[ViewVC] Diff of: cvs/AnyEvent/lib/AnyEvent.pm

Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.54 by root, Tue Apr 22 05:12:19 2008 UTC vs.
Revision 1.83 by root, Fri Apr 25 13:39:08 2008 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent - provide framework for multiple event loops	3	AnyEvent - provide framework for multiple event loops
4		4
5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl - various supported event loops	5	EV, Event, Coro::EV, Coro::Event, Glib, Tk, Perl, Event::Lib, Qt, POE - various supported event loops
6		6
7	=head1 SYNOPSIS	7	=head1 SYNOPSIS
8		8
9	use AnyEvent;	9	use AnyEvent;
10		10
80	module.	80	module.
81		81
82	During the first call of any watcher-creation method, the module tries	82	During the first call of any watcher-creation method, the module tries
83	to detect the currently loaded event loop by probing whether one of the	83	to detect the currently loaded event loop by probing whether one of the
84	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,	84	following modules is already loaded: L<Coro::EV>, L<Coro::Event>, L<EV>,
85	L<Event>, L<Glib>, L<Tk>. The first one found is used. If none are found,	85	L<Event>, L<Glib>, L<AnyEvent::Impl::Perl>, L<Tk>, L<Event::Lib>, L<Qt>,
86	the module tries to load these modules in the stated order. The first one	86	L<POE>. The first one found is used. If none are found, the module tries
		87	to load these modules (excluding Tk, Event::Lib, Qt and POE as the pure perl
		88	adaptor should always succeed) in the order given. The first one that can
87	that can be successfully loaded will be used. If, after this, still none	89	be successfully loaded will be used. If, after this, still none could be
88	could be found, AnyEvent will fall back to a pure-perl event loop, which	90	found, AnyEvent will fall back to a pure-perl event loop, which is not
89	is not very efficient, but should work everywhere.	91	very efficient, but should work everywhere.
90		92
91	Because AnyEvent first checks for modules that are already loaded, loading	93	Because AnyEvent first checks for modules that are already loaded, loading
92	an event model explicitly before first using AnyEvent will likely make	94	an event model explicitly before first using AnyEvent will likely make
93	that model the default. For example:	95	that model the default. For example:
94		96
…		…
134		136
135	Note that C<my $w; $w => combination. This is necessary because in Perl,	137	Note that C<my $w; $w => combination. This is necessary because in Perl,
136	my variables are only visible after the statement in which they are	138	my variables are only visible after the statement in which they are
137	declared.	139	declared.
138		140
139	=head2 IO WATCHERS	141	=head2 I/O WATCHERS
140		142
141	You can create an I/O watcher by calling the C<< AnyEvent->io >> method	143	You can create an I/O watcher by calling the C<< AnyEvent->io >> method
142	with the following mandatory key-value pairs as arguments:	144	with the following mandatory key-value pairs as arguments:
143		145
144	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for	146	C<fh> the Perl I<file handle> (I<not> file descriptor) to watch for
145	events. C<poll> must be a string that is either C<r> or C<w>, which	147	events. C<poll> must be a string that is either C<r> or C<w>, which
146	creates a watcher waiting for "r"eadable or "w"ritable events,	148	creates a watcher waiting for "r"eadable or "w"ritable events,
147	respectively. C<cb> is the callback to invoke each time the file handle	149	respectively. C<cb> is the callback to invoke each time the file handle
148	becomes ready.	150	becomes ready.
149		151
150	File handles will be kept alive, so as long as the watcher exists, the	152	The I/O watcher might use the underlying file descriptor or a copy of it.
151	file handle exists, too.
152
153	It is not allowed to close a file handle as long as any watcher is active	153	It is not allowed to close a file handle as long as any watcher is active
154	on the underlying file descriptor.	154	on the underlying file descriptor.
