> If there exist a getaddrinfo_a() in the posix standard, In principle, if you can assume modern POSIX, then you can also spawn a POSIX thread to call getaddri

> If there exist a getaddrinfo_a() in the posix standard, In principle, if you can assume modern POSIX, then you can also spawn a POSIX thread to call getaddrinfo() and wait asynchronously for the result. In practice getaddrinfo() isn't always thread-safe :/ But it's supposed to be.