Functions in Free-Format RPG IV

Here is the ultimate guide to writing RPG IV programs with functions in the free-format style. Let RPG expert and bestselling author Jim Martin show you the way. Want to generate a random number, manipulate a character string, or determine the number of elements in a data structure? There's a function for that. Jim will even show you how to write your own custom built-in functions (BIFs).

In this book, you will discover the role of functions in free-format RPG IV. Jim explains the details of BIFs and explores the use of C language functions, do-it-yourself functions (subprocedures), and prototyping and procedure interfaces for function connectivity of RPG IV main procedures with subprocedures and other modules. Because functions rely heavily on ILE, the book examines those ILE concepts that connect the parts of a multi-functional program, such as binding, import/export of data, service programs, and binding directories. In addition, you?ll find how to prototype IBM's APIs.

Modular programming is important, and it is powerful. Programmers need to understand modular concepts in depth, including all the interfacing tools needed to make programs perform well. Inside this book, you will find everything a free-format RPG IV programmer needs to know about using existing RPG IV BIFs, writing new functions, leveraging ILE concepts to use C functions, and using IBM APIs as functions.

With Functions in Free-Format RPG IV, you will:

• Take your free-format skills to the next level
• Master the entire range of functions and effectively leverage them
• Acquire the knowledge necessary to write your own functions
• Combine and nest built-in functions, subprocedures, C functions, and IBM APIs to produce highly modularized programs
• Understand ILE concepts such as binding by copy, binding by reference, import/export of data, service programs, signatures, and binding directories
• Learn how to analyze needs for a new program with respect to modularization and functions