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Revision 1.271 by root, Wed Aug 5 20:50:27 2009 UTC vs.
Revision 1.354 by root, Thu Aug 11 21:26:39 2011 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::Loop>,
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::Loop> 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 C<AnyEvent::Loop>. Like
144	C<AnyEvent::Impl::Perl>. Like other event modules you can load it	148	other event modules you can load it explicitly and enjoy the high
145	explicitly and enjoy the high availability of that event loop :)	149	availability of that event loop :)
146		150
147	=head1 WATCHERS	151	=head1 WATCHERS
148		152
149	AnyEvent has the central concept of a I<watcher>, which is an object that	153	AnyEvent has the central concept of a I<watcher>, which is an object that
150	stores relevant data for each kind of event you are waiting for, such as	154	stores relevant data for each kind of event you are waiting for, such as
…		…
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	});
…		…
210		214
211	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.
212	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
213	underlying file descriptor.	217	underlying file descriptor.
214		218
215	Some event loops issue spurious readyness notifications, so you should	219	Some event loops issue spurious readiness notifications, so you should
216	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
217	handles.	221	handles.
218		222
219	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
220	watcher.	224	watcher.
…		…
244		248
245	Although the callback might get passed parameters, their value and	249	Although the callback might get passed parameters, their value and
246	presence is undefined and you cannot rely on them. Portable AnyEvent	250	presence is undefined and you cannot rely on them. Portable AnyEvent
247	callbacks cannot use arguments passed to time watcher callbacks.	251	callbacks cannot use arguments passed to time watcher callbacks.
248		252
249	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
250	parameter, C<interval>, as a strictly positive number (> 0), then the	254	parameter, C<interval>, as a strictly positive number (> 0), then the
251	callback will be invoked regularly at that interval (in fractional	255	callback will be invoked regularly at that interval (in fractional
252	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
253	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.
254		258
255	The callback will be rescheduled before invoking the callback, but no	259	The callback will be rescheduled before invoking the callback, but no
256	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
257	only approximate.	261	only approximate.
258		262
259	Example: fire an event after 7.7 seconds.	263	Example: fire an event after 7.7 seconds.
260		264
261	my $w = AnyEvent->timer (after => 7.7, cb => sub {	265	my $w = AnyEvent->timer (after => 7.7, cb => sub {
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279		283
280	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
281	use absolute time internally. This makes a difference when your clock	285	use absolute time internally. This makes a difference when your clock
282	"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
283	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
284	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.
285		289
286	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
287	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
288	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)
289	timers.	293	timers.
290		294
291	AnyEvent always prefers relative timers, if available, matching the	295	AnyEvent always prefers relative timers, if available, matching the
292	AnyEvent API.	296	AnyEvent API.
…		…
314	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
315	function to call when you want to know the current time.>	319	function to call when you want to know the current time.>
316		320
317	This function is also often faster then C<< AnyEvent->time >>, and	321	This function is also often faster then C<< AnyEvent->time >>, and
318	thus the preferred method if you want some timestamp (for example,	322	thus the preferred method if you want some timestamp (for example,
319	L<AnyEvent::Handle> uses this to update it's activity timeouts).	323	L<AnyEvent::Handle> uses this to update its activity timeouts).
320		324
321	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
322	with your timing, you can skip it without bad conscience.	326	with your timing; you can skip it without a bad conscience.
323		327
324	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>
325	and L<EV> and the following set-up:	329	and L<EV> and the following set-up:
326		330
327	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
328	time=500 (assume no other callbacks delay processing). In your callback,	332	time=500 (assume no other callbacks delay processing). In your callback,
329	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
330	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
331	after three seconds.	335	after three seconds.
332		336
…		…
352	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into	356	difference between C<< AnyEvent->time >> and C<< AnyEvent->now >> into
353	account.	357	account.
354		358
355	=item AnyEvent->now_update	359	=item AnyEvent->now_update
356		360
357	Some event loops (such as L<EV> or L<AnyEvent::Impl::Perl>) cache	361	Some event loops (such as L<EV> or L<AnyEvent::Loop>) cache the current
358	the current time for each loop iteration (see the discussion of L<<	362	time for each loop iteration (see the discussion of L<< AnyEvent->now >>,
359	AnyEvent->now >>, above).	363	above).
360		364
361	When a callback runs for a long time (or when the process sleeps), then	365	When a callback runs for a long time (or when the process sleeps), then
362	this "current" time will differ substantially from the real time, which	366	this "current" time will differ substantially from the real time, which
363	might affect timers and time-outs.	367	might affect timers and time-outs.
364		368
365	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
366	event loop's idea of "current time".	370	event loop's idea of "current time".
		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).
367		378
368	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.
369		380
370	=back	381	=back
371		382
…		…
396		407
397	Example: exit on SIGINT	408	Example: exit on SIGINT
398		409
399	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });	410	my $w = AnyEvent->signal (signal => "INT", cb => sub { exit 1 });
400		411
		412	=head3 Restart Behaviour
		413
		414	While restart behaviour is up to the event loop implementation, most will
		415	not restart syscalls (that includes L<Async::Interrupt> and AnyEvent's
		416	pure perl implementation).
		417
		418	=head3 Safe/Unsafe Signals
		419
		420	Perl signals can be either "safe" (synchronous to opcode handling) or
		421	"unsafe" (asynchronous) - the former might get delayed indefinitely, the
		422	latter might corrupt your memory.
		423
		424	AnyEvent signal handlers are, in addition, synchronous to the event loop,
		425	i.e. they will not interrupt your running perl program but will only be
		426	called as part of the normal event handling (just like timer, I/O etc.
		427	callbacks, too).
		428
401	=head3 Signal Races, Delays and Workarounds	429	=head3 Signal Races, Delays and Workarounds
402		430
403	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching	431	Many event loops (e.g. Glib, Tk, Qt, IO::Async) do not support attaching
404	callbacks to signals in a generic way, which is a pity, as you cannot	432	callbacks to signals in a generic way, which is a pity, as you cannot
405	do race-free signal handling in perl, requiring C libraries for	433	do race-free signal handling in perl, requiring C libraries for
406	this. AnyEvent will try to do it's best, which means in some cases,	434	this. AnyEvent will try to do its best, which means in some cases,
407	signals will be delayed. The maximum time a signal might be delayed is	435	signals will be delayed. The maximum time a signal might be delayed is
408	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This	436	specified in C<$AnyEvent::MAX_SIGNAL_LATENCY> (default: 10 seconds). This
409	variable can be changed only before the first signal watcher is created,	437	variable can be changed only before the first signal watcher is created,
410	and should be left alone otherwise. This variable determines how often	438	and should be left alone otherwise. This variable determines how often
411	AnyEvent polls for signals (in case a wake-up was missed). Higher values	439	AnyEvent polls for signals (in case a wake-up was missed). Higher values
…		…
413	saving.	441	saving.
414		442
415	All these problems can be avoided by installing the optional	443	All these problems can be avoided by installing the optional
416	L<Async::Interrupt> module, which works with most event loops. It will not	444	L<Async::Interrupt> module, which works with most event loops. It will not
417	work with inherently broken event loops such as L<Event> or L<Event::Lib>	445	work with inherently broken event loops such as L<Event> or L<Event::Lib>
418	(and not with L<POE> currently, as POE does it's own workaround with	446	(and not with L<POE> currently, as POE does its own workaround with
419	one-second latency). For those, you just have to suffer the delays.	447	one-second latency). For those, you just have to suffer the delays.
420		448
421	=head2 CHILD PROCESS WATCHERS	449	=head2 CHILD PROCESS WATCHERS
422		450
423	$w = AnyEvent->child (pid => <process id>, cb => <callback>);	451	$w = AnyEvent->child (pid => <process id>, cb => <callback>);
424		452
425	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.
426		454
427	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,
428	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
429	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
430	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
431	(stopped/continued).	459	(stopped/continued).
432		460
…		…
454	thing in an AnyEvent program, you I<have> to create at least one	482	thing in an AnyEvent program, you I<have> to create at least one
455	watcher before you C<fork> the child (alternatively, you can call	483	watcher before you C<fork> the child (alternatively, you can call
456	C<AnyEvent::detect>).	484	C<AnyEvent::detect>).
457		485
458	As most event loops do not support waiting for child events, they will be	486	As most event loops do not support waiting for child events, they will be
459	emulated by AnyEvent in most cases, in which the latency and race problems	487	emulated by AnyEvent in most cases, in which case the latency and race
460	mentioned in the description of signal watchers apply.	488	problems mentioned in the description of signal watchers apply.
461		489
462	Example: fork a process and wait for it	490	Example: fork a process and wait for it
463		491
464	my $done = AnyEvent->condvar;	492	my $done = AnyEvent->condvar;
465		493
…		…
479		507
480	=head2 IDLE WATCHERS	508	=head2 IDLE WATCHERS
481		509
482	$w = AnyEvent->idle (cb => <callback>);	510	$w = AnyEvent->idle (cb => <callback>);
483		511
484	Sometimes there is a need to do something, but it is not so important	512	This will repeatedly invoke the callback after the process becomes idle,
485	to do it instantly, but only when there is nothing better to do. This	513	until either the watcher is destroyed or new events have been detected.
486	"nothing better to do" is usually defined to be "no other events need
487	attention by the event loop".
488		514
489	Idle watchers ideally get invoked when the event loop has nothing	515	Idle watchers are useful when there is a need to do something, but it
490	better to do, just before it would block the process to wait for new	516	is not so important (or wise) to do it instantly. The callback will be
491	events. Instead of blocking, the idle watcher is invoked.	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.
492		523
493	Most event loops unfortunately do not really support idle watchers (only	524	Unfortunately, most event loops do not really support idle watchers (only
494	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
495	will simply call the callback "from time to time".	526	will simply call the callback "from time to time".
