ref: 7bf8c43ed5c66b80bb4c9b1ac1c6fdcfe72b9f19 dir: /lib/c/isxdigit.c/
#define __USE_MACROS #include <ctype.h> #undef isxdigit int isxdigit(int c) { return (__ctype+1)[c] & (_D|_X); }