#include <QApplication>
#include <QLineEdit>
#include <QDoubleValidator>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    //Note that the number of decimal digits is 0 !
    QValidator* validator = new QDoubleValidator(0., 999., 0, NULL);

    //Set the locale to German: Note that the character ',' is the
    //decimal separator and the character '.' is the thousand-separator
    //in german. This is exactly the opposite to the english or
    //default C-Locale.
    validator->setLocale(QLocale::German);

    QValidator::State state;
    int pos;

    //The following line returns "intermediate" state, because the decimal
    //point is interpreted as the thousand-separator (german locale)
    state = validator->validate(QString("12.1234"), pos);

    //The following line returns "intermediate" state, because although
    //the string is invalid in german-locale, the comma is interpreted as
    //the thousand-separator in C-locale (which is the fallback)
    state = validator->validate(QString("12,1234"), pos);

    //The following line returns "intermediate" state, although
    //it should return "invalid". Seems to have nothing to do with the
    //locale, so should be a different/separate problem
    state = validator->validate(QString("121234"), pos);

    //Try yourself by uncommenting the following lines
    //QLineEdit* edit = new QLineEdit();
    //edit->setValidator(validator);
    //edit->show();

    //return a.exec();
    return 0;
}