throw an exception when any of C<sysread()>, C<recv()>, C<syswrite()> or C<send()>
are called on handle with the C<:utf8> layer.
+=head2 Signatured subs should not rely on @_
+
+Currently the experimental subroutine signature facility still populates
+C<@_> in addition to setting the parameter variables. In the next major
+release of perl this is likely to change, so that C<@_> is not populated by
+default (although a new mechanism will be provided to re-enable it).
+
=head1 Performance Enhancements
=over 4
return 123;
}
-When using a signature, the arguments are still available in the special
-array variable C<@_>, in addition to the lexical variables of the
-signature. There is a difference between the two ways of accessing the
+When using a signature, the arguments are currently still available in the
+special array variable C<@_>, in addition to the lexical variables of the
+signature, but in a future release of perl that may change to being not
+available by default. There is a difference between the two ways of
+accessing the
arguments: C<@_> I<aliases> the arguments, but the signature variables
get I<copies> of the arguments. So writing to a signature variable
only changes that variable, and has no effect on the caller's variables,