FreeTDS C-string conversion sample

int ncols, ncol;
char **values;

ncols = dbnumcols(dbproc);

for (ncol = 0; ncol < ncols; ncol++)
{
    int col_type = dbcoltype(dbproc, ncol + 1);

    if (dbwillconvert(col_type, SYBCHAR) != FALSE)
    {
        DBINT data_len;
        BYTE* data;

        data_len = dbdatlen(dbproc, ncol + 1);
        data = dbdata(dbproc, ncol + 1);

        if (data_len == 0) /* column is NULL */
        {
            values[ncol] = NULL;
        }

        else if (data == NULL) /* column is NULL, but probably shouldn't be */
        {
            values[ncol] = NULL;
        }

        else
        {
            char *value;
            int ret_value;
            int dest_len = 1000; /* any portable way to get real length of converted value? */

            if ((value = malloc(dest_len * sizeof(char))) == NULL) /* malloc failure */
            {
                /* raise error*/
            }

            ret_value = dbconvert(dbproc, col_type, data, data_len, SYBCHAR, (BYTE *) value, -1);

            if (ret_value == -1) /* conversion failure */
            {
                values[ncol] = NULL;
            }

            else
            {
                /* success: move value to values[ncol] */
            }
        }
    }

    else /* cannot be converted to SYBCHAR */
    {
        /* raise error */
    }
}