eui64_ntoa
eui64_ntoa(id, eui64_a, sizeof(eui64_a));
eui64_ntoa(&e, buf, sizeof(buf));
ATF_REQUIRE_MSG(eui64_ntoa(&test_eui64_id, a, sizeof(a)) == 0,
int eui64_ntoa(const struct eui64 *, char *, size_t);
eui64_ntoa(&eui, addr, sizeof(addr));
eui64_ntoa(&eui, addr, sizeof(addr));
eui64_ntoa(&eui, addr, sizeof(addr));