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Revision 1.282 by root, Tue Aug 11 01:18:27 2009 UTC vs.
Revision 1.382 by root, Thu Sep 1 23:46:26 2011 UTC

1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - the DBI of event loop programming	3	AnyEvent - the DBI of event loop programming
4		4
5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt	5	EV, Event, Glib, Tk, Perl, Event::Lib, Irssi, rxvt-unicode, IO::Async, Qt,
6	and POE are various supported event loops/environments.	6	FLTK and POE are various supported event loops/environments.
7		7
8	=head1 SYNOPSIS	8	=head1 SYNOPSIS
9		9
10	use AnyEvent;	10	use AnyEvent;
11		11
		12	# if you prefer function calls, look at the AE manpage for
		13	# an alternative API.
		14
12	# file descriptor readable	15	# file handle or descriptor readable
13	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });	16	my $w = AnyEvent->io (fh => $fh, poll => "r", cb => sub { ... });
14		17
15	# one-shot or repeating timers	18	# one-shot or repeating timers
16	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });	19	my $w = AnyEvent->timer (after => $seconds, cb => sub { ... });
17	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...	20	my $w = AnyEvent->timer (after => $seconds, interval => $seconds, cb => ...);
18		21
19	print AnyEvent->now; # prints current event loop time	22	print AnyEvent->now; # prints current event loop time
20	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.	23	print AnyEvent->time; # think Time::HiRes::time or simply CORE::time.
21		24
22	# POSIX signal	25	# POSIX signal
…		…
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 {
…		…
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
…		…
701	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
702	sending.	749	sending.
703		750
704	The ping example mentioned above is slightly more complicated, as the	751	The ping example mentioned above is slightly more complicated, as the
705	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
706	begung can potentially be zero:	753	begun can potentially be zero:
707		754
708	my $cv = AnyEvent->condvar;	755	my $cv = AnyEvent->condvar;
709		756
710	my %result;	757	my %result;
711	$cv->begin (sub { shift->send (\%result) });	758	$cv->begin (sub { shift->send (\%result) });
…		…
732	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
733	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
734	doesn't execute once).	781	doesn't execute once).
735		782
736	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
737	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
738	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
739	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,
740	call C<end>.	787	call C<end>.
741		788
742	=back	789	=back
…		…
749	=over 4	796	=over 4
750		797
751	=item $cv->recv	798	=item $cv->recv
752		799
753	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak	800	Wait (blocking if necessary) until the C<< ->send >> or C<< ->croak
754	>> methods have been called on c<$cv>, while servicing other watchers	801	>> methods have been called on C<$cv>, while servicing other watchers
755	normally.	802	normally.
756		803
757	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
758	will return immediately.	805	will return immediately.
759		806
…		…
776	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
777	condition variables with some kind of request results and supporting	824	condition variables with some kind of request results and supporting
778	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,
779	while still supporting blocking waits if the caller so desires).	826	while still supporting blocking waits if the caller so desires).
780		827
781	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
782	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
783	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
784	waits otherwise.	831	waits otherwise.
785		832
786	=item $bool = $cv->ready	833	=item $bool = $cv->ready
…		…
791	=item $cb = $cv->cb ($cb->($cv))	838	=item $cb = $cv->cb ($cb->($cv))
792		839
793	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
794	replaces it before doing so.	841	replaces it before doing so.
795		842
796	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
797	"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
798	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
799	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.
800		848
801	=back	849	=back
802		850
803	=head1 SUPPORTED EVENT LOOPS/BACKENDS	851	=head1 SUPPORTED EVENT LOOPS/BACKENDS
804		852
…		…
812	use. If EV is not installed, then AnyEvent will fall back to its own	860	use. If EV is not installed, then AnyEvent will fall back to its own
813	pure-perl implementation, which is available everywhere as it comes with	861	pure-perl implementation, which is available everywhere as it comes with
814	AnyEvent itself.	862	AnyEvent itself.
815		863
816	AnyEvent::Impl::EV based on EV (interface to libev, best choice).	864	AnyEvent::Impl::EV based on EV (interface to libev, best choice).
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
…		…
828	AnyEvent::Impl::Glib based on Glib, slow but very stable.	876	AnyEvent::Impl::Glib based on Glib, slow but very stable.
829	AnyEvent::Impl::Tk based on Tk, very broken.	877	AnyEvent::Impl::Tk based on Tk, very broken.
830	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.	878	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
831	AnyEvent::Impl::POE based on POE, very slow, some limitations.	879	AnyEvent::Impl::POE based on POE, very slow, some limitations.
832	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 (fltk 2 binding).
833		884
834	=item Backends with special needs.	885	=item Backends with special needs.
835		886
836	Qt requires the Qt::Application to be instantiated first, but will	887	Qt requires the Qt::Application to be instantiated first, but will
837	otherwise be picked up automatically. As long as the main program	888	otherwise be picked up automatically. As long as the main program
838	instantiates the application before any AnyEvent watchers are created,	889	instantiates the application before any AnyEvent watchers are created,
839	everything should just work.	890	everything should just work.
840		891
841	AnyEvent::Impl::Qt based on Qt.	892	AnyEvent::Impl::Qt based on Qt.
842		893
843	Support for IO::Async can only be partial, as it is too broken and
844	architecturally limited to even support the AnyEvent API. It also
845	is the only event loop that needs the loop to be set explicitly, so
846	it can only be used by a main program knowing about AnyEvent. See
847	L<AnyEvent::Impl::Async> for the gory details.
848
849	AnyEvent::Impl::IOAsync based on IO::Async, cannot be autoprobed.
850
851	=item Event loops that are indirectly supported via other backends.	894	=item Event loops that are indirectly supported via other backends.
852		895
853	Some event loops can be supported via other modules:	896	Some event loops can be supported via other modules:
854		897
855	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>.
…		…
880	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
881	backend has been autodetected.	924	backend has been autodetected.
882		925
883	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
884	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
885	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
886	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
887	will be C<urxvt::anyevent>).	930	will be C<urxvt::anyevent>).
888		931
889	=item AnyEvent::detect	932	=item AnyEvent::detect
890		933
891	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	934	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
892	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
893	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
894	runtime, and not e.g. while initialising of your module.	937	runtime, and not e.g. during initialisation of your module.
		938
		939	The effect of calling this function is as if a watcher had been created
		940	(specifically, actions that happen "when the first watcher is created"
		941	happen when calling detetc as well).
895		942
896	If you need to do some initialisation before AnyEvent watchers are	943	If you need to do some initialisation before AnyEvent watchers are
897	created, use C<post_detect>.	944	created, use C<post_detect>.
898		945
899	=item $guard = AnyEvent::post_detect { BLOCK }	946	=item $guard = AnyEvent::post_detect { BLOCK }
900		947
901	Arranges for the code block to be executed as soon as the event model is	948	Arranges for the code block to be executed as soon as the event model is
902	autodetected (or immediately if this has already happened).	949	autodetected (or immediately if that has already happened).
903		950
904	The block will be executed I<after> the actual backend has been detected	951	The block will be executed I<after> the actual backend has been detected
905	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been	952	(C<$AnyEvent::MODEL> is set), but I<before> any watchers have been
906	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do	953	created, so it is possible to e.g. patch C<@AnyEvent::ISA> or do
907	other initialisations - see the sources of L<AnyEvent::Strict> or	954	other initialisations - see the sources of L<AnyEvent::Strict> or
…		…
916	that automatically removes the callback again when it is destroyed (or	963	that automatically removes the callback again when it is destroyed (or
917	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for	964	C<undef> when the hook was immediately executed). See L<AnyEvent::AIO> for
918	a case where this is useful.	965	a case where this is useful.
919		966
920	Example: Create a watcher for the IO::AIO module and store it in	967	Example: Create a watcher for the IO::AIO module and store it in
921	C<$WATCHER>. Only do so after the event loop is initialised, though.	968	C<$WATCHER>, but do so only do so after the event loop is initialised.
922		969
923	our WATCHER;	970	our WATCHER;
924		971
925	my $guard = AnyEvent::post_detect {	972	my $guard = AnyEvent::post_detect {
926	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);	973	$WATCHER = AnyEvent->io (fh => IO::AIO::poll_fileno, poll => 'r', cb => \&IO::AIO::poll_cb);
…		…
934	$WATCHER ||= $guard;	981	$WATCHER ||= $guard;
935		982
936	=item @AnyEvent::post_detect	983	=item @AnyEvent::post_detect
937		984
938	If there are any code references in this array (you can C<push> to it	985	If there are any code references in this array (you can C<push> to it
939	before or after loading AnyEvent), then they will called directly after	986	before or after loading AnyEvent), then they will be called directly
940	the event loop has been chosen.	987	after the event loop has been chosen.
941		988
942	You should check C<$AnyEvent::MODEL> before adding to this array, though:	989	You should check C<$AnyEvent::MODEL> before adding to this array, though:
943	if it is defined then the event loop has already been detected, and the	990	if it is defined then the event loop has already been detected, and the
944	array will be ignored.	991	array will be ignored.
945		992
946	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows	993	Best use C<AnyEvent::post_detect { BLOCK }> when your application allows
947	it,as it takes care of these details.	994	it, as it takes care of these details.
948		995
949	This variable is mainly useful for modules that can do something useful	996	This variable is mainly useful for modules that can do something useful
950	when AnyEvent is used and thus want to know when it is initialised, but do	997	when AnyEvent is used and thus want to know when it is initialised, but do
951	not need to even load it by default. This array provides the means to hook	998	not need to even load it by default. This array provides the means to hook
952	into AnyEvent passively, without loading it.	999	into AnyEvent passively, without loading it.
953		1000
		1001	Example: To load Coro::AnyEvent whenever Coro and AnyEvent are used
		1002	together, you could put this into Coro (this is the actual code used by
		1003	Coro to accomplish this):
		1004
		1005	if (defined $AnyEvent::MODEL) {
		1006	# AnyEvent already initialised, so load Coro::AnyEvent
		1007	require Coro::AnyEvent;
		1008	} else {
		1009	# AnyEvent not yet initialised, so make sure to load Coro::AnyEvent
		1010	# as soon as it is
		1011	push @AnyEvent::post_detect, sub { require Coro::AnyEvent };
		1012	}
		1013
		1014	=item AnyEvent::postpone { BLOCK }
		1015
		1016	Arranges for the block to be executed as soon as possible, but not before
		1017	the call itself returns. In practise, the block will be executed just
		1018	before the event loop polls for new events, or shortly afterwards.
		1019
		1020	This function never returns anything (to make the C<return postpone { ...
		1021	}> idiom more useful.
		1022
		1023	To understand the usefulness of this function, consider a function that
		1024	asynchronously does something for you and returns some transaction
		1025	object or guard to let you cancel the operation. For example,
		1026	C<AnyEvent::Socket::tcp_connect>:
		1027
		1028	# start a conenction attempt unless one is active
		1029	$self->{connect_guard} ||= AnyEvent::Socket::tcp_connect "www.example.net", 80, sub {
		1030	delete $self->{connect_guard};
		1031	...
		1032	};
		1033
		1034	Imagine that this function could instantly call the callback, for
		1035	example, because it detects an obvious error such as a negative port
		1036	number. Invoking the callback before the function returns causes problems
		1037	however: the callback will be called and will try to delete the guard
		1038	object. But since the function hasn't returned yet, there is nothing to
		1039	delete. When the function eventually returns it will assign the guard
		1040	object to C<< $self->{connect_guard} >>, where it will likely never be
		1041	deleted, so the program thinks it is still trying to connect.
