
91	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
92	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
98	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
99	model, you should I<not> use this module.	112	model, you should I<not> use this module.
100		113
101	=head1 DESCRIPTION	114	=head1 DESCRIPTION
102		115
103	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
104	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
105	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
106	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
107		120
108	The interface itself is vaguely similar, but not identical to the L<Event>	121	The interface itself is vaguely similar, but not identical to the L<Event>
109	module.	122	module.
110		123
111	During the first call of any watcher-creation method, the module tries	124	During the first call of any watcher-creation method, the module tries
112	to detect the currently loaded event loop by probing whether one of the	125	to detect the currently loaded event loop by probing whether one of the
113	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
114	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
115	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
116	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
117	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
118	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
119	found, AnyEvent will fall back to a pure-perl event loop, which is not
120	very efficient, but should work everywhere.
121		132
122	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
123	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
124	that model the default. For example:	135	that model the default. For example:
125		136
…		…
127	use AnyEvent;	138	use AnyEvent;
128		139
129	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
130		141
131	The I<likely> means that, if any module loads another event model and	142	The I<likely> means that, if any module loads another event model and
132	starts using it, all bets are off. Maybe you should tell their authors to	143	starts using it, all bets are off - this case should be very rare though,
133	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
134		146
135	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
136	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	C<AnyEvent::Impl::Perl>. Like other event modules you can load it
137	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
138		150
…		…
147	callback when the event occurs (of course, only when the event model	159	callback when the event occurs (of course, only when the event model
148	is in control).	160	is in control).
149		161
150	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
151	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
152	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
153	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
154	widely between event loops.	166	widely between event loops.
155		167
156	To disable the watcher you have to destroy it (e.g. by setting the	168	To disable a watcher you have to destroy it (e.g. by setting the
157	variable you store it in to C<undef> or otherwise deleting all references	169	variable you store it in to C<undef> or otherwise deleting all references
158	to it).	170	to it).
159		171
160	All watchers are created by calling a method on the C<AnyEvent> class.	172	All watchers are created by calling a method on the C<AnyEvent> class.
161		173
162	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
163	example), or need to refer to their watcher object in other ways.	175	example), or need to refer to their watcher object in other ways.
164		176
165	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
166		178
167	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
168	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
169	undef $w;	181	undef $w;
170	});	182	});
…		…
172	Note that C<my $w; $w => combination. This is necessary because in Perl,	184	Note that C<my $w; $w => combination. This is necessary because in Perl,
173	my variables are only visible after the statement in which they are	185	my variables are only visible after the statement in which they are
174	declared.	186	declared.
175		187
176	=head2 I/O WATCHERS	188	=head2 I/O WATCHERS
		189
		190	$w = AnyEvent->io (
		191	fh => <filehandle_or_fileno>,
		192	poll => <"r" or "w">,
		193	cb => <callback>,
		194	);
177		195
178	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	196	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
179	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
180		198
181	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch	199	C<fh> is the Perl I<file handle> (or a naked file descriptor) to watch
…		…
196		214
197	The I/O watcher might use the underlying file descriptor or a copy of it.	215	The I/O watcher might use the underlying file descriptor or a copy of it.
198	You must not close a file handle as long as any watcher is active on the	216	You must not close a file handle as long as any watcher is active on the
199	underlying file descriptor.	217	underlying file descriptor.
200		218
201	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
202	always use non-blocking calls when reading/writing from/to your file	220	always use non-blocking calls when reading/writing from/to your file
203	handles.	221	handles.
204		222
205	Example: wait for readability of STDIN, then read a line and disable the	223	Example: wait for readability of STDIN, then read a line and disable the
206	watcher.	224	watcher.
…		…
211	undef $w;	229	undef $w;
212	});	230	});
213		231
214	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
215		233
		234	$w = AnyEvent->timer (after => <seconds>, cb => <callback>);
		235
		236	$w = AnyEvent->timer (
		237	after => <fractional_seconds>,
		238	interval => <fractional_seconds>,
		239	cb => <callback>,
		240	);
		241
216	You can create a time watcher by calling the C<< AnyEvent->timer >>	242	You can create a time watcher by calling the C<< AnyEvent->timer >>
217	method with the following mandatory arguments:	243	method with the following mandatory arguments:
218		244
219	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
220	supported) the callback should be invoked. C<cb> is the callback to invoke	246	supported) the callback should be invoked. C<cb> is the callback to invoke
…		…
222		248
223	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
224	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
225	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
226		252
227	The callback will normally be invoked once only. If you specify another	253	The callback will normally be invoked only once. If you specify another
228	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
229	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
230	seconds) after the first invocation. If C<interval> is specified with a	256	seconds) after the first invocation. If C<interval> is specified with a
231	false value, then it is treated as if it were missing.	257	false value, then it is treated as if it were not specified at all.
232		258
233	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
234	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
235	only approximate.	261	only approximate.
236		262
237	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
238		264
239	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
257		283
258	While most event loops expect timers to specified in a relative way, they	284	While most event loops expect timers to specified in a relative way, they
259	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
260	"jumps", for example, when ntp decides to set your clock backwards from	286	"jumps", for example, when ntp decides to set your clock backwards from
261	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to	287	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
262	fire "after" a second might actually take six years to finally fire.	288	fire "after a second" might actually take six years to finally fire.
263		289
264	AnyEvent cannot compensate for this. The only event loop that is conscious	290	AnyEvent cannot compensate for this. The only event loop that is conscious
265	about these issues is L<EV>, which offers both relative (ev_timer, based	291	of these issues is L<EV>, which offers both relative (ev_timer, based
266	on true relative time) and absolute (ev_periodic, based on wallclock time)	292	on true relative time) and absolute (ev_periodic, based on wallclock time)
267	timers.	293	timers.
268		294
269	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
270	AnyEvent API.	296	AnyEvent API.
…		…
292	I<In almost all cases (in all cases if you don't care), this is the	318	I<In almost all cases (in all cases if you don't care), this is the
293	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
294		320
295	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
296	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
297	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
298		324
299	The rest of this section is only of relevance if you try to be very exact	325	The rest of this section is only of relevance if you try to be very exact
300	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
301		327
302	For a practical example of when these times differ, consider L<Event::Lib>	328	For a practical example of when these times differ, consider L<Event::Lib>
303	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
304		330
305	The event loop is running and has just invoked one of your callback at	331	The event loop is running and has just invoked one of your callbacks at
306	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
307	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
308	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
309	after three seconds.	335	after three seconds.
310		336
…		…
341	might affect timers and time-outs.	367	might affect timers and time-outs.
342		368
343	When this is the case, you can call this method, which will update the	369	When this is the case, you can call this method, which will update the
344	event loop's idea of "current time".	370	event loop's idea of "current time".
345		371
		372	A typical example would be a script in a web server (e.g. C<mod_perl>) -
		373	when mod_perl executes the script, then the event loop will have the wrong
		374	idea about the "current time" (being potentially far in the past, when the
		375	script ran the last time). In that case you should arrange a call to C<<
		376	AnyEvent->now_update >> each time the web server process wakes up again
		377	(e.g. at the start of your script, or in a handler).
		378
346	Note that updating the time I<might> cause some events to be handled.	379	Note that updating the time I<might> cause some events to be handled.
347		380
348	=back	381	=back
349		382
350	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
351		386
352	You can watch for signals using a signal watcher, C<signal> is the signal	387	You can watch for signals using a signal watcher, C<signal> is the signal
353	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl	388	I<name> in uppercase and without any C<SIG> prefix, C<cb> is the Perl
354	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
355		390
…		…
372		407
373	Example: exit on SIGINT	408	Example: exit on SIGINT
374		409
375	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
376		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
377	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
378		430
379	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
380	callbacks to signals in a generic way, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
381	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
382	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
383	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
384	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
385	watcher is created, and should be left alone otherwise. Higher values	438	and should be left alone otherwise. This variable determines how often
		439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
386	will cause fewer spurious wake-ups, which is better for power and CPU	440	will cause fewer spurious wake-ups, which is better for power and CPU
		441	saving.
		442
387	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
388	L<Async::Interrupt> module. This will not work with inherently broken	444	L<Async::Interrupt> module, which works with most event loops. It will not
389	event loops such as L<Event> or L<Event::Lib> (and not with L<POE>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
390	currently, as POE does it's own workaround with one-second latency). With	446	(and not with L<POE> currently, as POE does its own workaround with
391	those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
392		448
393	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
394		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
395	You can also watch on a child process exit and catch its exit status.	453	You can also watch for a child process exit and catch its exit status.
396		454
397	The child process is specified by the C<pid> argument (if set to C<0>, it	455	The child process is specified by the C<pid> argument (on some backends,
398	watches for any child process exit). The watcher will triggered only when	456	using C<0> watches for any child process exit, on others this will
399	the child process has finished and an exit status is available, not on	457	croak). The watcher will be triggered only when the child process has
400	any trace events (stopped/continued).	458	finished and an exit status is available, not on any trace events
		459	(stopped/continued).
401		460
402	The callback will be called with the pid and exit status (as returned by	461	The callback will be called with the pid and exit status (as returned by
403	waitpid), so unlike other watcher types, you I<can> rely on child watcher	462	waitpid), so unlike other watcher types, you I<can> rely on child watcher
404	callback arguments.	463	callback arguments.
