sa
    Points either to a sockaddr_in structure (for IPv4) or to a
    sockaddr_in6 structure (for IPv6) that holds the IP address and
    port number.
 salen
    Specifies the length of either the sockaddr_in structure or the
    sockaddr_in6 structure.
 node
    Points to a buffer in which to receive the null-terminated
    network node name or alias corresponding to the address contained
    in the sa. A NULL pointer instructs getnameinfo() to not return
    a node name. The node argument and service argument must not both
    be zero.
 nodelen
    Specifies the length of the node buffer. A value of zero
    instructs getnameinfo() to not return a node name.
 service
    Points to a buffer in which to receive the null-terminated
    network service name associated with the port number contained
    in sa. A NULL pointer instructs getnameinfo() to not return a
    service name. The node argument and service argument must not
    both be 0.
 servicelen
    Specifies the length of the service buffer. A value of zero
    instructs getnameinfo() to not return a service name.
 flags
    Specifies changes to the default actions of getnameinfo(). By
    default, getnameinfo() searches for the fully-qualified domain
    name of the node in the hosts database and returns it. See Flags
    for a list of flags and their meanings.