For a normal end to operations, the application program can send a final request on all sessions. For an error or special condition, it can send the final request as well as store information about the nature of the error.

A VTAM® application program closes itself by issuing a CLOSE macroinstruction that specifies its ACB. The CLOSE request notifies VTAM to terminate the SSCP-LU session with the application program and to mark the program as no longer active in the VTAM network. When VTAM processes a CLOSE ACB, and that application is not enabled for persistence, it terminates all of the sessions related to that ACB. If the application is enabled for persistence, then the sessions are maintained for the duration of the time specified by the persistent sessions timer (PSTIMER on the SETLOGON).

• If the primary application program issues CLOSE to terminate its sessions, it also closes the backup extended recovery facility (XRF) sessions.
• If the primary application program issues CLSDST, it terminates an individual backup XRF session.
• If the backup application program issues CLOSE, it terminates the backup sessions and closes the backup application program.