155		155
156	Some event loops issue spurious readyness notifications, so you should	156	Some event loops issue spurious readyness notifications, so you should
157	always use non-blocking calls when reading/writing from/to your file	157	always use non-blocking calls when reading/writing from/to your file
…		…
206		206
207	There are two ways to handle timers: based on real time (relative, "fire	207	There are two ways to handle timers: based on real time (relative, "fire
208	in 10 seconds") and based on wallclock time (absolute, "fire at 12	208	in 10 seconds") and based on wallclock time (absolute, "fire at 12
209	o'clock").	209	o'clock").
210		210
211	While most event loops expect timers to specified in a relative way, they use	211	While most event loops expect timers to specified in a relative way, they
212	absolute time internally. This makes a difference when your clock "jumps",	212	use absolute time internally. This makes a difference when your clock
213	for example, when ntp decides to set your clock backwards from the wrong 2014-01-01 to	213	"jumps", for example, when ntp decides to set your clock backwards from
214	2008-01-01, a watcher that you created to fire "after" a second might actually take	214	the wrong date of 2014-01-01 to 2008-01-01, a watcher that is supposed to
215	six years to finally fire.	215	fire "after" a second might actually take six years to finally fire.
216		216
217	AnyEvent cannot compensate for this. The only event loop that is conscious	217	AnyEvent cannot compensate for this. The only event loop that is conscious
218	about these issues is L<EV>, which offers both relative (ev_timer) and	218	about these issues is L<EV>, which offers both relative (ev_timer, based
219	absolute (ev_periodic) timers.	219	on true relative time) and absolute (ev_periodic, based on wallclock time)
		220	timers.
220		221
221	AnyEvent always prefers relative timers, if available, matching the	222	AnyEvent always prefers relative timers, if available, matching the
222	AnyEvent API.	223	AnyEvent API.
223		224
224	=head2 SIGNAL WATCHERS	225	=head2 SIGNAL WATCHERS
225		226
226	You can watch for signals using a signal watcher, C<signal> is the signal	227	You can watch for signals using a signal watcher, C<signal> is the signal
227	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to	228	I<name> without any C<SIG> prefix, C<cb> is the Perl callback to
228	be invoked whenever a signal occurs.	229	be invoked whenever a signal occurs.
229		230
230	Multiple signals occurances can be clumped together into one callback	231	Multiple signal occurances can be clumped together into one callback
231	invocation, and callback invocation will be synchronous. synchronous means	232	invocation, and callback invocation will be synchronous. synchronous means
232	that it might take a while until the signal gets handled by the process,	233	that it might take a while until the signal gets handled by the process,
233	but it is guarenteed not to interrupt any other callbacks.	234	but it is guarenteed not to interrupt any other callbacks.
234		235
235	The main advantage of using these watchers is that you can share a signal	236	The main advantage of using these watchers is that you can share a signal
…		…
250	watches for any child process exit). The watcher will trigger as often	251	watches for any child process exit). The watcher will trigger as often
251	as status change for the child are received. This works by installing a	252	as status change for the child are received. This works by installing a
252	signal handler for C<SIGCHLD>. The callback will be called with the pid	253	signal handler for C<SIGCHLD>. The callback will be called with the pid
253	and exit status (as returned by waitpid).	254	and exit status (as returned by waitpid).
254		255
255	Example: wait for pid 1333	256	There is a slight catch to child watchers, however: you usually start them
		257	I<after> the child process was created, and this means the process could
		258	have exited already (and no SIGCHLD will be sent anymore).
		259
		260	Not all event models handle this correctly (POE doesn't), but even for
		261	event models that I<do> handle this correctly, they usually need to be
		262	loaded before the process exits (i.e. before you fork in the first place).
