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Revision 1.259 by root, Tue Jul 28 02:07:18 2009 UTC vs.
Revision 1.345 by root, Fri Dec 31 04:50:44 2010 UTC

…		…
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
…		…
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.
45		48
46	=head1 SUPPORT	49	=head1 SUPPORT
47		50
		51	An FAQ document is available as L<AnyEvent::FAQ>.
		52
48	There is a mailinglist for discussing all things AnyEvent, and an IRC	53	There also is a mailinglist for discussing all things AnyEvent, and an IRC
49	channel, too.	54	channel, too.
50		55
51	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software	56	See the AnyEvent project page at the B<Schmorpforge Ta-Sa Software
52	Repository>, at L<http://anyevent.schmorp.de>, for more info.	57	Repository>, at L<http://anyevent.schmorp.de>, for more info.
53		58
…		…
73	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
74	model you use.	79	model you use.
75		80
76	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
77	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
78	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
79	cannot use anything else, as they are simply incompatible to everything	84	cannot use anything else, as they are simply incompatible to everything
80	that isn't them. What's worse, all the potential users of your	85	that isn't them. What's worse, all the potential users of your
81	module are I<also> forced to use the same event loop you use.	86	module are I<also> forced to use the same event loop you use.
82		87
83	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works	88	AnyEvent is different: AnyEvent + POE works fine. AnyEvent + Glib works
84	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
85	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
86	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
87	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
88	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
89	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,
90	to AnyEvent, too, so it is future-proof).	95	so it is future-proof).
91		96
92	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
93	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
94	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
95	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
96	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
97	technically possible.	102	technically possible.
98		103
99	Of course, AnyEvent comes with a big (and fully optional!) toolbox	104	Of course, AnyEvent comes with a big (and fully optional!) toolbox
100	of useful functionality, such as an asynchronous DNS resolver, 100%	105	of useful functionality, such as an asynchronous DNS resolver, 100%
…		…
106	useful) and you want to force your users to use the one and only event	111	useful) and you want to force your users to use the one and only event
107	model, you should I<not> use this module.	112	model, you should I<not> use this module.
108		113
109	=head1 DESCRIPTION	114	=head1 DESCRIPTION
110		115
111	L<AnyEvent> provides an identical interface to multiple event loops. This	116	L<AnyEvent> provides a uniform interface to various event loops. This
112	allows module authors to utilise an event loop without forcing module	117	allows module authors to use event loop functionality without forcing
113	users to use the same event loop (as only a single event loop can coexist	118	module users to use a specific event loop implementation (since more
114	peacefully at any one time).	119	than one event loop cannot coexist peacefully).
115		120
116	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>
117	module.	122	module.
118		123
119	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
120	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
121	following modules is already loaded: L<EV>,	126	following modules is already loaded: L<EV>, L<AnyEvent::Impl::Perl>,
122	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,	127	L<Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>. The first one
123	L<POE>. The first one found is used. If none are found, the module tries	128	found is used. If none are detected, the module tries to load the first
124	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl	129	four modules in the order given; but note that if L<EV> is not
125	adaptor should always succeed) in the order given. The first one that can	130	available, the pure-perl L<AnyEvent::Impl::Perl> should always work, so
126	be successfully loaded will be used. If, after this, still none could be	131	the other two are not normally tried.
127	found, AnyEvent will fall back to a pure-perl event loop, which is not
128	very efficient, but should work everywhere.
129		132
130	Because AnyEvent first checks for modules that are already loaded, loading	133	Because AnyEvent first checks for modules that are already loaded, loading
131	an event model explicitly before first using AnyEvent will likely make	134	an event model explicitly before first using AnyEvent will likely make
132	that model the default. For example:	135	that model the default. For example:
133		136
…		…
135	use AnyEvent;	138	use AnyEvent;
136		139
137	# .. AnyEvent will likely default to Tk	140	# .. AnyEvent will likely default to Tk
138		141
139	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
140	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,
141	use AnyEvent so their modules work together with others seamlessly...	144	as very few modules hardcode event loops without announcing this very
		145	loudly.
142		146
143	The pure-perl implementation of AnyEvent is called	147	The pure-perl implementation of AnyEvent is called
144	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
145	explicitly and enjoy the high availability of that event loop :)	149	explicitly and enjoy the high availability of that event loop :)
146		150
…		…
155	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
156	is in control).	160	is in control).
157		161
158	Note that B<callbacks must not permanently change global variables>	162	Note that B<callbacks must not permanently change global variables>
159	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<	163	potentially in use by the event loop (such as C<$_> or C<$[>) and that B<<
160	callbacks must not C<die> >>. The former is good programming practise in	164	callbacks must not C<die> >>. The former is good programming practice in
161	Perl and the latter stems from the fact that exception handling differs	165	Perl and the latter stems from the fact that exception handling differs
162	widely between event loops.	166	widely between event loops.
163		167
164	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
165	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
166	to it).	170	to it).
167		171
168	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.
169		173
170	Many watchers either are used with "recursion" (repeating timers for	174	Many watchers either are used with "recursion" (repeating timers for
171	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.
172		176
173	An any way to achieve that is this pattern:	177	One way to achieve that is this pattern:
174		178
175	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {	179	my $w; $w = AnyEvent->type (arg => value ..., cb => sub {
176	# you can use $w here, for example to undef it	180	# you can use $w here, for example to undef it
177	undef $w;	181	undef $w;
178	});	182	});
…		…
180	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,
181	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
182	declared.	186	declared.
183		187
184	=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	);
185		195
186	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
187	with the following mandatory key-value pairs as arguments:	197	with the following mandatory key-value pairs as arguments:
188		198
189	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
…		…
204		214
205	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.
206	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
207	underlying file descriptor.	217	underlying file descriptor.
208		218
209	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
210	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
211	handles.	221	handles.
212		222
213	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
214	watcher.	224	watcher.
…		…
219	undef $w;	229	undef $w;
220	});	230	});
221		231
222	=head2 TIME WATCHERS	232	=head2 TIME WATCHERS
223		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
224	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 >>
225	method with the following mandatory arguments:	243	method with the following mandatory arguments:
226		244
227	C<after> specifies after how many seconds (fractional values are	245	C<after> specifies after how many seconds (fractional values are
228	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
…		…
230		248
231	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
232	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
233	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
234		252
235	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
236	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
237	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
238	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
239	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.
240		258
241	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
242	attempt is done to avoid timer drift in most backends, so the interval is	260	attempt is made to avoid timer drift in most backends, so the interval is
243	only approximate.	261	only approximate.
244		262
245	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
246		264
247	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
…		…
265		283
266	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
267	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
268	"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
269	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
270	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.
271		289
272	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
273	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
274	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)
275	timers.	293	timers.
276		294
277	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
278	AnyEvent API.	296	AnyEvent API.
…		…
300	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
301	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
302		320
303	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
304	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
305	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
306		324
307	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
308	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
309		327
310	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>
311	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
312		330
313	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
314	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
315	you wait a second by executing C<sleep 1> (blocking the process for a	333	you wait a second by executing C<sleep 1> (blocking the process for a
316	second) and then (at time=501) you create a relative timer that fires	334	second) and then (at time=501) you create a relative timer that fires
317	after three seconds.	335	after three seconds.
318		336
…		…
349	might affect timers and time-outs.	367	might affect timers and time-outs.
350		368
351	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
352	event loop's idea of "current time".	370	event loop's idea of "current time".
353		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
354	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.
355		380
356	=back	381	=back
357		382
358	=head2 SIGNAL WATCHERS	383	=head2 SIGNAL WATCHERS
		384
		385	$w = AnyEvent->signal (signal => <uppercase_signal_name>, cb => <callback>);
359		386
360	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
361	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
362	callback to be invoked whenever a signal occurs.	389	callback to be invoked whenever a signal occurs.
363		390
…		…
380		407
381	Example: exit on SIGINT	408	Example: exit on SIGINT
382		409
383	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
384		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
385	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
386		430
387	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
388	callbacks to signals in a generic way, which is a pity, as you cannot do	432	callbacks to signals in a generic way, which is a pity, as you cannot
389	race-free signal handling in perl. AnyEvent will try to do it's best, but	433	do race-free signal handling in perl, requiring C libraries for
		434	this. AnyEvent will try to do its best, which means in some cases,
390	in some cases, signals will be delayed. The maximum time a signal might	435	signals will be delayed. The maximum time a signal might be delayed is
391	be delayed is specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
392	seconds). This variable can be changed only before the first signal	437	variable can be changed only before the first signal watcher is created,
393	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
394	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
395	saving. All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
396	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
397	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>
398	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
399	those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
400		448
401	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
402		450
		451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
		452
403	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.
