If an exit requires an update-mode JOA, but cannot wait for a possible conflict to be resolved, use the following logic path:

1. Perform the action:

   $DOGJOE ACTION=(FETCH,UPDATE), JOE=joa, WAIT=NO

   where joa is the address of the JOA that IBM code provides to the exit.
2. If JES2 returns a return code indicating that the update mode JOA could not be created, you must manage the situation of lock not available.
3. If RC=0, perform rest of the exit logic by using the update mode JOA.
4. Perform the action:

   $DOGJOE ACTION=RETURN, CBADDR=joa

   where joa is the address that is returned in R0 from FETCH in the first step.