		263
		264	This means you cannot create a child watcher as the very first thing in an
		265	AnyEvent program, you I<have> to create at least one watcher before you
		266	C<fork> the child (alternatively, you can call C<AnyEvent::detect>).
		267
		268	Example: fork a process and wait for it
		269
		270	my $done = AnyEvent->condvar;
		271
		272	AnyEvent::detect; # force event module to be initialised
		273
		274	my $pid = fork or exit 5;
256		275
257	my $w = AnyEvent->child (	276	my $w = AnyEvent->child (
258	pid => 1333,	277	pid => $pid,
259	cb => sub {	278	cb => sub {
260	my ($pid, $status) = @_;	279	my ($pid, $status) = @_;
261	warn "pid $pid exited with status $status";	280	warn "pid $pid exited with status $status";
		281	$done->broadcast;
262	},	282	},
263	);	283	);
		284
		285	# do something else, then wait for process exit
		286	$done->wait;
264		287
265	=head2 CONDITION VARIABLES	288	=head2 CONDITION VARIABLES
266		289
267	Condition variables can be created by calling the C<< AnyEvent->condvar >>	290	Condition variables can be created by calling the C<< AnyEvent->condvar >>
268	method without any arguments.	291	method without any arguments.
…		…
353		376
354	The known classes so far are:	377	The known classes so far are:
355		378
356	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.	379	AnyEvent::Impl::CoroEV based on Coro::EV, best choice.
357	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.	380	AnyEvent::Impl::CoroEvent based on Coro::Event, second best choice.
358	AnyEvent::Impl::EV based on EV (an interface to libev, also best choice).	381	AnyEvent::Impl::EV based on EV (an interface to libev, best choice).
359	AnyEvent::Impl::Event based on Event, also second best choice :)	382	AnyEvent::Impl::Event based on Event, second best choice.
360	AnyEvent::Impl::Glib based on Glib, third-best choice.	383	AnyEvent::Impl::Glib based on Glib, third-best choice.
		384	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.
361	AnyEvent::Impl::Tk based on Tk, very bad choice.	385	AnyEvent::Impl::Tk based on Tk, very bad choice.
362	AnyEvent::Impl::Perl pure-perl implementation, inefficient but portable.	386	AnyEvent::Impl::Qt based on Qt, cannot be autoprobed (see its docs).
		387	AnyEvent::Impl::EventLib based on Event::Lib, leaks memory and worse.
		388	AnyEvent::Impl::POE based on POE, not generic enough for full support.
		389
		390	There is no support for WxWidgets, as WxWidgets has no support for
		391	watching file handles. However, you can use WxWidgets through the
		392	POE Adaptor, as POE has a Wx backend that simply polls 20 times per
		393	second, which was considered to be too horrible to even consider for
		394	AnyEvent. Likewise, other POE backends can be used by AnyEvent by using
		395	it's adaptor.
		396
		397	AnyEvent knows about L<Prima> and L<Wx> and will try to use L<POE> when
		398	autodetecting them.
