Byte Arrays

Often variable-length arrays of bytes are preferable to strings. Byte arrays differ from strings in the following three ways: (1) the length of the array (the byte count) is explicitly located in an unsigned integer, (2) the byte sequence is not terminated by a null character, and (3) the external representation of the bytes is the same as their internal representation. The primitive xdr_bytes() converts between the internal and external representations of byte arrays:

bool_t xdr_bytes(xdrs, bpp, lp, maxlength)
   XDR *xdrs;
   char **bpp;
   u_int *lp;
   u_int maxlength;

The usage of the first, second, and fourth parameters is identical to the first, second and third parameters of xdr_string() respectively. The length of the byte area is obtained by dereferencing lp when serializing; *lp is set to the byte length when deserializing.