ndk/prebuilt/linux-x86_64/lib/perl5/5.16.2/Thread.pm - android_tools - Git at Google

 package Thread;

 use strict;
 use warnings;
 no warnings 'redefine';

 our $VERSION = '3.02';
 $VERSION = eval $VERSION;

 BEGIN {
     use Config;
     if (! $Config{useithreads}) {
         die("This Perl not built to support threads\n");
     }
 }

 use threads 'yield';
 use threads::shared;

 require Exporter;
 our @ISA = qw(Exporter threads);
 our @EXPORT = qw(cond_wait cond_broadcast cond_signal);
 our @EXPORT_OK = qw(async yield);

 sub async (&;@) { return Thread->new(shift); }

 sub done { return ! shift->is_running(); }

 sub eval  { die("'eval' not implemented with 'ithreads'\n"); };
 sub flags { die("'flags' not implemented with 'ithreads'\n"); };

 1;

 __END__

 =head1 NAME

 Thread - Manipulate threads in Perl (for old code only)

 =head1 DEPRECATED

 The C<Thread> module served as the frontend to the old-style thread model,
 called I<5005threads>, that was introduced in release 5.005.  That model was
 deprecated, and has been removed in version 5.10.

 For old code and interim backwards compatibility, the C<Thread> module has
 been reworked to function as a frontend for the new interpreter threads
 (I<ithreads>) model.  However, some previous functionality is not available.
 Further, the data sharing models between the two thread models are completely
 different, and anything to do with data sharing has to be thought differently.
 With I<ithreads>, you must explicitly C<share()> variables between the
 threads.

 You are strongly encouraged to migrate any existing threaded code to the new
 model (i.e., use the C<threads> and C<threads::shared> modules) as soon as
 possible.

 =head1 HISTORY

 In Perl 5.005, the thread model was that all data is implicitly shared, and
 shared access to data has to be explicitly synchronized.  This model is called
 I<5005threads>.

 In Perl 5.6, a new model was introduced in which all is was thread local and
 shared access to data has to be explicitly declared.  This model is called
 I<ithreads>, for "interpreter threads".

 In Perl 5.6, the I<ithreads> model was not available as a public API; only as
 an internal API that was available for extension writers, and to implement
 fork() emulation on Win32 platforms.

 In Perl 5.8, the I<ithreads> model became available through the C<threads>
 module, and the I<5005threads> model was deprecated.

 In Perl 5.10, the I<5005threads> model was removed from the Perl interpreter.

 =head1 SYNOPSIS

     use Thread qw(:DEFAULT async yield);

     my $t = Thread->new(\&start_sub, @start_args);

     $result = $t->join;
     $t->detach;

     if ($t->done) {
         $t->join;
     }

     if($t->equal($another_thread)) {
         # ...
     }

     yield();

     my $tid = Thread->self->tid;

     lock($scalar);
     lock(@array);
     lock(%hash);

     my @list = Thread->list;

 =head1 DESCRIPTION

 The C<Thread> module provides multithreading support for Perl.

 =head1 FUNCTIONS

 =over 8

 =item $thread = Thread->new(\&start_sub)

 =item $thread = Thread->new(\&start_sub, LIST)

 C<new> starts a new thread of execution in the referenced subroutine. The
 optional list is passed as parameters to the subroutine. Execution
 continues in both the subroutine and the code after the C<new> call.

 C<Thread-&gt;new> returns a thread object representing the newly created
 thread.

 =item lock VARIABLE

 C<lock> places a lock on a variable until the lock goes out of scope.

 If the variable is locked by another thread, the C<lock> call will
 block until it's available.  C<lock> is recursive, so multiple calls
 to C<lock> are safe--the variable will remain locked until the
 outermost lock on the variable goes out of scope.

 Locks on variables only affect C<lock> calls--they do I<not> affect normal
 access to a variable. (Locks on subs are different, and covered in a bit.)
 If you really, I<really> want locks to block access, then go ahead and tie
 them to something and manage this yourself.  This is done on purpose.
 While managing access to variables is a good thing, Perl doesn't force
 you out of its living room...

