API to change QSetting:: applicationName() if application name is changed afterwards

In a Application constructor user call QCoreApplication::setApplicationName() but since QSettings member variable of class and is created before setApplicationName is called, then QSettings::applicationName() returns the default name (i.e. the exe base name).

Sample project attached. 

Workaround for this is to have pointer variable for QSetting and define it after setting application name. 

But it would be great there is some API to reset application name for QSetting Variable too.