ASE ODBC driver related questions

Question

Hi Friends,
I am using ODBC driver (the framework over ODBC API) to connect and read data from ASE database server on Windows.
I've few questions about ASE ODBC driver. Can you please guide me.
1) ASE has a DB option called "textsize" which sets the limit on amount data we can fetch in select statement.
     This option can be set either in the DSN configuration (Advanced->Textsize text field) or by "set textsize <number>" for a session.
     --- While scanning BLOBs (image data types), I want to increase this limit to 512MB in my application. But, I don't want to override the limit if user has Text Size field in the DSN configuration.
    * how can we (programatically) find out the Text Size value set in the DSN configuration?
       --- Is it possible using some ODBC function?
2) What is the maximum limit on the data returned by SQLGetData function call at a time?
     --- Can we determine the size of the data stored in a column, especially the BLOB (or image) columns using ODBC API?
         or do we need to run the query "select datalength(ColumnName) from tablename" ?
3) Which the most stable and reliable ODBC Driver Manager for Unix and Linux OSs? Is it unixODBC?
Many thanks in advance for your clarifications and time.
Best Regards

Answer 1

Thanks Paul.
This is not with SQLGetData. In fact, SQLGetData is working fine for me.
Getting this problem when executing query and accessing bound buffers as below (pseudo code):
// Set statement attribute to read by column, number of rows, static cursor and status pointer:
/*struct StmtAttrs
    SQLINTEGER attr;
    SQLPOINTER valptr;
    SQLINTEGER len;
    SQLHSTMT& stmt = m_stmtHdl.m_hdl;
    StmtAttrs parms[5] = \
    {{SQL_ATTR_ROW_BIND_TYPE, SQL_BIND_BY_COLUMN, 0},
    {SQL_ATTR_CURSOR_TYPE, (SQLPOINTER)SQL_CURSOR_STATIC, 0},
    {SQL_ATTR_ROW_ARRAY_SIZE, (SQLPOINTER)limit, 0},
    {SQL_ATTR_ROW_STATUS_PTR, &m_rowStatus[0], 0},
    {SQL_ATTR_ROWS_FETCHED_PTR, &m_rowsFetched, 0}};
    uint32_t i = 0;
    SQLINTEGER errcode;
    for (; i < 5; ++i)
        bool ret = sqlSetStmtAttr(stmt, parms[i].attr, parms[i].valptr, parms[i].len);
          // error handling code
//Bind the input buffers for number of columns using SQLBindCol:
//Prepare the query using SQLPrepare
// E.g.: select top 2039 numpk,convert(binary(256),ablob) from myccinfo.dbo.bigdata NOLOCK order by numpk asc ;
// Execute the query with SQLExecute(stmt);
// Fetch the data using SQLFetchScroll(stmt, SQL_FETCH_NEXT, 0);
// Iterate thru each column and the bound buffer to read the data