Service programs are typically used for common routines that are frequently called within an application and across applications. For example, the ILE COBOL compiler uses service programs to provide runtime services such as math functions and input/output routines. Service programs enable reuse of source programs, simplify maintenance, and reduce storage requirements. In many respects, a service program is similar to a subroutine library or procedure library.
You can update a service program without having to re-create the other program objects or service programs that use the updated service program provided that the interface is unchanged or changed only in an upward compatible manner. You control whether the changes are compatible with the existing support provided by the service program. To make compatible changes to a service program, new procedure names or data names should be added to the end of the export list and the same signature as before must be retained.
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