Use a return code in conjunction with its corresponding file status or reason code to determine the cause of a problem or failure when calling the MVSCASPB API.
| Code | Description | 
|---|---|
| 004 | An encountered key is a duplicate of the previous key (some indexes allow duplicate keys). | 
| 008 | End of file. | 
| 016 | File I/O error. | 
| 020 | Invalid function or invalid key. |