496		527
497	Example: read lines from STDIN, but only process them when the	528	Example: read lines from STDIN, but only process them when the
498	program is otherwise idle:	529	program is otherwise idle:
…		…
526	will actively watch for new events and call your callbacks.	557	will actively watch for new events and call your callbacks.
527		558
528	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
529	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).
530		561
531	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
532	because they represent a condition that must become true.	563	they represent a condition that must become true.
533		564
534	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.
535		566
536	Condition variables can be created by calling the C<< AnyEvent->condvar	567	Condition variables can be created by calling the C<< AnyEvent->condvar
537	>> method, usually without arguments. The only argument pair allowed is	568	>> method, usually without arguments. The only argument pair allowed is
…		…
542	After creation, the condition variable is "false" until it becomes "true"	573	After creation, the condition variable is "false" until it becomes "true"
543	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
544	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<<
545	->send >> method).	576	->send >> method).
546		577
547	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
548	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:
549	in time where multiple outstanding events have been processed. And yet	580
550	another way to call them is transactions - each condition variable can be	581	=over 4
551	used to represent a transaction, which finishes at some point and delivers	582
552	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
553	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
554		601
555	Condition variables are very useful to signal that something has finished,	602	Condition variables are very useful to signal that something has finished,
556	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,
557	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
558	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
…		…
571		618
572	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
573	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
574	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
575	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
576	it's C<new> method in your own C<new> method.	623	its C<new> method in your own C<new> method.
577		624
578	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
579	eventually calls C<< -> send >>, and the "consumer side", which waits	626	eventually calls C<< -> send >>, and the "consumer side", which waits
580	for the send to occur.	627	for the send to occur.
581		628
582	Example: wait for a timer.	629	Example: wait for a timer.
583		630
584	# wait till the result is ready	631	# condition: "wait till the timer is fired"
585	my $result_ready = AnyEvent->condvar;	632	my $timer_fired = AnyEvent->condvar;
586		633
587	# do something such as adding a timer	634	# create the timer - we could wait for, say
588	# or socket watcher the calls $result_ready->send	635	# a handle becomign ready, or even an
589	# when the "result" is ready.	636	# AnyEvent::HTTP request to finish, but
590	# in this case, we simply use a timer:	637	# in this case, we simply use a timer:
591	my $w = AnyEvent->timer (	638	my $w = AnyEvent->timer (
592	after => 1,	639	after => 1,
593	cb => sub { $result_ready->send },	640	cb => sub { $timer_fired->send },
594	);	641	);
595		642
596	# this "blocks" (while handling events) till the callback	643	# this "blocks" (while handling events) till the callback
597	# calls -<send	644	# calls ->send
598	$result_ready->recv;	645	$timer_fired->recv;
599		646
600	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
601	variables are also callable directly.	648	variables are also callable directly.
602		649
603	my $done = AnyEvent->condvar;	650	my $done = AnyEvent->condvar;
…		…
646	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
647	C<send>.	694	C<send>.
648		695
649	=item $cv->croak ($error)	696	=item $cv->croak ($error)
650		697
651	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
652	C<Carp::croak> with the given error message/object/scalar.	699	C<Carp::croak> with the given error message/object/scalar.
653		700
654	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
655	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
656	delays the error detetcion, but has the overwhelmign advantage that it	703	delays the error detection, but has the overwhelming advantage that it
657	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
658	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
659	the problem.	706	the problem.
660		707
661	=item $cv->begin ([group callback])	708	=item $cv->begin ([group callback])
662		709
663	=item $cv->end	710	=item $cv->end
…		…
666	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
667	to use a condition variable for the whole process.	714	to use a condition variable for the whole process.
668		715
669	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
670	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
671	>>, 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
672	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
673	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.
674		722
675	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
676	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
677	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).
678		726
…		…
700	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
701	sending.	749	sending.
702		750
703	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
704	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
705	begung can potentially be zero:	753	begun can potentially be zero:
706		754
707	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
708		756
709	my %result;	757	my %result;
710	$cv->begin (sub { $cv->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
711		759
712	for my $host (@list_of_hosts) {	760	for my $host (@list_of_hosts) {
713	$cv->begin;	761	$cv->begin;
714	ping_host_then_call_callback $host, sub {	762	ping_host_then_call_callback $host, sub {
715	$result{$host} = ...;	763	$result{$host} = ...;
…		…
731	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
732	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
733	doesn't execute once).	781	doesn't execute once).
734		782
735	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
736	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
737	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
738	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,
739	call C<end>.	787	call C<end>.
740		788
741	=back	789	=back
…		…
748	=over 4	796	=over 4
749		797
750	=item $cv->recv	798	=item $cv->recv
751		799
752	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
753	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
754	normally.	802	normally.
755		803
756	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
757	will return immediately.	805	will return immediately.
758		806
…		…
775	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
776	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
777	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,
778	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
779		827
780	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
781	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
782	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
783	waits otherwise.	831	waits otherwise.
784		832
785	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
790	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
791		839
792	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
793	replaces it before doing so.	841	replaces it before doing so.
794		842
795	The callback will be called when the condition becomes (or already was)	843	The callback will be called when the condition becomes "true", i.e. when
796	"true", i.e. when C<send> or C<croak> are called (or were called), with	844	C<send> or C<croak> are called, with the only argument being the
797	the only argument being the condition variable itself. Calling C<recv>	845	condition variable itself. If the condition is already true, the
		846	callback is called immediately when it is set. Calling C<recv> inside
798	inside the callback or at any later time is guaranteed not to block.	847	the callback or at any later time is guaranteed not to block.
799		848
800	=back	849	=back
801		850
802	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
803		852
…		…
806	=over 4	855	=over 4
807		856
808	=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.
809		858
810	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
811	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
812	that, will fall back to its own pure-perl implementation, which is	861	pure-perl implementation, which is available everywhere as it comes with
813	available everywhere as it comes with AnyEvent itself.	862	AnyEvent itself.
814		863
815	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
816	AnyEvent::Impl::Event based on Event, very stable, few glitches.
817	AnyEvent::Impl::Perl pure-perl implementation, fast and portable.	865	AnyEvent::Impl::Perl pure-perl AnyEvent::Loop, fast and portable.
818		866
819	=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.
820		868
821	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
822	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
823	them. This means that AnyEvent will automatically pick the right backend	871	them. This means that AnyEvent will automatically pick the right backend
824	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
825	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.
826		874
		875	AnyEvent::Impl::Event based on Event, very stable, few glitches.
827	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
828	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
829	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
830	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
831	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.
		883	AnyEvent::Impl::FLTK based on FLTK.
832		884
833	=item Backends with special needs.	885	=item Backends with special needs.
834		886
835	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
836	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
837	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
838	everything should just work.	890	everything should just work.
839		891
840	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
841		893
842	Support for IO::Async can only be partial, as it is too broken and
843	architecturally limited to even support the AnyEvent API. It also
844	is the only event loop that needs the loop to be set explicitly, so
845	it can only be used by a main program knowing about AnyEvent. See
846	L<AnyEvent::Impl::Async> for the gory details.
847
848	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
849
850	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
851		895
852	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
853		897
854	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.	898	There is no direct support for WxWidgets (L<Wx>) or L<Prima>.
…		…
879	Contains C<undef> until the first watcher is being created, before the	923	Contains C<undef> until the first watcher is being created, before the
880	backend has been autodetected.	924	backend has been autodetected.
881		925
882	Afterwards it contains the event model that is being used, which is the	926	Afterwards it contains the event model that is being used, which is the
883	name of the Perl class implementing the model. This class is usually one	927	name of the Perl class implementing the model. This class is usually one
884	of the C<AnyEvent::Impl:xxx> modules, but can be any other class in the	928	of the C<AnyEvent::Impl::xxx> modules, but can be any other class in the
885	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it	929	case AnyEvent has been extended at runtime (e.g. in I<rxvt-unicode> it
886	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
887		931
888	=item AnyEvent::detect	932	=item AnyEvent::detect
889		933
890	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
891	if necessary. You should only call this function right before you would	935	if necessary. You should only call this function right before you would
892	have created an AnyEvent watcher anyway, that is, as late as possible at	936	have created an AnyEvent watcher anyway, that is, as late as possible at
893	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
894		938
895	If you need to do some initialisation before AnyEvent watchers are	939	If you need to do some initialisation before AnyEvent watchers are
896	created, use C<post_detect>.	940	created, use C<post_detect>.
897		941
898	=item $guard = AnyEvent::post_detect { BLOCK }	942	=item $guard = AnyEvent::post_detect { BLOCK }
899		943
900	Arranges for the code block to be executed as soon as the event model is	944	Arranges for the code block to be executed as soon as the event model is
901	autodetected (or immediately if this has already happened).	945	autodetected (or immediately if that has already happened).
902		946
903	The block will be executed I<after> the actual backend has been detected	947	The block will be executed I<after> the actual backend has been detected
904	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	948	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
905	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	949	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
906	other initialisations - see the sources of L<AnyEvent::Strict> or	950	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
915	that automatically removes the callback again when it is destroyed (or	959	that automatically removes the callback again when it is destroyed (or
916	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	960	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
917	a case where this is useful.	961	a case where this is useful.
918		962
919	Example: Create a watcher for the IO::AIO module and store it in	963	Example: Create a watcher for the IO::AIO module and store it in
920	C<$WATCHER>. Only do so after the event loop is initialised, though.	964	C<$WATCHER>, but do so only do so after the event loop is initialised.
921		965
922	our WATCHER;	966	our WATCHER;
923		967
924	my $guard = AnyEvent::post_detect {	968	my $guard = AnyEvent::post_detect {
925	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	969	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
933	$WATCHER ||= $guard;	977	$WATCHER ||= $guard;
934		978
935	=item @AnyEvent::post_detect	979	=item @AnyEvent::post_detect
936		980
937	If there are any code references in this array (you can C<push> to it	981	If there are any code references in this array (you can C<push> to it
938	before or after loading AnyEvent), then they will called directly after	982	before or after loading AnyEvent), then they will be called directly
939	the event loop has been chosen.	983	after the event loop has been chosen.
