// see getaddrinfo(3): only return address if system has such a address configured
// useful if system is ipv4 only, to not get ipv6, but that fails if the system has
// no address configured: e.g. offline and trying to connect to localhost.
// see getaddrinfo(3): only return address if system has such a address configured
// useful if system is ipv4 only, to not get ipv6, but that fails if the system has
// no address configured: e.g. offline and trying to connect to localhost.