isdigit
#define isdigit(c) __sbistype((c), _CTYPE_D)
#undef isdigit
#define isdigit(c) _bcs_isdigit(c)
#undef isdigit
#define isdigit(c) _bcs_isdigit(c)
#undef isdigit
isdigit(int c)
#define isdigit(x) ((x) >= '0' && (x) <= '9')
static __inline int isdigit(int c)
# define isdigit(x) ((x) >= '0' && (x) <= '9')
isdigit(int c)
inline bool isdigit(char c)