405		464
…		…
446	# do something else, then wait for process exit	505	# do something else, then wait for process exit
447	$done->recv;	506	$done->recv;
448		507
449	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
450		509
451	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
452	to do it instantly, but only when there is nothing better to do. This
453	"nothing better to do" is usually defined to be "no other events need
454	attention by the event loop".
455		511
456	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
457	better to do, just before it would block the process to wait for new	513	until either the watcher is destroyed or new events have been detected.
458	events. Instead of blocking, the idle watcher is invoked.
459		514
460	Most event loops unfortunately do not really support idle watchers (only	515	Idle watchers are useful when there is a need to do something, but it
		516	is not so important (or wise) to do it instantly. The callback will be
		517	invoked only when there is "nothing better to do", which is usually
		518	defined as "all outstanding events have been handled and no new events
		519	have been detected". That means that idle watchers ideally get invoked
		520	when the event loop has just polled for new events but none have been
		521	detected. Instead of blocking to wait for more events, the idle watchers
		522	will be invoked.
		523
		524	Unfortunately, most event loops do not really support idle watchers (only
461	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent	525	EV, Event and Glib do it in a usable fashion) - for the rest, AnyEvent
462	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
463		527
464	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
465	program is otherwise idle:	529	program is otherwise idle:
…		…
481	});	545	});
482	});	546	});
483		547
484	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
485		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
486	If you are familiar with some event loops you will know that all of them	555	If you are familiar with some event loops you will know that all of them
487	require you to run some blocking "loop", "run" or similar function that	556	require you to run some blocking "loop", "run" or similar function that
488	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
489		558
490	AnyEvent is slightly different: it expects somebody else to run the event	559	AnyEvent is slightly different: it expects somebody else to run the event
491	loop and will only block when necessary (usually when told by the user).	560	loop and will only block when necessary (usually when told by the user).
492		561
493	The instrument to do that is called a "condition variable", so called	562	The tool to do that is called a "condition variable", so called because
494	because they represent a condition that must become true.	563	they represent a condition that must become true.
495		564
496	Now is probably a good time to look at the examples further below.	565	Now is probably a good time to look at the examples further below.
497		566
498	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
499	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
504	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
505	by calling the C<send> method (or calling the condition variable as if it	574	by calling the C<send> method (or calling the condition variable as if it
506	were a callback, read about the caveats in the description for the C<<	575	were a callback, read about the caveats in the description for the C<<
507	->send >> method).	576	->send >> method).
508		577
509	Condition variables are similar to callbacks, except that you can	578	Since condition variables are the most complex part of the AnyEvent API, here are
510	optionally wait for them. They can also be called merge points - points	579	some different mental models of what they are - pick the ones you can connect to:
511	in time where multiple outstanding events have been processed. And yet	580
512	another way to call them is transactions - each condition variable can be	581	=over 4
513	used to represent a transaction, which finishes at some point and delivers	582
514	a result.	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
		584	of callbacks). Unlike callbacks however, you can also wait for them to be called.
		585
		586	=item * Condition variables are signals - one side can emit or send them,
		587	the other side can wait for them, or install a handler that is called when
		588	the signal fires.
		589
		590	=item * Condition variables are like "Merge Points" - points in your program
		591	where you merge multiple independent results/control flows into one.
		592
		593	=item * Condition variables represent a transaction - functions that start
		594	some kind of transaction can return them, leaving the caller the choice
		595	between waiting in a blocking fashion, or setting a callback.
		596
		597	=item * Condition variables represent future values, or promises to deliver
		598	some result, long before the result is available.
		599
		600	=back
515		601
516	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
517	for example, if you write a module that does asynchronous http requests,	603	for example, if you write a module that does asynchronous http requests,
518	then a condition variable would be the ideal candidate to signal the	604	then a condition variable would be the ideal candidate to signal the
519	availability of results. The user can either act when the callback is	605	availability of results. The user can either act when the callback is
…		…
532		618
533	Condition variables are represented by hash refs in perl, and the keys	619	Condition variables are represented by hash refs in perl, and the keys
534	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing	620	used by AnyEvent itself are all named C<_ae_XXX> to make subclassing
535	easy (it is often useful to build your own transaction class on top of	621	easy (it is often useful to build your own transaction class on top of
536	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call	622	AnyEvent). To subclass, use C<AnyEvent::CondVar> as base class and call
537	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
538		624
539	There are two "sides" to a condition variable - the "producer side" which	625	There are two "sides" to a condition variable - the "producer side" which
540	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
541	for the send to occur.	627	for the send to occur.
542		628
543	Example: wait for a timer.	629	Example: wait for a timer.
544		630
545	# wait till the result is ready	631	# condition: "wait till the timer is fired"
546	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
547		633
548	# do something such as adding a timer	634	# create the timer - we could wait for, say
549	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
550	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
551	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
552	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
553	after => 1,	639	after => 1,
554	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
555	);	641	);
556		642
557	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
558	# calls -<send	644	# calls ->send
559	$result_ready->recv;	645	$timer_fired->recv;
560		646
561	Example: wait for a timer, but take advantage of the fact that condition	647	Example: wait for a timer, but take advantage of the fact that condition
562	variables are also callable directly.	648	variables are also callable directly.
563		649
564	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
607	they were a code reference). Calling them directly is the same as calling	693	they were a code reference). Calling them directly is the same as calling
608	C<send>.	694	C<send>.
609		695
610	=item $cv->croak ($error)	696	=item $cv->croak ($error)
611		697
612	Similar to send, but causes all call's to C<< ->recv >> to invoke	698	Similar to send, but causes all calls to C<< ->recv >> to invoke
613	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
614		700
615	This can be used to signal any errors to the condition variable	701	This can be used to signal any errors to the condition variable
616	user/consumer. Doing it this way instead of calling C<croak> directly	702	user/consumer. Doing it this way instead of calling C<croak> directly
617	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
618	diagnoses the error at the place where the result is expected, and not	704	diagnoses the error at the place where the result is expected, and not
619	deep in some event clalback without connection to the actual code causing	705	deep in some event callback with no connection to the actual code causing
620	the problem.	706	the problem.
621		707
622	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
623		709
624	=item $cv->end	710	=item $cv->end
…		…
627	one. For example, a function that pings many hosts in parallel might want	713	one. For example, a function that pings many hosts in parallel might want
628	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
629		715
630	Every call to C<< ->begin >> will increment a counter, and every call to	716	Every call to C<< ->begin >> will increment a counter, and every call to
631	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end	717	C<< ->end >> will decrement it. If the counter reaches C<0> in C<< ->end
632	>>, the (last) callback passed to C<begin> will be executed. That callback	718	>>, the (last) callback passed to C<begin> will be executed, passing the
633	is I<supposed> to call C<< ->send >>, but that is not required. If no	719	condvar as first argument. That callback is I<supposed> to call C<< ->send
634	callback was set, C<send> will be called without any arguments.	720	>>, but that is not required. If no group callback was set, C<send> will
		721	be called without any arguments.
635		722
636	You can think of C<< $cv->send >> giving you an OR condition (one call	723	You can think of C<< $cv->send >> giving you an OR condition (one call
637	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND	724	sends), while C<< $cv->begin >> and C<< $cv->end >> giving you an AND
638	condition (all C<begin> calls must be C<end>'ed before the condvar sends).	725	condition (all C<begin> calls must be C<end>'ed before the condvar sends).
639		726
…		…
661	one call to C<begin>, so the condvar waits for all calls to C<end> before	748	one call to C<begin>, so the condvar waits for all calls to C<end> before
662	sending.	749	sending.
663		750
664	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
665	there are results to be passwd back, and the number of tasks that are	752	there are results to be passwd back, and the number of tasks that are
666	begung can potentially be zero:	753	begun can potentially be zero:
667		754
668	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
669		756
670	my %result;	757	my %result;
671	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
672		759
673	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
674	$cv->begin;	761	$cv->begin;
675	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
676	$result{$host} = ...;	763	$result{$host} = ...;
…		…
692	to be called once the counter reaches C<0>, and second, it ensures that	779	to be called once the counter reaches C<0>, and second, it ensures that
693	C<send> is called even when C<no> hosts are being pinged (the loop	780	C<send> is called even when C<no> hosts are being pinged (the loop
694	doesn't execute once).	781	doesn't execute once).
695		782
696	This is the general pattern when you "fan out" into multiple (but	783	This is the general pattern when you "fan out" into multiple (but
697	potentially none) subrequests: use an outer C<begin>/C<end> pair to set	784	potentially zero) subrequests: use an outer C<begin>/C<end> pair to set
698	the callback and ensure C<end> is called at least once, and then, for each	785	the callback and ensure C<end> is called at least once, and then, for each
699	subrequest you start, call C<begin> and for each subrequest you finish,	786	subrequest you start, call C<begin> and for each subrequest you finish,
700	call C<end>.	787	call C<end>.
701		788
702	=back	789	=back
…		…
709	=over 4	796	=over 4
710		797
711	=item $cv->recv	798	=item $cv->recv
712		799
713	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
714	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
715	normally.	802	normally.
716		803
717	You can only wait once on a condition - additional calls are valid but	804	You can only wait once on a condition - additional calls are valid but
718	will return immediately.	805	will return immediately.
