Variable sized class - C++

class StringChild : public StringBase
    {
public:
    //some non-virtual functions
    static StringChild* CreateMe(int size);
private:
    unsigned char iBuf[1];
    };

return new(malloc(__builtin_offsetof(StringChild ,iBuf[size]))) StringChild();

return new(malloc(__builtin_offsetof(StringChild ,iBuf[size]))) StringChild();

obj->~StringChild();
free(obj);