		1042
		1043	This is where C<AnyEvent::postpone> should be used. Instead of calling the
		1044	callback directly on error:
		1045
		1046	$cb->(undef), return # signal error to callback, BAD!
		1047	if $some_error_condition;
		1048
		1049	It should use C<postpone>:
		1050
		1051	AnyEvent::postpone { $cb->(undef) }, return # signal error to callback, later
		1052	if $some_error_condition;
		1053
		1054	=item AnyEvent::log $level, $msg[, @args]
		1055
		1056	Log the given C<$msg> at the given C<$level>.
		1057
		1058	If L<AnyEvent::Log> is not loaded then this function makes a simple test
		1059	to see whether the message will be logged. If the test succeeds it will
		1060	load AnyEvent::Log and call C<AnyEvent::Log::log> - consequently, look at
		1061	the L<AnyEvent::Log> documentation for details.
		1062
		1063	If the test fails it will simply return. Right now this happens when a
		1064	numerical loglevel is used and it is larger than the level specified via
		1065	C<$ENV{PERL_ANYEVENT_VERBOSE}>.
		1066
		1067	If you want to sprinkle loads of logging calls around your code, consider
		1068	creating a logger callback with the C<AnyEvent::Log::logger> function,
		1069	which can reduce typing, codesize and can reduce the logging overhead
		1070	enourmously.
		1071
954	=back	1072	=back
955		1073
956	=head1 WHAT TO DO IN A MODULE	1074	=head1 WHAT TO DO IN A MODULE
957		1075
958	As a module author, you should C<use AnyEvent> and call AnyEvent methods	1076	As a module author, you should C<use AnyEvent> and call AnyEvent methods
…		…
968	because it will stall the whole program, and the whole point of using	1086	because it will stall the whole program, and the whole point of using
969	events is to stay interactive.	1087	events is to stay interactive.
970		1088
971	It is fine, however, to call C<< ->recv >> when the user of your module	1089	It is fine, however, to call C<< ->recv >> when the user of your module
972	requests it (i.e. if you create a http request object ad have a method	1090	requests it (i.e. if you create a http request object ad have a method
973	called C<results> that returns the results, it should call C<< ->recv >>	1091	called C<results> that returns the results, it may call C<< ->recv >>
974	freely, as the user of your module knows what she is doing. always).	1092	freely, as the user of your module knows what she is doing. Always).
975		1093
976	=head1 WHAT TO DO IN THE MAIN PROGRAM	1094	=head1 WHAT TO DO IN THE MAIN PROGRAM
977		1095
978	There will always be a single main program - the only place that should	1096	There will always be a single main program - the only place that should
979	dictate which event model to use.	1097	dictate which event model to use.
980		1098
981	If it doesn't care, it can just "use AnyEvent" and use it itself, or not	1099	If the program is not event-based, it need not do anything special, even
982	do anything special (it does not need to be event-based) and let AnyEvent	1100	when it depends on a module that uses an AnyEvent. If the program itself
983	decide which implementation to chose if some module relies on it.	1101	uses AnyEvent, but does not care which event loop is used, all it needs
		1102	to do is C<use AnyEvent>. In either case, AnyEvent will choose the best
		1103	available loop implementation.
984		1104
985	If the main program relies on a specific event model - for example, in	1105	If the main program relies on a specific event model - for example, in
986	Gtk2 programs you have to rely on the Glib module - you should load the	1106	Gtk2 programs you have to rely on the Glib module - you should load the
987	event module before loading AnyEvent or any module that uses it: generally	1107	event module before loading AnyEvent or any module that uses it: generally
988	speaking, you should load it as early as possible. The reason is that	1108	speaking, you should load it as early as possible. The reason is that
989	modules might create watchers when they are loaded, and AnyEvent will	1109	modules might create watchers when they are loaded, and AnyEvent will
990	decide on the event model to use as soon as it creates watchers, and it	1110	decide on the event model to use as soon as it creates watchers, and it
991	might chose the wrong one unless you load the correct one yourself.	1111	might choose the wrong one unless you load the correct one yourself.
992		1112
993	You can chose to use a pure-perl implementation by loading the	1113	You can chose to use a pure-perl implementation by loading the
994	C<AnyEvent::Impl::Perl> module, which gives you similar behaviour	1114	C<AnyEvent::Loop> module, which gives you similar behaviour
995	everywhere, but letting AnyEvent chose the model is generally better.	1115	everywhere, but letting AnyEvent chose the model is generally better.
996		1116
997	=head2 MAINLOOP EMULATION	1117	=head2 MAINLOOP EMULATION
998		1118
999	Sometimes (often for short test scripts, or even standalone programs who	1119	Sometimes (often for short test scripts, or even standalone programs who
…		…
1012		1132
1013		1133
1014	=head1 OTHER MODULES	1134	=head1 OTHER MODULES
1015		1135
1016	The following is a non-exhaustive list of additional modules that use	1136	The following is a non-exhaustive list of additional modules that use
1017	AnyEvent as a client and can therefore be mixed easily with other AnyEvent	1137	AnyEvent as a client and can therefore be mixed easily with other
1018	modules and other event loops in the same program. Some of the modules	1138	AnyEvent modules and other event loops in the same program. Some of the
1019	come with AnyEvent, most are available via CPAN.	1139	modules come as part of AnyEvent, the others are available via CPAN (see
		1140	L<http://search.cpan.org/search?m=module&q=anyevent%3A%3A*> for
		1141	a longer non-exhaustive list), and the list is heavily biased towards
		1142	modules of the AnyEvent author himself :)
1020		1143
1021	=over 4	1144	=over 4
1022		1145
1023	=item L<AnyEvent::Util>	1146	=item L<AnyEvent::Util>
1024		1147
1025	Contains various utility functions that replace often-used but blocking	1148	Contains various utility functions that replace often-used blocking
1026	functions such as C<inet_aton> by event-/callback-based versions.	1149	functions such as C<inet_aton> with event/callback-based versions.
1027		1150
1028	=item L<AnyEvent::Socket>	1151	=item L<AnyEvent::Socket>
1029		1152
1030	Provides various utility functions for (internet protocol) sockets,	1153	Provides various utility functions for (internet protocol) sockets,
1031	addresses and name resolution. Also functions to create non-blocking tcp	1154	addresses and name resolution. Also functions to create non-blocking tcp
…		…
1033		1156
1034	=item L<AnyEvent::Handle>	1157	=item L<AnyEvent::Handle>
1035		1158
1036	Provide read and write buffers, manages watchers for reads and writes,	1159	Provide read and write buffers, manages watchers for reads and writes,
1037	supports raw and formatted I/O, I/O queued and fully transparent and	1160	supports raw and formatted I/O, I/O queued and fully transparent and
1038	non-blocking SSL/TLS (via L<AnyEvent::TLS>.	1161	non-blocking SSL/TLS (via L<AnyEvent::TLS>).
1039		1162
1040	=item L<AnyEvent::DNS>	1163	=item L<AnyEvent::DNS>
1041		1164
1042	Provides rich asynchronous DNS resolver capabilities.	1165	Provides rich asynchronous DNS resolver capabilities.
1043		1166
		1167	=item L<AnyEvent::HTTP>, L<AnyEvent::IRC>, L<AnyEvent::XMPP>, L<AnyEvent::GPSD>, L<AnyEvent::IGS>, L<AnyEvent::FCP>
		1168
		1169	Implement event-based interfaces to the protocols of the same name (for
		1170	the curious, IGS is the International Go Server and FCP is the Freenet
		1171	Client Protocol).
		1172
1044	=item L<AnyEvent::HTTP>	1173	=item L<AnyEvent::AIO>
1045		1174
1046	A simple-to-use HTTP library that is capable of making a lot of concurrent	1175	Truly asynchronous (as opposed to non-blocking) I/O, should be in the
1047	HTTP requests.	1176	toolbox of every event programmer. AnyEvent::AIO transparently fuses
		1177	L<IO::AIO> and AnyEvent together, giving AnyEvent access to event-based
		1178	file I/O, and much more.
		1179
		1180	=item L<AnyEvent::Filesys::Notify>
		1181
		1182	AnyEvent is good for non-blocking stuff, but it can't detect file or
		1183	path changes (e.g. "watch this directory for new files", "watch this
		1184	file for changes"). The L<AnyEvent::Filesys::Notify> module promises to
		1185	do just that in a portbale fashion, supporting inotify on GNU/Linux and
		1186	some weird, without doubt broken, stuff on OS X to monitor files. It can
		1187	fall back to blocking scans at regular intervals transparently on other
		1188	platforms, so it's about as portable as it gets.
		1189
		1190	(I haven't used it myself, but I haven't heard anybody complaining about
		1191	it yet).
		1192
		1193	=item L<AnyEvent::DBI>
		1194
		1195	Executes L<DBI> requests asynchronously in a proxy process for you,
		1196	notifying you in an event-based way when the operation is finished.
1048		1197
1049	=item L<AnyEvent::HTTPD>	1198	=item L<AnyEvent::HTTPD>
1050		1199
1051	Provides a simple web application server framework.	1200	A simple embedded webserver.
1052		1201
1053	=item L<AnyEvent::FastPing>	1202	=item L<AnyEvent::FastPing>
1054		1203
1055	The fastest ping in the west.	1204	The fastest ping in the west.
1056		1205
1057	=item L<AnyEvent::DBI>
1058
1059	Executes L<DBI> requests asynchronously in a proxy process.
1060
1061	=item L<AnyEvent::AIO>
1062
1063	Truly asynchronous I/O, should be in the toolbox of every event
1064	programmer. AnyEvent::AIO transparently fuses L<IO::AIO> and AnyEvent
1065	together.
1066
1067	=item L<AnyEvent::BDB>
1068
1069	Truly asynchronous Berkeley DB access. AnyEvent::BDB transparently fuses
1070	L<BDB> and AnyEvent together.
1071
1072	=item L<AnyEvent::GPSD>
1073
1074	A non-blocking interface to gpsd, a daemon delivering GPS information.
1075
1076	=item L<AnyEvent::IRC>
1077
1078	AnyEvent based IRC client module family (replacing the older Net::IRC3).
1079
1080	=item L<AnyEvent::XMPP>
1081
1082	AnyEvent based XMPP (Jabber protocol) module family (replacing the older
1083	Net::XMPP2>.
1084
1085	=item L<AnyEvent::IGS>
1086
1087	A non-blocking interface to the Internet Go Server protocol (used by
1088	L<App::IGS>).
1089
1090	=item L<Net::FCP>
1091
1092	AnyEvent-based implementation of the Freenet Client Protocol, birthplace
1093	of AnyEvent.
