* isascii(3), i.e. is outside [0, 0x7f]. If start is NULL it returns
* false. Bytes are examined until a NUL byte, or, if end is not NULL,
* whilst start is before end. */
* isascii(3), i.e. is outside [0, 0x7f]. If start is NULL it returns
* false. Bytes are examined until a NUL byte, or, if end is not NULL,
* whilst start is before end. */