Extended Program Model Description

OPM continues to serve a useful purpose. However, OPM does not provide direct support for procedures as defined in languages like C. A procedure is a set of self-contained high-level language (HLL) statements that performs a particular task and then returns to the caller. Individual languages vary in the way that a procedure is defined. In C, a procedure is called a function.

To allow languages that define procedure calls between compilation units or languages that define procedures with local variables to run on the operating system, OPM was enhanced. These enhancements are called the Extended Program Model (EPM). Before ILE, EPM served as an interim solution for procedure-based languages like Pascal and C.

The IBM® i operating system no longer provides any EPM compilers.