1094
1095	=item L<Event::ExecFlow>
1096
1097	High level API for event-based execution flow control.
1098
1099	=item L<Coro>	1206	=item L<Coro>
1100		1207
1101	Has special support for AnyEvent via L<Coro::AnyEvent>.	1208	Has special support for AnyEvent via L<Coro::AnyEvent>, which allows you
		1209	to simply invert the flow control - don't call us, we will call you:
		1210
		1211	async {
		1212	Coro::AnyEvent::sleep 5; # creates a 5s timer and waits for it
		1213	print "5 seconds later!\n";
		1214
		1215	Coro::AnyEvent::readable *STDIN; # uses an I/O watcher
		1216	my $line = <STDIN>; # works for ttys
		1217
		1218	AnyEvent::HTTP::http_get "url", Coro::rouse_cb;
		1219	my ($body, $hdr) = Coro::rouse_wait;
		1220	};
1102		1221
1103	=back	1222	=back
1104		1223
1105	=cut	1224	=cut
1106		1225
1107	package AnyEvent;	1226	package AnyEvent;
1108		1227
1109	# basically a tuned-down version of common::sense	1228	# basically a tuned-down version of common::sense
1110	sub common_sense {	1229	sub common_sense {
1111	# no warnings	1230	# from common:.sense 3.4
1112	${^WARNING_BITS} ^= ${^WARNING_BITS};	1231	${^WARNING_BITS} ^= ${^WARNING_BITS} ^ "\x3c\x3f\x33\x00\x0f\xf0\x0f\xc0\xf0\xfc\x33\x00";
1113	# use strict vars subs	1232	# use strict vars subs - NO UTF-8, as Util.pm doesn't like this atm. (uts46data.pl)
1114	$^H |= 0x00000600;	1233	$^H |= 0x00000600;
1115	}	1234	}
1116		1235
1117	BEGIN { AnyEvent::common_sense }	1236	BEGIN { AnyEvent::common_sense }
1118		1237
1119	use Carp ();	1238	use Carp ();
1120		1239
1121	our $VERSION = '5.1';	1240	our $VERSION = '6.02';
1122	our $MODEL;	1241	our $MODEL;
1123
1124	our $AUTOLOAD;
1125	our @ISA;	1242	our @ISA;
1126
1127	our @REGISTRY;	1243	our @REGISTRY;
1128
1129	our $WIN32;
1130
1131	our $VERBOSE;	1244	our $VERBOSE;
		1245	our $MAX_SIGNAL_LATENCY = 10;
		1246	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred
1132		1247
1133	BEGIN {	1248	BEGIN {
1134	eval "sub WIN32(){ " . (($^O =~ /mswin32/i)*1) ." }";	1249	require "AnyEvent/constants.pl";
		1250
1135	eval "sub TAINT(){ " . (${^TAINT}*1) . " }";	1251	eval "sub TAINT (){" . (${^TAINT}*1) . "}";
1136		1252
1137	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}	1253	delete @ENV{grep /^PERL_ANYEVENT_/, keys %ENV}
1138	if ${^TAINT};	1254	if ${^TAINT};
1139		1255
1140	$VERBOSE = $ENV{PERL_ANYEVENT_VERBOSE}*1;	1256	$ENV{"PERL_ANYEVENT_$_"} = $ENV{"AE_$_"}
		1257	for grep s/^AE_// && !exists $ENV{"PERL_ANYEVENT_$_"}, keys %ENV;
1141		1258
1142	}	1259	@ENV{grep /^PERL_ANYEVENT_/, keys %ENV} = ()
		1260	if ${^TAINT};
1143		1261
1144	our $MAX_SIGNAL_LATENCY = 10;	1262	# $ENV{PERL_ANYEVENT_xxx} now valid
1145		1263
1146	our %PROTOCOL; # (ipv4|ipv6) => (1|2), higher numbers are preferred	1264	$VERBOSE = length $ENV{PERL_ANYEVENT_VERBOSE} ? $ENV{PERL_ANYEVENT_VERBOSE}*1 : 3;
1147		1265
1148	{
1149	my $idx;	1266	my $idx;
1150	$PROTOCOL{$_} = ++$idx	1267	$PROTOCOL{$_} = ++$idx
1151	for reverse split /\s*,\s*/,	1268	for reverse split /\s*,\s*/,
1152	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";	1269	$ENV{PERL_ANYEVENT_PROTOCOLS} || "ipv4,ipv6";
1153	}	1270	}
1154		1271
		1272	our @post_detect;
		1273
		1274	sub post_detect(&) {
		1275	my ($cb) = @_;
		1276
		1277	push @post_detect, $cb;
		1278
		1279	defined wantarray
		1280	? bless \$cb, "AnyEvent::Util::postdetect"
		1281	: ()
		1282	}
		1283
		1284	sub AnyEvent::Util::postdetect::DESTROY {
		1285	@post_detect = grep $_ != ${$_[0]}, @post_detect;
		1286	}
		1287
		1288	our $POSTPONE_W;
		1289	our @POSTPONE;
		1290
		1291	sub _postpone_exec {
		1292	undef $POSTPONE_W;
		1293
		1294	&{ shift @POSTPONE }
		1295	while @POSTPONE;
		1296	}
		1297
		1298	sub postpone(&) {
		1299	push @POSTPONE, shift;
		1300
		1301	$POSTPONE_W ||= AE::timer (0, 0, \&_postpone_exec);
		1302
		1303	()
		1304	}
		1305
		1306	sub log($$;@) {
		1307	# only load the big bloated module when we actually are about to log something
		1308	if ($_[0] <= $VERBOSE) { # also catches non-numeric levels(!)
		1309	require AnyEvent::Log;
		1310	# AnyEvent::Log overwrites this function
		1311	goto &log;
		1312	}
		1313
		1314	0 # not logged
		1315	}
		1316
		1317	if (length $ENV{PERL_ANYEVENT_LOG}) {
		1318	require AnyEvent::Log; # AnyEvent::Log does the thing for us
		1319	}
		1320
1155	my @models = (	1321	our @models = (
1156	[EV:: => AnyEvent::Impl::EV:: , 1],	1322	[EV:: => AnyEvent::Impl::EV:: , 1],
1157	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl:: , 1],	1323	[AnyEvent::Loop:: => AnyEvent::Impl::Perl:: , 1],
1158	# everything below here will not (normally) be autoprobed	1324	# everything below here will not (normally) be autoprobed
1159	# as the pureperl backend should work everywhere	1325	# as the pure perl backend should work everywhere
1160	# and is usually faster	1326	# and is usually faster
1161	[Event:: => AnyEvent::Impl::Event::, 1],	1327	[Event:: => AnyEvent::Impl::Event::, 1],
1162	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers	1328	[Glib:: => AnyEvent::Impl::Glib:: , 1], # becomes extremely slow with many watchers
1163	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy	1329	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
1164	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package	1330	[Irssi:: => AnyEvent::Impl::Irssi::], # Irssi has a bogus "Event" package
1165	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles	1331	[Tk:: => AnyEvent::Impl::Tk::], # crashes with many handles
1166	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program	1332	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
1167	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza	1333	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
1168	[Wx:: => AnyEvent::Impl::POE::],	1334	[Wx:: => AnyEvent::Impl::POE::],
1169	[Prima:: => AnyEvent::Impl::POE::],	1335	[Prima:: => AnyEvent::Impl::POE::],
1170	# IO::Async is just too broken - we would need workarounds for its	1336	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # a bitch to autodetect
1171	# byzantine signal and broken child handling, among others.	1337	[Cocoa::EventLoop:: => AnyEvent::Impl::Cocoa::],
1172	# IO::Async is rather hard to detect, as it doesn't have any	1338	[FLTK:: => AnyEvent::Impl::FLTK::],
1173	# obvious default class.
1174	[IO::Async:: => AnyEvent::Impl::IOAsync::], # requires special main program
1175	[IO::Async::Loop:: => AnyEvent::Impl::IOAsync::], # requires special main program
1176	[IO::Async::Notifier:: => AnyEvent::Impl::IOAsync::], # requires special main program
1177	[AnyEvent::Impl::IOAsync:: => AnyEvent::Impl::IOAsync::], # requires special main program
1178	);	1339	);
1179		1340
1180	our %method = map +($_ => 1),	1341	our @isa_hook;
		1342
		1343	sub _isa_set {
		1344	my @pkg = ("AnyEvent", (map $_->[0], grep defined, @isa_hook), $MODEL);
		1345
		1346	@{"$pkg[$_-1]::ISA"} = $pkg[$_]
		1347	for 1 .. $#pkg;
		1348
		1349	grep $_ && $_->[1], @isa_hook
		1350	and AE::_reset ();
		1351	}
		1352
		1353	# used for hooking AnyEvent::Strict and AnyEvent::Debug::Wrap into the class hierarchy
		1354	sub _isa_hook($$;$) {
		1355	my ($i, $pkg, $reset_ae) = @_;
		1356
		1357	$isa_hook[$i] = $pkg ? [$pkg, $reset_ae] : undef;
		1358
		1359	_isa_set;
		1360	}
		1361
		1362	# all autoloaded methods reserve the complete glob, not just the method slot.
		1363	# due to bugs in perls method cache implementation.
1181	qw(io timer time now now_update signal child idle condvar one_event DESTROY);	1364	our @methods = qw(io timer time now now_update signal child idle condvar);
1182		1365
1183	our @post_detect;
1184
1185	sub post_detect(&) {	1366	sub detect() {
1186	my ($cb) = @_;	1367	return $MODEL if $MODEL; # some programs keep references to detect
1187		1368
1188	if ($MODEL) {	1369	local $!; # for good measure
1189	$cb->();	1370	local $SIG{__DIE__}; # we use eval
1190		1371
1191	undef	1372	# free some memory
		1373	*detect = sub () { $MODEL };
		1374	# undef &func doesn't correctly update the method cache. grmbl.
		1375	# so we delete the whole glob. grmbl.
		1376	# otoh, perl doesn't let me undef an active usb, but it lets me free
		1377	# a glob with an active sub. hrm. i hope it works, but perl is
		1378	# usually buggy in this department. sigh.
