You can in general use the WORKING-STORAGE SECTION to define working data that a client program needs. However, if the program could simultaneously run on multiple threads, you might instead want to define the data in the LOCAL-STORAGE SECTION.

Each thread has access to a separate copy of LOCAL-STORAGE data but shares access to a single copy of WORKING-STORAGE data. If you define the data in the WORKING-STORAGE SECTION, you need to synchronize access to the data or ensure that no two threads can access it simultaneously.