404		454
405	The child process is specified by the C<pid> argument (one some backends,	455	The child process is specified by the C<pid> argument (on some backends,
406	using C<0> watches for any child process exit, on others this will	456	using C<0> watches for any child process exit, on others this will
407	croak). The watcher will be triggered only when the child process has	457	croak). The watcher will be triggered only when the child process has
408	finished and an exit status is available, not on any trace events	458	finished and an exit status is available, not on any trace events
409	(stopped/continued).	459	(stopped/continued).
410		460
…		…
455	# do something else, then wait for process exit	505	# do something else, then wait for process exit
456	$done->recv;	506	$done->recv;
457		507
458	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
459		509
460	Sometimes there is a need to do something, but it is not so important	510	$w = AnyEvent->idle (cb => <callback>);
461	to do it instantly, but only when there is nothing better to do. This
462	"nothing better to do" is usually defined to be "no other events need
463	attention by the event loop".
464		511
465	Idle watchers ideally get invoked when the event loop has nothing	512	This will repeatedly invoke the callback after the process becomes idle,
466	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.
467	events. Instead of blocking, the idle watcher is invoked.
468		514
469	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
470	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
471	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
472		527
473	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
474	program is otherwise idle:	529	program is otherwise idle:
…		…
490	});	545	});
491	});	546	});
492		547
493	=head2 CONDITION VARIABLES	548	=head2 CONDITION VARIABLES
494		549
		550	$cv = AnyEvent->condvar;
		551
		552	$cv->send (<list>);
		553	my @res = $cv->recv;
		554
495	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
496	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
497	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
498		558
499	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
500	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).
501		561
502	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
503	because they represent a condition that must become true.	563	they represent a condition that must become true.
504		564
505	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.
506		566
507	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
508	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
513	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
514	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
515	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<<
516	->send >> method).	576	->send >> method).
517		577
518	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
519	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:
520	in time where multiple outstanding events have been processed. And yet	580
521	another way to call them is transactions - each condition variable can be	581	=over 4
522	used to represent a transaction, which finishes at some point and delivers	582
523	a result. And yet some people know them as "futures" - a promise to	583	=item * Condition variables are like callbacks - you can call them (and pass them instead
524	compute/deliver something that you can wait for.	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
525		601
526	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
527	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,
528	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
529	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
…		…
542		618
543	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
544	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
545	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
546	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
547	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
548		624
549	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
550	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
551	for the send to occur.	627	for the send to occur.
552		628
553	Example: wait for a timer.	629	Example: wait for a timer.
554		630
555	# wait till the result is ready	631	# condition: "wait till the timer is fired"
556	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
557		633
558	# do something such as adding a timer	634	# create the timer - we could wait for, say
559	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
560	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
561	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
562	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
563	after => 1,	639	after => 1,
564	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
565	);	641	);
566		642
567	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
568	# calls -<send	644	# calls ->send
569	$result_ready->recv;	645	$timer_fired->recv;
570		646
571	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
572	variables are also callable directly.	648	variables are also callable directly.
573		649
574	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
617	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
618	C<send>.	694	C<send>.
619		695
620	=item $cv->croak ($error)	696	=item $cv->croak ($error)
621		697
622	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
623	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
624		700
625	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
626	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
627	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
628	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
629	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
630	the problem.	706	the problem.
631		707
632	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
633		709
634	=item $cv->end	710	=item $cv->end
…		…
637	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
638	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
639		715
640	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
641	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
642	>>, 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
643	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
644	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.
645		722
646	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
647	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
648	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).
649		726
…		…
671	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
672	sending.	749	sending.
673		750
674	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
675	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
676	begung can potentially be zero:	753	begun can potentially be zero:
677		754
678	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
679		756
680	my %result;	757	my %result;
681	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
682		759
683	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
684	$cv->begin;	761	$cv->begin;
685	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
686	$result{$host} = ...;	763	$result{$host} = ...;
…		…
702	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
703	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
704	doesn't execute once).	781	doesn't execute once).
705		782
706	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
707	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
708	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
709	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,
710	call C<end>.	787	call C<end>.
711		788
712	=back	789	=back
…		…
719	=over 4	796	=over 4
720		797
721	=item $cv->recv	798	=item $cv->recv
722		799
723	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
724	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
725	normally.	802	normally.
726		803
727	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
728	will return immediately.	805	will return immediately.
729		806
…		…
746	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
747	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
748	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,
749	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
750		827
751	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
752	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
753	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
754	waits otherwise.	831	waits otherwise.
755		832
756	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
762		839
763	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
764	replaces it before doing so.	841	replaces it before doing so.
765		842
766	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
767	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
768	variable itself. Calling C<recv> inside the callback or at any later time	845	condition variable itself. If the condition is already true, the
769	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.
770		848
771	=back	849	=back
772		850
773	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
774		852
…		…
777	=over 4	855	=over 4
778		856
779	=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.
780		858
781	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
782	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
783	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
784	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
785		863
786	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
787	AnyEvent::Impl::Event based on Event, very stable, few glitches.
788	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.
789		866
790	=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.
791		868
792	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
793	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
794	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
795	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
796	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.
797		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
798	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
799	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
800	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
801	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
802	AnyEvent::Impl::Irssi used when running within irssi.	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.
803		883
804	=item Backends with special needs.	884	=item Backends with special needs.
805		885
806	Qt requires the Qt::Application to be instantiated first, but will	886	Qt requires the Qt::Application to be instantiated first, but will
807	otherwise be picked up automatically. As long as the main program	887	otherwise be picked up automatically. As long as the main program
808	instantiates the application before any AnyEvent watchers are created,	888	instantiates the application before any AnyEvent watchers are created,
809	everything should just work.	889	everything should just work.
810		890
811	AnyEvent::Impl::Qt based on Qt.	891	AnyEvent::Impl::Qt based on Qt.
812		892
813	Support for IO::Async can only be partial, as it is too broken and
814	architecturally limited to even support the AnyEvent API. It also
815	is the only event loop that needs the loop to be set explicitly, so
816	it can only be used by a main program knowing about AnyEvent. See
817	L<AnyEvent::Impl::Async> for the gory details.
818
819	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
820
821	=item Event loops that are indirectly supported via other backends.	893	=item Event loops that are indirectly supported via other backends.
822		894
823	Some event loops can be supported via other modules:	895	Some event loops can be supported via other modules:
824		896
825	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	897	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
850	Contains C<undef> until the first watcher is being created, before the	922	Contains C<undef> until the first watcher is being created, before the
851	backend has been autodetected.	923	backend has been autodetected.
852		924
853	Afterwards it contains the event model that is being used, which is the	925	Afterwards it contains the event model that is being used, which is the
854	name of the Perl class implementing the model. This class is usually one	926	name of the Perl class implementing the model. This class is usually one
855	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	927	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
856	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	928	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
857	will be C<urxvt::anyevent>).	929	will be C<urxvt::anyevent>).
858		930
859	=item AnyEvent::detect	931	=item AnyEvent::detect
860		932
861	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	933	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
862	if necessary. You should only call this function right before you would	934	if necessary. You should only call this function right before you would
863	have created an AnyEvent watcher anyway, that is, as late as possible at	935	have created an AnyEvent watcher anyway, that is, as late as possible at
864	runtime, and not e.g. while initialising of your module.	936	runtime, and not e.g. during initialisation of your module.
865		937
866	If you need to do some initialisation before AnyEvent watchers are	938	If you need to do some initialisation before AnyEvent watchers are
867	created, use C<post_detect>.	939	created, use C<post_detect>.
868		940
869	=item $guard = AnyEvent::post_detect { BLOCK }	941	=item $guard = AnyEvent::post_detect { BLOCK }
870		942
871	Arranges for the code block to be executed as soon as the event model is	943	Arranges for the code block to be executed as soon as the event model is
872	autodetected (or immediately if this has already happened).	944	autodetected (or immediately if that has already happened).
873		945
874	The block will be executed I<after> the actual backend has been detected	946	The block will be executed I<after> the actual backend has been detected
875	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	947	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
876	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	948	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
877	other initialisations - see the sources of L<AnyEvent::Strict> or	949	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
886	that automatically removes the callback again when it is destroyed (or	958	that automatically removes the callback again when it is destroyed (or
887	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	959	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
888	a case where this is useful.	960	a case where this is useful.
889		961
890	Example: Create a watcher for the IO::AIO module and store it in	962	Example: Create a watcher for the IO::AIO module and store it in
891	C<$WATCHER>. Only do so after the event loop is initialised, though.	963	C<$WATCHER>, but do so only do so after the event loop is initialised.
