I hope QTextStream can add a operator bool() method, just like basic_istream in c++ STL:
operator bool() const

Now if i need know whether QTextStream has the right format, i need do as this:
QTextStream >> x;
if(ss.status() == QTextStream::Ok)
{
}

if QTextStream has operator bool() method, then i can do this:
if(QTextStream >> x)
{
}
This will be compatible with STL when convert code from STL to QT.
Thanks!