Qt Reference Documentation

All Modules

Qt Essentials

Qt essentials define the foundation of Qt on all platforms. They are available on all supported development platforms and on the tested target platforms. They will remain source and binary compatible during Qt 5.

Essential modules are general and useful for a majority of Qt applications. A module that is used for a special purpose is considered an add-on module even if it is available on all supported platforms.

The following table lists the Qt essentials:

Qt CoreCore non-graphical classes used by other modules.
Qt GUIBase classes for graphical user interface (GUI) components. Includes OpenGL.
Qt MultimediaClasses for audio, video, radio and camera functionality.
Qt Multimedia WidgetsWidget-based classes for implementing multimedia functionality.
Qt NetworkClasses to make network programming easier and more portable.
Qt QMLClasses for QML and JavaScript languages.
Qt QuickA declarative framework for building highly dynamic applications with custom user interfaces.
Qt Quick ControlsReusable Qt Quick based UI controls to create classic desktop-style user interfaces
Qt Quick LayoutsLayouts are items that are used to arrange Qt Quick 2 based items in the user interface.
Qt SQLClasses for database integration using SQL.
Qt TestClasses for unit testing Qt applications and libraries.
Qt WebKitClasses for a WebKit2 based implementation and a new QML API. See also Qt WebKit Widgets in the add-on modules.
Qt WebKit WidgetsWebKit1 and QWidget-based classes from Qt 4.
Qt WidgetsClasses to extend Qt GUI with C++ widgets.

If you use qmake to build your projects, the QtCore and QtGui modules are included by default. To link only against QtCore, add the following line to your .pro file:

On Windows, if you do not use qmake or other build tools such as CMake, you also need to link against the qtmain library.

Qt Add-Ons

Qt add-on modules bring additional value for specific purposes. These modules may only be available on some development platform for some target platforms. Some of them are included in the Qt releases on particular platforms. Each add-on module specifies its compatibility promise separately.

The following table lists the Qt add-ons:

ModuleDevelopment PlatformsTarget PlatformsDescription
Active QtWindowsClasses for applications which use ActiveX and COM
Qt ConcurrentClasses for writing multi-threaded programs without using low-level threading primitives.
Qt D-BusUnixClasses for inter-process communication over the D-Bus protocol.
Qt Graphical EffectsAllGraphical effects for use with Qt Quick 2.
Qt Image FormatsAllPlugins for additional image formats: TIFF, MNG, TGA, WBMP.
Qt OpenGLOpenGL support classes.

Note: Provided to ease porting from Qt 4.x. Please use the QOpenGL classes in QtGui for new code.

Qt Print SupportAllClasses to make printing easier and more portable.
Qt DeclarativeAllQt Declarative is provided for Qt 4 compatibility. The documentation is available through the Qt 4.8 Qt Quick documentation.
Qt ScriptAllClasses for making Qt applications scriptable. Provided for Qt 4.x compatibility. Please use the QJS* classes in the QtQml module for new code.
Qt Script ToolsAllAdditional components for applications that use Qt Script.
Qt SensorsAllAndroid, BlackBerry, iOS, and Mer.Provides access to sensor hardware and motion gesture recognition.
Qt Serial PortAllWindows, Linux, and Mac OS X.Provides access to hardware and virtual serial ports.
Qt SVGAllClasses for displaying the contents of SVG files.
Qt X11 ExtrasAllLinux/X11Provides specific APIs for X11.
Qt XMLC++ implementations of SAX and DOM.

Note: Deprecated, please use QXmlStreamReader and QXmlStreamWriter for new functionality.

Qt XML PatternsSupport for XPath, XQuery, XSLT and XML schema validation.

Qt Tools

Tools that are officially a part of Qt. The official tools run on all the supported development platforms.

The following table lists the Qt tools:

Qt DesignerClasses for extending Qt Designer.
Qt HelpClasses for online help.
Qt UI ToolsClasses for UI tools.

See also Class and Function Documentation.