 If a container object, such as a hash or array, is locked, all the
 elements of that container are not locked. For example, if a thread
 does a C<lock @a>, any other thread doing a C<lock($a[12])> won't
 block.

 Finally, C<lock> will traverse up references exactly I<one> level.
 C<lock(\$a)> is equivalent to C<lock($a)>, while C<lock(\\$a)> is not.

 =item async BLOCK;

 C<async> creates a thread to execute the block immediately following
 it.  This block is treated as an anonymous sub, and so must have a
 semi-colon after the closing brace. Like C<Thread-&gt;new>, C<async>
 returns a thread object.

 =item Thread->self

 The C<Thread-E<gt>self> function returns a thread object that represents
 the thread making the C<Thread-E<gt>self> call.

 =item Thread->list

 Returns a list of all non-joined, non-detached Thread objects.

 =item cond_wait VARIABLE

 The C<cond_wait> function takes a B<locked> variable as
 a parameter, unlocks the variable, and blocks until another thread
 does a C<cond_signal> or C<cond_broadcast> for that same locked
 variable. The variable that C<cond_wait> blocked on is relocked
 after the C<cond_wait> is satisfied.  If there are multiple threads
 C<cond_wait>ing on the same variable, all but one will reblock waiting
 to reaquire the lock on the variable.  (So if you're only using
 C<cond_wait> for synchronization, give up the lock as soon as
 possible.)

 =item cond_signal VARIABLE

 The C<cond_signal> function takes a locked variable as a parameter and
 unblocks one thread that's C<cond_wait>ing on that variable. If more than
 one thread is blocked in a C<cond_wait> on that variable, only one (and
 which one is indeterminate) will be unblocked.

 If there are no threads blocked in a C<cond_wait> on the variable,
 the signal is discarded.

 =item cond_broadcast VARIABLE

 The C<cond_broadcast> function works similarly to C<cond_signal>.
 C<cond_broadcast>, though, will unblock B<all> the threads that are
 blocked in a C<cond_wait> on the locked variable, rather than only
 one.

 =item yield

 The C<yield> function allows another thread to take control of the
 CPU. The exact results are implementation-dependent.

 =back

 =head1 METHODS

 =over 8

 =item join

 C<join> waits for a thread to end and returns any values the thread
 exited with.  C<join> will block until the thread has ended, though
 it won't block if the thread has already terminated.

 If the thread being C<join>ed C<die>d, the error it died with will
 be returned at this time. If you don't want the thread performing
 the C<join> to die as well, you should either wrap the C<join> in
 an C<eval> or use the C<eval> thread method instead of C<join>.

 =item detach

 C<detach> tells a thread that it is never going to be joined i.e.
 that all traces of its existence can be removed once it stops running.
 Errors in detached threads will not be visible anywhere - if you want
 to catch them, you should use $SIG{__DIE__} or something like that.

 =item equal

 C<equal> tests whether two thread objects represent the same thread and
 returns true if they do.

 =item tid

 The C<tid> method returns the tid of a thread. The tid is
 a monotonically increasing integer assigned when a thread is
 created. The main thread of a program will have a tid of zero,
 while subsequent threads will have tids assigned starting with one.

 =item done

 The C<done> method returns true if the thread you're checking has
 finished, and false otherwise.

 =back

 =head1 DEFUNCT

 The following were implemented with I<5005threads>, but are no longer
 available with I<ithreads>.

 =over 8

 =item lock(\&sub)

 With 5005threads, you could also C<lock> a sub such that any calls to that sub
 from another thread would block until the lock was released.

 Also, subroutines could be declared with the C<:locked> attribute which would
 serialize access to the subroutine, but allowed different threads
 non-simultaneous access.

 =item eval

 The C<eval> method wrapped an C<eval> around a C<join>, and so waited for a
 thread to exit, passing along any values the thread might have returned and
 placing any errors into C<$@>.

 =item flags

 The C<flags> method returned the flags for the thread - an integer value
 corresponding to the internal flags for the thread.

