QString::setNum() not working properly with doubles and precision in all cases

In some cases QString::setNum() may return a string that contains more number characters than the precision is set to, for instance when passing the following code

QString str;
str.setNum(.01234567899, 'g', 10);
qDebug() << str;

will print out the string "0.01234567899", while it actually should have printed out "0.012345679"