_D 22 include/linux/ctype.h #define isalnum(c) ((__ismask(c)&(_U|_L|_D)) != 0) _D 25 include/linux/ctype.h #define isdigit(c) ((__ismask(c)&(_D)) != 0) _D 26 include/linux/ctype.h #define isgraph(c) ((__ismask(c)&(_P|_U|_L|_D)) != 0) _D 28 include/linux/ctype.h #define isprint(c) ((__ismask(c)&(_P|_U|_L|_D|_SP)) != 0) _D 33 include/linux/ctype.h #define isxdigit(c) ((__ismask(c)&(_D|_X)) != 0)