In the main() function of a Mdt/Qt based application, a application class should be instanciated.

To reduce dependencies, several application classes exists:

Class	Description	Main dependencies
QCoreApplication	Can be used for non GUI applications that needs a event loop.	QtCore
QGuiApplication	Can be used for GUI application (like QtQuick).	QtGui
QApplication	Can be used for Widgets based GUI applications.	QtWidgets
QtSingleCoreApplication	Like QCoreApplication, also provides support for single instance of a application.	QtCore, QtNetwork
QtSingleApplication	Like QApplication, also provides support for single instance of a application.	QtWidgets, QtNetwork
Mdt::CoreApplication	Like QCoreApplication, also provide some additions, like file logging initialization.	QtCore
Mdt::SingleCoreApplication	Like QtSingleCoreApplication, also provide some additions, like file logging initialization.	QtCore, QtNetwork
Mdt::Application	Like QApplication, also provide some additions, like file logging initialization.	QtWidgets
Mdt::SingleApplication	Like QtSingleApplication, also provide some additions, like file logging initialization.	QtWidgets, QtNetwork