892		964
893	our WATCHER;	965	our WATCHER;
894		966
895	my $guard = AnyEvent::post_detect {	967	my $guard = AnyEvent::post_detect {
896	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	968	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
904	$WATCHER ||= $guard;	976	$WATCHER ||= $guard;
905		977
906	=item @AnyEvent::post_detect	978	=item @AnyEvent::post_detect
907		979
908	If there are any code references in this array (you can C<push> to it	980	If there are any code references in this array (you can C<push> to it
909	before or after loading AnyEvent), then they will called directly after	981	before or after loading AnyEvent), then they will be called directly
910	the event loop has been chosen.	982	after the event loop has been chosen.
911		983
912	You should check C<$AnyEvent::MODEL> before adding to this array, though:	984	You should check C<$AnyEvent::MODEL> before adding to this array, though:
913	if it is defined then the event loop has already been detected, and the	985	if it is defined then the event loop has already been detected, and the
914	array will be ignored.	986	array will be ignored.
915		987
916	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	988	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
917	it,as it takes care of these details.	989	it, as it takes care of these details.
918		990
919	This variable is mainly useful for modules that can do something useful	991	This variable is mainly useful for modules that can do something useful
920	when AnyEvent is used and thus want to know when it is initialised, but do	992	when AnyEvent is used and thus want to know when it is initialised, but do
921	not need to even load it by default. This array provides the means to hook	993	not need to even load it by default. This array provides the means to hook
922	into AnyEvent passively, without loading it.	994	into AnyEvent passively, without loading it.
923		995
		996	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		997	together, you could put this into Coro (this is the actual code used by
		998	Coro to accomplish this):
		999
		1000	if (defined $AnyEvent::MODEL) {
		1001	# AnyEvent already initialised, so load Coro::AnyEvent
		1002	require Coro::AnyEvent;
		1003	} else {
		1004	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1005	# as soon as it is
		1006	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1007	}
		1008
924	=back	1009	=back
925		1010
926	=head1 WHAT TO DO IN A MODULE	1011	=head1 WHAT TO DO IN A MODULE
927		1012
928	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1013	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
938	because it will stall the whole program, and the whole point of using	1023	because it will stall the whole program, and the whole point of using
939	events is to stay interactive.	1024	events is to stay interactive.
940		1025
941	It is fine, however, to call C<< ->recv >> when the user of your module	1026	It is fine, however, to call C<< ->recv >> when the user of your module
942	requests it (i.e. if you create a http request object ad have a method	1027	requests it (i.e. if you create a http request object ad have a method
943	called C<results> that returns the results, it should call C<< ->recv >>	1028	called C<results> that returns the results, it may call C<< ->recv >>
944	freely, as the user of your module knows what she is doing. always).	1029	freely, as the user of your module knows what she is doing. Always).
945		1030
946	=head1 WHAT TO DO IN THE MAIN PROGRAM	1031	=head1 WHAT TO DO IN THE MAIN PROGRAM
947		1032
948	There will always be a single main program - the only place that should	1033	There will always be a single main program - the only place that should
949	dictate which event model to use.	1034	dictate which event model to use.
950		1035
951	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1036	If the program is not event-based, it need not do anything special, even
952	do anything special (it does not need to be event-based) and let AnyEvent	1037	when it depends on a module that uses an AnyEvent. If the program itself
953	decide which implementation to chose if some module relies on it.	1038	uses AnyEvent, but does not care which event loop is used, all it needs
		1039	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1040	available loop implementation.
954		1041
955	If the main program relies on a specific event model - for example, in	1042	If the main program relies on a specific event model - for example, in
956	Gtk2 programs you have to rely on the Glib module - you should load the	1043	Gtk2 programs you have to rely on the Glib module - you should load the
957	event module before loading AnyEvent or any module that uses it: generally	1044	event module before loading AnyEvent or any module that uses it: generally
958	speaking, you should load it as early as possible. The reason is that	1045	speaking, you should load it as early as possible. The reason is that
959	modules might create watchers when they are loaded, and AnyEvent will	1046	modules might create watchers when they are loaded, and AnyEvent will
960	decide on the event model to use as soon as it creates watchers, and it	1047	decide on the event model to use as soon as it creates watchers, and it
961	might chose the wrong one unless you load the correct one yourself.	1048	might choose the wrong one unless you load the correct one yourself.
962		1049
963	You can chose to use a pure-perl implementation by loading the	1050	You can chose to use a pure-perl implementation by loading the
964	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1051	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour
965	everywhere, but letting AnyEvent chose the model is generally better.	1052	everywhere, but letting AnyEvent chose the model is generally better.
966		1053
…		…
984	=head1 OTHER MODULES	1071	=head1 OTHER MODULES
985		1072
986	The following is a non-exhaustive list of additional modules that use	1073	The following is a non-exhaustive list of additional modules that use
987	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1074	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
988	modules and other event loops in the same program. Some of the modules	1075	modules and other event loops in the same program. Some of the modules
989	come with AnyEvent, most are available via CPAN.	1076	come as part of AnyEvent, the others are available via CPAN.
990		1077
991	=over 4	1078	=over 4
992		1079
993	=item L<AnyEvent::Util>	1080	=item L<AnyEvent::Util>
994		1081
995	Contains various utility functions that replace often-used but blocking	1082	Contains various utility functions that replace often-used blocking
996	functions such as C<inet_aton> by event-/callback-based versions.	1083	functions such as C<inet_aton> with event/callback-based versions.
997		1084
998	=item L<AnyEvent::Socket>	1085	=item L<AnyEvent::Socket>
999		1086
1000	Provides various utility functions for (internet protocol) sockets,	1087	Provides various utility functions for (internet protocol) sockets,
1001	addresses and name resolution. Also functions to create non-blocking tcp	1088	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1003		1090
1004	=item L<AnyEvent::Handle>	1091	=item L<AnyEvent::Handle>
1005		1092
1006	Provide read and write buffers, manages watchers for reads and writes,	1093	Provide read and write buffers, manages watchers for reads and writes,
1007	supports raw and formatted I/O, I/O queued and fully transparent and	1094	supports raw and formatted I/O, I/O queued and fully transparent and
1008	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1095	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1009		1096
1010	=item L<AnyEvent::DNS>	1097	=item L<AnyEvent::DNS>
1011		1098
1012	Provides rich asynchronous DNS resolver capabilities.	1099	Provides rich asynchronous DNS resolver capabilities.
1013		1100
		1101	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1102
		1103	Implement event-based interfaces to the protocols of the same name (for
		1104	the curious, IGS is the International Go Server and FCP is the Freenet
		1105	Client Protocol).
		1106
		1107	=item L<AnyEvent::Handle::UDP>
		1108
		1109	Here be danger!
		1110
		1111	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1112	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1113	its use of a stream-based API with a protocol that isn't streamable, that
		1114	the only way to improve it is to delete it.
		1115
		1116	It features data corruption (but typically only under load) and general
		1117	confusion. On top, the author is not only clueless about UDP but also
		1118	fact-resistant - some gems of his understanding: "connect doesn't work
		1119	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1120	packets", "I don't need to implement proper error checking as UDP doesn't
		1121	support error checking" and so on - he doesn't even understand what's
		1122	wrong with his module when it is explained to him.
		1123
1014	=item L<AnyEvent::HTTP>	1124	=item L<AnyEvent::DBI>
1015		1125
1016	A simple-to-use HTTP library that is capable of making a lot of concurrent	1126	Executes L<DBI> requests asynchronously in a proxy process for you,
1017	HTTP requests.	1127	notifying you in an event-based way when the operation is finished.
		1128
		1129	=item L<AnyEvent::AIO>
		1130
		1131	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1132	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1133	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1134	file I/O, and much more.
1018		1135
1019	=item L<AnyEvent::HTTPD>	1136	=item L<AnyEvent::HTTPD>
1020		1137
1021	Provides a simple web application server framework.	1138	A simple embedded webserver.
1022		1139
1023	=item L<AnyEvent::FastPing>	1140	=item L<AnyEvent::FastPing>
1024		1141
1025	The fastest ping in the west.	1142	The fastest ping in the west.
1026
1027	=item L<AnyEvent::DBI>
1028
1029	Executes L<DBI> requests asynchronously in a proxy process.
1030
1031	=item L<AnyEvent::AIO>
1032
1033	Truly asynchronous I/O, should be in the toolbox of every event
1034	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1035	together.
1036
1037	=item L<AnyEvent::BDB>
1038
1039	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1040	L<BDB> and AnyEvent together.
