VMS Help TCPIP Services, Programming Interfaces, Sockets API, getsockname(), Arguments  *Conan The Librarian (sorry for the slow response - running on an old VAX)

 s
    A socket descriptor created with socket() function and bound to
    the socket name with the bind() function.
 name
    A pointer to the buffer in which getsockname() should return the
    socket name.
 namelen
    A pointer to an integer containing the size of the buffer pointed
    to by name. On return, the integer contains the actual size, in
    bytes, of the name returned.