format             80 kernel/defs.h  int            printf(char*, ...) __attribute__ ((format (printf, 1, 2)));
format             32 user/user.h    void fprintf(int, const char*, ...) __attribute__ ((format (printf, 2, 3)));
format             33 user/user.h    void printf(const char*, ...) __attribute__ ((format (printf, 1, 2)));