		1379	delete @{"AnyEvent::"}{@methods};
		1380	undef @methods;
		1381
		1382	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z0-9:]+)$/) {
		1383	my $model = $1;
		1384	$model = "AnyEvent::Impl::$model" unless $model =~ s/::$//;
		1385	if (eval "require $model") {
		1386	AnyEvent::log 7 => "loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.";
		1387	$MODEL = $model;
1192	} else {	1388	} else {
1193	push @post_detect, $cb;	1389	AnyEvent::log 5 => "unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@";
1194		1390	}
1195	defined wantarray
1196	? bless \$cb, "AnyEvent::Util::postdetect"
1197	: ()
1198	}	1391	}
1199	}
1200		1392
1201	sub AnyEvent::Util::postdetect::DESTROY {	1393	# check for already loaded models
1202	@post_detect = grep $_ != ${$_[0]}, @post_detect;
1203	}
1204
1205	sub detect() {
1206	unless ($MODEL) {	1394	unless ($MODEL) {
1207	local $SIG{__DIE__};	1395	for (@REGISTRY, @models) {
1208		1396	my ($package, $model) = @$_;
1209	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {	1397	if (${"$package\::VERSION"} > 0) {
1210	my $model = "AnyEvent::Impl::$1";
1211	if (eval "require $model") {	1398	if (eval "require $model") {
		1399	AnyEvent::log 7 => "autodetected model '$model', using it.";
1212	$MODEL = $model;	1400	$MODEL = $model;
1213	warn "AnyEvent: loaded model '$model' (forced by \$ENV{PERL_ANYEVENT_MODEL}), using it.\n" if $VERBOSE >= 2;	1401	last;
1214	} else {	1402	}
1215	warn "AnyEvent: unable to load model '$model' (from \$ENV{PERL_ANYEVENT_MODEL}):\n$@" if $VERBOSE;
1216	}	1403	}
1217	}	1404	}
1218		1405
1219	# check for already loaded models
1220	unless ($MODEL) {	1406	unless ($MODEL) {
		1407	# try to autoload a model
1221	for (@REGISTRY, @models) {	1408	for (@REGISTRY, @models) {
1222	my ($package, $model) = @$_;	1409	my ($package, $model, $autoload) = @$_;
		1410	if (
		1411	$autoload
		1412	and eval "require $package"
1223	if (${"$package\::VERSION"} > 0) {	1413	and ${"$package\::VERSION"} > 0
1224	if (eval "require $model") {	1414	and eval "require $model"
		1415	) {
		1416	AnyEvent::log 7 => "autoloaded model '$model', using it.";
1225	$MODEL = $model;	1417	$MODEL = $model;
1226	warn "AnyEvent: autodetected model '$model', using it.\n" if $VERBOSE >= 2;
1227	last;	1418	last;
1228	}
1229	}	1419	}
1230	}	1420	}
1231		1421
1232	unless ($MODEL) {
1233	# try to autoload a model
1234	for (@REGISTRY, @models) {
1235	my ($package, $model, $autoload) = @$_;
1236	if (
1237	$autoload
1238	and eval "require $package"
1239	and ${"$package\::VERSION"} > 0
1240	and eval "require $model"
1241	) {
1242	$MODEL = $model;
1243	warn "AnyEvent: autoloaded model '$model', using it.\n" if $VERBOSE >= 2;
1244	last;
1245	}
1246	}
1247
1248	$MODEL	1422	$MODEL
1249	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV, Event or Glib.\n";	1423	or die "AnyEvent: backend autodetection failed - did you properly install AnyEvent?";
1250	}
1251	}	1424	}
1252
1253	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
1254
1255	unshift @ISA, $MODEL;
1256
1257	require AnyEvent::Strict if $ENV{PERL_ANYEVENT_STRICT};
1258
1259	(shift @post_detect)->() while @post_detect;
1260	}	1425	}
1261		1426
		1427	# free memory only needed for probing
		1428	undef @models;
		1429	undef @REGISTRY;
		1430
		1431	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
		1432
		1433	# now nuke some methods that are overridden by the backend.
		1434	# SUPER usage is not allowed in these.
		1435	for (qw(time signal child idle)) {
		1436	undef &{"AnyEvent::Base::$_"}
		1437	if defined &{"$MODEL\::$_"};
		1438	}
		1439
		1440	_isa_set;
		1441
		1442	# we're officially open!
		1443
		1444	if ($ENV{PERL_ANYEVENT_STRICT}) {
		1445	require AnyEvent::Strict;
		1446	}
		1447
		1448	if ($ENV{PERL_ANYEVENT_DEBUG_WRAP}) {
		1449	require AnyEvent::Debug;
		1450	AnyEvent::Debug::wrap ($ENV{PERL_ANYEVENT_DEBUG_WRAP});
		1451	}
		1452
		1453	if (length $ENV{PERL_ANYEVENT_DEBUG_SHELL}) {
		1454	require AnyEvent::Socket;
		1455	require AnyEvent::Debug;
		1456
		1457	my $shell = $ENV{PERL_ANYEVENT_DEBUG_SHELL};
		1458	$shell =~ s/\$\$/$$/g;
		1459
		1460	my ($host, $service) = AnyEvent::Socket::parse_hostport ($shell);
		1461	$AnyEvent::Debug::SHELL = AnyEvent::Debug::shell ($host, $service);
		1462	}
		1463
		1464	# now the anyevent environment is set up as the user told us to, so
		1465	# call the actual user code - post detects
		1466
		1467	(shift @post_detect)->() while @post_detect;
		1468	undef @post_detect;
		1469
		1470	*post_detect = sub(&) {
		1471	shift->();
		1472
		1473	undef
		1474	};
		1475
1262	$MODEL	1476	$MODEL
1263	}	1477	}
1264		1478
1265	sub AUTOLOAD {	1479	for my $name (@methods) {
1266	(my $func = $AUTOLOAD) =~ s/.*://;	1480	*$name = sub {
1267		1481	detect;
1268	$method{$func}	1482	# we use goto because
1269	or Carp::croak "$func: not a valid method for AnyEvent objects";	1483	# a) it makes the thunk more transparent
1270		1484	# b) it allows us to delete the thunk later
1271	detect unless $MODEL;	1485	goto &{ UNIVERSAL::can AnyEvent => "SUPER::$name" }
1272		1486	};
1273	my $class = shift;
1274	$class->$func (@_);
1275	}	1487	}
1276		1488
1277	# utility function to dup a filehandle. this is used by many backends	1489	# utility function to dup a filehandle. this is used by many backends
1278	# to support binding more than one watcher per filehandle (they usually	1490	# to support binding more than one watcher per filehandle (they usually
1279	# allow only one watcher per fd, so we dup it to get a different one).	1491	# allow only one watcher per fd, so we dup it to get a different one).
…		…
1293		1505
1294	=head1 SIMPLIFIED AE API	1506	=head1 SIMPLIFIED AE API
1295		1507
1296	Starting with version 5.0, AnyEvent officially supports a second, much	1508	Starting with version 5.0, AnyEvent officially supports a second, much
1297	simpler, API that is designed to reduce the calling, typing and memory	1509	simpler, API that is designed to reduce the calling, typing and memory
1298	overhead.	1510	overhead by using function call syntax and a fixed number of parameters.
1299		1511
1300	See the L<AE> manpage for details.	1512	See the L<AE> manpage for details.
1301		1513
1302	=cut	1514	=cut
1303		1515
1304	package AE;	1516	package AE;
1305		1517
1306	our $VERSION = $AnyEvent::VERSION;	1518	our $VERSION = $AnyEvent::VERSION;
1307		1519
		1520	sub _reset() {
		1521	eval q{
		1522	# fall back to the main API by default - backends and AnyEvent::Base
		1523	# implementations can overwrite these.
		1524
1308	sub io($$$) {	1525	sub io($$$) {
1309	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])	1526	AnyEvent->io (fh => $_[0], poll => $_[1] ? "w" : "r", cb => $_[2])
1310	}	1527	}
1311		1528
1312	sub timer($$$) {	1529	sub timer($$$) {
1313	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])	1530	AnyEvent->timer (after => $_[0], interval => $_[1], cb => $_[2])
1314	}	1531	}
1315		1532
1316	sub signal($$) {	1533	sub signal($$) {
1317	AnyEvent->signal (signal => $_[0], cb => $_[1])	1534	AnyEvent->signal (signal => $_[0], cb => $_[1])
1318	}	1535	}
1319		1536
1320	sub child($$) {	1537	sub child($$) {
1321	AnyEvent->child (pid => $_[0], cb => $_[1])	1538	AnyEvent->child (pid => $_[0], cb => $_[1])
1322	}	1539	}
1323		1540
1324	sub idle($) {	1541	sub idle($) {
1325	AnyEvent->idle (cb => $_[0])	1542	AnyEvent->idle (cb => $_[0]);
1326	}	1543	}
1327		1544
1328	sub cv(;&) {	1545	sub cv(;&) {
1329	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())	1546	AnyEvent->condvar (@_ ? (cb => $_[0]) : ())
1330	}	1547	}
1331		1548
1332	sub now() {	1549	sub now() {
1333	AnyEvent->now	1550	AnyEvent->now
1334	}	1551	}
1335		1552
1336	sub now_update() {	1553	sub now_update() {
1337	AnyEvent->now_update	1554	AnyEvent->now_update
1338	}	1555	}
1339		1556
1340	sub time() {	1557	sub time() {
1341	AnyEvent->time	1558	AnyEvent->time
		1559	}
		1560
		1561	*postpone = \&AnyEvent::postpone;
		1562	*log = \&AnyEvent::log;
		1563	};
		1564	die if $@;
1342	}	1565	}
		1566
		1567	BEGIN { _reset }
1343		1568
1344	package AnyEvent::Base;	1569	package AnyEvent::Base;
1345		1570
1346	# default implementations for many methods	1571	# default implementations for many methods
1347		1572
1348	sub _time {	1573	sub time {
		1574	eval q{ # poor man's autoloading {}
1349	# probe for availability of Time::HiRes	1575	# probe for availability of Time::HiRes
1350	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {	1576	if (eval "use Time::HiRes (); Time::HiRes::time (); 1") {
1351	warn "AnyEvent: using Time::HiRes for sub-second timing accuracy.\n" if $VERBOSE >= 8;	1577	*time = sub { Time::HiRes::time () };
1352	*_time = \&Time::HiRes::time;	1578	*AE::time = \& Time::HiRes::time ;
		1579	*now = \&time;
		1580	AnyEvent::log 8 => "AnyEvent: using Time::HiRes for sub-second timing accuracy.";
1353	# if (eval "use POSIX (); (POSIX::times())...	1581	# if (eval "use POSIX (); (POSIX::times())...
