=item newXS
X<newXS>
-Used by C<xsubpp> to hook up XSUBs as Perl subs.
+Used by C<xsubpp> to hook up XSUBs as Perl subs. I<filename> needs to be
+static storage, as it is used directly as CvFILE(), without a copy being made.
=for hackers
Found in file op.c