According to <http://udrepper.livejournal.com/16362.html>, "it is
completely unacceptable today to use gethostbyname etc. These functions
simply don't work."

<http://people.redhat.com/drepper/userapi-ipv6.html> states that
gethostbyname is a historic call, and gethostbyname2 is only a stop-gap
solution. Apparently we should all by using getaddrinfo these days--but
the glibc manual does not document this function!

Section 16.6.2.4 "Host Names" documents fully the gethostbyname family
of calls, and says of the replacement calls only that "You can also use
`getaddrinfo' and `getnameinfo' to obtain this information". This makes
it sound rather like getaddrinfo, etc. are optional supplements to the
primary interface that most people use, gethostbyname.