#define _C_DIGIT 8 /* Digits */
#define _C_CTRL 16 /* Control characters */
#define _C_XDIGIT 32 /* Hexadecimal digits */
-#define _C_BLANK 64 /* Blanks */
+#define _C_BLANK 64 /* White spaces (spaces, tabs, newlines) */
#define _C_INNER 128 /* `inner punctuation' -- underscore etc. */
#define _C_ALPHA (_C_UPPER | _C_LOWER)