The global DESERV exit can be established for the system following the initialization of LPA. When establishing a global exit, obtain the DST (DESERV Screen Table) storage in common storage. The DST is used to identify a DESERV exit. Once established, the DESERV exit gets control anytime DESERV GET, PUT, RENAME, DELETE, or UPDATE functions are called. The exit entry point is given control twice for each invocation, once before DESERV is executed, and once immediately after the return from the DESERV function. The call to the exit indicates whether this call is before or after DESERV executes. The global exit routine must reside in commonly addressable storage.

If a DESERV FUNC=GET call is made for which there are no PDSEs in the concatenation, the DESERV code issues BLDL to search for the requested names. The global exit is called in this case. If both the SVCUPDTE facility and the DESERV global exit are used, before implementing the global DESERV exit consider the interactions of the DESERV global exit and the routine that is given control when the SVC is issued.