940		984
941	You should check C<$AnyEvent::MODEL> before adding to this array, though:	985	You should check C<$AnyEvent::MODEL> before adding to this array, though:
942	if it is defined then the event loop has already been detected, and the	986	if it is defined then the event loop has already been detected, and the
943	array will be ignored.	987	array will be ignored.
944		988
945	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	989	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
946	it,as it takes care of these details.	990	it, as it takes care of these details.
947		991
948	This variable is mainly useful for modules that can do something useful	992	This variable is mainly useful for modules that can do something useful
949	when AnyEvent is used and thus want to know when it is initialised, but do	993	when AnyEvent is used and thus want to know when it is initialised, but do
950	not need to even load it by default. This array provides the means to hook	994	not need to even load it by default. This array provides the means to hook
951	into AnyEvent passively, without loading it.	995	into AnyEvent passively, without loading it.
952		996
		997	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		998	together, you could put this into Coro (this is the actual code used by
		999	Coro to accomplish this):
		1000
		1001	if (defined $AnyEvent::MODEL) {
		1002	# AnyEvent already initialised, so load Coro::AnyEvent
		1003	require Coro::AnyEvent;
		1004	} else {
		1005	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1006	# as soon as it is
		1007	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1008	}
		1009
		1010	=item AnyEvent::postpone { BLOCK }
		1011
		1012	Arranges for the block to be executed as soon as possible, but not before
		1013	the call itself returns. In practise, the block will be executed just
		1014	before the event loop polls for new events, or shortly afterwards.
		1015
		1016	This function never returns anything (to make the C<return postpone { ...
		1017	}> idiom more useful.
		1018
		1019	To understand the usefulness of this function, consider a function that
		1020	asynchronously does something for you and returns some transaction
		1021	object or guard to let you cancel the operation. For example,
		1022	C<AnyEvent::Socket::tcp_connect>:
		1023
		1024	# start a conenction attempt unless one is active
		1025	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1026	delete $self->{connect_guard};
		1027	...
		1028	};
		1029
		1030	Imagine that this function could instantly call the callback, for
		1031	example, because it detects an obvious error such as a negative port
		1032	number. Invoking the callback before the function returns causes problems
		1033	however: the callback will be called and will try to delete the guard
		1034	object. But since the function hasn't returned yet, there is nothing to
		1035	delete. When the function eventually returns it will assign the guard
		1036	object to C<< $self->{connect_guard} >>, where it will likely never be
		1037	deleted, so the program thinks it is still trying to connect.
		1038
		1039	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1040	callback directly on error:
		1041
		1042	$cb->(undef), return # signal error to callback, BAD!
		1043	if $some_error_condition;
		1044
		1045	It should use C<postpone>:
		1046
		1047	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1048	if $some_error_condition;
		1049
953	=back	1050	=back
954		1051
955	=head1 WHAT TO DO IN A MODULE	1052	=head1 WHAT TO DO IN A MODULE
956		1053
957	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1054	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
967	because it will stall the whole program, and the whole point of using	1064	because it will stall the whole program, and the whole point of using
968	events is to stay interactive.	1065	events is to stay interactive.
969		1066
970	It is fine, however, to call C<< ->recv >> when the user of your module	1067	It is fine, however, to call C<< ->recv >> when the user of your module
971	requests it (i.e. if you create a http request object ad have a method	1068	requests it (i.e. if you create a http request object ad have a method
972	called C<results> that returns the results, it should call C<< ->recv >>	1069	called C<results> that returns the results, it may call C<< ->recv >>
973	freely, as the user of your module knows what she is doing. always).	1070	freely, as the user of your module knows what she is doing. Always).
974		1071
975	=head1 WHAT TO DO IN THE MAIN PROGRAM	1072	=head1 WHAT TO DO IN THE MAIN PROGRAM
976		1073
977	There will always be a single main program - the only place that should	1074	There will always be a single main program - the only place that should
978	dictate which event model to use.	1075	dictate which event model to use.
979		1076
980	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1077	If the program is not event-based, it need not do anything special, even
981	do anything special (it does not need to be event-based) and let AnyEvent	1078	when it depends on a module that uses an AnyEvent. If the program itself
982	decide which implementation to chose if some module relies on it.	1079	uses AnyEvent, but does not care which event loop is used, all it needs
		1080	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1081	available loop implementation.
983		1082
984	If the main program relies on a specific event model - for example, in	1083	If the main program relies on a specific event model - for example, in
985	Gtk2 programs you have to rely on the Glib module - you should load the	1084	Gtk2 programs you have to rely on the Glib module - you should load the
986	event module before loading AnyEvent or any module that uses it: generally	1085	event module before loading AnyEvent or any module that uses it: generally
987	speaking, you should load it as early as possible. The reason is that	1086	speaking, you should load it as early as possible. The reason is that
988	modules might create watchers when they are loaded, and AnyEvent will	1087	modules might create watchers when they are loaded, and AnyEvent will
989	decide on the event model to use as soon as it creates watchers, and it	1088	decide on the event model to use as soon as it creates watchers, and it
990	might chose the wrong one unless you load the correct one yourself.	1089	might choose the wrong one unless you load the correct one yourself.
991		1090
992	You can chose to use a pure-perl implementation by loading the	1091	You can chose to use a pure-perl implementation by loading the
993	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1092	C<AnyEvent::Loop> module, which gives you similar behaviour
994	everywhere, but letting AnyEvent chose the model is generally better.	1093	everywhere, but letting AnyEvent chose the model is generally better.
995		1094
996	=head2 MAINLOOP EMULATION	1095	=head2 MAINLOOP EMULATION
997		1096
998	Sometimes (often for short test scripts, or even standalone programs who	1097	Sometimes (often for short test scripts, or even standalone programs who
…		…
1013	=head1 OTHER MODULES	1112	=head1 OTHER MODULES
1014		1113
1015	The following is a non-exhaustive list of additional modules that use	1114	The following is a non-exhaustive list of additional modules that use
1016	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1115	AnyEvent as a client and can therefore be mixed easily with other AnyEvent
1017	modules and other event loops in the same program. Some of the modules	1116	modules and other event loops in the same program. Some of the modules
1018	come with AnyEvent, most are available via CPAN.	1117	come as part of AnyEvent, the others are available via CPAN.
1019		1118
1020	=over 4	1119	=over 4
1021		1120
1022	=item L<AnyEvent::Util>	1121	=item L<AnyEvent::Util>
1023		1122
1024	Contains various utility functions that replace often-used but blocking	1123	Contains various utility functions that replace often-used blocking
1025	functions such as C<inet_aton> by event-/callback-based versions.	1124	functions such as C<inet_aton> with event/callback-based versions.
1026		1125
1027	=item L<AnyEvent::Socket>	1126	=item L<AnyEvent::Socket>
1028		1127
1029	Provides various utility functions for (internet protocol) sockets,	1128	Provides various utility functions for (internet protocol) sockets,
1030	addresses and name resolution. Also functions to create non-blocking tcp	1129	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1032		1131
1033	=item L<AnyEvent::Handle>	1132	=item L<AnyEvent::Handle>
1034		1133
1035	Provide read and write buffers, manages watchers for reads and writes,	1134	Provide read and write buffers, manages watchers for reads and writes,
1036	supports raw and formatted I/O, I/O queued and fully transparent and	1135	supports raw and formatted I/O, I/O queued and fully transparent and
1037	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1136	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1038		1137
1039	=item L<AnyEvent::DNS>	1138	=item L<AnyEvent::DNS>
1040		1139
1041	Provides rich asynchronous DNS resolver capabilities.	1140	Provides rich asynchronous DNS resolver capabilities.
1042		1141
		1142	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1143
		1144	Implement event-based interfaces to the protocols of the same name (for
		1145	the curious, IGS is the International Go Server and FCP is the Freenet
		1146	Client Protocol).
		1147
		1148	=item L<AnyEvent::Handle::UDP>
		1149
		1150	Here be danger!
		1151
		1152	As Pauli would put it, "Not only is it not right, it's not even wrong!" -
		1153	there are so many things wrong with AnyEvent::Handle::UDP, most notably
		1154	its use of a stream-based API with a protocol that isn't streamable, that
		1155	the only way to improve it is to delete it.
		1156
		1157	It features data corruption (but typically only under load) and general
		1158	confusion. On top, the author is not only clueless about UDP but also
		1159	fact-resistant - some gems of his understanding: "connect doesn't work
		1160	with UDP", "UDP packets are not IP packets", "UDP only has datagrams, not
		1161	packets", "I don't need to implement proper error checking as UDP doesn't
		1162	support error checking" and so on - he doesn't even understand what's
		1163	wrong with his module when it is explained to him.
		1164
1043	=item L<AnyEvent::HTTP>	1165	=item L<AnyEvent::DBI>
1044		1166
1045	A simple-to-use HTTP library that is capable of making a lot of concurrent	1167	Executes L<DBI> requests asynchronously in a proxy process for you,
1046	HTTP requests.	1168	notifying you in an event-based way when the operation is finished.
		1169
		1170	=item L<AnyEvent::AIO>
		1171
		1172	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
		1173	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1174	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1175	file I/O, and much more.
1047		1176
1048	=item L<AnyEvent::HTTPD>	1177	=item L<AnyEvent::HTTPD>
1049		1178
1050	Provides a simple web application server framework.	1179	A simple embedded webserver.
1051		1180
1052	=item L<AnyEvent::FastPing>	1181	=item L<AnyEvent::FastPing>
1053		1182
1054	The fastest ping in the west.	1183	The fastest ping in the west.
1055
1056	=item L<AnyEvent::DBI>
1057
1058	Executes L<DBI> requests asynchronously in a proxy process.
1059
1060	=item L<AnyEvent::AIO>
1061
1062	Truly asynchronous I/O, should be in the toolbox of every event
1063	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1064	together.
