xdrs
    A pointer to an XDR stream handle created by one of the XDR
    stream-handle creation routines.
 objpp
    A pointer to a pointer to the structure containing the data
    being converted. If objpp is zero, the xdr_reference routine
    allocates the necessary storage when decoding. This argument must
    be nonzero during encoding.
 objsize
    The size of the structure in bytes.
 objproc
    The XDR procedure that filters the structure between its local
    form and its external representation.