1354	} else {	1582	} else {
		1583	*time = sub { CORE::time };
		1584	*AE::time = sub (){ CORE::time };
		1585	*now = \&time;
1355	warn "AnyEvent: using built-in time(), WARNING, no sub-second resolution!\n" if $VERBOSE;	1586	AnyEvent::log 3 => "using built-in time(), WARNING, no sub-second resolution!";
1356	*_time = sub { time }; # epic fail	1587	}
1357	}	1588	};
		1589	die if $@;
1358		1590
1359	&_time	1591	&time
1360	}	1592	}
1361		1593
1362	sub time { _time }	1594	*now = \&time;
1363	sub now { _time }
1364	sub now_update { }	1595	sub now_update { }
1365		1596
		1597	sub _poll {
		1598	Carp::croak "$AnyEvent::MODEL does not support blocking waits. Caught";
		1599	}
		1600
1366	# default implementation for ->condvar	1601	# default implementation for ->condvar
		1602	# in fact, the default should not be overwritten
1367		1603
1368	sub condvar {	1604	sub condvar {
		1605	eval q{ # poor man's autoloading {}
		1606	*condvar = sub {
1369	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"	1607	bless { @_ == 3 ? (_ae_cb => $_[2]) : () }, "AnyEvent::CondVar"
		1608	};
		1609
		1610	*AE::cv = sub (;&) {
		1611	bless { @_ ? (_ae_cb => shift) : () }, "AnyEvent::CondVar"
		1612	};
		1613	};
		1614	die if $@;
		1615
		1616	&condvar
1370	}	1617	}
1371		1618
1372	# default implementation for ->signal	1619	# default implementation for ->signal
1373		1620
1374	our $HAVE_ASYNC_INTERRUPT;	1621	our $HAVE_ASYNC_INTERRUPT;
1375		1622
1376	sub _have_async_interrupt() {	1623	sub _have_async_interrupt() {
1377	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}	1624	$HAVE_ASYNC_INTERRUPT = 1*(!$ENV{PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT}
1378	&& eval "use Async::Interrupt 1.0 (); 1")	1625	&& eval "use Async::Interrupt 1.02 (); 1")
1379	unless defined $HAVE_ASYNC_INTERRUPT;	1626	unless defined $HAVE_ASYNC_INTERRUPT;
1380		1627
1381	$HAVE_ASYNC_INTERRUPT	1628	$HAVE_ASYNC_INTERRUPT
1382	}	1629	}
1383		1630
1384	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);	1631	our ($SIGPIPE_R, $SIGPIPE_W, %SIG_CB, %SIG_EV, $SIG_IO);
1385	our (%SIG_ASY, %SIG_ASY_W);	1632	our (%SIG_ASY, %SIG_ASY_W);
1386	our ($SIG_COUNT, $SIG_TW);	1633	our ($SIG_COUNT, $SIG_TW);
1387		1634
1388	sub _signal_exec {
1389	$HAVE_ASYNC_INTERRUPT
1390	? $SIGPIPE_R->drain
1391	: sysread $SIGPIPE_R, my $dummy, 9;
1392
1393	while (%SIG_EV) {
1394	for (keys %SIG_EV) {
1395	delete $SIG_EV{$_};
1396	$_->() for values %{ $SIG_CB{$_} || {} };
1397	}
1398	}
1399	}
1400
1401	# install a dummy wakeup watcher to reduce signal catching latency	1635	# install a dummy wakeup watcher to reduce signal catching latency
		1636	# used by Impls
1402	sub _sig_add() {	1637	sub _sig_add() {
1403	unless ($SIG_COUNT++) {	1638	unless ($SIG_COUNT++) {
1404	# try to align timer on a full-second boundary, if possible	1639	# try to align timer on a full-second boundary, if possible
1405	my $NOW = AE::now;	1640	my $NOW = AE::now;
1406		1641
…		…
1416	undef $SIG_TW	1651	undef $SIG_TW
1417	unless --$SIG_COUNT;	1652	unless --$SIG_COUNT;
1418	}	1653	}
1419		1654
1420	our $_sig_name_init; $_sig_name_init = sub {	1655	our $_sig_name_init; $_sig_name_init = sub {
1421	eval q{ # poor man's autoloading	1656	eval q{ # poor man's autoloading {}
1422	undef $_sig_name_init;	1657	undef $_sig_name_init;
1423		1658
1424	if (_have_async_interrupt) {	1659	if (_have_async_interrupt) {
1425	*sig2num = \&Async::Interrupt::sig2num;	1660	*sig2num = \&Async::Interrupt::sig2num;
1426	*sig2name = \&Async::Interrupt::sig2name;	1661	*sig2name = \&Async::Interrupt::sig2name;
…		…
1450		1685
1451	sub signal {	1686	sub signal {
1452	eval q{ # poor man's autoloading {}	1687	eval q{ # poor man's autoloading {}
1453	# probe for availability of Async::Interrupt	1688	# probe for availability of Async::Interrupt
1454	if (_have_async_interrupt) {	1689	if (_have_async_interrupt) {
1455	warn "AnyEvent: using Async::Interrupt for race-free signal handling.\n" if $VERBOSE >= 8;	1690	AnyEvent::log 8 => "using Async::Interrupt for race-free signal handling.";
1456		1691
1457	$SIGPIPE_R = new Async::Interrupt::EventPipe;	1692	$SIGPIPE_R = new Async::Interrupt::EventPipe;
1458	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;	1693	$SIG_IO = AE::io $SIGPIPE_R->fileno, 0, \&_signal_exec;
1459		1694
1460	} else {	1695	} else {
1461	warn "AnyEvent: using emulated perl signal handling with latency timer.\n" if $VERBOSE >= 8;	1696	AnyEvent::log 8 => "using emulated perl signal handling with latency timer.";
1462
1463	require Fcntl;
1464		1697
1465	if (AnyEvent::WIN32) {	1698	if (AnyEvent::WIN32) {
1466	require AnyEvent::Util;	1699	require AnyEvent::Util;
1467		1700
1468	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();	1701	($SIGPIPE_R, $SIGPIPE_W) = AnyEvent::Util::portable_pipe ();
1469	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;	1702	AnyEvent::Util::fh_nonblocking ($SIGPIPE_R, 1) if $SIGPIPE_R;
1470	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case	1703	AnyEvent::Util::fh_nonblocking ($SIGPIPE_W, 1) if $SIGPIPE_W; # just in case
1471	} else {	1704	} else {
1472	pipe $SIGPIPE_R, $SIGPIPE_W;	1705	pipe $SIGPIPE_R, $SIGPIPE_W;
1473	fcntl $SIGPIPE_R, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_R;	1706	fcntl $SIGPIPE_R, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_R;
1474	fcntl $SIGPIPE_W, &Fcntl::F_SETFL, &Fcntl::O_NONBLOCK if $SIGPIPE_W; # just in case	1707	fcntl $SIGPIPE_W, AnyEvent::F_SETFL, AnyEvent::O_NONBLOCK if $SIGPIPE_W; # just in case
1475		1708
1476	# not strictly required, as $^F is normally 2, but let's make sure...	1709	# not strictly required, as $^F is normally 2, but let's make sure...
1477	fcntl $SIGPIPE_R, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1710	fcntl $SIGPIPE_R, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1478	fcntl $SIGPIPE_W, &Fcntl::F_SETFD, &Fcntl::FD_CLOEXEC;	1711	fcntl $SIGPIPE_W, AnyEvent::F_SETFD, AnyEvent::FD_CLOEXEC;
1479	}	1712	}
1480		1713
1481	$SIGPIPE_R	1714	$SIGPIPE_R
1482	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";	1715	or Carp::croak "AnyEvent: unable to create a signal reporting pipe: $!\n";
1483		1716
1484	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;	1717	$SIG_IO = AE::io $SIGPIPE_R, 0, \&_signal_exec;
1485	}	1718	}
1486		1719
1487	*signal = sub {	1720	*signal = $HAVE_ASYNC_INTERRUPT
		1721	? sub {
1488	my (undef, %arg) = @_;	1722	my (undef, %arg) = @_;
1489		1723
1490	my $signal = uc $arg{signal}
1491	or Carp::croak "required option 'signal' is missing";
1492
1493	if ($HAVE_ASYNC_INTERRUPT) {
1494	# async::interrupt	1724	# async::interrupt
1495
1496	$signal = sig2num $signal;	1725	my $signal = sig2num $arg{signal};
1497	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1726	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1498		1727
1499	$SIG_ASY{$signal} ||= new Async::Interrupt	1728	$SIG_ASY{$signal} ||= new Async::Interrupt
1500	cb => sub { undef $SIG_EV{$signal} },	1729	cb => sub { undef $SIG_EV{$signal} },
1501	signal => $signal,	1730	signal => $signal,
1502	pipe => [$SIGPIPE_R->filenos],	1731	pipe => [$SIGPIPE_R->filenos],
1503	pipe_autodrain => 0,	1732	pipe_autodrain => 0,
1504	;	1733	;
1505		1734
1506	} else {	1735	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1736	}
		1737	: sub {
		1738	my (undef, %arg) = @_;
		1739
1507	# pure perl	1740	# pure perl
1508
1509	# AE::Util has been loaded in signal
1510	$signal = sig2name $signal;	1741	my $signal = sig2name $arg{signal};
1511	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};	1742	$SIG_CB{$signal}{$arg{cb}} = $arg{cb};
1512		1743
1513	$SIG{$signal} ||= sub {	1744	$SIG{$signal} ||= sub {
1514	local $!;	1745	local $!;
1515	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;	1746	syswrite $SIGPIPE_W, "\x00", 1 unless %SIG_EV;
1516	undef $SIG_EV{$signal};	1747	undef $SIG_EV{$signal};
1517	};	1748	};
1518		1749
1519	# can't do signal processing without introducing races in pure perl,	1750	# can't do signal processing without introducing races in pure perl,
1520	# so limit the signal latency.	1751	# so limit the signal latency.
1521	_sig_add;	1752	_sig_add;
1522	}
1523		1753
1524	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"	1754	bless [$signal, $arg{cb}], "AnyEvent::Base::signal"
		1755	}
1525	};	1756	;
1526		1757
1527	*AnyEvent::Base::signal::DESTROY = sub {	1758	*AnyEvent::Base::signal::DESTROY = sub {
1528	my ($signal, $cb) = @{$_[0]};	1759	my ($signal, $cb) = @{$_[0]};
1529		1760
1530	_sig_del;	1761	_sig_del;
…		…
1537	# print weird messages, or just unconditionally exit	1768	# print weird messages, or just unconditionally exit
1538	# instead of getting the default action.	1769	# instead of getting the default action.
1539	undef $SIG{$signal}	1770	undef $SIG{$signal}
1540	unless keys %{ $SIG_CB{$signal} };	1771	unless keys %{ $SIG_CB{$signal} };
1541	};	1772	};
		1773
		1774	*_signal_exec = sub {
		1775	$HAVE_ASYNC_INTERRUPT
		1776	? $SIGPIPE_R->drain
		1777	: sysread $SIGPIPE_R, (my $dummy), 9;
		1778
		1779	while (%SIG_EV) {
		1780	for (keys %SIG_EV) {
		1781	delete $SIG_EV{$_};
		1782	&$_ for values %{ $SIG_CB{$_} || {} };
		1783	}
		1784	}
		1785	};
1542	};	1786	};
1543	die if $@;	1787	die if $@;
		1788
1544	&signal	1789	&signal
1545	}	1790	}
1546		1791
1547	# default implementation for ->child	1792	# default implementation for ->child
1548		1793
1549	our %PID_CB;	1794	our %PID_CB;
1550	our $CHLD_W;	1795	our $CHLD_W;
1551	our $CHLD_DELAY_W;	1796	our $CHLD_DELAY_W;
1552	our $WNOHANG;
1553		1797
		1798	# used by many Impl's
1554	sub _emit_childstatus($$) {	1799	sub _emit_childstatus($$) {
1555	my (undef, $rpid, $rstatus) = @_;	1800	my (undef, $rpid, $rstatus) = @_;
1556		1801
1557	$_->($rpid, $rstatus)	1802	$_->($rpid, $rstatus)
1558	for values %{ $PID_CB{$rpid} || {} },	1803	for values %{ $PID_CB{$rpid} || {} },
1559	values %{ $PID_CB{0} || {} };	1804	values %{ $PID_CB{0} || {} };
1560	}	1805	}
1561		1806
1562	sub _sigchld {
1563	my $pid;
1564
1565	AnyEvent->_emit_childstatus ($pid, $?)
1566	while ($pid = waitpid -1, $WNOHANG) > 0;
1567	}
1568
1569	sub child {	1807	sub child {
		1808	eval q{ # poor man's autoloading {}
		1809	*_sigchld = sub {
		1810	my $pid;
		1811
		1812	AnyEvent->_emit_childstatus ($pid, $?)
		1813	while ($pid = waitpid -1, WNOHANG) > 0;
		1814	};
		1815
		1816	*child = sub {
1570	my (undef, %arg) = @_;	1817	my (undef, %arg) = @_;
1571		1818
1572	defined (my $pid = $arg{pid} + 0)	1819	my $pid = $arg{pid};
1573	or Carp::croak "required option 'pid' is missing";	1820	my $cb = $arg{cb};
1574		1821
1575	$PID_CB{$pid}{$arg{cb}} = $arg{cb};	1822	$PID_CB{$pid}{$cb+0} = $cb;
1576		1823
1577	# WNOHANG is almost cetrainly 1 everywhere
1578	$WNOHANG ||= $^O =~ /^(?:openbsd|netbsd|linux|freebsd|cygwin|MSWin32)$/
1579	? 1
1580	: eval { local $SIG{__DIE__}; require POSIX; &POSIX::WNOHANG } || 1;
1581
1582	unless ($CHLD_W) {	1824	unless ($CHLD_W) {
1583	$CHLD_W = AE::signal CHLD => \&_sigchld;	1825	$CHLD_W = AE::signal CHLD => \&_sigchld;
1584	# child could be a zombie already, so make at least one round	1826	# child could be a zombie already, so make at least one round
1585	&_sigchld;	1827	&_sigchld;
1586	}	1828	}
1587		1829
1588	bless [$pid, $arg{cb}], "AnyEvent::Base::child"	1830	bless [$pid, $cb+0], "AnyEvent::Base::child"
1589	}	1831	};
1590		1832
1591	sub AnyEvent::Base::child::DESTROY {	1833	*AnyEvent::Base::child::DESTROY = sub {
1592	my ($pid, $cb) = @{$_[0]};	1834	my ($pid, $icb) = @{$_[0]};
1593		1835
1594	delete $PID_CB{$pid}{$cb};	1836	delete $PID_CB{$pid}{$icb};
1595	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };	1837	delete $PID_CB{$pid} unless keys %{ $PID_CB{$pid} };
1596		1838
1597	undef $CHLD_W unless keys %PID_CB;	1839	undef $CHLD_W unless keys %PID_CB;
		1840	};
		1841	};
		1842	die if $@;
		1843
		1844	&child
1598	}	1845	}
1599		1846
1600	# idle emulation is done by simply using a timer, regardless	1847	# idle emulation is done by simply using a timer, regardless
1601	# of whether the process is idle or not, and not letting	1848	# of whether the process is idle or not, and not letting
1602	# the callback use more than 50% of the time.	1849	# the callback use more than 50% of the time.
