eui64_ntoa
int eui64_ntoa(const struct eui64 *, char *, size_t);
eui64_ntoa(id, eui64_a, sizeof(eui64_a));
eui64_ntoa(&eui, addr, sizeof(addr));
eui64_ntoa(&eui, addr, sizeof(addr));
eui64_ntoa(&eui, addr, sizeof(addr));