719		806
…		…
736	caller decide whether the call will block or not (for example, by coupling	823	caller decide whether the call will block or not (for example, by coupling
737	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
738	callbacks so the caller knows that getting the result will not block,	825	callbacks so the caller knows that getting the result will not block,
739	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
740		827
741	You can ensure that C<< -recv >> never blocks by setting a callback and	828	You can ensure that C<< ->recv >> never blocks by setting a callback and
742	only calling C<< ->recv >> from within that callback (or at a later	829	only calling C<< ->recv >> from within that callback (or at a later
743	time). This will work even when the event loop does not support blocking	830	time). This will work even when the event loop does not support blocking
744	waits otherwise.	831	waits otherwise.
745		832
746	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
752		839
753	This is a mutator function that returns the callback set and optionally	840	This is a mutator function that returns the callback set and optionally
754	replaces it before doing so.	841	replaces it before doing so.
755		842
756	The callback will be called when the condition becomes "true", i.e. when	843	The callback will be called when the condition becomes "true", i.e. when
757	C<send> or C<croak> are called, with the only argument being the condition	844	C<send> or C<croak> are called, with the only argument being the
758	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
759	is guaranteed not to block.	846	callback is called immediately when it is set. Calling C<recv> inside
		847	the callback or at any later time is guaranteed not to block.
760		848
761	=back	849	=back
762		850
763	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
764		852
…		…
767	=over 4	855	=over 4
768		856
769	=item Backends that are autoprobed when no other event loop can be found.	857	=item Backends that are autoprobed when no other event loop can be found.
770		858
771	EV is the preferred backend when no other event loop seems to be in	859	EV is the preferred backend when no other event loop seems to be in
772	use. If EV is not installed, then AnyEvent will try Event, and, failing	860	use. If EV is not installed, then AnyEvent will fall back to its own
773	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
774	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
775		863
776	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
777	AnyEvent::Impl::Event based on Event, very stable, few glitches.
778	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
779		866
780	=item Backends that are transparently being picked up when they are used.	867	=item Backends that are transparently being picked up when they are used.
781		868
782	These will be used when they are currently loaded when the first watcher	869	These will be used if they are already loaded when the first watcher
783	is created, in which case it is assumed that the application is using	870	is created, in which case it is assumed that the application is using
784	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
785	when the main program loads an event module before anything starts to	872	when the main program loads an event module before anything starts to
786	create watchers. Nothing special needs to be done by the main program.	873	create watchers. Nothing special needs to be done by the main program.
787		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
788	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
789	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
790	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
791	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
		880	AnyEvent::Impl::Irssi used when running within irssi.
		881	AnyEvent::Impl::IOAsync based on IO::Async.
		882	AnyEvent::Impl::Cocoa based on Cocoa::EventLoop.
		883	AnyEvent::Impl::FLTK based on FLTK.
792		884
793	=item Backends with special needs.	885	=item Backends with special needs.
794		886
795	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
796	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
797	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
798	everything should just work.	890	everything should just work.
799		891
800	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
801		893
802	Support for IO::Async can only be partial, as it is too broken and
803	architecturally limited to even support the AnyEvent API. It also
804	is the only event loop that needs the loop to be set explicitly, so
805	it can only be used by a main program knowing about AnyEvent. See
806	L<AnyEvent::Impl::Async> for the gory details.
807
808	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
809
810	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
811		895
812	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
813		897
814	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
839	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
840	backend has been autodetected.	924	backend has been autodetected.
841		925
842	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
843	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
844	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
845	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
846	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
847		931
848	=item AnyEvent::detect	932	=item AnyEvent::detect
849		933
850	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
851	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
852	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
853	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
854		938
855	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
856	created, use C<post_detect>.	940	created, use C<post_detect>.
857		941
858	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
859		943
860	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
861	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
862		946
863	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
864	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
865	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
866	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
870	event module detection too early, for example, L<AnyEvent::AIO> creates	954	event module detection too early, for example, L<AnyEvent::AIO> creates
871	and installs the global L<IO::AIO> watcher in a C<post_detect> block to	955	and installs the global L<IO::AIO> watcher in a C<post_detect> block to
872	avoid autodetecting the event module at load time.	956	avoid autodetecting the event module at load time.
873		957
874	If called in scalar or list context, then it creates and returns an object	958	If called in scalar or list context, then it creates and returns an object
875	that automatically removes the callback again when it is destroyed. See	959	that automatically removes the callback again when it is destroyed (or
		960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
876	L<Coro::BDB> for a case where this is useful.	961	a case where this is useful.
		962
		963	Example: Create a watcher for the IO::AIO module and store it in
		964	C<$WATCHER>, but do so only do so after the event loop is initialised.
		965
		966	our WATCHER;
		967
		968	my $guard = AnyEvent::post_detect {
		969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
		970	};
		971
		972	# the ||= is important in case post_detect immediately runs the block,
		973	# as to not clobber the newly-created watcher. assigning both watcher and
		974	# post_detect guard to the same variable has the advantage of users being
		975	# able to just C<undef $WATCHER> if the watcher causes them grief.
		976
		977	$WATCHER ||= $guard;
877		978
878	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
879		980
880	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
881	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
882	the event loop has been chosen.	983	after the event loop has been chosen.
883		984
884	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
885	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
886	array will be ignored.	987	array will be ignored.
887		988
888	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
889	it,as it takes care of these details.	990	it, as it takes care of these details.
890		991
891	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
892	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
893	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
894	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
895		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
896	=back	1010	=back
897		1011
898	=head1 WHAT TO DO IN A MODULE	1012	=head1 WHAT TO DO IN A MODULE
899		1013
900	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1014	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
910	because it will stall the whole program, and the whole point of using	1024	because it will stall the whole program, and the whole point of using
911	events is to stay interactive.	1025	events is to stay interactive.
912		1026
913	It is fine, however, to call C<< ->recv >> when the user of your module	1027	It is fine, however, to call C<< ->recv >> when the user of your module
914	requests it (i.e. if you create a http request object ad have a method	1028	requests it (i.e. if you create a http request object ad have a method
915	called C<results> that returns the results, it should call C<< ->recv >>	1029	called C<results> that returns the results, it may call C<< ->recv >>
916	freely, as the user of your module knows what she is doing. always).	1030	freely, as the user of your module knows what she is doing. Always).
917		1031
918	=head1 WHAT TO DO IN THE MAIN PROGRAM	1032	=head1 WHAT TO DO IN THE MAIN PROGRAM
919		1033
920	There will always be a single main program - the only place that should	1034	There will always be a single main program - the only place that should
921	dictate which event model to use.	1035	dictate which event model to use.
922		1036
923	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1037	If the program is not event-based, it need not do anything special, even
924	do anything special (it does not need to be event-based) and let AnyEvent	1038	when it depends on a module that uses an AnyEvent. If the program itself
925	decide which implementation to chose if some module relies on it.	1039	uses AnyEvent, but does not care which event loop is used, all it needs
		1040	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1041	available loop implementation.
926		1042
927	If the main program relies on a specific event model - for example, in	1043	If the main program relies on a specific event model - for example, in
928	Gtk2 programs you have to rely on the Glib module - you should load the	1044	Gtk2 programs you have to rely on the Glib module - you should load the
929	event module before loading AnyEvent or any module that uses it: generally	1045	event module before loading AnyEvent or any module that uses it: generally
930	speaking, you should load it as early as possible. The reason is that	1046	speaking, you should load it as early as possible. The reason is that
931	modules might create watchers when they are loaded, and AnyEvent will	1047	modules might create watchers when they are loaded, and AnyEvent will
932	decide on the event model to use as soon as it creates watchers, and it	1048	decide on the event model to use as soon as it creates watchers, and it
933	might chose the wrong one unless you load the correct one yourself.	1049	might choose the wrong one unless you load the correct one yourself.
934		1050
935	You can chose to use a pure-perl implementation by loading the	1051	You can chose to use a pure-perl implementation by loading the
936	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1052	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
937	everywhere, but letting AnyEvent chose the model is generally better.	1053	everywhere, but letting AnyEvent chose the model is generally better.
938		1054
…		…
956	=head1 OTHER MODULES	1072	=head1 OTHER MODULES
957		1073
958	The following is a non-exhaustive list of additional modules that use	1074	The following is a non-exhaustive list of additional modules that use
959	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1075	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
960	modules and other event loops in the same program. Some of the modules	1076	modules and other event loops in the same program. Some of the modules
961	come with AnyEvent, most are available via CPAN.	1077	come as part of AnyEvent, the others are available via CPAN.
962		1078
963	=over 4	1079	=over 4
964		1080
965	=item L<AnyEvent::Util>	1081	=item L<AnyEvent::Util>
966		1082
967	Contains various utility functions that replace often-used but blocking	1083	Contains various utility functions that replace often-used blocking
968	functions such as C<inet_aton> by event-/callback-based versions.	1084	functions such as C<inet_aton> with event/callback-based versions.
