Summary of Steps

When issuing the IEFSSREQ macro you can follow these steps:

Set up the environment:
- Obtain storage for control blocks
- Set up register 1 and 13 (Note that the save area must be accessible to the function routine.)
- Initialize the SSOB
- Initialize the SSOB function dependent area (if required)
- Initialize the SSIB (if necessary)
- Enter supervisor state (if necessary)
Make the request:
- Invoke IEFSSREQ
- Return to problem state (if necessary)
Check the return codes:
- Check the SSI return code in register 15 and the subsystem return code in SSOBRETN, and take appropriate action.
- Free the storage.

Example 5 in Examples — Subsystem Interface Routines shows a coding example of a routine making a request of a subsystem.