The get symbol service retrieves symbols from the symbol table in the dump directory. This service can also be used to initialize the BLSRESSY macro for your exit routine, whether your symbol is in the symbol table or not. IBM® recommends that you use this service prior to invoking the equate symbol service, which creates and adds entries to the symbol table. Use of these services can reduce the access time for subsequent references to the same control block or data area.

The get symbol service can retrieve literal values for symbols. The definition of a symbolic literal specifies the address space as LITERAL(0), which is an address space containing no storage.

Reference

For more information on the BLSRESSY mapping macro, see z/OS MVS™ Data Areas in the z/OS® Internet Library: &zosliburl;.