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

    EACCES             The calling process does not have appropriate
                       permissions.
    EBADF              The socket descriptor is invalid.
    EDOM               The send and receive timeout values are too
                       large to fit in the timeout fields of the
                       socket structure.
    EFAULT             The address pointed to by the optval argument
                       is not in a valid (writable) part of the
                       process space, or the optlen argument is not
                       in a valid part of the process address space.
    EINVAL             The optval or optlen argument is invalid; or
                       the socket is shut down.
    ENOBUFS            The system has insufficient resources to
                       complete the call.
    ENOTSOCK           The socket descriptor is invalid.
    ENOPROTOOPT        The option is unknown or the protocol is
                       unsupported.
    EOPNOTSUPP         The operation is not supported by the socket
                       protocol.
    ENOPROTOOPT        The option is unknown.
    ENOTSOCK           The socket descriptor is invalid.