Casting struct into int

Question

Is there a clean way of casting a struct into an uint64_t or any other int, given that struct in <= to the sizeof int? The only thing I can think of is only an \'ok\' sol

Answer 1

A non-portable solution:

struct smallst {
  int a;
  char b;
};

void make_uint64_t(struct smallst *ps, uint64_t *pi) {
  memcpy(pi, ps, sizeof(struct smallst));
}

You may face problems if you, for example, pack the struct on a little-endian machine and unpack it on a big-endian machine.