1603	sub idle {	1850	sub idle {
		1851	eval q{ # poor man's autoloading {}
		1852	*idle = sub {
1604	my (undef, %arg) = @_;	1853	my (undef, %arg) = @_;
1605		1854
1606	my ($cb, $w, $rcb) = $arg{cb};	1855	my ($cb, $w, $rcb) = $arg{cb};
1607		1856
1608	$rcb = sub {	1857	$rcb = sub {
1609	if ($cb) {	1858	if ($cb) {
1610	$w = _time;	1859	$w = AE::time;
1611	&$cb;	1860	&$cb;
1612	$w = _time - $w;	1861	$w = AE::time - $w;
1613		1862
1614	# never use more then 50% of the time for the idle watcher,	1863	# never use more then 50% of the time for the idle watcher,
1615	# within some limits	1864	# within some limits
1616	$w = 0.0001 if $w < 0.0001;	1865	$w = 0.0001 if $w < 0.0001;
1617	$w = 5 if $w > 5;	1866	$w = 5 if $w > 5;
1618		1867
1619	$w = AE::timer $w, 0, $rcb;	1868	$w = AE::timer $w, 0, $rcb;
1620	} else {	1869	} else {
1621	# clean up...	1870	# clean up...
1622	undef $w;	1871	undef $w;
1623	undef $rcb;	1872	undef $rcb;
		1873	}
		1874	};
		1875
		1876	$w = AE::timer 0.05, 0, $rcb;
		1877
		1878	bless \\$cb, "AnyEvent::Base::idle"
1624	}	1879	};
		1880
		1881	*AnyEvent::Base::idle::DESTROY = sub {
		1882	undef $${$_[0]};
		1883	};
1625	};	1884	};
		1885	die if $@;
1626		1886
1627	$w = AE::timer 0.05, 0, $rcb;	1887	&idle
1628
1629	bless \\$cb, "AnyEvent::Base::idle"
1630	}
1631
1632	sub AnyEvent::Base::idle::DESTROY {
1633	undef $${$_[0]};
1634	}	1888	}
1635		1889
1636	package AnyEvent::CondVar;	1890	package AnyEvent::CondVar;
1637		1891
1638	our @ISA = AnyEvent::CondVar::Base::;	1892	our @ISA = AnyEvent::CondVar::Base::;
		1893
		1894	# only to be used for subclassing
		1895	sub new {
		1896	my $class = shift;
		1897	bless AnyEvent->condvar (@_), $class
		1898	}
1639		1899
1640	package AnyEvent::CondVar::Base;	1900	package AnyEvent::CondVar::Base;
1641		1901
1642	#use overload	1902	#use overload
1643	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },	1903	# '&{}' => sub { my $self = shift; sub { $self->send (@_) } },
…		…
1653		1913
1654	sub _send {	1914	sub _send {
1655	# nop	1915	# nop
1656	}	1916	}
1657		1917
		1918	sub _wait {
		1919	AnyEvent->_poll until $_[0]{_ae_sent};
		1920	}
		1921
1658	sub send {	1922	sub send {
1659	my $cv = shift;	1923	my $cv = shift;
1660	$cv->{_ae_sent} = [@_];	1924	$cv->{_ae_sent} = [@_];
1661	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};	1925	(delete $cv->{_ae_cb})->($cv) if $cv->{_ae_cb};
1662	$cv->_send;	1926	$cv->_send;
…		…
1669		1933
1670	sub ready {	1934	sub ready {
1671	$_[0]{_ae_sent}	1935	$_[0]{_ae_sent}
1672	}	1936	}
1673		1937
1674	sub _wait {
1675	$WAITING
1676	and !$_[0]{_ae_sent}
1677	and Carp::croak "AnyEvent::CondVar: recursive blocking wait detected";
1678
1679	local $WAITING = 1;
1680	AnyEvent->one_event while !$_[0]{_ae_sent};
1681	}
1682
1683	sub recv {	1938	sub recv {
		1939	unless ($_[0]{_ae_sent}) {
		1940	$WAITING
		1941	and Carp::croak "AnyEvent::CondVar: recursive blocking wait attempted";
		1942
		1943	local $WAITING = 1;
1684	$_[0]->_wait;	1944	$_[0]->_wait;
		1945	}
1685		1946
1686	Carp::croak $_[0]{_ae_croak} if $_[0]{_ae_croak};	1947	$_[0]{_ae_croak}
1687	wantarray ? @{ $_[0]{_ae_sent} } : $_[0]{_ae_sent}[0]	1948	and Carp::croak $_[0]{_ae_croak};
		1949
		1950	wantarray
		1951	? @{ $_[0]{_ae_sent} }
		1952	: $_[0]{_ae_sent}[0]
1688	}	1953	}
1689		1954
1690	sub cb {	1955	sub cb {
1691	my $cv = shift;	1956	my $cv = shift;
1692		1957
…		…
1708	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };	1973	&{ $_[0]{_ae_end_cb} || sub { $_[0]->send } };
1709	}	1974	}
1710		1975
1711	# undocumented/compatibility with pre-3.4	1976	# undocumented/compatibility with pre-3.4
1712	*broadcast = \&send;	1977	*broadcast = \&send;
1713	*wait = \&_wait;	1978	*wait = \&recv;
1714		1979
1715	=head1 ERROR AND EXCEPTION HANDLING	1980	=head1 ERROR AND EXCEPTION HANDLING
1716		1981
1717	In general, AnyEvent does not do any error handling - it relies on the	1982	In general, AnyEvent does not do any error handling - it relies on the
1718	caller to do that if required. The L<AnyEvent::Strict> module (see also	1983	caller to do that if required. The L<AnyEvent::Strict> module (see also
…		…
1730	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and	1995	$Event/EV::DIED->() >>, L<Glib> uses C<< install_exception_handler >> and
1731	so on.	1996	so on.
1732		1997
1733	=head1 ENVIRONMENT VARIABLES	1998	=head1 ENVIRONMENT VARIABLES
1734		1999
1735	The following environment variables are used by this module or its	2000	AnyEvent supports a number of environment variables that tune the
1736	submodules.	2001	runtime behaviour. They are usually evaluated when AnyEvent is
		2002	loaded, initialised, or a submodule that uses them is loaded. Many of
		2003	them also cause AnyEvent to load additional modules - for example,
		2004	C<PERL_ANYEVENT_DEBUG_WRAP> causes the L<AnyEvent::Debug> module to be
		2005	loaded.
1737		2006
1738	Note that AnyEvent will remove I<all> environment variables starting with	2007	All the environment variables documented here start with
1739	C<PERL_ANYEVENT_> from C<%ENV> when it is loaded while taint mode is	2008	C<PERL_ANYEVENT_>, which is what AnyEvent considers its own
1740	enabled.	2009	namespace. Other modules are encouraged (but by no means required) to use
		2010	C<PERL_ANYEVENT_SUBMODULE> if they have registered the AnyEvent::Submodule
		2011	namespace on CPAN, for any submodule. For example, L<AnyEvent::HTTP> could
		2012	be expected to use C<PERL_ANYEVENT_HTTP_PROXY> (it should not access env
		2013	variables starting with C<AE_>, see below).
		2014
		2015	All variables can also be set via the C<AE_> prefix, that is, instead
		2016	of setting C<PERL_ANYEVENT_VERBOSE> you can also set C<AE_VERBOSE>. In
		2017	case there is a clash btween anyevent and another program that uses
		2018	C<AE_something> you can set the corresponding C<PERL_ANYEVENT_something>
		2019	variable to the empty string, as those variables take precedence.
		2020
		2021	When AnyEvent is first loaded, it copies all C<AE_xxx> env variables
		2022	to their C<PERL_ANYEVENT_xxx> counterpart unless that variable already
		2023	exists. If taint mode is on, then AnyEvent will remove I<all> environment
		2024	variables starting with C<PERL_ANYEVENT_> from C<%ENV> (or replace them
		2025	with C<undef> or the empty string, if the corresaponding C<AE_> variable
		2026	is set).
		2027
		2028	The exact algorithm is currently:
		2029
		2030	1. if taint mode enabled, delete all PERL_ANYEVENT_xyz variables from %ENV
		2031	2. copy over AE_xyz to PERL_ANYEVENT_xyz unless the latter alraedy exists
		2032	3. if taint mode enabled, set all PERL_ANYEVENT_xyz variables to undef.
		2033
		2034	This ensures that child processes will not see the C<AE_> variables.
		2035
		2036	The following environment variables are currently known to AnyEvent:
1741		2037
1742	=over 4	2038	=over 4
1743		2039
1744	=item C<PERL_ANYEVENT_VERBOSE>	2040	=item C<PERL_ANYEVENT_VERBOSE>
1745		2041
1746	By default, AnyEvent will be completely silent except in fatal	2042	By default, AnyEvent will only log messages with loglevel C<3>
1747	conditions. You can set this environment variable to make AnyEvent more	2043	(C<critical>) or higher (see L<AnyEvent::Log>). You can set this
		2044	environment variable to a numerical loglevel to make AnyEvent more (or
1748	talkative.	2045	less) talkative.
1749		2046
		2047	If you want to do more than just set the global logging level
		2048	you should have a look at C<PERL_ANYEVENT_LOG>, which allows much more
		2049	complex specifications.
		2050
		2051	When set to C<0> (C<off>), then no messages whatsoever will be logged with
		2052	the default logging settings.
		2053
1750	When set to C<1> or higher, causes AnyEvent to warn about unexpected	2054	When set to C<5> or higher (C<warn>), causes AnyEvent to warn about
1751	conditions, such as not being able to load the event model specified by	2055	unexpected conditions, such as not being able to load the event model
1752	C<PERL_ANYEVENT_MODEL>.	2056	specified by C<PERL_ANYEVENT_MODEL>, or a guard callback throwing an
		2057	exception - this is the minimum recommended level.
