User header labels (UHLx) may follow the HDR2 label. To make the user header labels available to your program, ANSI and user header or trailer labels (AUL) must be coded on the DD statement and the address of an input user header label routine must be specified in the DCB exit list. If you omit AUL or the user header label entry in the DCB exit list, the system positions the tape past the tape mark immediately after processing either the HDR2 label or the HDR1 label if the HDR2 label is not present. User label processing and the DCB exit list are described in z/OS DFSMS Using Data Sets.