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

    EBADF              The socket descriptor is invalid.
    ECONNRESET         A connection was forcibly closed by a peer.
    EFAULT             The data was specified to be received into a
                       nonexistent or protected part of the process
                       address space.
    EINTR              A signal interrupted the recv() function
                       before any data was available.
    EINVAL             The MSG_OOB flag is set and no out-of-band
                       data is available.
    ENOBUFS            The system has insufficient resources to
                       complete the call.
    ENOMEM             The system did not have sufficient memory to
                       fulfill the request.
    ENOTCONN           A receive is attempted on a connection-
                       oriented socket that is not connected.
    ENOTSOCK           The socket descriptor is invalid.
    EOPNOTSUPP         The specified flags are not supported for this
                       socket type or protocol.
    EWOULDBLOCK        The socket is marked nonblocking, and no data
                       is waiting to be received.