The sqllen field of the SQLDA is a 2-byte integer in which the DBMS Server returns the length of a column. If a long varchar or long byte column that is longer than the maximum value possible for sqllen (32,768) is described, a 0 is returned in sqllen.

Long varchar and long byte columns can contain a maximum of 2 GB of data. To prevent data truncation, be sure that the receiving variable to which the SQLDA sqldata field points is large enough to accommodate the data in the large object columns your program is reading. If data is truncated to fit in the receiving variable, the sqlwarn member of the sqlca structure is set to indicate truncation.