 =back

 =head1 SEE ALSO

 L<threads>, L<threads::shared>, L<Thread::Queue>, L<Thread::Semaphore>

 =cut
	package Thread;

	use strict;
	use warnings;
	no warnings 'redefine';

	our $VERSION = '3.02';
	$VERSION = eval $VERSION;

	BEGIN {
	use Config;
	if (! $Config{useithreads}) {
	die("This Perl not built to support threads\n");
	}
	}

	use threads 'yield';
	use threads::shared;

	require Exporter;
	our @ISA = qw(Exporter threads);
	our @EXPORT = qw(cond_wait cond_broadcast cond_signal);
	our @EXPORT_OK = qw(async yield);

	sub async (&;@) { return Thread->new(shift); }

	sub done { return ! shift->is_running(); }

	sub eval { die("'eval' not implemented with 'ithreads'\n"); };
	sub flags { die("'flags' not implemented with 'ithreads'\n"); };

	1;

	__END__

	=head1 NAME

	Thread - Manipulate threads in Perl (for old code only)

	=head1 DEPRECATED

	The C<Thread> module served as the frontend to the old-style thread model,
	called I<5005threads>, that was introduced in release 5.005. That model was
	deprecated, and has been removed in version 5.10.

	For old code and interim backwards compatibility, the C<Thread> module has
	been reworked to function as a frontend for the new interpreter threads
	(I<ithreads>) model. However, some previous functionality is not available.
	Further, the data sharing models between the two thread models are completely
	different, and anything to do with data sharing has to be thought differently.
	With I<ithreads>, you must explicitly C<share()> variables between the
	threads.

	You are strongly encouraged to migrate any existing threaded code to the new
	model (i.e., use the C<threads> and C<threads::shared> modules) as soon as
	possible.

	=head1 HISTORY

	In Perl 5.005, the thread model was that all data is implicitly shared, and
	shared access to data has to be explicitly synchronized. This model is called
	I<5005threads>.

	In Perl 5.6, a new model was introduced in which all is was thread local and
	shared access to data has to be explicitly declared. This model is called
	I<ithreads>, for "interpreter threads".

	In Perl 5.6, the I<ithreads> model was not available as a public API; only as
	an internal API that was available for extension writers, and to implement
	fork() emulation on Win32 platforms.

	In Perl 5.8, the I<ithreads> model became available through the C<threads>
	module, and the I<5005threads> model was deprecated.

	In Perl 5.10, the I<5005threads> model was removed from the Perl interpreter.

	=head1 SYNOPSIS

	use Thread qw(:DEFAULT async yield);

	my $t = Thread->new(\&start_sub, @start_args);

	$result = $t->join;
	$t->detach;

	if ($t->done) {
	$t->join;
	}

	if($t->equal($another_thread)) {
	# ...
	}

	yield();

	my $tid = Thread->self->tid;

	lock($scalar);
	lock(@array);
	lock(%hash);

	my @list = Thread->list;

	=head1 DESCRIPTION

	The C<Thread> module provides multithreading support for Perl.

	=head1 FUNCTIONS

	=over 8

	=item $thread = Thread->new(\&start_sub)

	=item $thread = Thread->new(\&start_sub, LIST)

	C<new> starts a new thread of execution in the referenced subroutine. The
	optional list is passed as parameters to the subroutine. Execution
	continues in both the subroutine and the code after the C<new> call.

	C<Thread->new> returns a thread object representing the newly created
	thread.

	=item lock VARIABLE

	C<lock> places a lock on a variable until the lock goes out of scope.

	If the variable is locked by another thread, the C<lock> call will
	block until it's available. C<lock> is recursive, so multiple calls
	to C<lock> are safe--the variable will remain locked until the
	outermost lock on the variable goes out of scope.

	Locks on variables only affect C<lock> calls--they do I<not> affect normal
	access to a variable. (Locks on subs are different, and covered in a bit.)
	If you really, I<really> want locks to block access, then go ahead and tie
	them to something and manage this yourself. This is done on purpose.
	While managing access to variables is a good thing, Perl doesn't force
	you out of its living room...

