Opaque Data

Opaque data is used in XDR to describe untyped data, that is, sequences of arbitrary bytes. It may be declared either as a fixed length or variable length array. Examples:

opaque diskblock[512]; --> char diskblock[512];
opaque filedata<1024>; --> struct {
                           u_int filedata_len;
                           char *filedata_val;
                     } filedata;