The SunOS XDR Library

The SunOS library contains functions to convert each of the primitive types to/from their XDR representation.

• Users write their own functions to convert more complex data structures.

• Each XDR conversion routine (including those written by users) takes two parameters: an XDR stream pointer and a pointer to the data to convert.

• An XDR stream is a handle which is used to specify the source/destination of XDR data.

• Ways exist of obtaining XDR streams which are connected to standard input/output (e.g. files opened using fopen()), memory (useful for bundling data before sending it off as a datagram), and TCP/IP stream connections.

• When an XDR stream is created the user specifies whether it will be used for encoding (symbolic constant XDR_ENCODE) or decoding (symbolic constant XDR_DECODE).

• The same XDR conversion routines are used for both encoding and decoding data: the type of the XDR stream tells the conversion routine what to do.