isalpha
#define isalpha(x) (is_alpha[x])
#define isalpha(c) __sbistype((c), _CTYPE_A)
#undef isalpha
#define isalpha(c) _bcs_isalpha(c)
#undef isalpha
#define isalpha(c) _bcs_isalpha(c)
#undef isalpha
isalpha(int c)
isalpha(int c)
#define isalpha(c) (isupper(c) || islower(c))