ext/PerlIO/Scalar/Scalar.pm PerlIO layer for scalars
ext/PerlIO/Scalar/Scalar.xs PerlIO layer for scalars
ext/PerlIO/t/encoding.t See if PerlIO encoding conversion works
+ext/PerlIO/t/fail.t See if bad layers fail
ext/PerlIO/t/fallback.t See if PerlIO fallbacks work
ext/PerlIO/t/scalar.t See if PerlIO::Scalar works
ext/PerlIO/t/via.t See if PerlIO::Via works