1065
1066	=item L<AnyEvent::BDB>
1067
1068	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1069	L<BDB> and AnyEvent together.
1070
1071	=item L<AnyEvent::GPSD>
1072
1073	A non-blocking interface to gpsd, a daemon delivering GPS information.
1074
1075	=item L<AnyEvent::IRC>
1076
1077	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1078
1079	=item L<AnyEvent::XMPP>
1080
1081	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1082	Net::XMPP2>.
1083
1084	=item L<AnyEvent::IGS>
1085
1086	A non-blocking interface to the Internet Go Server protocol (used by
1087	L<App::IGS>).
1088
1089	=item L<Net::FCP>
1090
1091	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1092	of AnyEvent.
1093
1094	=item L<Event::ExecFlow>
1095
1096	High level API for event-based execution flow control.
1097		1184
1098	=item L<Coro>	1185	=item L<Coro>
1099		1186
1100	Has special support for AnyEvent via L<Coro::AnyEvent>.	1187	Has special support for AnyEvent via L<Coro::AnyEvent>.
1101		1188
…		…
1105		1192
1106	package AnyEvent;	1193	package AnyEvent;
1107		1194
1108	# basically a tuned-down version of common::sense	1195	# basically a tuned-down version of common::sense
1109	sub common_sense {	1196	sub common_sense {
1110	# no warnings	1197	# from common:.sense 3.4
1111	${^WARNING_BITS} ^= ${^WARNING_BITS};	1198	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1112	# use strict vars subs	1199	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1113	$^H |= 0x00000600;	1200	$^H |= 0x00000600;
1114	}	1201	}
1115		1202
1116	BEGIN { AnyEvent::common_sense }	1203	BEGIN { AnyEvent::common_sense }
1117		1204
1118	use Carp ();	1205	use Carp ();
1119		1206
1120	our $VERSION = 4.901;	1207	our $VERSION = '5.34';
1121	our $MODEL;	1208	our $MODEL;
1122		1209
1123	our $AUTOLOAD;	1210	our $AUTOLOAD;
1124	our @ISA;	1211	our @ISA;
1125		1212
1126	our @REGISTRY;	1213	our @REGISTRY;
1127		1214
1128	our $WIN32;
1129
1130	our $VERBOSE;	1215	our $VERBOSE;
1131		1216
1132	BEGIN {	1217	BEGIN {
1133	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1218	require "AnyEvent/constants.pl";
		1219
1134	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1220	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1135		1221
1136	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1222	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1137	if ${^TAINT};	1223	if ${^TAINT};
1138		1224
1139	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1225	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;
…		…
1151	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1237	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1152	}	1238	}
1153		1239
1154	my @models = (	1240	my @models = (
1155	[EV:: => AnyEvent::Impl::EV:: , 1],	1241	[EV:: => AnyEvent::Impl::EV:: , 1],
		1242	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
		1243	# everything below here will not (normally) be autoprobed
		1244	# as the pure perl backend should work everywhere
		1245	# and is usually faster
1156	[Event:: => AnyEvent::Impl::Event::, 1],	1246	[Event:: => AnyEvent::Impl::Event::, 1],
1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],
1158	# everything below here will not (normally) be autoprobed
1159	# as the pureperl backend should work everywhere
1160	# and is usually faster
1161	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1247	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1162	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1248	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1163	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1249	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1164	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1250	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1165	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1251	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1166	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1252	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1167	[Wx:: => AnyEvent::Impl::POE::],	1253	[Wx:: => AnyEvent::Impl::POE::],
1168	[Prima:: => AnyEvent::Impl::POE::],	1254	[Prima:: => AnyEvent::Impl::POE::],
1169	# IO::Async is just too broken - we would need workarounds for its
1170	# byzantine signal and broken child handling, among others.
1171	# IO::Async is rather hard to detect, as it doesn't have any
1172	# obvious default class.
1173	# [0, IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1174	# [0, IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program	1255	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::],
1175	# [0, IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program	1256	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
		1257	[FLTK:: => AnyEvent::Impl::FLTK::],
1176	);	1258	);
1177		1259
1178	our %method = map +($_ => 1),	1260	our %method = map +($_ => 1),
1179	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1261	qw(io timer time now now_update signal child idle condvar DESTROY);
1180		1262
1181	our @post_detect;	1263	our @post_detect;
1182		1264
1183	sub post_detect(&) {	1265	sub post_detect(&) {
1184	my ($cb) = @_;	1266	my ($cb) = @_;
1185		1267
1186	if ($MODEL) {
1187	$cb->();
1188
1189	undef
1190	} else {
1191	push @post_detect, $cb;	1268	push @post_detect, $cb;
1192		1269
1193	defined wantarray	1270	defined wantarray
1194	? bless \$cb, "AnyEvent::Util::postdetect"	1271	? bless \$cb, "AnyEvent::Util::postdetect"
1195	: ()	1272	: ()
1196	}
1197	}	1273	}
1198		1274
1199	sub AnyEvent::Util::postdetect::DESTROY {	1275	sub AnyEvent::Util::postdetect::DESTROY {
1200	@post_detect = grep $_ != ${$_[0]}, @post_detect;	1276	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1201	}	1277	}
1202		1278
1203	sub detect() {	1279	sub detect() {
		1280	# free some memory
		1281	*detect = sub () { $MODEL };
		1282
		1283	local $!; # for good measure
		1284	local $SIG{__DIE__};
		1285
		1286	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		1287	my $model = "AnyEvent::Impl::$1";
		1288	if (eval "require $model") {
		1289	$MODEL = $model;
		1290	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;
		1291	} else {
		1292	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
		1293	}
		1294	}
		1295
		1296	# check for already loaded models
1204	unless ($MODEL) {	1297	unless ($MODEL) {
1205	local $SIG{__DIE__};	1298	for (@REGISTRY, @models) {
1206		1299	my ($package, $model) = @$_;
1207	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1300	if (${"$package\::VERSION"} > 0) {
1208	my $model = "AnyEvent::Impl::$1";
1209	if (eval "require $model") {	1301	if (eval "require $model") {
1210	$MODEL = $model;	1302	$MODEL = $model;
1211	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1303	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1212	} else {	1304	last;
1213	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;	1305	}
1214	}	1306	}
1215	}	1307	}
1216		1308
1217	# check for already loaded models
1218	unless ($MODEL) {	1309	unless ($MODEL) {
		1310	# try to autoload a model
1219	for (@REGISTRY, @models) {	1311	for (@REGISTRY, @models) {
1220	my ($package, $model) = @$_;	1312	my ($package, $model, $autoload) = @$_;
		1313	if (
		1314	$autoload
		1315	and eval "require $package"
1221	if (${"$package\::VERSION"} > 0) {	1316	and ${"$package\::VERSION"} > 0
1222	if (eval "require $model") {	1317	and eval "require $model"
		1318	) {
1223	$MODEL = $model;	1319	$MODEL = $model;
1224	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;	1320	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1225	last;	1321	last;
1226	}
1227	}	1322	}
1228	}	1323	}
1229		1324
1230	unless ($MODEL) {
1231	# try to autoload a model
1232	for (@REGISTRY, @models) {
1233	my ($package, $model, $autoload) = @$_;
1234	if (
1235	$autoload
1236	and eval "require $package"
1237	and ${"$package\::VERSION"} > 0
1238	and eval "require $model"
1239	) {
1240	$MODEL = $model;
1241	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1242	last;
1243	}
1244	}
1245
1246	$MODEL	1325	$MODEL
1247	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1326	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?\n";
1248	}
1249	}	1327	}
1250
1251	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1252
1253	unshift @ISA, $MODEL;
1254
1255	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1256
1257	(shift @post_detect)->() while @post_detect;
1258	}	1328	}
		1329
		1330	@models = (); # free probe data
		1331
		1332	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1333	unshift @ISA, $MODEL;
		1334
		1335	# now nuke some methods that are overridden by the backend.
		1336	# SUPER is not allowed.
		1337	for (qw(time signal child idle)) {
		1338	undef &{"AnyEvent::Base::$_"}
		1339	if defined &{"$MODEL\::$_"};
		1340	}
		1341
		1342	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1343	eval { require AnyEvent::Strict };
		1344	warn "AnyEvent: cannot load AnyEvent::Strict: $@"
		1345	if $@ && $VERBOSE;
		1346	}
		1347
		1348	(shift @post_detect)->() while @post_detect;
		1349
		1350	*post_detect = sub(&) {
		1351	shift->();
		1352
		1353	undef
		1354	};
1259		1355
1260	$MODEL	1356	$MODEL
1261	}	1357	}
1262		1358
1263	sub AUTOLOAD {	1359	sub AUTOLOAD {
1264	(my $func = $AUTOLOAD) =~ s/.*://;	1360	(my $func = $AUTOLOAD) =~ s/.*://;
1265		1361
1266	$method{$func}	1362	$method{$func}
1267	or Carp::croak "$func: not a valid method for AnyEvent objects";	1363	or Carp::croak "$func: not a valid AnyEvent class method";
1268		1364
1269	detect unless $MODEL;	1365	detect;
1270		1366
1271	my $class = shift;	1367	my $class = shift;
1272	$class->$func (@_);	1368	$class->$func (@_);
		1369	}
		1370
		1371	our $POSTPONE_W;
		1372	our @POSTPONE;
		1373
		1374	sub _postpone_exec {
		1375	undef $POSTPONE_W;
		1376	(pop @POSTPONE)->()
		1377	while @POSTPONE;
		1378	}
		1379
		1380	sub postpone(&) {
		1381	push @POSTPONE, shift;
		1382
		1383	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1384
		1385	()
1273	}	1386	}
1274		1387
1275	# utility function to dup a filehandle. this is used by many backends	1388	# utility function to dup a filehandle. this is used by many backends
1276	# to support binding more than one watcher per filehandle (they usually	1389	# to support binding more than one watcher per filehandle (they usually
1277	# allow only one watcher per fd, so we dup it to get a different one).	1390	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1287	# we assume CLOEXEC is already set by perl in all important cases	1400	# we assume CLOEXEC is already set by perl in all important cases
1288		1401
1289	($fh2, $rw)	1402	($fh2, $rw)
1290	}	1403	}
1291		1404
		1405	=head1 SIMPLIFIED AE API
		1406
		1407	Starting with version 5.0, AnyEvent officially supports a second, much
		1408	simpler, API that is designed to reduce the calling, typing and memory
		1409	overhead by using function call syntax and a fixed number of parameters.
