QSqlQuery.value() with QString type

// Code snippet 
...
m_db = QSqlDatabase::database("MyODBCConnectionName");
QSqlQuery query(m_db);
if (query.exec("SELECT myText FROM table1"))
{
    // myText in an NVARCHAR in table1 and table1 isn't empty
    QString val = query.value(0).toString(); //
    // val = "CONTENT_OF_myText"
}
...

// in src/sql/drivers/odbc/qsql_odbc.cpp

...

static QString qGetStringData(SQLHANDLE hStmt, int column, int colSize, bool unicode = false)
{
QString fieldVal;
SQLRETURN r = SQL_ERROR;
SQLLEN lengthIndicator = 0;

// NB! colSize must be a multiple of 2 for unicode enabled DBs
if (colSize <= 0) {
colSize = 256;
} else if (colSize > 65536) { // limit buffer size to 64 KB
colSize = 65536;
} else {
colSize++; // make sure there is room for more than the 0 termination
}
if(unicode) {
r = SQLGetData(hStmt,
column+1,
SQL_C_TCHAR,
NULL,
0,
&lengthIndicator);
if ((r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO) && lengthIndicator > 0)
colSize = lengthIndicator/sizeof(SQLTCHAR) + 1;
QVarLengthArray<SQLTCHAR> buf(colSize);
memset(buf.data(), 0, colSize*sizeof(SQLTCHAR));
while (true) {
r = SQLGetData(hStmt,
column+1,
SQL_C_TCHAR,
(SQLPOINTER)buf.data(),
colSize*sizeof(SQLTCHAR),
&lengthIndicator);
if (r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO) {
if (lengthIndicator == SQL_NULL_DATA || lengthIndicator == SQL_NO_TOTAL) {
fieldVal.clear();
break;
}
// if SQL_SUCCESS_WITH_INFO is returned, indicating that
// more data can be fetched, the length indicator does NOT
// contain the number of bytes returned - it contains the
// total number of bytes that CAN be fetched
// colSize-1: remove 0 termination when there is more data to fetch
int rSize = (r == SQL_SUCCESS_WITH_INFO) ? colSize : lengthIndicator/sizeof(SQLTCHAR);
fieldVal += fromSQLTCHAR(buf, rSize);
if (lengthIndicator < SQLLEN(colSize*sizeof(SQLTCHAR))) {
// workaround for Drivermanagers that don't return SQL_NO_DATA
break;
}
} else if (r == SQL_NO_DATA) {
break;
} else {
qWarning() << "qGetStringData: Error while fetching data (" << qWarnODBCHandle(SQL_HANDLE_STMT, hStmt) << ')';
fieldVal.clear();
break;
}
}
} else {
r = SQLGetData(hStmt,
column+1,
SQL_C_CHAR,
NULL,
0,
&lengthIndicator);
if ((r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO) && lengthIndicator > 0)
colSize = lengthIndicator + 1;
QVarLengthArray<SQLCHAR> buf(colSize);
while (true) {
r = SQLGetData(hStmt,
column+1,
SQL_C_CHAR,
(SQLPOINTER)buf.data(),
colSize,
&lengthIndicator);
if (r == SQL_SUCCESS || r == SQL_SUCCESS_WITH_INFO) {
if (lengthIndicator == SQL_NULL_DATA || lengthIndicator == SQL_NO_TOTAL) {
fieldVal.clear();
break;
}
// if SQL_SUCCESS_WITH_INFO is returned, indicating that
// more data can be fetched, the length indicator does NOT
// contain the number of bytes returned - it contains the
// total number of bytes that CAN be fetched
// colSize-1: remove 0 termination when there is more data to fetch
int rSize = (r == SQL_SUCCESS_WITH_INFO) ? colSize : lengthIndicator;
fieldVal += QString::fromUtf8((const char *)buf.constData(), rSize);
if (lengthIndicator < SQLLEN(colSize)) {
// workaround for Drivermanagers that don't return SQL_NO_DATA
break;
}
} else if (r == SQL_NO_DATA) {
break;
} else {
qWarning() << "qGetStringData: Error while fetching data (" << qWarnODBCHandle(SQL_HANDLE_STMT, hStmt) << ')';
fieldVal.clear();
break;
}
}
}
return fieldVal;
}