ISDIGIT
#define ISDIGIT(x) isdigit((u_char)(x))
#define ISDIGIT(a) (((a) >= '0') && ((a) <= '9'))
#define ISDIGIT(x) isdigit((u_char)(x))
#define ISDIGIT(c) (isascii ((unsigned char)c) && isdigit ((unsigned char)c))