To make backward-compatible changes to an ILE C/C++ service program, you use the binder language. This language allows you to define a list of procedure names and data item names that can be exported. The Export Symbol (EXPORT) command in the binder language identifies the procedure and data item names that make up the signature for the service program module.
New procedure or data item names should be added to the end of the export list to ensure changes are compatible. A signature is generated by the order in which the modules are processed and the order in which the symbols are exported from the copied modules. A service program becomes difficult to update once the exports are used by other ILE C/C++ programs. If the service program is changed, the order or number of exports could change. If the signature changes all ILE C/C++ programs and service programs that use the changed service program have to be re-created.
The following example shows how to add a new procedure called cost2() to service program COST without having to re-create the existing program COSTDPT1 that requires an export from COST.
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