Hum...
Apparently, before this bug was fixed, glibc's getaddrinfo() would
retrieve the list of interfaces at every call, even if AI_ADDRCONFIG
was not set:
http://sourceware.org/git/?p=glibc.git;a=commitdiff;h=fa3fc0fe5f452d0aa7e435d8f32e992958683819

Which can mean a large overhead.
Also, from a quick look at the source, it will also retrieve the list
of interfaces if more than one address matches (e.g. for TCP, UDP, or
if AF_UNSPEC is passed).
So using getaddrinfo() could incur a non-negligible overhead.

So it might be better to just use inet_pton() instead.