ISDIGIT            38 gnulib-tests/test-inttostr.c #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)
ISDIGIT           296 lib/strftime.c #define ISDIGIT(Ch) ((unsigned int) (Ch) - L_('0') <= 9)
ISDIGIT           103 src/system.h   #define ISDIGIT(c) ((unsigned int) (c) - '0' <= 9)