These classes providing various global services to your application such as event handling, access to system settings, internationalization, etc.
| QClipboard | The QClipboard class provides access to the window system clipboard. |
| QDesktopWidget | The QDesktopWidget class provides access to screen information on multi-head systems. |
| QEvent | The QEvent class is the base class of all event classes. Event objects contain event parameters. |
| QFontDatabase | The QFontDatabase class provides information about the fonts available in the underlying window system. |
| QMutex | The QMutex class provides access serialization between threads. |
| QMutexLocker | The QMutexLocker class is a convenience class that simplifies locking and unlocking mutexes. |
| QPixmapCache | The QPixmapCache class provides an application-wide cache for pixmaps. |
| QReadLocker | The QReadLocker class is a convenience class that simplifies locking and unlocking read-write locks for read access. |
| QReadWriteLock | The QReadWriteLock class provides read-write locking. |
| QSemaphore | The QSemaphore class provides a general counting semaphore. |
| QSessionManager | The QSessionManager class provides access to the session manager. |
| QThread | The QThread class provides platform-independent threads. |
| QThreadStorage | The QThreadStorage class provides per-thread data storage. |
| QTranslator | The QTranslator class provides internationalization support for text output. |
| QWaitCondition | The QWaitCondition class provides a condition variable for synchronizing threads. |
| QWriteLocker | The QWriteLocker class is a convenience class that simplifies locking and unlocking read-write locks for write access. |