The IXLALTER function provides for the expansion or contraction of the size of a structure and/or for the reapportionment of the entry-to-element ratio of the structure. For a lock structure, only a change to the size of the structure is valid. A request to change the entry-to-element ratio is meaningless because there are no data elements in a lock structure, only record data entries. The system rejects such a request to change the ratio with nonzero return and reason codes.

Depending on whether or not the lock structure was allocated with record data, changing the size of a lock structure either increases or decreases the record data entries only.