		1410
		1411	See the L<AE> manpage for details.
		1412
		1413	=cut
		1414
		1415	package AE;
		1416
		1417	our $VERSION = $AnyEvent::VERSION;
		1418
		1419	# fall back to the main API by default - backends and AnyEvent::Base
		1420	# implementations can overwrite these.
		1421
		1422	sub io($$$) {
		1423	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
		1424	}
		1425
		1426	sub timer($$$) {
		1427	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
		1428	}
		1429
		1430	sub signal($$) {
		1431	AnyEvent->signal (signal => $_[0], cb => $_[1])
		1432	}
		1433
		1434	sub child($$) {
		1435	AnyEvent->child (pid => $_[0], cb => $_[1])
		1436	}
		1437
		1438	sub idle($) {
		1439	AnyEvent->idle (cb => $_[0])
		1440	}
		1441
		1442	sub cv(;&) {
		1443	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
		1444	}
		1445
		1446	sub now() {
		1447	AnyEvent->now
		1448	}
		1449
		1450	sub now_update() {
		1451	AnyEvent->now_update
		1452	}
		1453
		1454	sub time() {
		1455	AnyEvent->time
		1456	}
		1457
		1458	*postpone = \&AnyEvent::postpone;
		1459
1292	package AnyEvent::Base;	1460	package AnyEvent::Base;
1293		1461
1294	# default implementations for many methods	1462	# default implementations for many methods
1295		1463
1296	sub _time {	1464	sub time {
		1465	eval q{ # poor man's autoloading {}
1297	# probe for availability of Time::HiRes	1466	# probe for availability of Time::HiRes
1298	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1467	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1299	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1468	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;
1300	*_time = \&Time::HiRes::time;	1469	*AE::time = \&Time::HiRes::time;
1301	# if (eval "use POSIX (); (POSIX::times())...	1470	# if (eval "use POSIX (); (POSIX::times())...
1302	} else {	1471	} else {
1303	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1472	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;
1304	*_time = sub { time }; # epic fail	1473	*AE::time = sub (){ time }; # epic fail
		1474	}
		1475
		1476	*time = sub { AE::time }; # different prototypes
1305	}	1477	};
		1478	die if $@;
1306		1479
1307	&_time	1480	&time
1308	}	1481	}
1309		1482
1310	sub time { _time }	1483	*now = \&time;
1311	sub now { _time }	1484
1312	sub now_update { }	1485	sub now_update { }
1313		1486
		1487	sub _poll {
		1488	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1489	}
		1490
1314	# default implementation for ->condvar	1491	# default implementation for ->condvar
		1492	# in fact, the default should not be overwritten
1315		1493
1316	sub condvar {	1494	sub condvar {
		1495	eval q{ # poor man's autoloading {}
		1496	*condvar = sub {
1317	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1497	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1498	};
		1499
		1500	*AE::cv = sub (;&) {
		1501	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1502	};
		1503	};
		1504	die if $@;
		1505
		1506	&condvar
1318	}	1507	}
1319		1508
1320	# default implementation for ->signal	1509	# default implementation for ->signal
1321		1510
1322	our $HAVE_ASYNC_INTERRUPT;	1511	our $HAVE_ASYNC_INTERRUPT;
1323		1512
1324	sub _have_async_interrupt() {	1513	sub _have_async_interrupt() {
1325	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1514	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1326	&& eval "use Async::Interrupt 1.0 (); 1")	1515	&& eval "use Async::Interrupt 1.02 (); 1")
1327	unless defined $HAVE_ASYNC_INTERRUPT;	1516	unless defined $HAVE_ASYNC_INTERRUPT;
1328		1517
1329	$HAVE_ASYNC_INTERRUPT	1518	$HAVE_ASYNC_INTERRUPT
1330	}	1519	}
1331		1520
1332	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1521	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1333	our (%SIG_ASY, %SIG_ASY_W);	1522	our (%SIG_ASY, %SIG_ASY_W);
1334	our ($SIG_COUNT, $SIG_TW);	1523	our ($SIG_COUNT, $SIG_TW);
1335		1524
1336	sub _signal_exec {
1337	$HAVE_ASYNC_INTERRUPT
1338	? $SIGPIPE_R->drain
1339	: sysread $SIGPIPE_R, my $dummy, 9;
1340
1341	while (%SIG_EV) {
1342	for (keys %SIG_EV) {
1343	delete $SIG_EV{$_};
1344	$_->() for values %{ $SIG_CB{$_} || {} };
1345	}
1346	}
1347	}
1348
1349	# install a dummy wakeup watcher to reduce signal catching latency	1525	# install a dummy wakeup watcher to reduce signal catching latency
		1526	# used by Impls
1350	sub _sig_add() {	1527	sub _sig_add() {
1351	unless ($SIG_COUNT++) {	1528	unless ($SIG_COUNT++) {
1352	# try to align timer on a full-second boundary, if possible	1529	# try to align timer on a full-second boundary, if possible
1353	my $NOW = AnyEvent->now;	1530	my $NOW = AE::now;
1354		1531
1355	$SIG_TW = AnyEvent->timer (	1532	$SIG_TW = AE::timer
1356	after => $MAX_SIGNAL_LATENCY - ($NOW - int $NOW),	1533	$MAX_SIGNAL_LATENCY - ($NOW - int $NOW),
1357	interval => $MAX_SIGNAL_LATENCY,	1534	$MAX_SIGNAL_LATENCY,
1358	cb => sub { }, # just for the PERL_ASYNC_CHECK	1535	sub { } # just for the PERL_ASYNC_CHECK
1359	);	1536	;
1360	}	1537	}
1361	}	1538	}
1362		1539
1363	sub _sig_del {	1540	sub _sig_del {
1364	undef $SIG_TW	1541	undef $SIG_TW
1365	unless --$SIG_COUNT;	1542	unless --$SIG_COUNT;
1366	}	1543	}
1367		1544
1368	our $_sig_name_init; $_sig_name_init = sub {	1545	our $_sig_name_init; $_sig_name_init = sub {
1369	eval q{ # poor man's autoloading	1546	eval q{ # poor man's autoloading {}
1370	undef $_sig_name_init;	1547	undef $_sig_name_init;
1371		1548
1372	if (_have_async_interrupt) {	1549	if (_have_async_interrupt) {
1373	*sig2num = \&Async::Interrupt::sig2num;	1550	*sig2num = \&Async::Interrupt::sig2num;
1374	*sig2name = \&Async::Interrupt::sig2name;	1551	*sig2name = \&Async::Interrupt::sig2name;
…		…
1401	# probe for availability of Async::Interrupt	1578	# probe for availability of Async::Interrupt
1402	if (_have_async_interrupt) {	1579	if (_have_async_interrupt) {
1403	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1580	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;
1404		1581
1405	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1582	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1406	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R->fileno, poll => "r", cb => \&_signal_exec);	1583	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1407		1584
1408	} else {	1585	} else {
1409	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1586	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;
1410
1411	require Fcntl;
1412		1587
1413	if (AnyEvent::WIN32) {	1588	if (AnyEvent::WIN32) {
1414	require AnyEvent::Util;	1589	require AnyEvent::Util;
1415		1590
1416	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1591	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1417	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1592	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1418	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1593	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1419	} else {	1594	} else {
1420	pipe $SIGPIPE_R, $SIGPIPE_W;	1595	pipe $SIGPIPE_R, $SIGPIPE_W;
1421	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1596	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1422	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1597	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1423		1598
1424	# not strictly required, as $^F is normally 2, but let's make sure...	1599	# not strictly required, as $^F is normally 2, but let's make sure...
1425	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1600	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1426	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1601	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1427	}	1602	}
1428		1603
1429	$SIGPIPE_R	1604	$SIGPIPE_R
1430	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1605	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1431		1606
1432	$SIG_IO = AnyEvent->io (fh => $SIGPIPE_R, poll => "r", cb => \&_signal_exec);	1607	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1433	}	1608	}
1434		1609
1435	*signal = sub {	1610	*signal = $HAVE_ASYNC_INTERRUPT
		1611	? sub {
1436	my (undef, %arg) = @_;	1612	my (undef, %arg) = @_;
1437		1613
1438	my $signal = uc $arg{signal}
1439	or Carp::croak "required option 'signal' is missing";
1440
1441	if ($HAVE_ASYNC_INTERRUPT) {
1442	# async::interrupt	1614	# async::interrupt
1443
1444	$signal = sig2num $signal;	1615	my $signal = sig2num $arg{signal};
1445	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1616	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1446		1617
1447	$SIG_ASY{$signal} ||= new Async::Interrupt	1618	$SIG_ASY{$signal} ||= new Async::Interrupt
1448	cb => sub { undef $SIG_EV{$signal} },	1619	cb => sub { undef $SIG_EV{$signal} },
1449	signal => $signal,	1620	signal => $signal,
1450	pipe => [$SIGPIPE_R->filenos],	1621	pipe => [$SIGPIPE_R->filenos],
1451	pipe_autodrain => 0,	1622	pipe_autodrain => 0,
1452	;	1623	;
1453		1624
1454	} else {	1625	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1626	}
		1627	: sub {
		1628	my (undef, %arg) = @_;
		1629
1455	# pure perl	1630	# pure perl
1456
1457	# AE::Util has been loaded in signal
1458	$signal = sig2name $signal;	1631	my $signal = sig2name $arg{signal};
1459	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1632	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1460		1633
1461	$SIG{$signal} ||= sub {	1634	$SIG{$signal} ||= sub {
1462	local $!;	1635	local $!;
1463	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1636	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1464	undef $SIG_EV{$signal};	1637	undef $SIG_EV{$signal};
1465	};	1638	};
1466		1639
1467	# can't do signal processing without introducing races in pure perl,	1640	# can't do signal processing without introducing races in pure perl,
1468	# so limit the signal latency.	1641	# so limit the signal latency.
