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

    This function converts 32-bit unsigned integers from host byte
    order to network byte order.
    Network byte order is the format in which data bytes are expected
    to be transmitted through a network. All hosts on a network
    should send data in network byte order. Not all hosts have an
    internal data representation format that is identical to the
    network byte order. The host byte order is the format in which
    bytes are ordered internally on a specific host. The host byte
    order on OpenVMS systems differs from the network byte order.
    This function is most often used with internet addresses.
    Network byte order places the byte with the most significant
    bits at lower addresses, whereas OpenVMS systems place the most
    significant bits at the highest address.
                                   NOTE
       The 64-bit return from OpenVMS Alpha systems has zero-
       extended bits in the high 32 bits of R0.