As described in Using the RACF callable services, Linkage Conventions for the Callable Services, IRRSXT00 is invoked by the SAF callable services router before and after RACF® is called. It receives as input, a function code indicating which callable service is being called, and the parameter list that will be passed to RACF. The first parameter in the parameter list points to a work area. The exit can use the first 152 bytes of this work area. The first word of the work area is set to zero before the pre-RACF call to the exit. the exit should set another value in this word to indicate to the post-RACF exit call that it is the second call. The first four words of the work area are passed unchanged from the pre-RACF to the post-RACF exit.

The pre-RACF exit can change the content of the parameter list that will be passed to the external security product. It can also indicate with return codes that the external security product should be bypassed and control returned to the caller. The SAF return code is set based on the exit return code. If the external security product is bypassed, the exit routine must provide all of the output including RACF-compatible return and reason codes that the invokers of the services expect.

The post-RACF exit can look at or change the output from RACF including the RACF return and reason codes. No exit return codes are defined from this exit call. SAF return codes are set based on the RACF return codes, not on an exit return code.