1041
1042	=item L<AnyEvent::GPSD>
1043
1044	A non-blocking interface to gpsd, a daemon delivering GPS information.
1045
1046	=item L<AnyEvent::IRC>
1047
1048	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1049
1050	=item L<AnyEvent::XMPP>
1051
1052	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1053	Net::XMPP2>.
1054
1055	=item L<AnyEvent::IGS>
1056
1057	A non-blocking interface to the Internet Go Server protocol (used by
1058	L<App::IGS>).
1059
1060	=item L<Net::FCP>
1061
1062	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1063	of AnyEvent.
1064
1065	=item L<Event::ExecFlow>
1066
1067	High level API for event-based execution flow control.
1068		1143
1069	=item L<Coro>	1144	=item L<Coro>
1070		1145
1071	Has special support for AnyEvent via L<Coro::AnyEvent>.	1146	Has special support for AnyEvent via L<Coro::AnyEvent>.
1072		1147
…		…
1076		1151
1077	package AnyEvent;	1152	package AnyEvent;
1078		1153
1079	# basically a tuned-down version of common::sense	1154	# basically a tuned-down version of common::sense
1080	sub common_sense {	1155	sub common_sense {
1081	# no warnings	1156	# from common:.sense 3.3
1082	${^WARNING_BITS} ^= ${^WARNING_BITS};	1157	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf3\x0f\xc0\xf0\xfc\x33\x00";
1083	# use strict vars subs	1158	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1084	$^H |= 0x00000600;	1159	$^H |= 0x00000600;
1085	}	1160	}
1086		1161
1087	BEGIN { AnyEvent::common_sense }	1162	BEGIN { AnyEvent::common_sense }
1088		1163
1089	use Carp ();	1164	use Carp ();
1090		1165
1091	our $VERSION = 4.88;	1166	our $VERSION = '5.3';
1092	our $MODEL;	1167	our $MODEL;
1093		1168
1094	our $AUTOLOAD;	1169	our $AUTOLOAD;
1095	our @ISA;	1170	our @ISA;
1096		1171
1097	our @REGISTRY;	1172	our @REGISTRY;
1098		1173
1099	our $WIN32;
1100
1101	our $VERBOSE;	1174	our $VERBOSE;
1102		1175
1103	BEGIN {	1176	BEGIN {
1104	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1177	require "AnyEvent/constants.pl";
		1178
1105	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1179	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1106		1180
1107	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1181	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1108	if ${^TAINT};	1182	if ${^TAINT};
1109		1183
1110	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1184	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1122	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1196	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1123	}	1197	}
1124		1198
1125	my @models = (	1199	my @models = (
1126	[EV:: => AnyEvent::Impl::EV:: , 1],	1200	[EV:: => AnyEvent::Impl::EV:: , 1],
1127	[Event:: => AnyEvent::Impl::Event::, 1],
1128	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1201	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1129	# everything below here will not (normally) be autoprobed	1202	# everything below here will not (normally) be autoprobed
1130	# as the pureperl backend should work everywhere	1203	# as the pureperl backend should work everywhere
1131	# and is usually faster	1204	# and is usually faster
		1205	[Event:: => AnyEvent::Impl::Event::, 1],
1132	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1206	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1133	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1207	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1134	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1208	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1135	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1209	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1136	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1210	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1137	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1211	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1138	[Wx:: => AnyEvent::Impl::POE::],	1212	[Wx:: => AnyEvent::Impl::POE::],
1139	[Prima:: => AnyEvent::Impl::POE::],	1213	[Prima:: => AnyEvent::Impl::POE::],
1140	# IO::Async is just too broken - we would need workarounds for its
1141	# byzantine signal and broken child handling, among others.
1142	# IO::Async is rather hard to detect, as it doesn't have any
1143	# obvious default class.
1144	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1145	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1214	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1146	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1215	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1147	);	1216	);
1148		1217
1149	our %method = map +($_ => 1),	1218	our %method = map +($_ => 1),
1150	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1219	qw(io timer time now now_update signal child idle condvar one_event DESTROY);
1151		1220
1152	our @post_detect;	1221	our @post_detect;
1153		1222
1154	sub post_detect(&) {	1223	sub post_detect(&) {
1155	my ($cb) = @_;	1224	my ($cb) = @_;
1156		1225
1157	if ($MODEL) {
1158	$cb->();
1159
1160	undef
1161	} else {
1162	push @post_detect, $cb;	1226	push @post_detect, $cb;
1163		1227
1164	defined wantarray	1228	defined wantarray
1165	? bless \$cb, "AnyEvent::Util::postdetect"	1229	? bless \$cb, "AnyEvent::Util::postdetect"
1166	: ()	1230	: ()
1167	}
1168	}	1231	}
1169		1232
1170	sub AnyEvent::Util::postdetect::DESTROY {	1233	sub AnyEvent::Util::postdetect::DESTROY {
1171	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1234	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1172	}	1235	}
1173		1236
1174	sub detect() {	1237	sub detect() {
		1238	# free some memory
		1239	*detect = sub () { $MODEL };
		1240
		1241	local $!; # for good measure
		1242	local $SIG{__DIE__};
		1243
		1244	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1245	my $model = "AnyEvent::Impl::$1";
		1246	if (eval "require $model") {
		1247	$MODEL = $model;
		1248	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1249	} else {
		1250	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1251	}
		1252	}
		1253
		1254	# check for already loaded models
1175	unless ($MODEL) {	1255	unless ($MODEL) {
1176	local $SIG{__DIE__};	1256	for (@REGISTRY, @models) {
1177		1257	my ($package, $model) = @$_;
1178	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1258	if (${"$package\::VERSION"} > 0) {
1179	my $model = "AnyEvent::Impl::$1";
1180	if (eval "require $model") {	1259	if (eval "require $model") {
1181	$MODEL = $model;	1260	$MODEL = $model;
1182	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1261	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1183	} else {	1262	last;
1184	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1263	}
1185	}	1264	}
1186	}	1265	}
1187		1266
1188	# check for already loaded models
1189	unless ($MODEL) {	1267	unless ($MODEL) {
		1268	# try to autoload a model
1190	for (@REGISTRY, @models) {	1269	for (@REGISTRY, @models) {
1191	my ($package, $model) = @$_;	1270	my ($package, $model, $autoload) = @$_;
		1271	if (
		1272	$autoload
		1273	and eval "require $package"
1192	if (${"$package\::VERSION"} > 0) {	1274	and ${"$package\::VERSION"} > 0
1193	if (eval "require $model") {	1275	and eval "require $model"
		1276	) {
1194	$MODEL = $model;	1277	$MODEL = $model;
1195	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1278	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1196	last;	1279	last;
1197	}
1198	}	1280	}
1199	}	1281	}
1200		1282
1201	unless ($MODEL) {
1202	# try to autoload a model
1203	for (@REGISTRY, @models) {
1204	my ($package, $model, $autoload) = @$_;
1205	if (
1206	$autoload
1207	and eval "require $package"
1208	and ${"$package\::VERSION"} > 0
1209	and eval "require $model"
1210	) {
1211	$MODEL = $model;
1212	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1213	last;
1214	}
1215	}
1216
1217	$MODEL	1283	$MODEL
1218	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1284	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1219	}
1220	}	1285	}
1221
1222	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1223
1224	unshift @ISA, $MODEL;
1225
1226	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1227
1228	(shift @post_detect)->() while @post_detect;
1229	}	1286	}
		1287
		1288	@models = (); # free probe data
		1289
		1290	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1291	unshift @ISA, $MODEL;
		1292
		1293	# now nuke some methods that are overridden by the backend.
		1294	# SUPER is not allowed.
		1295	for (qw(time signal child idle)) {
		1296	undef &{"AnyEvent::Base::$_"}
		1297	if defined &{"$MODEL\::$_"};
		1298	}
		1299
		1300	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1301	eval { require AnyEvent::Strict };
		1302	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1303	if $@ && $VERBOSE;
		1304	}
		1305
		1306	(shift @post_detect)->() while @post_detect;
		1307
		1308	*post_detect = sub(&) {
		1309	shift->();
		1310
		1311	undef
		1312	};
1230		1313
1231	$MODEL	1314	$MODEL
1232	}	1315	}
1233		1316
1234	sub AUTOLOAD {	1317	sub AUTOLOAD {
1235	(my $func = $AUTOLOAD) =~ s/.*://;	1318	(my $func = $AUTOLOAD) =~ s/.*://;
1236		1319
1237	$method{$func}	1320	$method{$func}
1238	or Carp::croak "$func: not a valid method for AnyEvent objects";	1321	or Carp::croak "$func: not a valid AnyEvent class method";
1239		1322
1240	detect unless $MODEL;	1323	detect;
1241		1324
1242	my $class = shift;	1325	my $class = shift;
1243	$class->$func (@_);	1326	$class->$func (@_);
1244	}	1327	}
1245		1328
…		…
1258	# we assume CLOEXEC is already set by perl in all important cases	1341	# we assume CLOEXEC is already set by perl in all important cases
1259		1342
1260	($fh2, $rw)	1343	($fh2, $rw)
1261	}	1344	}
1262		1345
		1346	=head1 SIMPLIFIED AE API
		1347
		1348	Starting with version 5.0, AnyEvent officially supports a second, much
		1349	simpler, API that is designed to reduce the calling, typing and memory
		1350	overhead by using function call syntax and a fixed number of parameters.