363		399
364	=item AnyEvent::detect	400	=item AnyEvent::detect
365		401
366	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model	402	Returns C<$AnyEvent::MODEL>, forcing autodetection of the event model
367	if necessary. You should only call this function right before you would	403	if necessary. You should only call this function right before you would
…		…
418	no warnings;	454	no warnings;
419	use strict;	455	use strict;
420		456
421	use Carp;	457	use Carp;
422		458
423	our $VERSION = '3.12';	459	our $VERSION = '3.3';
424	our $MODEL;	460	our $MODEL;
425		461
426	our $AUTOLOAD;	462	our $AUTOLOAD;
427	our @ISA;	463	our @ISA;
428		464
…		…
435	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],	471	[Coro::Event:: => AnyEvent::Impl::CoroEvent::],
436	[EV:: => AnyEvent::Impl::EV::],	472	[EV:: => AnyEvent::Impl::EV::],
437	[Event:: => AnyEvent::Impl::Event::],	473	[Event:: => AnyEvent::Impl::Event::],
438	[Glib:: => AnyEvent::Impl::Glib::],	474	[Glib:: => AnyEvent::Impl::Glib::],
439	[Tk:: => AnyEvent::Impl::Tk::],	475	[Tk:: => AnyEvent::Impl::Tk::],
		476	[Wx:: => AnyEvent::Impl::POE::],
		477	[Prima:: => AnyEvent::Impl::POE::],
440	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],	478	[AnyEvent::Impl::Perl:: => AnyEvent::Impl::Perl::],
		479	# everything below here will not be autoprobed as the pureperl backend should work everywhere
		480	[Event::Lib:: => AnyEvent::Impl::EventLib::], # too buggy
		481	[Qt:: => AnyEvent::Impl::Qt::], # requires special main program
		482	[POE::Kernel:: => AnyEvent::Impl::POE::], # lasciate ogni speranza
441	);	483	);
442		484
443	our %method = map +($_ => 1), qw(io timer condvar broadcast wait signal one_event DESTROY);	485	our %method = map +($_ => 1), qw(io timer signal child condvar broadcast wait one_event DESTROY);
444		486
445	sub detect() {	487	sub detect() {
446	unless ($MODEL) {	488	unless ($MODEL) {
447	no strict 'refs';	489	no strict 'refs';
448		490
		491	if ($ENV{PERL_ANYEVENT_MODEL} =~ /^([a-zA-Z]+)$/) {
		492	my $model = "AnyEvent::Impl::$1";
		493	if (eval "require $model") {
		494	$MODEL = $model;
		495	warn "AnyEvent: loaded model '$model' (forced by \$PERL_ANYEVENT_MODEL), using it.\n" if $verbose > 1;
		496	} else {
		497	warn "AnyEvent: unable to load model '$model' (from \$PERL_ANYEVENT_MODEL):\n$@" if $verbose;
		498	}
		499	}
		500
449	# check for already loaded models	501	# check for already loaded models
		502	unless ($MODEL) {
450	for (@REGISTRY, @models) {	503	for (@REGISTRY, @models) {
451	my ($package, $model) = @$_;	504	my ($package, $model) = @$_;
452	if (${"$package\::VERSION"} > 0) {	505	if (${"$package\::VERSION"} > 0) {
453	if (eval "require $model") {	506	if (eval "require $model") {
454	$MODEL = $model;	507	$MODEL = $model;
455	warn "AnyEvent: found model '$model', using it.\n" if $verbose > 1;	508	warn "AnyEvent: autodetected model '$model', using it.\n" if $verbose > 1;
456	last;	509	last;
		510	}
457	}	511	}
458	}	512	}
459	}
460		513
461	unless ($MODEL) {	514	unless ($MODEL) {
462	# try to load a model	515	# try to load a model
463		516
464	for (@REGISTRY, @models) {	517	for (@REGISTRY, @models) {
465	my ($package, $model) = @$_;	518	my ($package, $model) = @$_;
466	if (eval "require $package"	519	if (eval "require $package"
467	and ${"$package\::VERSION"} > 0	520	and ${"$package\::VERSION"} > 0
468	and eval "require $model") {	521	and eval "require $model") {
469	$MODEL = $model;	522	$MODEL = $model;
470	warn "AnyEvent: autoprobed and loaded model '$model', using it.\n" if $verbose > 1;	523	warn "AnyEvent: autoprobed model '$model', using it.\n" if $verbose > 1;
471	last;	524	last;
		525	}
472	}	526	}
		527
		528	$MODEL
		529	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event) or Glib.";
473	}	530	}
474
475	$MODEL
476	or die "No event module selected for AnyEvent and autodetect failed. Install any one of these modules: EV (or Coro+EV), Event (or Coro+Event), Glib or Tk.";
477	}	531	}
478		532
479	unshift @ISA, $MODEL;	533	unshift @ISA, $MODEL;
480	push @{"$MODEL\::ISA"}, "AnyEvent::Base";	534	push @{"$MODEL\::ISA"}, "AnyEvent::Base";
481	}	535	}
…		…
637		691
638	=head1 ENVIRONMENT VARIABLES	692	=head1 ENVIRONMENT VARIABLES
639		693
640	The following environment variables are used by this module:	694	The following environment variables are used by this module:
641		695
642	C<PERL_ANYEVENT_VERBOSE> when set to C<2> or higher, cause AnyEvent to	696	=over 4
643	report to STDERR which event model it chooses.	697
		698	=item C<PERL_ANYEVENT_VERBOSE>
		699
		700	By default, AnyEvent will be completely silent except in fatal
		701	conditions. You can set this environment variable to make AnyEvent more
		702	talkative.
