Using OPS/REXX › The Interaction of OPS/REXX with Other Languages › Requirements for Non-REXX External Functions

Requirements for Non-REXX External Functions

An OPS/REXX external function or routine not written in REXX must meet these requirements:

• It must be a load module. The CA OPS/MVS product uses the z/OS LOAD macro to load the external routine.
• If the routine is called from an AOF rule:
  • The load module must be reentrant.
  • The code must be able to run in cross-memory mode.
  • The code cannot issue SVC calls (such as GETMAIN, WTO, I/O, and so on).
  • The code cannot acquire resources from the home address space.

These restrictions are inflexible and require in-depth knowledge of cross-memory mode programming. In many cases, you must move data to areas accessible in cross-memory mode, suspend cross-memory mode to be able to call a system service, or both.