-# define ISSPACE(Ch) isspace (Ch)
-# define ISALPHA(Ch) isalpha (Ch)
-# define TOUPPER(Ch) toupper (Ch)
+# define ISSPACE(Ch) (IN_CTYPE_DOMAIN (Ch) && isspace (Ch))
+# define ISALPHA(Ch) (IN_CTYPE_DOMAIN (Ch) && isalpha (Ch))
+# define TOUPPER(Ch) (IN_CTYPE_DOMAIN (Ch) ? toupper (Ch) : (Ch))