[egenix-users] Null termination differences in drivers - comment in mxODBC.c

[Martin J. Evans]

Could anyone explain the origin of the following comment in mxODBC.c
(specifically the reference to the Easysoft Oracle driver)?

How do you reproduce this?

Thanks.

            if (null_terminated) {
                /* Remove null termination; various ODBC drivers have bugs
                   in the way the handle null-termination:

                   * EasySoft ODBC for Oracle does not null-terminate character
                     columns, even though it should

                   * MS SQL Server ODBC always null-terminates Unicode columns
                     with two nulls, even when fetching the data as SQL_C_CHAR
                     where it should only append one null-termination character

                   The ODBC standard is unclear about what to do, but
                   using sizeof(SQLWCHAR) seems to work in most
                   cases. We have to careful here, since some database
                   drivers allow passing binary data back through
                   character columns, so embedded nulls are well
                   possible.

                   Thanks to Tommi Auvinen for helping to track down
                   the MS SQL Server problem.

                */
                char *data = (char *)newdata;
                int endofdata = offset + received - 1;
                if (data[endofdata] == '\0') {
                    received--;
#ifdef SQL_WCHAR
                    if (data[endofdata - 1] == '\0') {
                        if (var->ctype == SQL_C_WCHAR ||
                            var->sqltype == SQL_WCHAR ||
                            var->sqltype == SQL_WVARCHAR ||
                            var->sqltype == SQL_WLONGVARCHAR)
                            received -= sizeof(SQLWCHAR) - 1;
                    }
#endif
                }
            }


--
Martin J. Evans
Easysoft Ltd, UK
Development