With the IBM-supplied default setting for COBOL's reusable environment behavior (IGZERREO with NESTENC=NO), when a reusable environment is active and a nested enclave is created that contains a COBOL program, COBOL will diagnose this with error message IGZ0168S.

COBOL's reusable environment behavior can be modified (IGZERREO with NESTENC=YES) so that a nested enclave containing a COBOL program will continue to run, even though a reusable environment is still active in the parent enclave.

• When you run a COBOL program in a nested enclave.
• The COBOL program is not part of the reusable environment.
• When the nested enclave ends, all the resources associated with the nested enclave are freed.

If a STOP RUN is done in the nested enclave, it only terminates the nested enclave, and does not terminate the COBOL reusable environment.