The Client Option returns two types of error messages:
Server error messages that are returned from SQL Server, Open Server™, or the DB2 UDB Option for CICS. Server error messages are retrieved with the CTBDIAG function call using a SERVERMSG structure.
Client error messages that are internally generated by Client-Library when it detects an error locally. Client error messages are retrieved with the CTBDIAG function call using a CLIENTMSG structure.