		703
		704	When set to C<1> or higher, causes AnyEvent to warn about unexpected
		705	conditions, such as not being able to load the event model specified by
		706	C<PERL_ANYEVENT_MODEL>.
		707
		708	When set to C<2> or higher, cause AnyEvent to report to STDERR which event
		709	model it chooses.
		710
		711	=item C<PERL_ANYEVENT_MODEL>
		712
		713	This can be used to specify the event model to be used by AnyEvent, before
		714	autodetection and -probing kicks in. It must be a string consisting
		715	entirely of ASCII letters. The string C<AnyEvent::Impl::> gets prepended
		716	and the resulting module name is loaded and if the load was successful,
		717	used as event model. If it fails to load AnyEvent will proceed with
		718	autodetection and -probing.
		719
		720	This functionality might change in future versions.
		721
		722	For example, to force the pure perl model (L<AnyEvent::Impl::Perl>) you
		723	could start your program like this:
		724
		725	PERL_ANYEVENT_MODEL=Perl perl ...
		726
		727	=back
644		728
645	=head1 EXAMPLE PROGRAM	729	=head1 EXAMPLE PROGRAM
646		730
647	The following program uses an IO watcher to read data from STDIN, a timer	731	The following program uses an I/O watcher to read data from STDIN, a timer
648	to display a message once per second, and a condition variable to quit the	732	to display a message once per second, and a condition variable to quit the
649	program when the user enters quit:	733	program when the user enters quit:
650		734
651	use AnyEvent;	735	use AnyEvent;
652		736
…		…
796	$quit->broadcast;	880	$quit->broadcast;
797	});	881	});
798		882
799	$quit->wait;	883	$quit->wait;
800		884
		885
		886	=head1 BENCHMARK
		887
		888	To give you an idea of the performance and overheads that AnyEvent adds
		889	over the event loops themselves (and to give you an impression of the
		890	speed of various event loops), here is a benchmark of various supported
		891	event models natively and with anyevent. The benchmark creates a lot of
		892	timers (with a zero timeout) and I/O watchers (watching STDOUT, a pty, to
		893	become writable, which it is), lets them fire exactly once and destroys
		894	them again.
		895
		896	Rewriting the benchmark to use many different sockets instead of using
		897	the same filehandle for all I/O watchers results in a much longer runtime
		898	(socket creation is expensive), but qualitatively the same figures, so it
		899	was not used.
		900
		901	=head2 Explanation of the columns
		902
		903	I<watcher> is the number of event watchers created/destroyed. Since
		904	different event models feature vastly different performances, each event
		905	loop was given a number of watchers so that overall runtime is acceptable
		906	and similar between tested event loop (and keep them from crashing): Glib
		907	would probably take thousands of years if asked to process the same number
		908	of watchers as EV in this benchmark.
		909
		910	I<bytes> is the number of bytes (as measured by the resident set size,
		911	RSS) consumed by each watcher. This method of measuring captures both C
		912	and Perl-based overheads.
		913
		914	I<create> is the time, in microseconds (millionths of seconds), that it
		915	takes to create a single watcher. The callback is a closure shared between
		916	all watchers, to avoid adding memory overhead. That means closure creation
		917	and memory usage is not included in the figures.
