To stop using VTAM® services, an application program uses the CLOSE macroinstruction. The CLOSE macroinstruction terminates all sessions that VTAM started for the application program and halts communication between VTAM and the application program. As far as VTAM is concerned, the application program becomes totally inactive. The application program can continue to perform other processing not related to VTAM, however.

For more details on ACBs and the OPEN and CLOSE processes, refer to z/OS Communications Server: SNA Programming.