1469	_sig_add;	1642	_sig_add;
1470	}
1471		1643
1472	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1644	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1645	}
1473	};	1646	;
1474		1647
1475	*AnyEvent::Base::signal::DESTROY = sub {	1648	*AnyEvent::Base::signal::DESTROY = sub {
1476	my ($signal, $cb) = @{$_[0]};	1649	my ($signal, $cb) = @{$_[0]};
1477		1650
1478	_sig_del;	1651	_sig_del;
…		…
1485	# print weird messages, or just unconditionally exit	1658	# print weird messages, or just unconditionally exit
1486	# instead of getting the default action.	1659	# instead of getting the default action.
1487	undef $SIG{$signal}	1660	undef $SIG{$signal}
1488	unless keys %{ $SIG_CB{$signal} };	1661	unless keys %{ $SIG_CB{$signal} };
1489	};	1662	};
		1663
		1664	*_signal_exec = sub {
		1665	$HAVE_ASYNC_INTERRUPT
		1666	? $SIGPIPE_R->drain
		1667	: sysread $SIGPIPE_R, (my $dummy), 9;
		1668
		1669	while (%SIG_EV) {
		1670	for (keys %SIG_EV) {
		1671	delete $SIG_EV{$_};
		1672	$_->() for values %{ $SIG_CB{$_} || {} };
		1673	}
		1674	}
		1675	};
1490	};	1676	};
1491	die if $@;	1677	die if $@;
		1678
1492	&signal	1679	&signal
1493	}	1680	}
1494		1681
1495	# default implementation for ->child	1682	# default implementation for ->child
1496		1683
1497	our %PID_CB;	1684	our %PID_CB;
1498	our $CHLD_W;	1685	our $CHLD_W;
1499	our $CHLD_DELAY_W;	1686	our $CHLD_DELAY_W;
1500	our $WNOHANG;
1501		1687
		1688	# used by many Impl's
1502	sub _emit_childstatus($$) {	1689	sub _emit_childstatus($$) {
1503	my (undef, $rpid, $rstatus) = @_;	1690	my (undef, $rpid, $rstatus) = @_;
1504		1691
1505	$_->($rpid, $rstatus)	1692	$_->($rpid, $rstatus)
1506	for values %{ $PID_CB{$rpid} || {} },	1693	for values %{ $PID_CB{$rpid} || {} },
1507	values %{ $PID_CB{0} || {} };	1694	values %{ $PID_CB{0} || {} };
1508	}	1695	}
1509		1696
1510	sub _sigchld {
1511	my $pid;
1512
1513	AnyEvent->_emit_childstatus ($pid, $?)
1514	while ($pid = waitpid -1, $WNOHANG) > 0;
1515	}
1516
1517	sub child {	1697	sub child {
		1698	eval q{ # poor man's autoloading {}
		1699	*_sigchld = sub {
		1700	my $pid;
		1701
		1702	AnyEvent->_emit_childstatus ($pid, $?)
		1703	while ($pid = waitpid -1, WNOHANG) > 0;
		1704	};
		1705
		1706	*child = sub {
1518	my (undef, %arg) = @_;	1707	my (undef, %arg) = @_;
1519		1708
1520	defined (my $pid = $arg{pid} + 0)	1709	my $pid = $arg{pid};
1521	or Carp::croak "required option 'pid' is missing";	1710	my $cb = $arg{cb};
1522		1711
1523	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1712	$PID_CB{$pid}{$cb+0} = $cb;
1524		1713
1525	# WNOHANG is almost cetrainly 1 everywhere
1526	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1527	? 1
1528	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1529
1530	unless ($CHLD_W) {	1714	unless ($CHLD_W) {
1531	$CHLD_W = AnyEvent->signal (signal => 'CHLD', cb => \&_sigchld);	1715	$CHLD_W = AE::signal CHLD => \&_sigchld;
1532	# child could be a zombie already, so make at least one round	1716	# child could be a zombie already, so make at least one round
1533	&_sigchld;	1717	&_sigchld;
1534	}	1718	}
1535		1719
1536	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1720	bless [$pid, $cb+0], "AnyEvent::Base::child"
1537	}	1721	};
1538		1722
1539	sub AnyEvent::Base::child::DESTROY {	1723	*AnyEvent::Base::child::DESTROY = sub {
1540	my ($pid, $cb) = @{$_[0]};	1724	my ($pid, $icb) = @{$_[0]};
1541		1725
1542	delete $PID_CB{$pid}{$cb};	1726	delete $PID_CB{$pid}{$icb};
1543	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1727	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1544		1728
1545	undef $CHLD_W unless keys %PID_CB;	1729	undef $CHLD_W unless keys %PID_CB;
		1730	};
		1731	};
		1732	die if $@;
		1733
		1734	&child
1546	}	1735	}
1547		1736
1548	# idle emulation is done by simply using a timer, regardless	1737	# idle emulation is done by simply using a timer, regardless
1549	# of whether the process is idle or not, and not letting	1738	# of whether the process is idle or not, and not letting
1550	# the callback use more than 50% of the time.	1739	# the callback use more than 50% of the time.
1551	sub idle {	1740	sub idle {
		1741	eval q{ # poor man's autoloading {}
		1742	*idle = sub {
1552	my (undef, %arg) = @_;	1743	my (undef, %arg) = @_;
1553		1744
1554	my ($cb, $w, $rcb) = $arg{cb};	1745	my ($cb, $w, $rcb) = $arg{cb};
1555		1746
1556	$rcb = sub {	1747	$rcb = sub {
1557	if ($cb) {	1748	if ($cb) {
1558	$w = _time;	1749	$w = _time;
1559	&$cb;	1750	&$cb;
1560	$w = _time - $w;	1751	$w = _time - $w;
1561		1752
1562	# never use more then 50% of the time for the idle watcher,	1753	# never use more then 50% of the time for the idle watcher,
1563	# within some limits	1754	# within some limits
1564	$w = 0.0001 if $w < 0.0001;	1755	$w = 0.0001 if $w < 0.0001;
1565	$w = 5 if $w > 5;	1756	$w = 5 if $w > 5;
1566		1757
1567	$w = AnyEvent->timer (after => $w, cb => $rcb);	1758	$w = AE::timer $w, 0, $rcb;
1568	} else {	1759	} else {
1569	# clean up...	1760	# clean up...
1570	undef $w;	1761	undef $w;
1571	undef $rcb;	1762	undef $rcb;
		1763	}
		1764	};
		1765
		1766	$w = AE::timer 0.05, 0, $rcb;
		1767
		1768	bless \\$cb, "AnyEvent::Base::idle"
1572	}	1769	};
		1770
		1771	*AnyEvent::Base::idle::DESTROY = sub {
		1772	undef $${$_[0]};
		1773	};
1573	};	1774	};
		1775	die if $@;
1574		1776
1575	$w = AnyEvent->timer (after => 0.05, cb => $rcb);	1777	&idle
1576
1577	bless \\$cb, "AnyEvent::Base::idle"
1578	}
1579
1580	sub AnyEvent::Base::idle::DESTROY {
1581	undef $${$_[0]};
1582	}	1778	}
1583		1779
1584	package AnyEvent::CondVar;	1780	package AnyEvent::CondVar;
1585		1781
1586	our @ISA = AnyEvent::CondVar::Base::;	1782	our @ISA = AnyEvent::CondVar::Base::;
		1783
		1784	# only to be used for subclassing
		1785	sub new {
		1786	my $class = shift;
		1787	bless AnyEvent->condvar (@_), $class
		1788	}
1587		1789
1588	package AnyEvent::CondVar::Base;	1790	package AnyEvent::CondVar::Base;
1589		1791
1590	#use overload	1792	#use overload
1591	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1793	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1601		1803
1602	sub _send {	1804	sub _send {
1603	# nop	1805	# nop
1604	}	1806	}
1605		1807
		1808	sub _wait {
		1809	AnyEvent->_poll until $_[0]{_ae_sent};
		1810	}
		1811
1606	sub send {	1812	sub send {
1607	my $cv = shift;	1813	my $cv = shift;
1608	$cv->{_ae_sent} = [@_];	1814	$cv->{_ae_sent} = [@_];
1609	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1815	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1610	$cv->_send;	1816	$cv->_send;
…		…
1617		1823
1618	sub ready {	1824	sub ready {
1619	$_[0]{_ae_sent}	1825	$_[0]{_ae_sent}
1620	}	1826	}
1621		1827
1622	sub _wait {
1623	$WAITING
1624	and !$_[0]{_ae_sent}
1625	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1626
1627	local $WAITING = 1;
1628	AnyEvent->one_event while !$_[0]{_ae_sent};
1629	}
1630
1631	sub recv {	1828	sub recv {
		1829	unless ($_[0]{_ae_sent}) {
		1830	$WAITING
		1831	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1832
		1833	local $WAITING = 1;
1632	$_[0]->_wait;	1834	$_[0]->_wait;
		1835	}
1633		1836
1634	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1837	$_[0]{_ae_croak}
1635	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1838	and Carp::croak $_[0]{_ae_croak};
		1839
		1840	wantarray
		1841	? @{ $_[0]{_ae_sent} }
		1842	: $_[0]{_ae_sent}[0]
1636	}	1843	}
1637		1844
1638	sub cb {	1845	sub cb {
1639	my $cv = shift;	1846	my $cv = shift;
1640		1847
…		…
1656	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1863	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1657	}	1864	}
1658		1865
1659	# undocumented/compatibility with pre-3.4	1866	# undocumented/compatibility with pre-3.4
1660	*broadcast = \&send;	1867	*broadcast = \&send;
1661	*wait = \&_wait;	1868	*wait = \&recv;
1662
1663	#############################################################################
1664	# "new" API, currently only emulation of it
1665	#############################################################################
1666
1667	package AE;
1668
1669	sub io($$$) {
1670	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1671	}
1672
1673	sub timer($$$) {
1674	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2]);
1675	}
1676
1677	sub signal($$) {
1678	AnyEvent->signal (signal => $_[0], cb => $_[1]);
1679	}
1680
1681	sub child($$) {
1682	AnyEvent->child (pid => $_[0], cb => $_[1]);
1683	}
1684
1685	sub idle($) {
1686	AnyEvent->idle (cb => $_[0]);
1687	}
1688
1689	sub cv() {
1690	AnyEvent->condvar
1691	}
1692
1693	sub now() {
1694	AnyEvent->now
1695	}
1696
1697	sub now_update() {
1698	AnyEvent->now_update
1699	}
1700
1701	sub time() {
1702	AnyEvent->time
1703	}
1704		1869
1705	=head1 ERROR AND EXCEPTION HANDLING	1870	=head1 ERROR AND EXCEPTION HANDLING
1706		1871
1707	In general, AnyEvent does not do any error handling - it relies on the	1872	In general, AnyEvent does not do any error handling - it relies on the
1708	caller to do that if required. The L<AnyEvent::Strict> module (see also	1873	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1755	check the arguments passed to most method calls. If it finds any problems,	1920	check the arguments passed to most method calls. If it finds any problems,
1756	it will croak.	1921	it will croak.