		918
		919	I<invoke> is the time, in microseconds, used to invoke a simple
		920	callback. The callback simply counts down a Perl variable and after it was
		921	invoked "watcher" times, it would C<< ->broadcast >> a condvar once to
		922	signal the end of this phase.
		923
		924	I<destroy> is the time, in microseconds, that it takes to destroy a single
		925	watcher.
		926
		927	=head2 Results
		928
		929	name watchers bytes create invoke destroy comment
		930	EV/EV 400000 244 0.56 0.46 0.31 EV native interface
		931	EV/Any 100000 244 2.50 0.46 0.29 EV + AnyEvent watchers
		932	CoroEV/Any 100000 244 2.49 0.44 0.29 coroutines + Coro::Signal
		933	Perl/Any 100000 513 4.92 0.87 1.12 pure perl implementation
		934	Event/Event 16000 516 31.88 31.30 0.85 Event native interface
		935	Event/Any 16000 936 39.17 33.63 1.43 Event + AnyEvent watchers
		936	Glib/Any 16000 1357 98.22 12.41 54.00 quadratic behaviour
		937	Tk/Any 2000 1860 26.97 67.98 14.00 SEGV with >> 2000 watchers
		938	POE/Event 2000 6644 108.64 736.02 14.73 via POE::Loop::Event
		939	POE/Select 2000 6343 94.13 809.12 565.96 via POE::Loop::Select
		940
		941	=head2 Discussion
		942
		943	The benchmark does I<not> measure scalability of the event loop very
		944	well. For example, a select-based event loop (such as the pure perl one)
		945	can never compete with an event loop that uses epoll when the number of
		946	file descriptors grows high. In this benchmark, all events become ready at
		947	the same time, so select/poll-based implementations get an unnatural speed
		948	boost.
		949
		950	C<EV> is the sole leader regarding speed and memory use, which are both
		951	maximal/minimal, respectively. Even when going through AnyEvent, there are
		952	only two event loops that use slightly less memory (the C<Event> module
		953	natively and the pure perl backend), and no faster event models, not even
		954	C<Event> natively.
		955
		956	The pure perl implementation is hit in a few sweet spots (both the
		957	zero timeout and the use of a single fd hit optimisations in the perl
		958	interpreter and the backend itself, and all watchers become ready at the
		959	same time). Nevertheless this shows that it adds very little overhead in
		960	itself. Like any select-based backend its performance becomes really bad
		961	with lots of file descriptors (and few of them active), of course, but
		962	this was not subject of this benchmark.
		963
		964	The C<Event> module has a relatively high setup and callback invocation cost,
		965	but overall scores on the third place.
		966
		967	C<Glib>'s memory usage is quite a bit bit higher, but it features a
		968	faster callback invocation and overall ends up in the same class as
		969	C<Event>. However, Glib scales extremely badly, doubling the number of
		970	watchers increases the processing time by more than a factor of four,
		971	making it completely unusable when using larger numbers of watchers
		972	(note that only a single file descriptor was used in the benchmark, so
		973	inefficiencies of C<poll> do not account for this).
		974
		975	The C<Tk> adaptor works relatively well. The fact that it crashes with
		976	more than 2000 watchers is a big setback, however, as correctness takes
		977	precedence over speed. Nevertheless, its performance is surprising, as the
		978	file descriptor is dup()ed for each watcher. This shows that the dup()
		979	employed by some adaptors is not a big performance issue (it does incur a
		980	hidden memory cost inside the kernel, though, that is not reflected in the
		981	figures above).
