Use the index value to identify the data item that is not defined, the data item for which the connection, task, or process does not hold the cast-out lock, the data item that specified parity bits that are not valid, or the data item that requested an incompatible update for the change indicator.

For example, you specify a list of five name elements for data items named A, B, C, D, and E. The list starts at offset 1 of the buffer. When you issue the REQUEST=UNLOCK_CASTOUT request, FIRSTNAME specifies an index of 1 (for data item A) and LASTNAME an index of 5 (for data item E). If data item C is not defined to the cache structure, the system prematurely completes the request and returns an index value of 3 in CAAULINDEX that corresponds to data item C.