Override a pointer attribute with a static array

typedef struct chlnglck{
    friend struct chlnglck_8;
    friend struct chlnglck_10;
    friend struct chlnglck_12;

    chlng nb;
    uint64_t wt;
}chlnglck;

struct chlnglck_8 : chlnglck{
    char ress[255];
    chlnglck();
};

struct chlnglck_10 : chlnglck{
    char ress[1024];
    chlnglck();
};

Here is my code. I would want to know how I could mention the ress attribute in the parent class chlnglck.

Is there a way or not knowing I have to use fixed size array in the child classes?

No std::string please.