969		1085
970	=item L<AnyEvent::Socket>	1086	=item L<AnyEvent::Socket>
971		1087
972	Provides various utility functions for (internet protocol) sockets,	1088	Provides various utility functions for (internet protocol) sockets,
973	addresses and name resolution. Also functions to create non-blocking tcp	1089	addresses and name resolution. Also functions to create non-blocking tcp
…		…
975		1091
976	=item L<AnyEvent::Handle>	1092	=item L<AnyEvent::Handle>
977		1093
978	Provide read and write buffers, manages watchers for reads and writes,	1094	Provide read and write buffers, manages watchers for reads and writes,
979	supports raw and formatted I/O, I/O queued and fully transparent and	1095	supports raw and formatted I/O, I/O queued and fully transparent and
980	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1096	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
981		1097
982	=item L<AnyEvent::DNS>	1098	=item L<AnyEvent::DNS>
983		1099
984	Provides rich asynchronous DNS resolver capabilities.	1100	Provides rich asynchronous DNS resolver capabilities.
985		1101
		1102	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1103
		1104	Implement event-based interfaces to the protocols of the same name (for
		1105	the curious, IGS is the International Go Server and FCP is the Freenet
		1106	Client Protocol).
		1107
		1108	=item L<AnyEvent::Handle::UDP>
		1109
		1110	Here be danger!
		1111
		1112	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1113	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1114	its use of a stream-based API with a protocol that isn't streamable, that
		1115	the only way to improve it is to delete it.
		1116
		1117	It features data corruption (but typically only under load) and general
		1118	confusion. On top, the author is not only clueless about UDP but also
		1119	fact-resistant - some gems of his understanding: "connect doesn't work
		1120	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1121	packets", "I don't need to implement proper error checking as UDP doesn't
		1122	support error checking" and so on - he doesn't even understand what's
		1123	wrong with his module when it is explained to him.
		1124
986	=item L<AnyEvent::HTTP>	1125	=item L<AnyEvent::DBI>
987		1126
988	A simple-to-use HTTP library that is capable of making a lot of concurrent	1127	Executes L<DBI> requests asynchronously in a proxy process for you,
989	HTTP requests.	1128	notifying you in an event-based way when the operation is finished.
		1129
		1130	=item L<AnyEvent::AIO>
		1131
		1132	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1133	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1134	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1135	file I/O, and much more.
990		1136
991	=item L<AnyEvent::HTTPD>	1137	=item L<AnyEvent::HTTPD>
992		1138
993	Provides a simple web application server framework.	1139	A simple embedded webserver.
994		1140
995	=item L<AnyEvent::FastPing>	1141	=item L<AnyEvent::FastPing>
996		1142
997	The fastest ping in the west.	1143	The fastest ping in the west.
998
999	=item L<AnyEvent::DBI>
1000
1001	Executes L<DBI> requests asynchronously in a proxy process.
1002
1003	=item L<AnyEvent::AIO>
1004
1005	Truly asynchronous I/O, should be in the toolbox of every event
1006	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1007	together.
1008
1009	=item L<AnyEvent::BDB>
1010
1011	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1012	L<BDB> and AnyEvent together.
1013
1014	=item L<AnyEvent::GPSD>
1015
1016	A non-blocking interface to gpsd, a daemon delivering GPS information.
1017
1018	=item L<AnyEvent::IRC>
1019
1020	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1021
1022	=item L<AnyEvent::XMPP>
1023
1024	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1025	Net::XMPP2>.
1026
1027	=item L<AnyEvent::IGS>
1028
1029	A non-blocking interface to the Internet Go Server protocol (used by
1030	L<App::IGS>).
1031
1032	=item L<Net::FCP>
1033
1034	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1035	of AnyEvent.
1036
1037	=item L<Event::ExecFlow>
1038
1039	High level API for event-based execution flow control.
1040		1144
1041	=item L<Coro>	1145	=item L<Coro>
1042		1146
1043	Has special support for AnyEvent via L<Coro::AnyEvent>.	1147	Has special support for AnyEvent via L<Coro::AnyEvent>.
1044		1148
…		…
1048		1152
1049	package AnyEvent;	1153	package AnyEvent;
1050		1154
1051	# basically a tuned-down version of common::sense	1155	# basically a tuned-down version of common::sense
1052	sub common_sense {	1156	sub common_sense {
1053	# no warnings	1157	# from common:.sense 3.4
1054	${^WARNING_BITS} ^= ${^WARNING_BITS};	1158	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1055	# use strict vars subs	1159	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1056	$^H |= 0x00000600;	1160	$^H |= 0x00000600;
1057	}	1161	}
1058		1162
1059	BEGIN { AnyEvent::common_sense }	1163	BEGIN { AnyEvent::common_sense }
1060		1164
1061	use Carp ();	1165	use Carp ();
1062		1166
1063	our $VERSION = 4.85;	1167	our $VERSION = '5.34';
1064	our $MODEL;	1168	our $MODEL;
1065		1169
1066	our $AUTOLOAD;	1170	our $AUTOLOAD;
1067	our @ISA;	1171	our @ISA;
1068		1172
1069	our @REGISTRY;	1173	our @REGISTRY;
1070		1174
1071	our $WIN32;
1072
1073	our $VERBOSE;	1175	our $VERBOSE;
1074		1176
1075	BEGIN {	1177	BEGIN {
1076	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1178	require "AnyEvent/constants.pl";
		1179
1077	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1180	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1078		1181
1079	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1182	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1080	if ${^TAINT};	1183	if ${^TAINT};
1081		1184
1082	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1185	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1093	for reverse split /\s*,\s*/,	1196	for reverse split /\s*,\s*/,
1094	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1197	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1095	}	1198	}
1096		1199
1097	my @models = (	1200	my @models = (
1098	[EV:: => AnyEvent::Impl::EV::],	1201	[EV:: => AnyEvent::Impl::EV:: , 1],
1099	[Event:: => AnyEvent::Impl::Event::],
1100	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	1202	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1101	# everything below here will not be autoprobed	1203	# everything below here will not (normally) be autoprobed
1102	# as the pureperl backend should work everywhere	1204	# as the pureperl backend should work everywhere
1103	# and is usually faster	1205	# and is usually faster
		1206	[Event:: => AnyEvent::Impl::Event::, 1],
1104	[Glib:: => AnyEvent::Impl::Glib::], # becomes extremely slow with many watchers	1207	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1105	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1208	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		1209	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1106	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1210	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1107	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1211	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1108	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1212	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1109	[Wx:: => AnyEvent::Impl::POE::],	1213	[Wx:: => AnyEvent::Impl::POE::],
1110	[Prima:: => AnyEvent::Impl::POE::],	1214	[Prima:: => AnyEvent::Impl::POE::],
1111	# IO::Async is just too broken - we would need workarounds for its
1112	# byzantine signal and broken child handling, among others.
1113	# IO::Async is rather hard to detect, as it doesn't have any
1114	# obvious default class.
1115	# [IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1116	# [IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1117	# [IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1216	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1217	[FLTK:: => AnyEvent::Impl::FLTK::],
1118	);	1218	);
1119		1219
1120	our %method = map +($_ => 1),	1220	our %method = map +($_ => 1),
1121	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1221	qw(io timer time now now_update signal child idle condvar DESTROY);
1122		1222
1123	our @post_detect;	1223	our @post_detect;
1124		1224
1125	sub post_detect(&) {	1225	sub post_detect(&) {
1126	my ($cb) = @_;	1226	my ($cb) = @_;
1127		1227
1128	if ($MODEL) {
1129	$cb->();
1130
1131	1
1132	} else {
1133	push @post_detect, $cb;	1228	push @post_detect, $cb;
1134		1229
1135	defined wantarray	1230	defined wantarray
1136	? bless \$cb, "AnyEvent::Util::postdetect"	1231	? bless \$cb, "AnyEvent::Util::postdetect"
1137	: ()	1232	: ()
1138	}
1139	}	1233	}
1140		1234
1141	sub AnyEvent::Util::postdetect::DESTROY {	1235	sub AnyEvent::Util::postdetect::DESTROY {
1142	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1236	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1143	}	1237	}
1144		1238
1145	sub detect() {	1239	sub detect() {
		1240	# free some memory
		1241	*detect = sub () { $MODEL };
		1242
		1243	local $!; # for good measure
		1244	local $SIG{__DIE__};
		1245
		1246	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1247	my $model = "AnyEvent::Impl::$1";
		1248	if (eval "require $model") {
		1249	$MODEL = $model;
		1250	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1251	} else {
		1252	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1253	}
		1254	}
		1255
		1256	# check for already loaded models
1146	unless ($MODEL) {	1257	unless ($MODEL) {
1147	local $SIG{__DIE__};	1258	for (@REGISTRY, @models) {
1148		1259	my ($package, $model) = @$_;
1149	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1260	if (${"$package\::VERSION"} > 0) {
1150	my $model = "AnyEvent::Impl::$1";
1151	if (eval "require $model") {	1261	if (eval "require $model") {
1152	$MODEL = $model;	1262	$MODEL = $model;
1153	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1263	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1154	} else {	1264	last;
1155	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1265	}
1156	}	1266	}
1157	}	1267	}
1158		1268
1159	# check for already loaded models
1160	unless ($MODEL) {	1269	unless ($MODEL) {
		1270	# try to autoload a model
1161	for (@REGISTRY, @models) {	1271	for (@REGISTRY, @models) {
1162	my ($package, $model) = @$_;	1272	my ($package, $model, $autoload) = @$_;
		1273	if (
		1274	$autoload
		1275	and eval "require $package"
1163	if (${"$package\::VERSION"} > 0) {	1276	and ${"$package\::VERSION"} > 0
1164	if (eval "require $model") {	1277	and eval "require $model"
		1278	) {
1165	$MODEL = $model;	1279	$MODEL = $model;
1166	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1280	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1167	last;	1281	last;
1168	}
1169	}	1282	}
1170	}	1283	}
1171		1284
1172	unless ($MODEL) {
1173	# try to load a model
1174
1175	for (@REGISTRY, @models) {
1176	my ($package, $model) = @$_;
1177	if (eval "require $package"
1178	and ${"$package\::VERSION"} > 0
1179	and eval "require $model") {
1180	$MODEL = $model;
1181	warn "AnyEvent: autoprobed model '$model', using it.\n" if $VERBOSE >= 2;
1182	last;
1183	}
1184	}
1185
1186	$MODEL	1285	$MODEL
1187	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1286	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1188	}
1189	}	1287	}
1190
1191	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1192
1193	unshift @ISA, $MODEL;
1194
1195	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1196
1197	(shift @post_detect)->() while @post_detect;
1198	}	1288	}
		1289
		1290	@models = (); # free probe data
		1291
		1292	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1293	unshift @ISA, $MODEL;
		1294
		1295	# now nuke some methods that are overridden by the backend.
