Copybook (Programming)

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. A copybook is a section of code written in a high-level programming language or assembly language that can be copied and inserted into several different programs. It is often used to define the physical layout of program data, pieces of procedural code and prototypes. The term "copybook" may have originated from use of COBOL on IBM mainframe operating systems: COPY is the COBOL keyword for this, and the master item was stored as a "book" within a larger library of source code. RPG IV supports the COPYBOOK concept exactly as in COBOL; here COPYBOOKs are most commonly used to define PROTOTYPEs of RPG IV procedures.