		982
		983	C<POE>, regardless of underlying event loop (wether using its pure perl
		984	select-based backend or the Event module) shows abysmal performance and
		985	memory usage: Watchers use almost 30 times as much memory as EV watchers,
		986	and 10 times as much memory as both Event or EV via AnyEvent. Watcher
		987	invocation is almost 900 times slower than with AnyEvent's pure perl
		988	implementation. The design of the POE adaptor class in AnyEvent can not
		989	really account for this, as session creation overhead is small compared
		990	to execution of the state machine, which is coded pretty optimally within
		991	L<AnyEvent::Impl::POE>. POE simply seems to be abysmally slow.
		992
		993	=head2 Summary
		994
		995	Using EV through AnyEvent is faster than any other event loop, but most
		996	event loops have acceptable performance with or without AnyEvent.
		997
		998	The overhead AnyEvent adds is usually much smaller than the overhead of
		999	the actual event loop, only with extremely fast event loops such as the EV
		1000	adds AnyEvent significant overhead.
		1001
		1002	And you should simply avoid POE like the plague if you want performance or
		1003	reasonable memory usage.
		1004
		1005
		1006	=head1 FORK
		1007
		1008	Most event libraries are not fork-safe. The ones who are usually are
		1009	because they are so inefficient. Only L<EV> is fully fork-aware.
		1010
		1011	If you have to fork, you must either do so I<before> creating your first
		1012	watcher OR you must not use AnyEvent at all in the child.
		1013
		1014
		1015	=head1 SECURITY CONSIDERATIONS
		1016
		1017	AnyEvent can be forced to load any event model via
		1018	$ENV{PERL_ANYEVENT_MODEL}. While this cannot (to my knowledge) be used to
		1019	execute arbitrary code or directly gain access, it can easily be used to
		1020	make the program hang or malfunction in subtle ways, as AnyEvent watchers
		1021	will not be active when the program uses a different event model than
		1022	specified in the variable.
		1023
		1024	You can make AnyEvent completely ignore this variable by deleting it
		1025	before the first watcher gets created, e.g. with a C<BEGIN> block:
		1026
		1027	BEGIN { delete $ENV{PERL_ANYEVENT_MODEL} }
		1028
		1029	use AnyEvent;
		1030
		1031
801	=head1 SEE ALSO	1032	=head1 SEE ALSO
802		1033
803	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,	1034	Event modules: L<Coro::EV>, L<EV>, L<EV::Glib>, L<Glib::EV>,
804	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>.	1035	L<Coro::Event>, L<Event>, L<Glib::Event>, L<Glib>, L<Coro>, L<Tk>,
		1036	L<Event::Lib>, L<Qt>, L<POE>.
805		1037
806	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,	1038	Implementations: L<AnyEvent::Impl::CoroEV>, L<AnyEvent::Impl::EV>,
		1039	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>, L<AnyEvent::Impl::Glib>,
		1040	L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>, L<AnyEvent::Impl::EventLib>,
807	L<AnyEvent::Impl::CoroEvent>, L<AnyEvent::Impl::Event>,	1041	L<AnyEvent::Impl::Qt>, L<AnyEvent::Impl::POE>.
808	L<AnyEvent::Impl::Glib>, L<AnyEvent::Impl::Tk>, L<AnyEvent::Impl::Perl>.
809		1042
810	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.	1043	Nontrivial usage examples: L<Net::FCP>, L<Net::XMPP2>.
		1044
811		1045
812	=head1 AUTHOR	1046	=head1 AUTHOR
813		1047
814	Marc Lehmann <schmorp@schmorp.de>	1048	Marc Lehmann <schmorp@schmorp.de>
815	http://home.schmorp.de/	1049	http://home.schmorp.de/

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Comparing AnyEvent/lib/AnyEvent.pm (file contents): Revision 1.54 by root, Tue Apr 22 05:12:19 2008 UTC vs. Revision 1.83 by root, Fri Apr 25 13:39:08 2008 UTC

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Comparing AnyEvent/lib/AnyEvent.pm (file contents):
Revision 1.54 by root, Tue Apr 22 05:12:19 2008 UTC vs.
Revision 1.83 by root, Fri Apr 25 13:39:08 2008 UTC