		1296	# SUPER is not allowed.
		1297	for (qw(time signal child idle)) {
		1298	undef &{"AnyEvent::Base::$_"}
		1299	if defined &{"$MODEL\::$_"};
		1300	}
		1301
		1302	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1303	eval { require AnyEvent::Strict };
		1304	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1305	if $@ && $VERBOSE;
		1306	}
		1307
		1308	(shift @post_detect)->() while @post_detect;
		1309
		1310	*post_detect = sub(&) {
		1311	shift->();
		1312
		1313	undef
		1314	};
1199		1315
1200	$MODEL	1316	$MODEL
1201	}	1317	}
1202		1318
1203	sub AUTOLOAD {	1319	sub AUTOLOAD {
1204	(my $func = $AUTOLOAD) =~ s/.*://;	1320	(my $func = $AUTOLOAD) =~ s/.*://;
1205		1321
1206	$method{$func}	1322	$method{$func}
1207	or Carp::croak "$func: not a valid method for AnyEvent objects";	1323	or Carp::croak "$func: not a valid AnyEvent class method";
1208		1324
1209	detect unless $MODEL;	1325	detect;
1210		1326
1211	my $class = shift;	1327	my $class = shift;
1212	$class->$func (@_);	1328	$class->$func (@_);
1213	}	1329	}
1214		1330
…		…
1227	# we assume CLOEXEC is already set by perl in all important cases	1343	# we assume CLOEXEC is already set by perl in all important cases
1228		1344
1229	($fh2, $rw)	1345	($fh2, $rw)
1230	}	1346	}
1231		1347
		1348	=head1 SIMPLIFIED AE API
		1349
		1350	Starting with version 5.0, AnyEvent officially supports a second, much
		1351	simpler, API that is designed to reduce the calling, typing and memory
		1352	overhead by using function call syntax and a fixed number of parameters.
		1353
		1354	See the L<AE> manpage for details.
		1355
		1356	=cut
		1357
		1358	package AE;
		1359
		1360	our $VERSION = $AnyEvent::VERSION;
		1361
		1362	# fall back to the main API by default - backends and AnyEvent::Base
		1363	# implementations can overwrite these.
		1364
		1365	sub io($$$) {
		1366	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1367	}
		1368
		1369	sub timer($$$) {
		1370	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1371	}
		1372
		1373	sub signal($$) {
		1374	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1375	}
		1376
		1377	sub child($$) {
		1378	AnyEvent->child (pid => $_[0], cb => $_[1])
		1379	}
		1380
		1381	sub idle($) {
		1382	AnyEvent->idle (cb => $_[0])
		1383	}
		1384
		1385	sub cv(;&) {
		1386	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1387	}
		1388
		1389	sub now() {
		1390	AnyEvent->now
		1391	}
		1392
		1393	sub now_update() {
		1394	AnyEvent->now_update
		1395	}
		1396
		1397	sub time() {
		1398	AnyEvent->time
		1399	}
		1400
1232	package AnyEvent::Base;	1401	package AnyEvent::Base;
1233		1402
1234	# default implementations for many methods	1403	# default implementations for many methods
1235		1404
1236	sub _time {	1405	sub time {
		1406	eval q{ # poor man's autoloading {}
1237	# probe for availability of Time::HiRes	1407	# probe for availability of Time::HiRes
1238	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1408	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1239	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1409	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1240	*_time = \&Time::HiRes::time;	1410	*AE::time = \&Time::HiRes::time;
1241	# if (eval "use POSIX (); (POSIX::times())...	1411	# if (eval "use POSIX (); (POSIX::times())...
1242	} else {	1412	} else {
1243	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1413	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1244	*_time = sub { time }; # epic fail	1414	*AE::time = sub (){ time }; # epic fail
		1415	}
		1416
		1417	*time = sub { AE::time }; # different prototypes
1245	}	1418	};
		1419	die if $@;
1246		1420
1247	&_time	1421	&time
1248	}	1422	}
1249		1423
1250	sub time { _time }	1424	*now = \&time;
1251	sub now { _time }	1425
1252	sub now_update { }	1426	sub now_update { }
1253		1427
1254	# default implementation for ->condvar	1428	# default implementation for ->condvar
1255		1429
1256	sub condvar {	1430	sub condvar {
		1431	eval q{ # poor man's autoloading {}
		1432	*condvar = sub {
1257	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1433	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1434	};
		1435
		1436	*AE::cv = sub (;&) {
		1437	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1438	};
		1439	};
		1440	die if $@;
		1441
		1442	&condvar
1258	}	1443	}
1259		1444
1260	# default implementation for ->signal	1445	# default implementation for ->signal
1261		1446
1262	our $HAVE_ASYNC_INTERRUPT;	1447	our $HAVE_ASYNC_INTERRUPT;
		1448
		1449	sub _have_async_interrupt() {
		1450	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1451	&& eval "use Async::Interrupt 1.02 (); 1")
		1452	unless defined $HAVE_ASYNC_INTERRUPT;
		1453
		1454	$HAVE_ASYNC_INTERRUPT
		1455	}
		1456
1263	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1457	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1264	our (%SIG_ASY, %SIG_ASY_W);	1458	our (%SIG_ASY, %SIG_ASY_W);
1265	our ($SIG_COUNT, $SIG_TW);	1459	our ($SIG_COUNT, $SIG_TW);
1266		1460
1267	sub _signal_exec {
1268	$HAVE_ASYNC_INTERRUPT
1269	? $SIGPIPE_R->drain
1270	: sysread $SIGPIPE_R, my $dummy, 9;
1271
1272	while (%SIG_EV) {
1273	for (keys %SIG_EV) {
1274	delete $SIG_EV{$_};
1275	$_->() for values %{ $SIG_CB{$_} || {} };
1276	}
1277	}
1278	}
1279
1280	# install a dumym wakeupw atcher to reduce signal catching latency	1461	# install a dummy wakeup watcher to reduce signal catching latency
		1462	# used by Impls
1281	sub _sig_add() {	1463	sub _sig_add() {
1282	unless ($SIG_COUNT++) {	1464	unless ($SIG_COUNT++) {
1283	# try to align timer on a full-second boundary, if possible	1465	# try to align timer on a full-second boundary, if possible
1284	my $NOW = AnyEvent->now;	1466	my $NOW = AE::now;
1285		1467
1286	$SIG_TW = AnyEvent->timer (	1468	$SIG_TW = AE::timer
1287	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1469	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1288	interval => $MAX_SIGNAL_LATENCY,	1470	$MAX_SIGNAL_LATENCY,
1289	cb => sub { }, # just for the PERL_ASYNC_CHECK	1471	sub { } # just for the PERL_ASYNC_CHECK
1290	);	1472	;
1291	}	1473	}
1292	}	1474	}
1293		1475
1294	sub _sig_del {	1476	sub _sig_del {
1295	undef $SIG_TW	1477	undef $SIG_TW
1296	unless --$SIG_COUNT;	1478	unless --$SIG_COUNT;
1297	}	1479	}
1298		1480
		1481	our $_sig_name_init; $_sig_name_init = sub {
		1482	eval q{ # poor man's autoloading {}
		1483	undef $_sig_name_init;
		1484
		1485	if (_have_async_interrupt) {
		1486	*sig2num = \&Async::Interrupt::sig2num;
		1487	*sig2name = \&Async::Interrupt::sig2name;
		1488	} else {
		1489	require Config;
		1490
		1491	my %signame2num;
		1492	@signame2num{ split ' ', $Config::Config{sig_name} }
		1493	= split ' ', $Config::Config{sig_num};
		1494
		1495	my @signum2name;
		1496	@signum2name[values %signame2num] = keys %signame2num;
		1497
		1498	*sig2num = sub($) {
		1499	$_[0] > 0 ? shift : $signame2num{+shift}
		1500	};
		1501	*sig2name = sub ($) {
		1502	$_[0] > 0 ? $signum2name[+shift] : shift
		1503	};
		1504	}
		1505	};
		1506	die if $@;
		1507	};
		1508
		1509	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1510	sub sig2name($) { &$_sig_name_init; &sig2name }
		1511
1299	sub _signal {	1512	sub signal {
1300	my (undef, %arg) = @_;	1513	eval q{ # poor man's autoloading {}
		1514	# probe for availability of Async::Interrupt
		1515	if (_have_async_interrupt) {
		1516	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1301		1517
1302	my $signal = uc $arg{signal}	1518	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1303	or Carp::croak "required option 'signal' is missing";	1519	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1304		1520
1305	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1521	} else {
		1522	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1306		1523
1307	if ($HAVE_ASYNC_INTERRUPT) {	1524	if (AnyEvent::WIN32) {
1308	# async::interrupt	1525	require AnyEvent::Util;
1309		1526
1310	$SIG_ASY{$signal} ||= do {	1527	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1311	my $asy = new Async::Interrupt	1528	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1312	cb => sub { undef $SIG_EV{$signal} },	1529	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1313	signal => $signal,	1530	} else {
1314	pipe => [$SIGPIPE_R->filenos],	1531	pipe $SIGPIPE_R, $SIGPIPE_W;
		1532	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1533	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1534
		1535	# not strictly required, as $^F is normally 2, but let's make sure...