1757		1922
1758	In other words, enables "strict" mode.	1923	In other words, enables "strict" mode.
1759		1924
1760	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	1925	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1761	>>, it is definitely recommended to keep it off in production. Keeping	1926	>>, it is definitely recommended to keep it off in production. Keeping
1762	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	1927	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1763	can be very useful, however.	1928	can be very useful, however.
1764		1929
1765	=item C<PERL_ANYEVENT_MODEL>	1930	=item C<PERL_ANYEVENT_MODEL>
…		…
1771	used as event model. If it fails to load AnyEvent will proceed with	1936	used as event model. If it fails to load AnyEvent will proceed with
1772	auto detection and -probing.	1937	auto detection and -probing.
1773		1938
1774	This functionality might change in future versions.	1939	This functionality might change in future versions.
1775		1940
1776	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	1941	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1777	could start your program like this:	1942	could start your program like this:
1778		1943
1779	PERL_ANYEVENT_MODEL=Perl perl ...	1944	PERL_ANYEVENT_MODEL=Perl perl ...
1780		1945
1781	=item C<PERL_ANYEVENT_PROTOCOLS>	1946	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1902	warn "read: $input\n"; # output what has been read	2067	warn "read: $input\n"; # output what has been read
1903	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2068	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1904	},	2069	},
1905	);	2070	);
1906		2071
1907	my $time_watcher; # can only be used once
1908
1909	sub new_timer {
1910	$timer = AnyEvent->timer (after => 1, cb => sub {	2072	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1911	warn "timeout\n"; # print 'timeout' about every second	2073	warn "timeout\n"; # print 'timeout' at most every second
1912	&new_timer; # and restart the time
1913	});	2074	});
1914	}
1915
1916	new_timer; # create first timer
1917		2075
1918	$cv->recv; # wait until user enters /^q/i	2076	$cv->recv; # wait until user enters /^q/i
1919		2077
1920	=head1 REAL-WORLD EXAMPLE	2078	=head1 REAL-WORLD EXAMPLE
1921		2079
…		…
1994		2152
1995	The actual code goes further and collects all errors (C<die>s, exceptions)	2153	The actual code goes further and collects all errors (C<die>s, exceptions)
1996	that occurred during request processing. The C<result> method detects	2154	that occurred during request processing. The C<result> method detects
1997	whether an exception as thrown (it is stored inside the $txn object)	2155	whether an exception as thrown (it is stored inside the $txn object)
1998	and just throws the exception, which means connection errors and other	2156	and just throws the exception, which means connection errors and other
1999	problems get reported tot he code that tries to use the result, not in a	2157	problems get reported to the code that tries to use the result, not in a
2000	random callback.	2158	random callback.
2001		2159
2002	All of this enables the following usage styles:	2160	All of this enables the following usage styles:
2003		2161
2004	1. Blocking:	2162	1. Blocking:
…		…
2052	through AnyEvent. The benchmark creates a lot of timers (with a zero	2210	through AnyEvent. The benchmark creates a lot of timers (with a zero
2053	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,	2211	timeout) and I/O watchers (watching STDOUT, a pty, to become writable,
2054	which it is), lets them fire exactly once and destroys them again.	2212	which it is), lets them fire exactly once and destroys them again.
2055		2213
2056	Source code for this benchmark is found as F<eg/bench> in the AnyEvent	2214	Source code for this benchmark is found as F<eg/bench> in the AnyEvent
2057	distribution.	2215	distribution. It uses the L<AE> interface, which makes a real difference
		2216	for the EV and Perl backends only.
2058		2217
2059	=head3 Explanation of the columns	2218	=head3 Explanation of the columns
2060		2219
2061	I<watcher> is the number of event watchers created/destroyed. Since	2220	I<watcher> is the number of event watchers created/destroyed. Since
2062	different event models feature vastly different performances, each event	2221	different event models feature vastly different performances, each event
…		…
2083	watcher.	2242	watcher.
2084		2243
2085	=head3 Results	2244	=head3 Results
2086		2245
2087	name watchers bytes create invoke destroy comment	2246	name watchers bytes create invoke destroy comment
2088	EV/EV 400000 224 0.47 0.35 0.27 EV native interface	2247	EV/EV 100000 223 0.47 0.43 0.27 EV native interface
2089	EV/Any 100000 224 2.88 0.34 0.27 EV + AnyEvent watchers	2248	EV/Any 100000 223 0.48 0.42 0.26 EV + AnyEvent watchers
2090	CoroEV/Any 100000 224 2.85 0.35 0.28 coroutines + Coro::Signal	2249	Coro::EV/Any 100000 223 0.47 0.42 0.26 coroutines + Coro::Signal
2091	Perl/Any 100000 452 4.13 0.73 0.95 pure perl implementation	2250	Perl/Any 100000 431 2.70 0.74 0.92 pure perl implementation
2092	Event/Event 16000 517 32.20 31.80 0.81 Event native interface	2251	Event/Event 16000 516 31.16 31.84 0.82 Event native interface
2093	Event/Any 16000 590 35.85 31.55 1.06 Event + AnyEvent watchers	2252	Event/Any 16000 1203 42.61 34.79 1.80 Event + AnyEvent watchers
2094	IOAsync/Any 16000 989 38.10 32.77 11.13 via IO::Async::Loop::IO_Poll	2253	IOAsync/Any 16000 1911 41.92 27.45 16.81 via IO::Async::Loop::IO_Poll
2095	IOAsync/Any 16000 990 37.59 29.50 10.61 via IO::Async::Loop::Epoll	2254	IOAsync/Any 16000 1726 40.69 26.37 15.25 via IO::Async::Loop::Epoll
2096	Glib/Any 16000 1357 102.33 12.31 51.00 quadratic behaviour	2255	Glib/Any 16000 1118 89.00 12.57 51.17 quadratic behaviour
2097	Tk/Any 2000 1860 27.20 66.31 14.00 SEGV with >> 2000 watchers	2256	Tk/Any 2000 1346 20.96 10.75 8.00 SEGV with >> 2000 watchers
2098	POE/Event 2000 6328 109.99 751.67 14.02 via POE::Loop::Event	2257	POE/Any 2000 6951 108.97 795.32 14.24 via POE::Loop::Event
2099	POE/Select 2000 6027 94.54 809.13 579.80 via POE::Loop::Select	2258	POE/Any 2000 6648 94.79 774.40 575.51 via POE::Loop::Select
2100		2259
2101	=head3 Discussion	2260	=head3 Discussion
2102		2261
2103	The benchmark does I<not> measure scalability of the event loop very	2262	The benchmark does I<not> measure scalability of the event loop very
2104	well. For example, a select-based event loop (such as the pure perl one)	2263	well. For example, a select-based event loop (such as the pure perl one)
…		…
2116	benchmark machine, handling an event takes roughly 1600 CPU cycles with	2275	benchmark machine, handling an event takes roughly 1600 CPU cycles with
2117	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU	2276	EV, 3100 CPU cycles with AnyEvent's pure perl loop and almost 3000000 CPU
2118	cycles with POE.	2277	cycles with POE.
2119		2278
2120	C<EV> is the sole leader regarding speed and memory use, which are both	2279	C<EV> is the sole leader regarding speed and memory use, which are both
2121	maximal/minimal, respectively. Even when going through AnyEvent, it uses	2280	maximal/minimal, respectively. When using the L<AE> API there is zero
		2281	overhead (when going through the AnyEvent API create is about 5-6 times
		2282	slower, with other times being equal, so still uses far less memory than
2122	far less memory than any other event loop and is still faster than Event	2283	any other event loop and is still faster than Event natively).
2123	natively.
2124		2284
2125	The pure perl implementation is hit in a few sweet spots (both the	2285	The pure perl implementation is hit in a few sweet spots (both the
2126	constant timeout and the use of a single fd hit optimisations in the perl	2286	constant timeout and the use of a single fd hit optimisations in the perl
2127	interpreter and the backend itself). Nevertheless this shows that it	2287	interpreter and the backend itself). Nevertheless this shows that it
2128	adds very little overhead in itself. Like any select-based backend its	2288	adds very little overhead in itself. Like any select-based backend its
…		…
2202	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100	2362	In this benchmark, we use 10000 socket pairs (20000 sockets), of which 100
2203	(1%) are active. This mirrors the activity of large servers with many	2363	(1%) are active. This mirrors the activity of large servers with many
2204	connections, most of which are idle at any one point in time.	2364	connections, most of which are idle at any one point in time.
