XDR Library Filter Primitives

The eXternal Data Representation (XDR) primitives are subroutines that define the basic and constructed data types.

The XDR language provides programmers with a specification for uniform representations that includes filter primitives for basic and constructed data types. The basic data types include integers, enumerations, booleans, hyperintegers, floating points, and void data. The constructed data types include strings, structures, byte arrays, arrays, opaque data, unions, and pointers.

The XDR standard translates both basic and constructed data types. For basic data types, XDR provides basic filter primitives (see XDR Basic Filter Primitives) that serialize information from the local host's representation to the XDR representation and deserialize information from the XDR representation to the local host's representation. For constructed data types, XDR provides constructed filter primitives (see XDR Constructed Filter Primitives) that allow the use of basic data types, such as integers and floating-point numbers, to create more complex constructs such as arrays and discriminated unions.

Remote Procedure Calls (RPCs) use XDR to establish uniform representations for data types to transfer the call message data between machines. Although the XDR constructs resemble the C programming language, C language constructs define the code for programs. XDR, however, standardizes the representation of data types directly in the programming code.