		1536	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1537	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1315	;	1538	}
1316	$asy->pipe_autodrain (0);
1317		1539
1318	$asy	1540	$SIGPIPE_R
		1541	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1542
		1543	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1544	}
		1545
		1546	*signal = $HAVE_ASYNC_INTERRUPT
		1547	? sub {
		1548	my (undef, %arg) = @_;
		1549
		1550	# async::interrupt
		1551	my $signal = sig2num $arg{signal};
		1552	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1553
		1554	$SIG_ASY{$signal} ||= new Async::Interrupt
		1555	cb => sub { undef $SIG_EV{$signal} },
		1556	signal => $signal,
		1557	pipe => [$SIGPIPE_R->filenos],
		1558	pipe_autodrain => 0,
		1559	;
		1560
		1561	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1562	}
		1563	: sub {
		1564	my (undef, %arg) = @_;
		1565
		1566	# pure perl
		1567	my $signal = sig2name $arg{signal};
		1568	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1569
		1570	$SIG{$signal} ||= sub {
		1571	local $!;
		1572	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1573	undef $SIG_EV{$signal};
		1574	};
		1575
		1576	# can't do signal processing without introducing races in pure perl,
		1577	# so limit the signal latency.
		1578	_sig_add;
		1579
		1580	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1581	}
		1582	;
		1583
		1584	*AnyEvent::Base::signal::DESTROY = sub {
		1585	my ($signal, $cb) = @{$_[0]};
		1586
		1587	_sig_del;
		1588
		1589	delete $SIG_CB{$signal}{$cb};
		1590
		1591	$HAVE_ASYNC_INTERRUPT
		1592	? delete $SIG_ASY{$signal}
		1593	: # delete doesn't work with older perls - they then
		1594	# print weird messages, or just unconditionally exit
		1595	# instead of getting the default action.
		1596	undef $SIG{$signal}
		1597	unless keys %{ $SIG_CB{$signal} };
1319	};	1598	};
1320		1599
1321	} else {	1600	*_signal_exec = sub {
1322	# pure perl	1601	$HAVE_ASYNC_INTERRUPT
		1602	? $SIGPIPE_R->drain
		1603	: sysread $SIGPIPE_R, (my $dummy), 9;
1323		1604
1324	$SIG{$signal} ||= sub {	1605	while (%SIG_EV) {
1325	local $!;	1606	for (keys %SIG_EV) {
1326	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1607	delete $SIG_EV{$_};
1327	undef $SIG_EV{$signal};	1608	$_->() for values %{ $SIG_CB{$_} || {} };
		1609	}
		1610	}
1328	};	1611	};
1329
1330	# can't do signal processing without introducing races in pure perl,
1331	# so limit the signal latency.
1332	_sig_add;
1333	}	1612	};
		1613	die if $@;
1334		1614
1335	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1336	}
1337
1338	sub signal {
1339	# probe for availability of Async::Interrupt
1340	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1341	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1342
1343	$HAVE_ASYNC_INTERRUPT = 1;
1344	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1345	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1346
1347	} else {
1348	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1349
1350	require Fcntl;
1351
1352	if (AnyEvent::WIN32) {
1353	require AnyEvent::Util;
1354
1355	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1356	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1357	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1358	} else {
1359	pipe $SIGPIPE_R, $SIGPIPE_W;
1360	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1361	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1362
1363	# not strictly required, as $^F is normally 2, but let's make sure...
1364	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1365	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1366	}
1367
1368	$SIGPIPE_R
1369	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1370
1371	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1372	}
1373
1374	*signal = \&_signal;
1375	&signal	1615	&signal
1376	}
1377
1378	sub AnyEvent::Base::signal::DESTROY {
1379	my ($signal, $cb) = @{$_[0]};
1380
1381	_sig_del;
1382
1383	delete $SIG_CB{$signal}{$cb};
1384
1385	$HAVE_ASYNC_INTERRUPT
1386	? delete $SIG_ASY{$signal}
1387	: # delete doesn't work with older perls - they then
1388	# print weird messages, or just unconditionally exit
1389	# instead of getting the default action.
1390	undef $SIG{$signal}
1391	unless keys %{ $SIG_CB{$signal} };
1392	}	1616	}
1393		1617
1394	# default implementation for ->child	1618	# default implementation for ->child
1395		1619
1396	our %PID_CB;	1620	our %PID_CB;
1397	our $CHLD_W;	1621	our $CHLD_W;
1398	our $CHLD_DELAY_W;	1622	our $CHLD_DELAY_W;
1399	our $WNOHANG;
1400		1623
1401	sub _sigchld {	1624	# used by many Impl's
1402	while (0 < (my $pid = waitpid -1, $WNOHANG)) {	1625	sub _emit_childstatus($$) {
1403	$_->($pid, $?)	1626	my (undef, $rpid, $rstatus) = @_;
		1627
		1628	$_->($rpid, $rstatus)
1404	for values %{ $PID_CB{$pid} || {} },	1629	for values %{ $PID_CB{$rpid} || {} },
1405	values %{ $PID_CB{0} || {} };	1630	values %{ $PID_CB{0} || {} };
1406	}
1407	}	1631	}
1408		1632
1409	sub child {	1633	sub child {
		1634	eval q{ # poor man's autoloading {}
		1635	*_sigchld = sub {
		1636	my $pid;
		1637
		1638	AnyEvent->_emit_childstatus ($pid, $?)
		1639	while ($pid = waitpid -1, WNOHANG) > 0;
		1640	};
		1641
		1642	*child = sub {
1410	my (undef, %arg) = @_;	1643	my (undef, %arg) = @_;
1411		1644
1412	defined (my $pid = $arg{pid} + 0)	1645	defined (my $pid = $arg{pid} + 0)
1413	or Carp::croak "required option 'pid' is missing";	1646	or Carp::croak "required option 'pid' is missing";
1414		1647
1415	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1648	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1416		1649
1417	# WNOHANG is almost cetrainly 1 everywhere
1418	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1419	? 1
1420	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1421
1422	unless ($CHLD_W) {	1650	unless ($CHLD_W) {
1423	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1651	$CHLD_W = AE::signal CHLD => \&_sigchld;
1424	# child could be a zombie already, so make at least one round	1652	# child could be a zombie already, so make at least one round
1425	&_sigchld;	1653	&_sigchld;
1426	}	1654	}
1427		1655
1428	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1656	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1429	}	1657	};
1430		1658
1431	sub AnyEvent::Base::child::DESTROY {	1659	*AnyEvent::Base::child::DESTROY = sub {
1432	my ($pid, $cb) = @{$_[0]};	1660	my ($pid, $cb) = @{$_[0]};
1433		1661
1434	delete $PID_CB{$pid}{$cb};	1662	delete $PID_CB{$pid}{$cb};
1435	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1663	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1436		1664
1437	undef $CHLD_W unless keys %PID_CB;	1665	undef $CHLD_W unless keys %PID_CB;
		1666	};
		1667	};
		1668	die if $@;
		1669
		1670	&child
1438	}	1671	}
1439		1672
1440	# idle emulation is done by simply using a timer, regardless	1673	# idle emulation is done by simply using a timer, regardless
1441	# of whether the process is idle or not, and not letting	1674	# of whether the process is idle or not, and not letting
1442	# the callback use more than 50% of the time.	1675	# the callback use more than 50% of the time.
1443	sub idle {	1676	sub idle {
		1677	eval q{ # poor man's autoloading {}
		1678	*idle = sub {
1444	my (undef, %arg) = @_;	1679	my (undef, %arg) = @_;
1445		1680
1446	my ($cb, $w, $rcb) = $arg{cb};	1681	my ($cb, $w, $rcb) = $arg{cb};
1447		1682
1448	$rcb = sub {	1683	$rcb = sub {
1449	if ($cb) {	1684	if ($cb) {
1450	$w = _time;	1685	$w = _time;
1451	&$cb;	1686	&$cb;
1452	$w = _time - $w;	1687	$w = _time - $w;
1453		1688
1454	# never use more then 50% of the time for the idle watcher,	1689	# never use more then 50% of the time for the idle watcher,
1455	# within some limits	1690	# within some limits
1456	$w = 0.0001 if $w < 0.0001;	1691	$w = 0.0001 if $w < 0.0001;
1457	$w = 5 if $w > 5;	1692	$w = 5 if $w > 5;
1458		1693
1459	$w = AnyEvent->timer (after => $w, cb => $rcb);	1694	$w = AE::timer $w, 0, $rcb;
1460	} else {	1695	} else {
1461	# clean up...	1696	# clean up...