1753		2058
1754	When set to C<2> or higher, cause AnyEvent to report to STDERR which event	2059	When set to C<7> or higher (info), cause AnyEvent to report which event model it
1755	model it chooses.	2060	chooses.
1756		2061
1757	When set to C<8> or higher, then AnyEvent will report extra information on	2062	When set to C<8> or higher (debug), then AnyEvent will report extra information on
1758	which optional modules it loads and how it implements certain features.	2063	which optional modules it loads and how it implements certain features.
		2064
		2065	=item C<PERL_ANYEVENT_LOG>
		2066
		2067	Accepts rather complex logging specifications. For example, you could log
		2068	all C<debug> messages of some module to stderr, warnings and above to
		2069	stderr, and errors and above to syslog, with:
		2070
		2071	PERL_ANYEVENT_LOG=Some::Module=debug,+log:filter=warn,+%syslog:%syslog=error,syslog
		2072
		2073	For the rather extensive details, see L<AnyEvent::Log>.
		2074
		2075	This variable is evaluated when AnyEvent (or L<AnyEvent::Log>) is loaded,
		2076	so will take effect even before AnyEvent has initialised itself.
		2077
		2078	Note that specifying this environment variable causes the L<AnyEvent::Log>
		2079	module to be loaded, while C<PERL_ANYEVENT_VERBOSE> does not, so only
		2080	using the latter saves a few hundred kB of memory until the first message
		2081	is being logged.
1759		2082
1760	=item C<PERL_ANYEVENT_STRICT>	2083	=item C<PERL_ANYEVENT_STRICT>
1761		2084
1762	AnyEvent does not do much argument checking by default, as thorough	2085	AnyEvent does not do much argument checking by default, as thorough
1763	argument checking is very costly. Setting this variable to a true value	2086	argument checking is very costly. Setting this variable to a true value
…		…
1765	check the arguments passed to most method calls. If it finds any problems,	2088	check the arguments passed to most method calls. If it finds any problems,
1766	it will croak.	2089	it will croak.
1767		2090
1768	In other words, enables "strict" mode.	2091	In other words, enables "strict" mode.
1769		2092
1770	Unlike C<use strict> (or it's modern cousin, C<< use L<common::sense>	2093	Unlike C<use strict> (or its modern cousin, C<< use L<common::sense>
1771	>>, it is definitely recommended to keep it off in production. Keeping	2094	>>, it is definitely recommended to keep it off in production. Keeping
1772	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs	2095	C<PERL_ANYEVENT_STRICT=1> in your environment while developing programs
1773	can be very useful, however.	2096	can be very useful, however.
1774		2097
		2098	=item C<PERL_ANYEVENT_DEBUG_SHELL>
		2099
		2100	If this env variable is set, then its contents will be interpreted by
		2101	C<AnyEvent::Socket::parse_hostport> (after replacing every occurance of
		2102	C<$$> by the process pid) and an C<AnyEvent::Debug::shell> is bound on
		2103	that port. The shell object is saved in C<$AnyEvent::Debug::SHELL>.
		2104
		2105	This happens when the first watcher is created.
		2106
		2107	For example, to bind a debug shell on a unix domain socket in
		2108	F<< /tmp/debug<pid>.sock >>, you could use this:
		2109
		2110	PERL_ANYEVENT_DEBUG_SHELL=/tmp/debug\$\$.sock perlprog
		2111
		2112	Note that creating sockets in F</tmp> is very unsafe on multiuser
		2113	systems.
		2114
		2115	=item C<PERL_ANYEVENT_DEBUG_WRAP>
		2116
		2117	Can be set to C<0>, C<1> or C<2> and enables wrapping of all watchers for
		2118	debugging purposes. See C<AnyEvent::Debug::wrap> for details.
		2119
1775	=item C<PERL_ANYEVENT_MODEL>	2120	=item C<PERL_ANYEVENT_MODEL>
1776		2121
1777	This can be used to specify the event model to be used by AnyEvent, before	2122	This can be used to specify the event model to be used by AnyEvent, before
1778	auto detection and -probing kicks in. It must be a string consisting	2123	auto detection and -probing kicks in.
1779	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended	2124
		2125	It normally is a string consisting entirely of ASCII letters (e.g. C<EV>
		2126	or C<IOAsync>). The string C<AnyEvent::Impl::> gets prepended and the
1780	and the resulting module name is loaded and if the load was successful,	2127	resulting module name is loaded and - if the load was successful - used as
1781	used as event model. If it fails to load AnyEvent will proceed with	2128	event model backend. If it fails to load then AnyEvent will proceed with
1782	auto detection and -probing.	2129	auto detection and -probing.
1783		2130
1784	This functionality might change in future versions.	2131	If the string ends with C<::> instead (e.g. C<AnyEvent::Impl::EV::>) then
		2132	nothing gets prepended and the module name is used as-is (hint: C<::> at
		2133	the end of a string designates a module name and quotes it appropriately).
1785		2134
1786	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you	2135	For example, to force the pure perl model (L<AnyEvent::Loop::Perl>) you
1787	could start your program like this:	2136	could start your program like this:
1788		2137
1789	PERL_ANYEVENT_MODEL=Perl perl ...	2138	PERL_ANYEVENT_MODEL=Perl perl ...
1790		2139
1791	=item C<PERL_ANYEVENT_PROTOCOLS>	2140	=item C<PERL_ANYEVENT_PROTOCOLS>
…		…
1807	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>	2156	but support both and try to use both. C<PERL_ANYEVENT_PROTOCOLS=ipv4>
1808	- only support IPv4, never try to resolve or contact IPv6	2157	- only support IPv4, never try to resolve or contact IPv6
1809	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or	2158	addresses. C<PERL_ANYEVENT_PROTOCOLS=ipv6,ipv4> support either IPv4 or
1810	IPv6, but prefer IPv6 over IPv4.	2159	IPv6, but prefer IPv6 over IPv4.
1811		2160
		2161	=item C<PERL_ANYEVENT_HOSTS>
		2162
		2163	This variable, if specified, overrides the F</etc/hosts> file used by
		2164	L<AnyEvent::Socket>C<::resolve_sockaddr>, i.e. hosts aliases will be read
		2165	from that file instead.
		2166
1812	=item C<PERL_ANYEVENT_EDNS0>	2167	=item C<PERL_ANYEVENT_EDNS0>
1813		2168
1814	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension	2169	Used by L<AnyEvent::DNS> to decide whether to use the EDNS0 extension for
1815	for DNS. This extension is generally useful to reduce DNS traffic, but	2170	DNS. This extension is generally useful to reduce DNS traffic, especially
1816	some (broken) firewalls drop such DNS packets, which is why it is off by	2171	when DNSSEC is involved, but some (broken) firewalls drop such DNS
1817	default.	2172	packets, which is why it is off by default.
1818		2173
1819	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce	2174	Setting this variable to C<1> will cause L<AnyEvent::DNS> to announce
1820	EDNS0 in its DNS requests.	2175	EDNS0 in its DNS requests.
1821		2176
1822	=item C<PERL_ANYEVENT_MAX_FORKS>	2177	=item C<PERL_ANYEVENT_MAX_FORKS>
…		…
1830	resolver - this is the maximum number of parallel DNS requests that are	2185	resolver - this is the maximum number of parallel DNS requests that are
1831	sent to the DNS server.	2186	sent to the DNS server.
1832		2187
1833	=item C<PERL_ANYEVENT_RESOLV_CONF>	2188	=item C<PERL_ANYEVENT_RESOLV_CONF>
1834		2189
1835	The file to use instead of F</etc/resolv.conf> (or OS-specific	2190	The absolute path to a F<resolv.conf>-style file to use instead of
1836	configuration) in the default resolver. When set to the empty string, no	2191	F</etc/resolv.conf> (or the OS-specific configuration) in the default
1837	default config will be used.	2192	resolver, or the empty string to select the default configuration.
1838		2193
1839	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.	2194	=item C<PERL_ANYEVENT_CA_FILE>, C<PERL_ANYEVENT_CA_PATH>.
1840		2195
1841	When neither C<ca_file> nor C<ca_path> was specified during	2196	When neither C<ca_file> nor C<ca_path> was specified during
1842	L<AnyEvent::TLS> context creation, and either of these environment	2197	L<AnyEvent::TLS> context creation, and either of these environment
1843	variables exist, they will be used to specify CA certificate locations	2198	variables are nonempty, they will be used to specify CA certificate
1844	instead of a system-dependent default.	2199	locations instead of a system-dependent default.
1845		2200
1846	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>	2201	=item C<PERL_ANYEVENT_AVOID_GUARD> and C<PERL_ANYEVENT_AVOID_ASYNC_INTERRUPT>
1847		2202
1848	When these are set to C<1>, then the respective modules are not	2203	When these are set to C<1>, then the respective modules are not
1849	loaded. Mostly good for testing AnyEvent itself.	2204	loaded. Mostly good for testing AnyEvent itself.
…		…
1912	warn "read: $input\n"; # output what has been read	2267	warn "read: $input\n"; # output what has been read
1913	$cv->send if $input =~ /^q/i; # quit program if /^q/i	2268	$cv->send if $input =~ /^q/i; # quit program if /^q/i
1914	},	2269	},
1915	);	2270	);
1916		2271
1917	my $time_watcher; # can only be used once
1918
1919	sub new_timer {
1920	$timer = AnyEvent->timer (after => 1, cb => sub {	2272	my $time_watcher = AnyEvent->timer (after => 1, interval => 1, cb => sub {
1921	warn "timeout\n"; # print 'timeout' about every second	2273	warn "timeout\n"; # print 'timeout' at most every second
1922	&new_timer; # and restart the time
1923	});	2274	});
1924	}
1925
1926	new_timer; # create first timer
1927		2275
1928	$cv->recv; # wait until user enters /^q/i	2276	$cv->recv; # wait until user enters /^q/i
1929		2277
1930	=head1 REAL-WORLD EXAMPLE	2278	=head1 REAL-WORLD EXAMPLE
1931		2279
…		…
2004		2352
2005	The actual code goes further and collects all errors (C<die>s, exceptions)	2353	The actual code goes further and collects all errors (C<die>s, exceptions)
2006	that occurred during request processing. The C<result> method detects	2354	that occurred during request processing. The C<result> method detects
2007	whether an exception as thrown (it is stored inside the $txn object)	2355	whether an exception as thrown (it is stored inside the $txn object)
2008	and just throws the exception, which means connection errors and other	2356	and just throws the exception, which means connection errors and other
2009	problems get reported tot he code that tries to use the result, not in a	2357	problems get reported to the code that tries to use the result, not in a
2010	random callback.	2358	random callback.
2011		2359
2012	All of this enables the following usage styles:	2360	All of this enables the following usage styles:
2013		2361
2014	1. Blocking:	2362	1. Blocking:
…		…
2188	(even when used without AnyEvent), but most event loops have acceptable	2536	(even when used without AnyEvent), but most event loops have acceptable
2189	performance with or without AnyEvent.	2537	performance with or without AnyEvent.
2190		2538
2191	=item * The overhead AnyEvent adds is usually much smaller than the overhead of	2539	=item * The overhead AnyEvent adds is usually much smaller than the overhead of
2192	the actual event loop, only with extremely fast event loops such as EV	2540	the actual event loop, only with extremely fast event loops such as EV
2193	adds AnyEvent significant overhead.	2541	does AnyEvent add significant overhead.
