When a user is finishing using a data set on a volume, EOV or CLOSE calls the file end on volume exit routine.

For input this exit is called from EOV unless it is end of data or the labels are NSL and the user has specified in the DCB exit list that trailer label processing is to be deferred from EOV to CLOSE. For output this exit is called from EOV except for the last volume in which case it is called from CLOSE. CLOSE TYPE=T results in this exit being called if the last user operation was a write. This causes CLOSE to write trailer labels but not close the DCB.

If the caller is EOV, then there might be an exit call later for the next volume for input or output or the next data set in the concatenation.

The exit caller has checked or written any trailer labels and disposed of the volume or is about to do so. The return code will not affect the system action. The call is to inform the tape management system which can gather statistics.

The file end on volume exit will receive a UCB address from TEPMUCB in IFGTEP, from DEBUCBA and from TIOEFSRT. All three sources will allow a 31–bit UCB address. TEPMICB will sometimes be an uncaptured 31–bit address. If the DEB31UCB bit is on, the UCB address and modeset byte will be different as described in IEZDEB. If they use the DCBTIOT field to find the TIOT entry address, they should be changed to use TEPMDSAB to point to the DSAB, which points to the TIOT entry or XTIOT.