You can use the POINT macro to begin retrieving records sequentially at a place other than the beginning of the data set. The POINT macro places VSAM at the record with the specified key or relative byte address. However, it does not provide data access to the record. If you specify a generic key (a leading portion of the key field), the record pointed to is the first of the records having the same generic key. The POINT macro can position VSAM for either forward or backward processing, if FWD or BWD was specified in the RPL OPTCD parameter.

If, after positioning, you issue a direct request through the same request parameter list, VSAM drops positioning unless NSP or UPD was specified in the RPL OPTCD parameter.

When a POINT is followed by a VSAM GET/PUT request, both the POINT and the subsequent request must be in the same processing mode. For example, a POINT with RPL OPTCD=(KEY,SEQ,FWD) must be followed by GET/PUT with RPL OPTCD=(KEY,SEQ,FWD); otherwise, the GET/PUT request is rejected.

For skip-sequential retrieval, you must indicate the key of the next record to be retrieved. VSAM skips to the next record's index entry by using horizontal pointers in the sequence set to find the appropriate sequence-set index record and scan its entries. The key of the next record to be retrieved must always be higher in sequence than the key of the preceding record retrieved.

If your request fails, with an error code, positioning cannot be maintained. To determine if positioning is maintained when a logical error occurs, see z/OS DFSMS Macro Instructions for Data Sets. Positioning is always released when you specify the ENDREQ macro.

When using POINT with shared buffering, it is important to ensure that either a GET DIR,NUP or an ENDREQ eventually follows to release positioning or a hang might occur with other requests needing the buffers that the POINT is holding.