Consoles and Migration ID Exits › User Exits for Migration IDs › User Exit Requirements
User Exit Requirements
The migration ID determination user exit must meet the following requirements:
- The exit must be assembled and link-edited into an accessible load library. Any name is suitable (the name is specified in the SYSPARMS command to activate the user exit).
- Because your product region executes in APF-authorized mode, the exit must be in an APF-authorized library.
- The exit must obey standard linkage conventions:
- R1 contains the address of the parameter list.
- R2 to R12 must be saved on entry and restored on exit.
- R13 points to a standard save area.
- R14 holds the return address and AMODE.
- R15 holds the entry point address.
- The exit can be AMODE 24 or 31, and RMODE 24 or ANY. All parameters are passed below the 16M line. The exit is called in the link-edited AMODE. It returns using BSM 0,14 (with the value in R14 as at entry). However, BR 14 also works.
- The exit is called from the main task. It must not issue any operating system waits or use services that take a significant length of time. Doing so would severely impact processing.
- If the exit abends, it is disabled.