The KDE Core Functionality Library

All KDE programs use this library to provide basic functionality such as the configuration system, IPC, internationalization and locale support, site-independent access to the filesystem and a large number of other (but no less important) things. All KDE applications should link to the kdecore library. Also, using a KApplication derived class instead of QApplication is almost mandatory if you expect your application to behave nicely within the KDE environment.