Qt Core

Getting Started

All other Qt modules rely on this module. To include the definitions of the module's classes, use the following directive:

#include <QtCore>

If you use qmake to build your projects, Qt Core is included by default.

Core Functionalities

Qt adds these features to C++:

  • a very powerful mechanism for seamless object communication called signals and slots
  • queryable and designable object properties
  • hierarchical and queryable object trees that organize
  • object ownership in a natural way with guarded pointers (QPointer)
  • a dynamic cast that works across library boundaries

The following pages provide more information about Qt's core features:

Threading and Concurrent Programming

Qt provides thread support in the form of platform-independent threading classes, a thread-safe way of posting events, and signal-slot connections across threads. Multithreaded programming is also a useful paradigm for performing time-consuming operations without freezing the user interface of an application.

The Thread Support in Qt page contains information on implementing threads in applications. Additional concurrent classes are provided by the Qt Concurrent module.

Input/Output, Resources, and Containers

Qt provides a resource system for organizing application files and assets, a set of containers, and classes for receiving input and printing output.

In addition, Qt Core provides a platform-independent mechanism for storing binary files in the application's executable.

Additional Frameworks

Qt Core also provides some of Qt's key frameworks.


These are links to the API reference materials.

© 2016 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.