		1351
		1352	See the L<AE> manpage for details.
		1353
		1354	=cut
		1355
		1356	package AE;
		1357
		1358	our $VERSION = $AnyEvent::VERSION;
		1359
		1360	# fall back to the main API by default - backends and AnyEvent::Base
		1361	# implementations can overwrite these.
		1362
		1363	sub io($$$) {
		1364	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1365	}
		1366
		1367	sub timer($$$) {
		1368	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1369	}
		1370
		1371	sub signal($$) {
		1372	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1373	}
		1374
		1375	sub child($$) {
		1376	AnyEvent->child (pid => $_[0], cb => $_[1])
		1377	}
		1378
		1379	sub idle($) {
		1380	AnyEvent->idle (cb => $_[0])
		1381	}
		1382
		1383	sub cv(;&) {
		1384	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1385	}
		1386
		1387	sub now() {
		1388	AnyEvent->now
		1389	}
		1390
		1391	sub now_update() {
		1392	AnyEvent->now_update
		1393	}
		1394
		1395	sub time() {
		1396	AnyEvent->time
		1397	}
		1398
1263	package AnyEvent::Base;	1399	package AnyEvent::Base;
1264		1400
1265	# default implementations for many methods	1401	# default implementations for many methods
1266		1402
1267	sub _time {	1403	sub time {
		1404	eval q{ # poor man's autoloading {}
1268	# probe for availability of Time::HiRes	1405	# probe for availability of Time::HiRes
1269	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1406	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1270	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1407	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1271	*_time = \&Time::HiRes::time;	1408	*AE::time = \&Time::HiRes::time;
1272	# if (eval "use POSIX (); (POSIX::times())...	1409	# if (eval "use POSIX (); (POSIX::times())...
1273	} else {	1410	} else {
1274	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1411	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1275	*_time = sub { time }; # epic fail	1412	*AE::time = sub (){ time }; # epic fail
		1413	}
		1414
		1415	*time = sub { AE::time }; # different prototypes
1276	}	1416	};
		1417	die if $@;
1277		1418
1278	&_time	1419	&time
1279	}	1420	}
1280		1421
1281	sub time { _time }	1422	*now = \&time;
1282	sub now { _time }	1423
1283	sub now_update { }	1424	sub now_update { }
1284		1425
1285	# default implementation for ->condvar	1426	# default implementation for ->condvar
1286		1427
1287	sub condvar {	1428	sub condvar {
		1429	eval q{ # poor man's autoloading {}
		1430	*condvar = sub {
1288	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1431	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1432	};
		1433
		1434	*AE::cv = sub (;&) {
		1435	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1436	};
		1437	};
		1438	die if $@;
		1439
		1440	&condvar
1289	}	1441	}
1290		1442
1291	# default implementation for ->signal	1443	# default implementation for ->signal
1292		1444
1293	our $HAVE_ASYNC_INTERRUPT;	1445	our $HAVE_ASYNC_INTERRUPT;
		1446
		1447	sub _have_async_interrupt() {
		1448	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
		1449	&& eval "use Async::Interrupt 1.02 (); 1")
		1450	unless defined $HAVE_ASYNC_INTERRUPT;
		1451
		1452	$HAVE_ASYNC_INTERRUPT
		1453	}
		1454
1294	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1455	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1295	our (%SIG_ASY, %SIG_ASY_W);	1456	our (%SIG_ASY, %SIG_ASY_W);
1296	our ($SIG_COUNT, $SIG_TW);	1457	our ($SIG_COUNT, $SIG_TW);
1297		1458
1298	sub _signal_exec {
1299	$HAVE_ASYNC_INTERRUPT
1300	? $SIGPIPE_R->drain
1301	: sysread $SIGPIPE_R, my $dummy, 9;
1302
1303	while (%SIG_EV) {
1304	for (keys %SIG_EV) {
1305	delete $SIG_EV{$_};
1306	$_->() for values %{ $SIG_CB{$_} || {} };
1307	}
1308	}
1309	}
1310
1311	# install a dumym wakeupw atcher to reduce signal catching latency	1459	# install a dummy wakeup watcher to reduce signal catching latency
		1460	# used by Impls
1312	sub _sig_add() {	1461	sub _sig_add() {
1313	unless ($SIG_COUNT++) {	1462	unless ($SIG_COUNT++) {
1314	# try to align timer on a full-second boundary, if possible	1463	# try to align timer on a full-second boundary, if possible
1315	my $NOW = AnyEvent->now;	1464	my $NOW = AE::now;
1316		1465
1317	$SIG_TW = AnyEvent->timer (	1466	$SIG_TW = AE::timer
1318	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1467	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1319	interval => $MAX_SIGNAL_LATENCY,	1468	$MAX_SIGNAL_LATENCY,
1320	cb => sub { }, # just for the PERL_ASYNC_CHECK	1469	sub { } # just for the PERL_ASYNC_CHECK
1321	);	1470	;
1322	}	1471	}
1323	}	1472	}
1324		1473
1325	sub _sig_del {	1474	sub _sig_del {
1326	undef $SIG_TW	1475	undef $SIG_TW
1327	unless --$SIG_COUNT;	1476	unless --$SIG_COUNT;
1328	}	1477	}
1329		1478
		1479	our $_sig_name_init; $_sig_name_init = sub {
		1480	eval q{ # poor man's autoloading {}
		1481	undef $_sig_name_init;
		1482
		1483	if (_have_async_interrupt) {
		1484	*sig2num = \&Async::Interrupt::sig2num;
		1485	*sig2name = \&Async::Interrupt::sig2name;
		1486	} else {
		1487	require Config;
		1488
		1489	my %signame2num;
		1490	@signame2num{ split ' ', $Config::Config{sig_name} }
		1491	= split ' ', $Config::Config{sig_num};
		1492
		1493	my @signum2name;
		1494	@signum2name[values %signame2num] = keys %signame2num;
		1495
		1496	*sig2num = sub($) {
		1497	$_[0] > 0 ? shift : $signame2num{+shift}
		1498	};
		1499	*sig2name = sub ($) {
		1500	$_[0] > 0 ? $signum2name[+shift] : shift
		1501	};
		1502	}
		1503	};
		1504	die if $@;
		1505	};
		1506
		1507	sub sig2num ($) { &$_sig_name_init; &sig2num }
		1508	sub sig2name($) { &$_sig_name_init; &sig2name }
		1509
1330	sub _signal {	1510	sub signal {
1331	my (undef, %arg) = @_;	1511	eval q{ # poor man's autoloading {}
		1512	# probe for availability of Async::Interrupt
		1513	if (_have_async_interrupt) {
		1514	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1332		1515
1333	my $signal = uc $arg{signal}	1516	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1334	or Carp::croak "required option 'signal' is missing";	1517	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1335		1518
1336	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1519	} else {
		1520	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1337		1521
1338	if ($HAVE_ASYNC_INTERRUPT) {	1522	if (AnyEvent::WIN32) {
1339	# async::interrupt	1523	require AnyEvent::Util;
1340		1524
1341	$SIG_ASY{$signal} ||= do {	1525	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1342	my $asy = new Async::Interrupt	1526	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1343	cb => sub { undef $SIG_EV{$signal} },	1527	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1344	signal => $signal,	1528	} else {
1345	pipe => [$SIGPIPE_R->filenos],	1529	pipe $SIGPIPE_R, $SIGPIPE_W;
		1530	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
		1531	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
		1532
		1533	# not strictly required, as $^F is normally 2, but let's make sure...
