The RTEREUS runtime option for initializing the COBOL reusable environment is supported by Language Environment, although it is not recommended as an installation default. For important considerations, see the RTEREUS discussion under Recommended runtime options for non-CICS applications. For RES environments, the behavior of RTEREUS is the same as it was in VS COBOL II with the exception of using SVC LINK (for example, ISPF "SELECT PGM()").
Under Language Environment, if an assembler program issues an SVC LINK while running in a reusable environment, Language Environment raises a condition resulting in severity-3 message IGZ0168S. With VS COBOL II, no error is detected, but the secondary run unit's environment is not reusable. You can modify the behavior under Language Environment to be similar to the behavior under VS COBOL II by modifying the IGZERREO CSECT. However, a STOP RUN in the nested enclave will terminate only the nested enclave and not the parent enclave.
If the operating system is the invoker of the first COBOL program, RTEREUS will be ignored.
You can specify RTEREUS using the installation-wide default routine CEEDOPT, the application-specific options routine CEEUOPT, or in the assembler user exit.
For important IMS considerations see Precautions if establishing a reusable environment under IMS.