2205		2365
2206	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent	2366	Source code for this benchmark is found as F<eg/bench2> in the AnyEvent
2207	distribution.	2367	distribution. It uses the L<AE> interface, which makes a real difference
		2368	for the EV and Perl backends only.
2208		2369
2209	=head3 Explanation of the columns	2370	=head3 Explanation of the columns
2210		2371
2211	I<sockets> is the number of sockets, and twice the number of "servers" (as	2372	I<sockets> is the number of sockets, and twice the number of "servers" (as
2212	each server has a read and write socket end).	2373	each server has a read and write socket end).
…		…
2220	a new one that moves the timeout into the future.	2381	a new one that moves the timeout into the future.
2221		2382
2222	=head3 Results	2383	=head3 Results
2223		2384
2224	name sockets create request	2385	name sockets create request
2225	EV 20000 69.01 11.16	2386	EV 20000 62.66 7.99
2226	Perl 20000 73.32 35.87	2387	Perl 20000 68.32 32.64
2227	IOAsync 20000 157.00 98.14 epoll	2388	IOAsync 20000 174.06 101.15 epoll
2228	IOAsync 20000 159.31 616.06 poll	2389	IOAsync 20000 174.67 610.84 poll
2229	Event 20000 212.62 257.32	2390	Event 20000 202.69 242.91
2230	Glib 20000 651.16 1896.30	2391	Glib 20000 557.01 1689.52
2231	POE 20000 349.67 12317.24 uses POE::Loop::Event	2392	POE 20000 341.54 12086.32 uses POE::Loop::Event
2232		2393
2233	=head3 Discussion	2394	=head3 Discussion
2234		2395
2235	This benchmark I<does> measure scalability and overall performance of the	2396	This benchmark I<does> measure scalability and overall performance of the
2236	particular event loop.	2397	particular event loop.
…		…
2362	As you can see, the AnyEvent + EV combination even beats the	2523	As you can see, the AnyEvent + EV combination even beats the
2363	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2524	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2364	backend easily beats IO::Lambda and POE.	2525	backend easily beats IO::Lambda and POE.
2365		2526
2366	And even the 100% non-blocking version written using the high-level (and	2527	And even the 100% non-blocking version written using the high-level (and
2367	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2528	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2368	large margin, even though it does all of DNS, tcp-connect and socket I/O	2529	higher level ("unoptimised") abstractions by a large margin, even though
2369	in a non-blocking way.	2530	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2370		2531
2371	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2532	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2372	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2533	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2373	part of the IO::lambda distribution and were used without any changes.	2534	part of the IO::Lambda distribution and were used without any changes.
2374		2535
2375		2536
2376	=head1 SIGNALS	2537	=head1 SIGNALS
2377		2538
2378	AnyEvent currently installs handlers for these signals:	2539	AnyEvent currently installs handlers for these signals:
…		…
2415	unless defined $SIG{PIPE};	2576	unless defined $SIG{PIPE};
2416		2577
2417	=head1 RECOMMENDED/OPTIONAL MODULES	2578	=head1 RECOMMENDED/OPTIONAL MODULES
2418		2579
2419	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2580	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2420	it's built-in modules) are required to use it.	2581	its built-in modules) are required to use it.
2421		2582
2422	That does not mean that AnyEvent won't take advantage of some additional	2583	That does not mean that AnyEvent won't take advantage of some additional
2423	modules if they are installed.	2584	modules if they are installed.
2424		2585
2425	This section epxlains which additional modules will be used, and how they	2586	This section explains which additional modules will be used, and how they
2426	affect AnyEvent's operetion.	2587	affect AnyEvent's operation.
2427		2588
2428	=over 4	2589	=over 4
2429		2590
2430	=item L<Async::Interrupt>	2591	=item L<Async::Interrupt>
2431		2592
…		…
2436	catch the signals) with some delay (default is 10 seconds, look for	2597	catch the signals) with some delay (default is 10 seconds, look for
2437	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2598	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2438		2599
2439	If this module is available, then it will be used to implement signal	2600	If this module is available, then it will be used to implement signal
2440	catching, which means that signals will not be delayed, and the event loop	2601	catching, which means that signals will not be delayed, and the event loop
2441	will not be interrupted regularly, which is more efficient (And good for	2602	will not be interrupted regularly, which is more efficient (and good for
2442	battery life on laptops).	2603	battery life on laptops).
2443		2604
2444	This affects not just the pure-perl event loop, but also other event loops	2605	This affects not just the pure-perl event loop, but also other event loops
2445	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2606	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2446		2607
…		…
2458	automatic timer adjustments even when no monotonic clock is available,	2619	automatic timer adjustments even when no monotonic clock is available,
2459	can take avdantage of advanced kernel interfaces such as C<epoll> and	2620	can take avdantage of advanced kernel interfaces such as C<epoll> and
2460	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2621	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2461	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2622	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2462		2623
		2624	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2625	then this module will do nothing for you.
		2626
2463	=item L<Guard>	2627	=item L<Guard>
2464		2628
2465	The guard module, when used, will be used to implement	2629	The guard module, when used, will be used to implement
2466	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2630	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2467	lot less memory), but otherwise doesn't affect guard operation much. It is	2631	lot less memory), but otherwise doesn't affect guard operation much. It is
2468	purely used for performance.	2632	purely used for performance.
2469		2633
2470	=item L<JSON> and L<JSON::XS>	2634	=item L<JSON> and L<JSON::XS>
2471		2635
2472	This module is required when you want to read or write JSON data via	2636	One of these modules is required when you want to read or write JSON data
2473	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2637	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2474	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2638	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2475
2476	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2477	installed.
2478		2639
2479	=item L<Net::SSLeay>	2640	=item L<Net::SSLeay>
2480		2641
2481	Implementing TLS/SSL in Perl is certainly interesting, but not very	2642	Implementing TLS/SSL in Perl is certainly interesting, but not very
2482	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2643	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2483	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2644	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2484		2645
2485	=item L<Time::HiRes>	2646	=item L<Time::HiRes>
2486		2647
2487	This module is part of perl since release 5.008. It will be used when the	2648	This module is part of perl since release 5.008. It will be used when the
2488	chosen event library does not come with a timing source on it's own. The	2649	chosen event library does not come with a timing source of its own. The
2489	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2650	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2490	try to use a monotonic clock for timing stability.	2651	try to use a monotonic clock for timing stability.
2491		2652
2492	=back	2653	=back
2493		2654
2494		2655
2495	=head1 FORK	2656	=head1 FORK
2496		2657
2497	Most event libraries are not fork-safe. The ones who are usually are	2658	Most event libraries are not fork-safe. The ones who are usually are
2498	because they rely on inefficient but fork-safe C<select> or C<poll>	2659	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2499	calls. Only L<EV> is fully fork-aware.	2660	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2661	are usually badly thought-out hacks that are incompatible with fork in
		2662	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2663	continue event-processing in both parent and child (or both, if you know
		2664	what you are doing).
		2665
		2666	This means that, in general, you cannot fork and do event processing in
		2667	the child if the event library was initialised before the fork (which
		2668	usually happens when the first AnyEvent watcher is created, or the library
		2669	is loaded).
2500		2670
2501	If you have to fork, you must either do so I<before> creating your first	2671	If you have to fork, you must either do so I<before> creating your first
2502	watcher OR you must not use AnyEvent at all in the child OR you must do	2672	watcher OR you must not use AnyEvent at all in the child OR you must do
2503	something completely out of the scope of AnyEvent.	2673	something completely out of the scope of AnyEvent.
		2674
		2675	The problem of doing event processing in the parent I<and> the child
		2676	is much more complicated: even for backends that I<are> fork-aware or
		2677	fork-safe, their behaviour is not usually what you want: fork clones all
		2678	watchers, that means all timers, I/O watchers etc. are active in both
		2679	parent and child, which is almost never what you want. USing C<exec>
		2680	to start worker children from some kind of manage rprocess is usually
		2681	preferred, because it is much easier and cleaner, at the expense of having
		2682	to have another binary.
2504		2683
2505		2684
2506	=head1 SECURITY CONSIDERATIONS	2685	=head1 SECURITY CONSIDERATIONS
2507		2686
2508	AnyEvent can be forced to load any event model via	2687	AnyEvent can be forced to load any event model via
…		…
2538	pronounced).	2717	pronounced).
2539		2718
2540		2719
2541	=head1 SEE ALSO	2720	=head1 SEE ALSO
2542		2721
		2722	Tutorial/Introduction: L<AnyEvent::Intro>.
		2723
		2724	FAQ: L<AnyEvent::FAQ>.
		2725
2543	Utility functions: L<AnyEvent::Util>.	2726	Utility functions: L<AnyEvent::Util>.
2544		2727
2545	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2728	Event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>, L<Glib::EV>,
2546	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2729	L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.
2547		2730
2548	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2731	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2549	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2732	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2550	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2733	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2551	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2734	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.
…		…
2553	Non-blocking file handles, sockets, TCP clients and	2736	Non-blocking file handles, sockets, TCP clients and
2554	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2737	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2555		2738
2556	Asynchronous DNS: L<AnyEvent::DNS>.	2739	Asynchronous DNS: L<AnyEvent::DNS>.
2557		2740
2558	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2741	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2559	L<Coro::Event>,
2560		2742
2561	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2743	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2562	L<AnyEvent::HTTP>.	2744	L<AnyEvent::HTTP>.
2563		2745
2564		2746
2565	=head1 AUTHOR	2747	=head1 AUTHOR
2566		2748

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