		1534	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
		1535	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1346	;	1536	}
1347	$asy->pipe_autodrain (0);
1348		1537
1349	$asy	1538	$SIGPIPE_R
		1539	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
		1540
		1541	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
		1542	}
		1543
		1544	*signal = $HAVE_ASYNC_INTERRUPT
		1545	? sub {
		1546	my (undef, %arg) = @_;
		1547
		1548	# async::interrupt
		1549	my $signal = sig2num $arg{signal};
		1550	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1551
		1552	$SIG_ASY{$signal} ||= new Async::Interrupt
		1553	cb => sub { undef $SIG_EV{$signal} },
		1554	signal => $signal,
		1555	pipe => [$SIGPIPE_R->filenos],
		1556	pipe_autodrain => 0,
		1557	;
		1558
		1559	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1560	}
		1561	: sub {
		1562	my (undef, %arg) = @_;
		1563
		1564	# pure perl
		1565	my $signal = sig2name $arg{signal};
		1566	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
		1567
		1568	$SIG{$signal} ||= sub {
		1569	local $!;
		1570	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
		1571	undef $SIG_EV{$signal};
		1572	};
		1573
		1574	# can't do signal processing without introducing races in pure perl,
		1575	# so limit the signal latency.
		1576	_sig_add;
		1577
		1578	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1579	}
		1580	;
		1581
		1582	*AnyEvent::Base::signal::DESTROY = sub {
		1583	my ($signal, $cb) = @{$_[0]};
		1584
		1585	_sig_del;
		1586
		1587	delete $SIG_CB{$signal}{$cb};
		1588
		1589	$HAVE_ASYNC_INTERRUPT
		1590	? delete $SIG_ASY{$signal}
		1591	: # delete doesn't work with older perls - they then
		1592	# print weird messages, or just unconditionally exit
		1593	# instead of getting the default action.
		1594	undef $SIG{$signal}
		1595	unless keys %{ $SIG_CB{$signal} };
1350	};	1596	};
1351		1597
1352	} else {	1598	*_signal_exec = sub {
1353	# pure perl	1599	$HAVE_ASYNC_INTERRUPT
		1600	? $SIGPIPE_R->drain
		1601	: sysread $SIGPIPE_R, (my $dummy), 9;
1354		1602
1355	$SIG{$signal} ||= sub {	1603	while (%SIG_EV) {
1356	local $!;	1604	for (keys %SIG_EV) {
1357	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1605	delete $SIG_EV{$_};
1358	undef $SIG_EV{$signal};	1606	$_->() for values %{ $SIG_CB{$_} || {} };
		1607	}
		1608	}
1359	};	1609	};
1360
1361	# can't do signal processing without introducing races in pure perl,
1362	# so limit the signal latency.
1363	_sig_add;
1364	}	1610	};
		1611	die if $@;
1365		1612
1366	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
1367	}
1368
1369	sub signal {
1370	# probe for availability of Async::Interrupt
1371	if (!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT} && eval "use Async::Interrupt 0.6 (); 1") {
1372	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1373
1374	$HAVE_ASYNC_INTERRUPT = 1;
1375	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1376	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);
1377
1378	} else {
1379	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1380
1381	require Fcntl;
1382
1383	if (AnyEvent::WIN32) {
1384	require AnyEvent::Util;
1385
1386	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1387	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R) if $SIGPIPE_R;
1388	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W) if $SIGPIPE_W; # just in case
1389	} else {
1390	pipe $SIGPIPE_R, $SIGPIPE_W;
1391	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;
1392	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case
1393
1394	# not strictly required, as $^F is normally 2, but let's make sure...
1395	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1396	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;
1397	}
1398
1399	$SIGPIPE_R
1400	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1401
1402	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);
1403	}
1404
1405	*signal = \&_signal;
1406	&signal	1613	&signal
1407	}
1408
1409	sub AnyEvent::Base::signal::DESTROY {
1410	my ($signal, $cb) = @{$_[0]};
1411
1412	_sig_del;
1413
1414	delete $SIG_CB{$signal}{$cb};
1415
1416	$HAVE_ASYNC_INTERRUPT
1417	? delete $SIG_ASY{$signal}
1418	: # delete doesn't work with older perls - they then
1419	# print weird messages, or just unconditionally exit
1420	# instead of getting the default action.
1421	undef $SIG{$signal}
1422	unless keys %{ $SIG_CB{$signal} };
1423	}	1614	}
1424		1615
1425	# default implementation for ->child	1616	# default implementation for ->child
1426		1617
1427	our %PID_CB;	1618	our %PID_CB;
1428	our $CHLD_W;	1619	our $CHLD_W;
1429	our $CHLD_DELAY_W;	1620	our $CHLD_DELAY_W;
1430	our $WNOHANG;
1431		1621
		1622	# used by many Impl's
1432	sub _emit_childstatus($$) {	1623	sub _emit_childstatus($$) {
1433	my (undef, $rpid, $rstatus) = @_;	1624	my (undef, $rpid, $rstatus) = @_;
1434		1625
1435	$_->($rpid, $rstatus)	1626	$_->($rpid, $rstatus)
1436	for values %{ $PID_CB{$rpid} || {} },	1627	for values %{ $PID_CB{$rpid} || {} },
1437	values %{ $PID_CB{0} || {} };	1628	values %{ $PID_CB{0} || {} };
1438	}	1629	}
1439		1630
1440	sub _sigchld {
1441	my $pid;
1442
1443	AnyEvent->_emit_childstatus ($pid, $?)
1444	while ($pid = waitpid -1, $WNOHANG) > 0;
1445	}
1446
1447	sub child {	1631	sub child {
		1632	eval q{ # poor man's autoloading {}
		1633	*_sigchld = sub {
		1634	my $pid;
		1635
		1636	AnyEvent->_emit_childstatus ($pid, $?)
		1637	while ($pid = waitpid -1, WNOHANG) > 0;
		1638	};
		1639
		1640	*child = sub {
1448	my (undef, %arg) = @_;	1641	my (undef, %arg) = @_;
1449		1642
1450	defined (my $pid = $arg{pid} + 0)	1643	defined (my $pid = $arg{pid} + 0)
1451	or Carp::croak "required option 'pid' is missing";	1644	or Carp::croak "required option 'pid' is missing";
1452		1645
1453	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1646	$PID_CB{$pid}{$arg{cb}} = $arg{cb};
1454		1647
1455	# WNOHANG is almost cetrainly 1 everywhere
1456	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1457	? 1
1458	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1459
1460	unless ($CHLD_W) {	1648	unless ($CHLD_W) {
1461	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1649	$CHLD_W = AE::signal CHLD => \&_sigchld;
1462	# child could be a zombie already, so make at least one round	1650	# child could be a zombie already, so make at least one round
1463	&_sigchld;	1651	&_sigchld;
1464	}	1652	}
1465		1653
1466	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1654	bless [$pid, $arg{cb}], "AnyEvent::Base::child"
1467	}	1655	};
1468		1656
1469	sub AnyEvent::Base::child::DESTROY {	1657	*AnyEvent::Base::child::DESTROY = sub {
1470	my ($pid, $cb) = @{$_[0]};	1658	my ($pid, $cb) = @{$_[0]};
1471		1659
1472	delete $PID_CB{$pid}{$cb};	1660	delete $PID_CB{$pid}{$cb};
1473	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1661	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1474		1662
1475	undef $CHLD_W unless keys %PID_CB;	1663	undef $CHLD_W unless keys %PID_CB;
		1664	};
		1665	};
		1666	die if $@;
		1667
		1668	&child
1476	}	1669	}
1477		1670
1478	# idle emulation is done by simply using a timer, regardless	1671	# idle emulation is done by simply using a timer, regardless
1479	# of whether the process is idle or not, and not letting	1672	# of whether the process is idle or not, and not letting
1480	# the callback use more than 50% of the time.	1673	# the callback use more than 50% of the time.
1481	sub idle {	1674	sub idle {
		1675	eval q{ # poor man's autoloading {}
		1676	*idle = sub {
1482	my (undef, %arg) = @_;	1677	my (undef, %arg) = @_;
1483		1678
1484	my ($cb, $w, $rcb) = $arg{cb};	1679	my ($cb, $w, $rcb) = $arg{cb};
1485		1680
1486	$rcb = sub {	1681	$rcb = sub {
1487	if ($cb) {	1682	if ($cb) {
1488	$w = _time;	1683	$w = _time;
1489	&$cb;	1684	&$cb;
1490	$w = _time - $w;	1685	$w = _time - $w;
1491		1686
1492	# never use more then 50% of the time for the idle watcher,	1687	# never use more then 50% of the time for the idle watcher,
1493	# within some limits	1688	# within some limits
1494	$w = 0.0001 if $w < 0.0001;	1689	$w = 0.0001 if $w < 0.0001;
1495	$w = 5 if $w > 5;	1690	$w = 5 if $w > 5;
1496		1691
1497	$w = AnyEvent->timer (after => $w, cb => $rcb);	1692	$w = AE::timer $w, 0, $rcb;
1498	} else {	1693	} else {
1499	# clean up...	1694	# clean up...
