Type SANE_String represents a text string as a sequence
of C char values. The end of the sequence is indicated by a
'\0' (NUL) character.
typedef SANE_Char *SANE_String; typedef const SANE_Char *SANE_String_Const;The type SANE_String_Const is provided by SANE to enable declaring strings whose contents is unchangable. Note that in ANSI C, the declaration
const SANE_String str;declares a string pointer that is constant (not a string pointer that points to a constant value).