Locating a specific sequential dependent segment

When you have position on a particular root segment, you can retrieve the position information and the area name of a specific sequential dependent segment of that root.

If you have a position established on a sequential dependent segment, the search starts from that position. IMS returns the position information for the first sequential dependent segment that satisfies the command.

To retrieve this information, you issue a POS command with a qualification statement containing the segment name of the sequential dependent. The current position after this kind of POS command is in the same place that it is after a GNP command.

After a successful POS command, the I/O area contains:

LL: A 2-byte field giving the total length of the data in the I/O area, in binary.
Area Name: An 8-byte field giving the ddname from the AREA statement.
Position: An 8-byte field containing the position information for the requested segment.
If the sequential dependent segment that is the target of the POS command is inserted in the same synchronization interval, no position information is returned. Bytes 11-18 contain X'FF'; other fields contain normal data.
Unused CIs: A 4-byte field containing the number of unused CIs in the sequential dependent part.
Unused CIs: A 4-byte field containing the number of unused CIs in the independent overflow part.