	If a container object, such as a hash or array, is locked, all the
	elements of that container are not locked. For example, if a thread
	does a C<lock @a>, any other thread doing a C<lock($a[12])> won't
	block.

	Finally, C<lock> will traverse up references exactly I<one> level.
	C<lock(\$a)> is equivalent to C<lock($a)>, while C<lock(\\$a)> is not.

	=item async BLOCK;

	C<async> creates a thread to execute the block immediately following
	it. This block is treated as an anonymous sub, and so must have a
	semi-colon after the closing brace. Like C<Thread->new>, C<async>
	returns a thread object.

	=item Thread->self

	The C<Thread-E<gt>self> function returns a thread object that represents
	the thread making the C<Thread-E<gt>self> call.

	=item Thread->list

	Returns a list of all non-joined, non-detached Thread objects.

	=item cond_wait VARIABLE

	The C<cond_wait> function takes a B<locked> variable as
	a parameter, unlocks the variable, and blocks until another thread
	does a C<cond_signal> or C<cond_broadcast> for that same locked
	variable. The variable that C<cond_wait> blocked on is relocked
	after the C<cond_wait> is satisfied. If there are multiple threads
	C<cond_wait>ing on the same variable, all but one will reblock waiting
	to reaquire the lock on the variable. (So if you're only using
	C<cond_wait> for synchronization, give up the lock as soon as
	possible.)

	=item cond_signal VARIABLE

	The C<cond_signal> function takes a locked variable as a parameter and
	unblocks one thread that's C<cond_wait>ing on that variable. If more than
	one thread is blocked in a C<cond_wait> on that variable, only one (and
	which one is indeterminate) will be unblocked.

	If there are no threads blocked in a C<cond_wait> on the variable,
	the signal is discarded.

	=item cond_broadcast VARIABLE

	The C<cond_broadcast> function works similarly to C<cond_signal>.
	C<cond_broadcast>, though, will unblock B<all> the threads that are
	blocked in a C<cond_wait> on the locked variable, rather than only
	one.

	=item yield

	The C<yield> function allows another thread to take control of the
	CPU. The exact results are implementation-dependent.

	=back

	=head1 METHODS

	=over 8

	=item join

	C<join> waits for a thread to end and returns any values the thread
	exited with. C<join> will block until the thread has ended, though
	it won't block if the thread has already terminated.

	If the thread being C<join>ed C<die>d, the error it died with will
	be returned at this time. If you don't want the thread performing
	the C<join> to die as well, you should either wrap the C<join> in
	an C<eval> or use the C<eval> thread method instead of C<join>.

	=item detach

	C<detach> tells a thread that it is never going to be joined i.e.
	that all traces of its existence can be removed once it stops running.
	Errors in detached threads will not be visible anywhere - if you want
	to catch them, you should use $SIG{__DIE__} or something like that.

	=item equal

	C<equal> tests whether two thread objects represent the same thread and
	returns true if they do.

	=item tid

	The C<tid> method returns the tid of a thread. The tid is
	a monotonically increasing integer assigned when a thread is
	created. The main thread of a program will have a tid of zero,
	while subsequent threads will have tids assigned starting with one.

	=item done

	The C<done> method returns true if the thread you're checking has
	finished, and false otherwise.

	=back

	=head1 DEFUNCT

	The following were implemented with I<5005threads>, but are no longer
	available with I<ithreads>.

	=over 8

	=item lock(\&sub)

	With 5005threads, you could also C<lock> a sub such that any calls to that sub
	from another thread would block until the lock was released.

	Also, subroutines could be declared with the C<:locked> attribute which would
	serialize access to the subroutine, but allowed different threads
	non-simultaneous access.

	=item eval

	The C<eval> method wrapped an C<eval> around a C<join>, and so waited for a
	thread to exit, passing along any values the thread might have returned and
	placing any errors into C<$@>.

	=item flags

	The C<flags> method returned the flags for the thread - an integer value
	corresponding to the internal flags for the thread.

	=back

	=head1 SEE ALSO

	L<threads>, L<threads::shared>, L<Thread::Queue>, L<Thread::Semaphore>

	=cut