Set Up the Environment

With exceptions, your requesting program must be in the same state (problem or supervisor) as the subsystem. For IBM-supplied functions, see the specific function code descriptions in SSI Function Codes Your Program Can Request for information on the environmental requirements that must be met. The SSI supports address mode (AMODE) switching. Your program must include mapping macros for the CVT and the JESCT control blocks.

Note that the IEFSSREQ macro uses the JESSSREQ field in the JESCT control block to locate the SSI routing routine.

You must tell the SSI the function you are requesting and the subsystem with which you want to communicate. You make a request by obtaining storage for the following control blocks:

SSOB
SSOB function dependent area (if required)
SSIB.

These control blocks, and your program's save area, must reside in an area addressable by the called subsystem's function routine.