1462	undef $w;	1697	undef $w;
1463	undef $rcb;	1698	undef $rcb;
		1699	}
		1700	};
		1701
		1702	$w = AE::timer 0.05, 0, $rcb;
		1703
		1704	bless \\$cb, "AnyEvent::Base::idle"
1464	}	1705	};
		1706
		1707	*AnyEvent::Base::idle::DESTROY = sub {
		1708	undef $${$_[0]};
		1709	};
1465	};	1710	};
		1711	die if $@;
1466		1712
1467	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1713	&idle
1468
1469	bless \\$cb, "AnyEvent::Base::idle"
1470	}
1471
1472	sub AnyEvent::Base::idle::DESTROY {
1473	undef $${$_[0]};
1474	}	1714	}
1475		1715
1476	package AnyEvent::CondVar;	1716	package AnyEvent::CondVar;
1477		1717
1478	our @ISA = AnyEvent::CondVar::Base::;	1718	our @ISA = AnyEvent::CondVar::Base::;
		1719
		1720	# only to be used for subclassing
		1721	sub new {
		1722	my $class = shift;
		1723	bless AnyEvent->condvar (@_), $class
		1724	}
1479		1725
1480	package AnyEvent::CondVar::Base;	1726	package AnyEvent::CondVar::Base;
1481		1727
1482	#use overload	1728	#use overload
1483	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1729	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1493		1739
1494	sub _send {	1740	sub _send {
1495	# nop	1741	# nop
1496	}	1742	}
1497		1743
		1744	sub _wait {
		1745	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1746	}
		1747
1498	sub send {	1748	sub send {
1499	my $cv = shift;	1749	my $cv = shift;
1500	$cv->{_ae_sent} = [@_];	1750	$cv->{_ae_sent} = [@_];
1501	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1751	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1502	$cv->_send;	1752	$cv->_send;
…		…
1509		1759
1510	sub ready {	1760	sub ready {
1511	$_[0]{_ae_sent}	1761	$_[0]{_ae_sent}
1512	}	1762	}
1513		1763
1514	sub _wait {
1515	$WAITING
1516	and !$_[0]{_ae_sent}
1517	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1518
1519	local $WAITING = 1;
1520	AnyEvent->one_event while !$_[0]{_ae_sent};
1521	}
1522
1523	sub recv {	1764	sub recv {
		1765	unless ($_[0]{_ae_sent}) {
		1766	$WAITING
		1767	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
		1768
		1769	local $WAITING = 1;
1524	$_[0]->_wait;	1770	$_[0]->_wait;
		1771	}
1525		1772
1526	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1773	$_[0]{_ae_croak}
1527	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1774	and Carp::croak $_[0]{_ae_croak};
		1775
		1776	wantarray
		1777	? @{ $_[0]{_ae_sent} }
		1778	: $_[0]{_ae_sent}[0]
1528	}	1779	}
1529		1780
1530	sub cb {	1781	sub cb {
1531	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1782	my $cv = shift;
		1783
		1784	@_
		1785	and $cv->{_ae_cb} = shift
		1786	and $cv->{_ae_sent}
		1787	and (delete $cv->{_ae_cb})->($cv);
		1788
1532	$_[0]{_ae_cb}	1789	$cv->{_ae_cb}
1533	}	1790	}
1534		1791
1535	sub begin {	1792	sub begin {
1536	++$_[0]{_ae_counter};	1793	++$_[0]{_ae_counter};
1537	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1794	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1542	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1799	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1543	}	1800	}
1544		1801
1545	# undocumented/compatibility with pre-3.4	1802	# undocumented/compatibility with pre-3.4
1546	*broadcast = \&send;	1803	*broadcast = \&send;
1547	*wait = \&_wait;	1804	*wait = \&recv;
1548		1805
1549	=head1 ERROR AND EXCEPTION HANDLING	1806	=head1 ERROR AND EXCEPTION HANDLING
1550		1807
1551	In general, AnyEvent does not do any error handling - it relies on the	1808	In general, AnyEvent does not do any error handling - it relies on the
1552	caller to do that if required. The L<AnyEvent::Strict> module (see also	1809	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1599	check the arguments passed to most method calls. If it finds any problems,	1856	check the arguments passed to most method calls. If it finds any problems,
1600	it will croak.	1857	it will croak.
1601		1858
1602	In other words, enables "strict" mode.	1859	In other words, enables "strict" mode.
1603		1860
1604	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1861	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1605	>>, it is definitely recommended to keep it off in production. Keeping	1862	>>, it is definitely recommended to keep it off in production. Keeping
1606	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1863	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1607	can be very useful, however.	1864	can be very useful, however.
1608		1865
1609	=item C<PERL_ANYEVENT_MODEL>	1866	=item C<PERL_ANYEVENT_MODEL>
…		…
1746	warn "read: $input\n"; # output what has been read	2003	warn "read: $input\n"; # output what has been read
1747	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2004	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1748	},	2005	},
1749	);	2006	);
1750		2007
1751	my $time_watcher; # can only be used once
1752
1753	sub new_timer {
1754	$timer = AnyEvent->timer (after => 1, cb => sub {	2008	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1755	warn "timeout\n"; # print 'timeout' about every second	2009	warn "timeout\n"; # print 'timeout' at most every second
1756	&new_timer; # and restart the time
1757	});	2010	});
1758	}
1759
1760	new_timer; # create first timer
1761		2011
1762	$cv->recv; # wait until user enters /^q/i	2012	$cv->recv; # wait until user enters /^q/i
1763		2013
1764	=head1 REAL-WORLD EXAMPLE	2014	=head1 REAL-WORLD EXAMPLE
1765		2015
…		…
1838		2088
1839	The actual code goes further and collects all errors (C<die>s, exceptions)	2089	The actual code goes further and collects all errors (C<die>s, exceptions)
1840	that occurred during request processing. The C<result> method detects	2090	that occurred during request processing. The C<result> method detects
1841	whether an exception as thrown (it is stored inside the $txn object)	2091	whether an exception as thrown (it is stored inside the $txn object)
1842	and just throws the exception, which means connection errors and other	2092	and just throws the exception, which means connection errors and other
1843	problems get reported tot he code that tries to use the result, not in a	2093	problems get reported to the code that tries to use the result, not in a
1844	random callback.	2094	random callback.
1845		2095
1846	All of this enables the following usage styles:	2096	All of this enables the following usage styles:
1847		2097
1848	1. Blocking:	2098	1. Blocking:
…		…
1896	through AnyEvent. The benchmark creates a lot of timers (with a zero	2146	through AnyEvent. The benchmark creates a lot of timers (with a zero
1897	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2147	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1898	which it is), lets them fire exactly once and destroys them again.	2148	which it is), lets them fire exactly once and destroys them again.
1899		2149
1900	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2150	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1901	distribution.	2151	distribution. It uses the L<AE> interface, which makes a real difference
		2152	for the EV and Perl backends only.
1902		2153
1903	=head3 Explanation of the columns	2154	=head3 Explanation of the columns
1904		2155
1905	I<watcher> is the number of event watchers created/destroyed. Since	2156	I<watcher> is the number of event watchers created/destroyed. Since
1906	different event models feature vastly different performances, each event	2157	different event models feature vastly different performances, each event
…		…
1927	watcher.	2178	watcher.
1928		2179
1929	=head3 Results	2180	=head3 Results
1930		2181
1931	name watchers bytes create invoke destroy comment	2182	name watchers bytes create invoke destroy comment
1932	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2183	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1933	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2184	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1934	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2185	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1935	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2186	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1936	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2187	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1937	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2188	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1938	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2189	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1939	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2190	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1940	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2191	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1941	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2192	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1942	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2193	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1943	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2194	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1944		2195
1945	=head3 Discussion	2196	=head3 Discussion
1946		2197
1947	The benchmark does I<not> measure scalability of the event loop very	2198	The benchmark does I<not> measure scalability of the event loop very
1948	well. For example, a select-based event loop (such as the pure perl one)	2199	well. For example, a select-based event loop (such as the pure perl one)
…		…
1960	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2211	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1961	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2212	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
1962	cycles with POE.	2213	cycles with POE.
1963		2214
1964	C<EV> is the sole leader regarding speed and memory use, which are both	2215	C<EV> is the sole leader regarding speed and memory use, which are both
1965	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2216	maximal/minimal, respectively. When using the L<AE> API there is zero
		2217	overhead (when going through the AnyEvent API create is about 5-6 times
		2218	slower, with other times being equal, so still uses far less memory than
1966	far less memory than any other event loop and is still faster than Event	2219	any other event loop and is still faster than Event natively).
1967	natively.
1968		2220
1969	The pure perl implementation is hit in a few sweet spots (both the	2221	The pure perl implementation is hit in a few sweet spots (both the
1970	constant timeout and the use of a single fd hit optimisations in the perl	2222	constant timeout and the use of a single fd hit optimisations in the perl
1971	interpreter and the backend itself). Nevertheless this shows that it	2223	interpreter and the backend itself). Nevertheless this shows that it
1972	adds very little overhead in itself. Like any select-based backend its	2224	adds very little overhead in itself. Like any select-based backend its
…		…
2046	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2298	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2047	(1%) are active. This mirrors the activity of large servers with many	2299	(1%) are active. This mirrors the activity of large servers with many
2048	connections, most of which are idle at any one point in time.	2300	connections, most of which are idle at any one point in time.