1500	undef $w;	1695	undef $w;
1501	undef $rcb;	1696	undef $rcb;
		1697	}
		1698	};
		1699
		1700	$w = AE::timer 0.05, 0, $rcb;
		1701
		1702	bless \\$cb, "AnyEvent::Base::idle"
1502	}	1703	};
		1704
		1705	*AnyEvent::Base::idle::DESTROY = sub {
		1706	undef $${$_[0]};
		1707	};
1503	};	1708	};
		1709	die if $@;
1504		1710
1505	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1711	&idle
1506
1507	bless \\$cb, "AnyEvent::Base::idle"
1508	}
1509
1510	sub AnyEvent::Base::idle::DESTROY {
1511	undef $${$_[0]};
1512	}	1712	}
1513		1713
1514	package AnyEvent::CondVar;	1714	package AnyEvent::CondVar;
1515		1715
1516	our @ISA = AnyEvent::CondVar::Base::;	1716	our @ISA = AnyEvent::CondVar::Base::;
		1717
		1718	# only to be used for subclassing
		1719	sub new {
		1720	my $class = shift;
		1721	bless AnyEvent->condvar (@_), $class
		1722	}
1517		1723
1518	package AnyEvent::CondVar::Base;	1724	package AnyEvent::CondVar::Base;
1519		1725
1520	#use overload	1726	#use overload
1521	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1727	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1564	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1770	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};
1565	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1771	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]
1566	}	1772	}
1567		1773
1568	sub cb {	1774	sub cb {
1569	$_[0]{_ae_cb} = $_[1] if @_ > 1;	1775	my $cv = shift;
		1776
		1777	@_
		1778	and $cv->{_ae_cb} = shift
		1779	and $cv->{_ae_sent}
		1780	and (delete $cv->{_ae_cb})->($cv);
		1781
1570	$_[0]{_ae_cb}	1782	$cv->{_ae_cb}
1571	}	1783	}
1572		1784
1573	sub begin {	1785	sub begin {
1574	++$_[0]{_ae_counter};	1786	++$_[0]{_ae_counter};
1575	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;	1787	$_[0]{_ae_end_cb} = $_[1] if @_ > 1;
…		…
1637	check the arguments passed to most method calls. If it finds any problems,	1849	check the arguments passed to most method calls. If it finds any problems,
1638	it will croak.	1850	it will croak.
1639		1851
1640	In other words, enables "strict" mode.	1852	In other words, enables "strict" mode.
1641		1853
1642	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1854	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1643	>>, it is definitely recommended to keep it off in production. Keeping	1855	>>, it is definitely recommended to keep it off in production. Keeping
1644	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1856	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1645	can be very useful, however.	1857	can be very useful, however.
1646		1858
1647	=item C<PERL_ANYEVENT_MODEL>	1859	=item C<PERL_ANYEVENT_MODEL>
…		…
1784	warn "read: $input\n"; # output what has been read	1996	warn "read: $input\n"; # output what has been read
1785	$cv->send if $input =~ /^q/i; # quit program if /^q/i	1997	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1786	},	1998	},
1787	);	1999	);
1788		2000
1789	my $time_watcher; # can only be used once
1790
1791	sub new_timer {
1792	$timer = AnyEvent->timer (after => 1, cb => sub {	2001	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1793	warn "timeout\n"; # print 'timeout' about every second	2002	warn "timeout\n"; # print 'timeout' at most every second
1794	&new_timer; # and restart the time
1795	});	2003	});
1796	}
1797
1798	new_timer; # create first timer
1799		2004
1800	$cv->recv; # wait until user enters /^q/i	2005	$cv->recv; # wait until user enters /^q/i
1801		2006
1802	=head1 REAL-WORLD EXAMPLE	2007	=head1 REAL-WORLD EXAMPLE
1803		2008
…		…
1876		2081
1877	The actual code goes further and collects all errors (C<die>s, exceptions)	2082	The actual code goes further and collects all errors (C<die>s, exceptions)
1878	that occurred during request processing. The C<result> method detects	2083	that occurred during request processing. The C<result> method detects
1879	whether an exception as thrown (it is stored inside the $txn object)	2084	whether an exception as thrown (it is stored inside the $txn object)
1880	and just throws the exception, which means connection errors and other	2085	and just throws the exception, which means connection errors and other
1881	problems get reported tot he code that tries to use the result, not in a	2086	problems get reported to the code that tries to use the result, not in a
1882	random callback.	2087	random callback.
1883		2088
1884	All of this enables the following usage styles:	2089	All of this enables the following usage styles:
1885		2090
1886	1. Blocking:	2091	1. Blocking:
…		…
1934	through AnyEvent. The benchmark creates a lot of timers (with a zero	2139	through AnyEvent. The benchmark creates a lot of timers (with a zero
1935	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2140	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
1936	which it is), lets them fire exactly once and destroys them again.	2141	which it is), lets them fire exactly once and destroys them again.
1937		2142
1938	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2143	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
1939	distribution.	2144	distribution. It uses the L<AE> interface, which makes a real difference
		2145	for the EV and Perl backends only.
1940		2146
1941	=head3 Explanation of the columns	2147	=head3 Explanation of the columns
1942		2148
1943	I<watcher> is the number of event watchers created/destroyed. Since	2149	I<watcher> is the number of event watchers created/destroyed. Since
1944	different event models feature vastly different performances, each event	2150	different event models feature vastly different performances, each event
…		…
1965	watcher.	2171	watcher.
1966		2172
1967	=head3 Results	2173	=head3 Results
1968		2174
1969	name watchers bytes create invoke destroy comment	2175	name watchers bytes create invoke destroy comment
1970	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2176	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
1971	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2177	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
1972	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2178	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
1973	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2179	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
1974	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2180	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
1975	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2181	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
1976	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2182	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
1977	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2183	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
1978	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2184	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
1979	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2185	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
1980	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2186	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
1981	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2187	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
1982		2188
1983	=head3 Discussion	2189	=head3 Discussion
1984		2190
1985	The benchmark does I<not> measure scalability of the event loop very	2191	The benchmark does I<not> measure scalability of the event loop very
1986	well. For example, a select-based event loop (such as the pure perl one)	2192	well. For example, a select-based event loop (such as the pure perl one)
…		…
1998	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2204	benchmark machine, handling an event takes roughly 1600 CPU cycles with
1999	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2205	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2000	cycles with POE.	2206	cycles with POE.
2001		2207
2002	C<EV> is the sole leader regarding speed and memory use, which are both	2208	C<EV> is the sole leader regarding speed and memory use, which are both
2003	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2209	maximal/minimal, respectively. When using the L<AE> API there is zero
		2210	overhead (when going through the AnyEvent API create is about 5-6 times
		2211	slower, with other times being equal, so still uses far less memory than
2004	far less memory than any other event loop and is still faster than Event	2212	any other event loop and is still faster than Event natively).
2005	natively.
2006		2213
2007	The pure perl implementation is hit in a few sweet spots (both the	2214	The pure perl implementation is hit in a few sweet spots (both the
2008	constant timeout and the use of a single fd hit optimisations in the perl	2215	constant timeout and the use of a single fd hit optimisations in the perl
2009	interpreter and the backend itself). Nevertheless this shows that it	2216	interpreter and the backend itself). Nevertheless this shows that it
2010	adds very little overhead in itself. Like any select-based backend its	2217	adds very little overhead in itself. Like any select-based backend its
…		…
2084	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2291	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2085	(1%) are active. This mirrors the activity of large servers with many	2292	(1%) are active. This mirrors the activity of large servers with many
2086	connections, most of which are idle at any one point in time.	2293	connections, most of which are idle at any one point in time.
2087		2294
2088	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2295	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2089	distribution.	2296	distribution. It uses the L<AE> interface, which makes a real difference
		2297	for the EV and Perl backends only.
2090		2298
2091	=head3 Explanation of the columns	2299	=head3 Explanation of the columns
2092		2300
2093	I<sockets> is the number of sockets, and twice the number of "servers" (as	2301	I<sockets> is the number of sockets, and twice the number of "servers" (as
2094	each server has a read and write socket end).	2302	each server has a read and write socket end).
…		…
2102	a new one that moves the timeout into the future.	2310	a new one that moves the timeout into the future.
