getaddrinfo(3)

protocol independent name-to-address lookup function
supercedes gethostbyname(3)
also converts numeric addresses
inet_pton(3) / inet_aton(3) / inet_addr(3)
we do not need to do both any longer!
sets up list of information for socket(2), connect(2)/bind(2)
family, socket type, protocol number, socket address structure etc.
User does not need to know sockaddr in detail.