2194		2542
2195	=item * You should avoid POE like the plague if you want performance or	2543	=item * You should avoid POE like the plague if you want performance or
2196	reasonable memory usage.	2544	reasonable memory usage.
2197		2545
2198	=back	2546	=back
…		…
2375	As you can see, the AnyEvent + EV combination even beats the	2723	As you can see, the AnyEvent + EV combination even beats the
2376	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl	2724	hand-optimised "raw sockets benchmark", while AnyEvent + its pure perl
2377	backend easily beats IO::Lambda and POE.	2725	backend easily beats IO::Lambda and POE.
2378		2726
2379	And even the 100% non-blocking version written using the high-level (and	2727	And even the 100% non-blocking version written using the high-level (and
2380	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda by a	2728	slow :) L<AnyEvent::Handle> abstraction beats both POE and IO::Lambda
2381	large margin, even though it does all of DNS, tcp-connect and socket I/O	2729	higher level ("unoptimised") abstractions by a large margin, even though
2382	in a non-blocking way.	2730	it does all of DNS, tcp-connect and socket I/O in a non-blocking way.
2383		2731
2384	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and	2732	The two AnyEvent benchmarks programs can be found as F<eg/ae0.pl> and
2385	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are	2733	F<eg/ae2.pl> in the AnyEvent distribution, the remaining benchmarks are
2386	part of the IO::lambda distribution and were used without any changes.	2734	part of the IO::Lambda distribution and were used without any changes.
2387		2735
2388		2736
2389	=head1 SIGNALS	2737	=head1 SIGNALS
2390		2738
2391	AnyEvent currently installs handlers for these signals:	2739	AnyEvent currently installs handlers for these signals:
…		…
2428	unless defined $SIG{PIPE};	2776	unless defined $SIG{PIPE};
2429		2777
2430	=head1 RECOMMENDED/OPTIONAL MODULES	2778	=head1 RECOMMENDED/OPTIONAL MODULES
2431		2779
2432	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and	2780	One of AnyEvent's main goals is to be 100% Pure-Perl(tm): only perl (and
2433	it's built-in modules) are required to use it.	2781	its built-in modules) are required to use it.
2434		2782
2435	That does not mean that AnyEvent won't take advantage of some additional	2783	That does not mean that AnyEvent won't take advantage of some additional
2436	modules if they are installed.	2784	modules if they are installed.
2437		2785
2438	This section epxlains which additional modules will be used, and how they	2786	This section explains which additional modules will be used, and how they
2439	affect AnyEvent's operetion.	2787	affect AnyEvent's operation.
2440		2788
2441	=over 4	2789	=over 4
2442		2790
2443	=item L<Async::Interrupt>	2791	=item L<Async::Interrupt>
2444		2792
…		…
2449	catch the signals) with some delay (default is 10 seconds, look for	2797	catch the signals) with some delay (default is 10 seconds, look for
2450	C<$AnyEvent::MAX_SIGNAL_LATENCY>).	2798	C<$AnyEvent::MAX_SIGNAL_LATENCY>).
2451		2799
2452	If this module is available, then it will be used to implement signal	2800	If this module is available, then it will be used to implement signal
2453	catching, which means that signals will not be delayed, and the event loop	2801	catching, which means that signals will not be delayed, and the event loop
2454	will not be interrupted regularly, which is more efficient (And good for	2802	will not be interrupted regularly, which is more efficient (and good for
2455	battery life on laptops).	2803	battery life on laptops).
2456		2804
2457	This affects not just the pure-perl event loop, but also other event loops	2805	This affects not just the pure-perl event loop, but also other event loops
2458	that have no signal handling on their own (e.g. Glib, Tk, Qt).	2806	that have no signal handling on their own (e.g. Glib, Tk, Qt).
2459		2807
…		…
2471	automatic timer adjustments even when no monotonic clock is available,	2819	automatic timer adjustments even when no monotonic clock is available,
2472	can take avdantage of advanced kernel interfaces such as C<epoll> and	2820	can take avdantage of advanced kernel interfaces such as C<epoll> and
2473	C<kqueue>, and is the fastest backend I<by far>. You can even embed	2821	C<kqueue>, and is the fastest backend I<by far>. You can even embed
2474	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).	2822	L<Glib>/L<Gtk2> in it (or vice versa, see L<EV::Glib> and L<Glib::EV>).
2475		2823
		2824	If you only use backends that rely on another event loop (e.g. C<Tk>),
		2825	then this module will do nothing for you.
		2826
2476	=item L<Guard>	2827	=item L<Guard>
2477		2828
2478	The guard module, when used, will be used to implement	2829	The guard module, when used, will be used to implement
2479	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a	2830	C<AnyEvent::Util::guard>. This speeds up guards considerably (and uses a
2480	lot less memory), but otherwise doesn't affect guard operation much. It is	2831	lot less memory), but otherwise doesn't affect guard operation much. It is
2481	purely used for performance.	2832	purely used for performance.
2482		2833
2483	=item L<JSON> and L<JSON::XS>	2834	=item L<JSON> and L<JSON::XS>
2484		2835
2485	This module is required when you want to read or write JSON data via	2836	One of these modules is required when you want to read or write JSON data
2486	L<AnyEvent::Handle>. It is also written in pure-perl, but can take	2837	via L<AnyEvent::Handle>. L<JSON> is also written in pure-perl, but can take
2487	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.	2838	advantage of the ultra-high-speed L<JSON::XS> module when it is installed.
2488
2489	In fact, L<AnyEvent::Handle> will use L<JSON::XS> by default if it is
2490	installed.
2491		2839
2492	=item L<Net::SSLeay>	2840	=item L<Net::SSLeay>
2493		2841
2494	Implementing TLS/SSL in Perl is certainly interesting, but not very	2842	Implementing TLS/SSL in Perl is certainly interesting, but not very
2495	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with	2843	worthwhile: If this module is installed, then L<AnyEvent::Handle> (with
2496	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.	2844	the help of L<AnyEvent::TLS>), gains the ability to do TLS/SSL.
2497		2845
2498	=item L<Time::HiRes>	2846	=item L<Time::HiRes>
2499		2847
2500	This module is part of perl since release 5.008. It will be used when the	2848	This module is part of perl since release 5.008. It will be used when the
2501	chosen event library does not come with a timing source on it's own. The	2849	chosen event library does not come with a timing source of its own. The
2502	pure-perl event loop (L<AnyEvent::Impl::Perl>) will additionally use it to	2850	pure-perl event loop (L<AnyEvent::Loop>) will additionally load it to
2503	try to use a monotonic clock for timing stability.	2851	try to use a monotonic clock for timing stability.
2504		2852
2505	=back	2853	=back
2506		2854
2507		2855
2508	=head1 FORK	2856	=head1 FORK
2509		2857
2510	Most event libraries are not fork-safe. The ones who are usually are	2858	Most event libraries are not fork-safe. The ones who are usually are
2511	because they rely on inefficient but fork-safe C<select> or C<poll>	2859	because they rely on inefficient but fork-safe C<select> or C<poll> calls
2512	calls. Only L<EV> is fully fork-aware.	2860	- higher performance APIs such as BSD's kqueue or the dreaded Linux epoll
		2861	are usually badly thought-out hacks that are incompatible with fork in
		2862	one way or another. Only L<EV> is fully fork-aware and ensures that you
		2863	continue event-processing in both parent and child (or both, if you know
		2864	what you are doing).
		2865
		2866	This means that, in general, you cannot fork and do event processing in
		2867	the child if the event library was initialised before the fork (which
		2868	usually happens when the first AnyEvent watcher is created, or the library
		2869	is loaded).
2513		2870
2514	If you have to fork, you must either do so I<before> creating your first	2871	If you have to fork, you must either do so I<before> creating your first
2515	watcher OR you must not use AnyEvent at all in the child OR you must do	2872	watcher OR you must not use AnyEvent at all in the child OR you must do
2516	something completely out of the scope of AnyEvent.	2873	something completely out of the scope of AnyEvent.
		2874
		2875	The problem of doing event processing in the parent I<and> the child
		2876	is much more complicated: even for backends that I<are> fork-aware or
		2877	fork-safe, their behaviour is not usually what you want: fork clones all
		2878	watchers, that means all timers, I/O watchers etc. are active in both
		2879	parent and child, which is almost never what you want. USing C<exec>
		2880	to start worker children from some kind of manage rprocess is usually
		2881	preferred, because it is much easier and cleaner, at the expense of having
		2882	to have another binary.
2517		2883
2518		2884
2519	=head1 SECURITY CONSIDERATIONS	2885	=head1 SECURITY CONSIDERATIONS
2520		2886
2521	AnyEvent can be forced to load any event model via	2887	AnyEvent can be forced to load any event model via
…		…
2551	pronounced).	2917	pronounced).
2552		2918
2553		2919
2554	=head1 SEE ALSO	2920	=head1 SEE ALSO
2555		2921
2556	Utility functions: L<AnyEvent::Util>.	2922	Tutorial/Introduction: L<AnyEvent::Intro>.
2557		2923
2558	Event modules: L<EV>, L<EV::Glib>, L<Glib::EV>, L<Event>, L<Glib::Event>,	2924	FAQ: L<AnyEvent::FAQ>.
2559	L<Glib>, L<Tk>, L<Event::Lib>, L<Qt>, L<POE>.	2925
		2926	Utility functions: L<AnyEvent::Util> (misc. grab-bag), L<AnyEvent::Log>
		2927	(simply logging).
		2928
		2929	Development/Debugging: L<AnyEvent::Strict> (stricter checking),
		2930	L<AnyEvent::Debug> (interactive shell, watcher tracing).
		2931
		2932	Supported event modules: L<AnyEvent::Loop>, L<EV>, L<EV::Glib>,
		2933	L<Glib::EV>, L<Event>, L<Glib::Event>, L<Glib>, L<Tk>, L<Event::Lib>,
		2934	L<Qt>, L<POE>, L<FLTK>.
2560		2935
2561	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,	2936	Implementations: L<AnyEvent::Impl::EV>, L<AnyEvent::Impl::Event>,
2562	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,	2937	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>,
2563	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,	2938	L<AnyEvent::Impl::EventLib>, L<AnyEvent::Impl::Qt>,
2564	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>.	2939	L<AnyEvent::Impl::POE>, L<AnyEvent::Impl::IOAsync>, L<Anyevent::Impl::Irssi>,
		2940	L<AnyEvent::Impl::FLTK>.
2565		2941
2566	Non-blocking file handles, sockets, TCP clients and	2942	Non-blocking handles, pipes, stream sockets, TCP clients and
2567	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.	2943	servers: L<AnyEvent::Handle>, L<AnyEvent::Socket>, L<AnyEvent::TLS>.
2568		2944
2569	Asynchronous DNS: L<AnyEvent::DNS>.	2945	Asynchronous DNS: L<AnyEvent::DNS>.
2570		2946
2571	Coroutine support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>,	2947	Thread support: L<Coro>, L<Coro::AnyEvent>, L<Coro::EV>, L<Coro::Event>.
2572	L<Coro::Event>,
2573		2948
2574	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::XMPP>,	2949	Nontrivial usage examples: L<AnyEvent::GPSD>, L<AnyEvent::IRC>,
2575	L<AnyEvent::HTTP>.	2950	L<AnyEvent::HTTP>.
2576		2951
2577		2952
2578	=head1 AUTHOR	2953	=head1 AUTHOR
2579		2954

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