2103		2311
2104	=head3 Results	2312	=head3 Results
2105		2313
2106	name sockets create request	2314	name sockets create request
2107	EV 20000 69.01 11.16	2315	EV 20000 62.66 7.99
2108	Perl 20000 73.32 35.87	2316	Perl 20000 68.32 32.64
2109	IOAsync 20000 157.00 98.14 epoll	2317	IOAsync 20000 174.06 101.15 epoll
2110	IOAsync 20000 159.31 616.06 poll	2318	IOAsync 20000 174.67 610.84 poll
2111	Event 20000 212.62 257.32	2319	Event 20000 202.69 242.91
2112	Glib 20000 651.16 1896.30	2320	Glib 20000 557.01 1689.52
2113	POE 20000 349.67 12317.24 uses POE::Loop::Event	2321	POE 20000 341.54 12086.32 uses POE::Loop::Event
2114		2322
2115	=head3 Discussion	2323	=head3 Discussion
2116		2324
2117	This benchmark I<does> measure scalability and overall performance of the	2325	This benchmark I<does> measure scalability and overall performance of the
2118	particular event loop.	2326	particular event loop.
…		…
2244	As you can see, the AnyEvent + EV combination even beats the	2452	As you can see, the AnyEvent + EV combination even beats the
2245	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2453	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2246	backend easily beats IO::Lambda and POE.	2454	backend easily beats IO::Lambda and POE.
2247		2455
2248	And even the 100% non-blocking version written using the high-level (and	2456	And even the 100% non-blocking version written using the high-level (and
2249	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2457	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2250	large margin, even though it does all of DNS, tcp-connect and socket I/O	2458	higher level ("unoptimised") abstractions by a large margin, even though
2251	in a non-blocking way.	2459	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2252		2460
2253	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2461	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2254	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2462	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2255	part of the IO::lambda distribution and were used without any changes.	2463	part of the IO::Lambda distribution and were used without any changes.
2256		2464
2257		2465
2258	=head1 SIGNALS	2466	=head1 SIGNALS
2259		2467
2260	AnyEvent currently installs handlers for these signals:	2468	AnyEvent currently installs handlers for these signals:
…		…
2297	unless defined $SIG{PIPE};	2505	unless defined $SIG{PIPE};
2298		2506
2299	=head1 RECOMMENDED/OPTIONAL MODULES	2507	=head1 RECOMMENDED/OPTIONAL MODULES
2300		2508
2301	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2509	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2302	it's built-in modules) are required to use it.	2510	its built-in modules) are required to use it.
2303		2511
2304	That does not mean that AnyEvent won't take advantage of some additional	2512	That does not mean that AnyEvent won't take advantage of some additional
2305	modules if they are installed.	2513	modules if they are installed.
2306		2514
2307	This section epxlains which additional modules will be used, and how they	2515	This section explains which additional modules will be used, and how they
2308	affect AnyEvent's operetion.	2516	affect AnyEvent's operation.
2309		2517
2310	=over 4	2518	=over 4
2311		2519
2312	=item L<Async::Interrupt>	2520	=item L<Async::Interrupt>
2313		2521
…		…
2318	catch the signals) with some delay (default is 10 seconds, look for	2526	catch the signals) with some delay (default is 10 seconds, look for
2319	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2527	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2320		2528
2321	If this module is available, then it will be used to implement signal	2529	If this module is available, then it will be used to implement signal
2322	catching, which means that signals will not be delayed, and the event loop	2530	catching, which means that signals will not be delayed, and the event loop
2323	will not be interrupted regularly, which is more efficient (And good for	2531	will not be interrupted regularly, which is more efficient (and good for
2324	battery life on laptops).	2532	battery life on laptops).
2325		2533
2326	This affects not just the pure-perl event loop, but also other event loops	2534	This affects not just the pure-perl event loop, but also other event loops
2327	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2535	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2328		2536
…		…
2340	automatic timer adjustments even when no monotonic clock is available,	2548	automatic timer adjustments even when no monotonic clock is available,
2341	can take avdantage of advanced kernel interfaces such as C<epoll> and	2549	can take avdantage of advanced kernel interfaces such as C<epoll> and
2342	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2550	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2343	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2551	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2344		2552
		2553	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2554	then this module will do nothing for you.
		2555
2345	=item L<Guard>	2556	=item L<Guard>
2346		2557
2347	The guard module, when used, will be used to implement	2558	The guard module, when used, will be used to implement
2348	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2559	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2349	lot less memory), but otherwise doesn't affect guard operation much. It is	2560	lot less memory), but otherwise doesn't affect guard operation much. It is
2350	purely used for performance.	2561	purely used for performance.
2351		2562
2352	=item L<JSON> and L<JSON::XS>	2563	=item L<JSON> and L<JSON::XS>
2353		2564
2354	This module is required when you want to read or write JSON data via	2565	One of these modules is required when you want to read or write JSON data
2355	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2566	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2356	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2567	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2357
2358	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2359	installed.
2360		2568
2361	=item L<Net::SSLeay>	2569	=item L<Net::SSLeay>
2362		2570
2363	Implementing TLS/SSL in Perl is certainly interesting, but not very	2571	Implementing TLS/SSL in Perl is certainly interesting, but not very
2364	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2572	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2365	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2573	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2366		2574
2367	=item L<Time::HiRes>	2575	=item L<Time::HiRes>
2368		2576
2369	This module is part of perl since release 5.008. It will be used when the	2577	This module is part of perl since release 5.008. It will be used when the
2370	chosen event library does not come with a timing source on it's own. The	2578	chosen event library does not come with a timing source of its own. The
2371	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2579	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to
2372	try to use a monotonic clock for timing stability.	2580	try to use a monotonic clock for timing stability.
2373		2581
2374	=back	2582	=back
2375		2583
2376		2584
2377	=head1 FORK	2585	=head1 FORK
2378		2586
2379	Most event libraries are not fork-safe. The ones who are usually are	2587	Most event libraries are not fork-safe. The ones who are usually are
2380	because they rely on inefficient but fork-safe C<select> or C<poll>	2588	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2381	calls. Only L<EV> is fully fork-aware.	2589	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2590	are usually badly thought-out hacks that are incompatible with fork in
		2591	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2592	continue event-processing in both parent and child (or both, if you know
		2593	what you are doing).
		2594
		2595	This means that, in general, you cannot fork and do event processing in
		2596	the child if the event library was initialised before the fork (which
		2597	usually happens when the first AnyEvent watcher is created, or the library
		2598	is loaded).
2382		2599
2383	If you have to fork, you must either do so I<before> creating your first	2600	If you have to fork, you must either do so I<before> creating your first
2384	watcher OR you must not use AnyEvent at all in the child OR you must do	2601	watcher OR you must not use AnyEvent at all in the child OR you must do
2385	something completely out of the scope of AnyEvent.	2602	something completely out of the scope of AnyEvent.
		2603
		2604	The problem of doing event processing in the parent I<and> the child
		2605	is much more complicated: even for backends that I<are> fork-aware or
		2606	fork-safe, their behaviour is not usually what you want: fork clones all
		2607	watchers, that means all timers, I/O watchers etc. are active in both
		2608	parent and child, which is almost never what you want. USing C<exec>
		2609	to start worker children from some kind of manage rprocess is usually
		2610	preferred, because it is much easier and cleaner, at the expense of having
		2611	to have another binary.
2386		2612
2387		2613
2388	=head1 SECURITY CONSIDERATIONS	2614	=head1 SECURITY CONSIDERATIONS
2389		2615
2390	AnyEvent can be forced to load any event model via	2616	AnyEvent can be forced to load any event model via
…		…
2420	pronounced).	2646	pronounced).
2421		2647
2422		2648
2423	=head1 SEE ALSO	2649	=head1 SEE ALSO
2424		2650
		2651	Tutorial/Introduction: L<AnyEvent::Intro>.
		2652
		2653	FAQ: L<AnyEvent::FAQ>.
		2654
2425	Utility functions: L<AnyEvent::Util>.	2655	Utility functions: L<AnyEvent::Util>.
2426		2656
2427	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2657	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,
2428	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2658	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2429		2659
…		…
2435	Non-blocking file handles, sockets, TCP clients and	2665	Non-blocking file handles, sockets, TCP clients and
2436	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2666	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2437		2667
2438	Asynchronous DNS: L<AnyEvent::DNS>.	2668	Asynchronous DNS: L<AnyEvent::DNS>.
2439		2669
2440	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2670	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2441	L<Coro::Event>,
2442		2671
2443	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2672	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2444	L<AnyEvent::HTTP>.	2673	L<AnyEvent::HTTP>.
2445		2674
2446		2675
2447	=head1 AUTHOR	2676	=head1 AUTHOR
2448		2677

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