2049		2301
2050	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2302	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2051	distribution.	2303	distribution. It uses the L<AE> interface, which makes a real difference
		2304	for the EV and Perl backends only.
2052		2305
2053	=head3 Explanation of the columns	2306	=head3 Explanation of the columns
2054		2307
2055	I<sockets> is the number of sockets, and twice the number of "servers" (as	2308	I<sockets> is the number of sockets, and twice the number of "servers" (as
2056	each server has a read and write socket end).	2309	each server has a read and write socket end).
…		…
2064	a new one that moves the timeout into the future.	2317	a new one that moves the timeout into the future.
2065		2318
2066	=head3 Results	2319	=head3 Results
2067		2320
2068	name sockets create request	2321	name sockets create request
2069	EV 20000 69.01 11.16	2322	EV 20000 62.66 7.99
2070	Perl 20000 73.32 35.87	2323	Perl 20000 68.32 32.64
2071	IOAsync 20000 157.00 98.14 epoll	2324	IOAsync 20000 174.06 101.15 epoll
2072	IOAsync 20000 159.31 616.06 poll	2325	IOAsync 20000 174.67 610.84 poll
2073	Event 20000 212.62 257.32	2326	Event 20000 202.69 242.91
2074	Glib 20000 651.16 1896.30	2327	Glib 20000 557.01 1689.52
2075	POE 20000 349.67 12317.24 uses POE::Loop::Event	2328	POE 20000 341.54 12086.32 uses POE::Loop::Event
2076		2329
2077	=head3 Discussion	2330	=head3 Discussion
2078		2331
2079	This benchmark I<does> measure scalability and overall performance of the	2332	This benchmark I<does> measure scalability and overall performance of the
2080	particular event loop.	2333	particular event loop.
…		…
2206	As you can see, the AnyEvent + EV combination even beats the	2459	As you can see, the AnyEvent + EV combination even beats the
2207	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2460	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2208	backend easily beats IO::Lambda and POE.	2461	backend easily beats IO::Lambda and POE.
2209		2462
2210	And even the 100% non-blocking version written using the high-level (and	2463	And even the 100% non-blocking version written using the high-level (and
2211	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2464	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2212	large margin, even though it does all of DNS, tcp-connect and socket I/O	2465	higher level ("unoptimised") abstractions by a large margin, even though
2213	in a non-blocking way.	2466	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2214		2467
2215	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2468	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2216	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2469	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2217	part of the IO::lambda distribution and were used without any changes.	2470	part of the IO::Lambda distribution and were used without any changes.
2218		2471
2219		2472
2220	=head1 SIGNALS	2473	=head1 SIGNALS
2221		2474
2222	AnyEvent currently installs handlers for these signals:	2475	AnyEvent currently installs handlers for these signals:
…		…
2259	unless defined $SIG{PIPE};	2512	unless defined $SIG{PIPE};
2260		2513
2261	=head1 RECOMMENDED/OPTIONAL MODULES	2514	=head1 RECOMMENDED/OPTIONAL MODULES
2262		2515
2263	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2516	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2264	it's built-in modules) are required to use it.	2517	its built-in modules) are required to use it.
2265		2518
2266	That does not mean that AnyEvent won't take advantage of some additional	2519	That does not mean that AnyEvent won't take advantage of some additional
2267	modules if they are installed.	2520	modules if they are installed.
2268		2521
2269	This section epxlains which additional modules will be used, and how they	2522	This section explains which additional modules will be used, and how they
2270	affect AnyEvent's operetion.	2523	affect AnyEvent's operation.
2271		2524
2272	=over 4	2525	=over 4
2273		2526
2274	=item L<Async::Interrupt>	2527	=item L<Async::Interrupt>
2275		2528
…		…
2280	catch the signals) with some delay (default is 10 seconds, look for	2533	catch the signals) with some delay (default is 10 seconds, look for
2281	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2534	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2282		2535
2283	If this module is available, then it will be used to implement signal	2536	If this module is available, then it will be used to implement signal
2284	catching, which means that signals will not be delayed, and the event loop	2537	catching, which means that signals will not be delayed, and the event loop
2285	will not be interrupted regularly, which is more efficient (And good for	2538	will not be interrupted regularly, which is more efficient (and good for
2286	battery life on laptops).	2539	battery life on laptops).
2287		2540
2288	This affects not just the pure-perl event loop, but also other event loops	2541	This affects not just the pure-perl event loop, but also other event loops
2289	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2542	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2290		2543
…		…
2302	automatic timer adjustments even when no monotonic clock is available,	2555	automatic timer adjustments even when no monotonic clock is available,
2303	can take avdantage of advanced kernel interfaces such as C<epoll> and	2556	can take avdantage of advanced kernel interfaces such as C<epoll> and
2304	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2557	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2305	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2558	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2306		2559
		2560	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2561	then this module will do nothing for you.
		2562
2307	=item L<Guard>	2563	=item L<Guard>
2308		2564
2309	The guard module, when used, will be used to implement	2565	The guard module, when used, will be used to implement
2310	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2566	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2311	lot less memory), but otherwise doesn't affect guard operation much. It is	2567	lot less memory), but otherwise doesn't affect guard operation much. It is
2312	purely used for performance.	2568	purely used for performance.
2313		2569
2314	=item L<JSON> and L<JSON::XS>	2570	=item L<JSON> and L<JSON::XS>
2315		2571
2316	This module is required when you want to read or write JSON data via	2572	One of these modules is required when you want to read or write JSON data
2317	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2573	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2318	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2574	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2319
2320	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2321	installed.
2322		2575
2323	=item L<Net::SSLeay>	2576	=item L<Net::SSLeay>
2324		2577
2325	Implementing TLS/SSL in Perl is certainly interesting, but not very	2578	Implementing TLS/SSL in Perl is certainly interesting, but not very
2326	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2579	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2327	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2580	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2328		2581
2329	=item L<Time::HiRes>	2582	=item L<Time::HiRes>
2330		2583
2331	This module is part of perl since release 5.008. It will be used when the	2584	This module is part of perl since release 5.008. It will be used when the
2332	chosen event library does not come with a timing source on it's own. The	2585	chosen event library does not come with a timing source of its own. The
2333	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2586	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2334	try to use a monotonic clock for timing stability.	2587	try to use a monotonic clock for timing stability.
2335		2588
2336	=back	2589	=back
2337		2590
2338		2591
2339	=head1 FORK	2592	=head1 FORK
2340		2593
2341	Most event libraries are not fork-safe. The ones who are usually are	2594	Most event libraries are not fork-safe. The ones who are usually are
2342	because they rely on inefficient but fork-safe C<select> or C<poll>	2595	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2343	calls. Only L<EV> is fully fork-aware.	2596	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2597	are usually badly thought-out hacks that are incompatible with fork in
		2598	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2599	continue event-processing in both parent and child (or both, if you know
		2600	what you are doing).
		2601
		2602	This means that, in general, you cannot fork and do event processing in
		2603	the child if the event library was initialised before the fork (which
		2604	usually happens when the first AnyEvent watcher is created, or the library
		2605	is loaded).
2344		2606
2345	If you have to fork, you must either do so I<before> creating your first	2607	If you have to fork, you must either do so I<before> creating your first
2346	watcher OR you must not use AnyEvent at all in the child OR you must do	2608	watcher OR you must not use AnyEvent at all in the child OR you must do
2347	something completely out of the scope of AnyEvent.	2609	something completely out of the scope of AnyEvent.
		2610
		2611	The problem of doing event processing in the parent I<and> the child
		2612	is much more complicated: even for backends that I<are> fork-aware or
		2613	fork-safe, their behaviour is not usually what you want: fork clones all
		2614	watchers, that means all timers, I/O watchers etc. are active in both
		2615	parent and child, which is almost never what you want. USing C<exec>
		2616	to start worker children from some kind of manage rprocess is usually
		2617	preferred, because it is much easier and cleaner, at the expense of having
		2618	to have another binary.
2348		2619
2349		2620
2350	=head1 SECURITY CONSIDERATIONS	2621	=head1 SECURITY CONSIDERATIONS
2351		2622
2352	AnyEvent can be forced to load any event model via	2623	AnyEvent can be forced to load any event model via
…		…
2382	pronounced).	2653	pronounced).
2383		2654
2384		2655
2385	=head1 SEE ALSO	2656	=head1 SEE ALSO
2386		2657
		2658	Tutorial/Introduction: L<AnyEvent::Intro>.
		2659
		2660	FAQ: L<AnyEvent::FAQ>.
		2661
2387	Utility functions: L<AnyEvent::Util>.	2662	Utility functions: L<AnyEvent::Util>.
2388		2663
2389	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2664	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2390	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2665	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2391		2666
2392	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2667	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2393	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2668	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2394	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2669	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2395	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>.	2670	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
2396		2671
2397	Non-blocking file handles, sockets, TCP clients and	2672	Non-blocking file handles, sockets, TCP clients and
2398	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2673	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2399		2674
2400	Asynchronous DNS: L<AnyEvent::DNS>.	2675	Asynchronous DNS: L<AnyEvent::DNS>.
2401		2676
2402	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2677	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2403	L<Coro::Event>,
2404		2678
2405	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2679	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2406	L<AnyEvent::HTTP>.	2680	L<AnyEvent::HTTP>.
2407		2681
2408		2682
2409	=head1 AUTHOR	2683	=head1 AUTHOR
2410		2684

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