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 Core||Core non-graphical classes used by other modules.|
|Qt GUI||Base classes for graphical user interface (GUI) components. Includes OpenGL.|
|Qt Multimedia||Classes for audio, video, radio and camera functionality.|
|Qt Network||Classes to make network programming easier and more portable.|
|Qt Quick||A declarative framework for building highly dynamic applications with custom user interfaces.|
|Qt SQL||Classes for database integration using SQL.|
|Qt Test||Classes for unit testing Qt applications and libraries.|
|Qt WebKit||Classes for a WebKit2 based implementation and a new QML API. See also Qt WebKit Widgets in the add-on modules.|
|Qt WebKit Widgets||WebKit1 and QWidget-based classes from Qt 4.|
|Qt Widgets||Classes to extend Qt GUI with C++ widgets.|
QT -= gui
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-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:
|Module||Development Platforms||Target Platforms||Description|
|Active Qt||Windows||Classes for applications which use ActiveX and COM|
|Qt Concurrent||Classes for writing multi-threaded programs without using low-level threading primitives.|
|Qt D-Bus||Unix||Classes for inter-process communication over the D-Bus protocol.|
|Qt Graphical Effects||All||Graphical effects for use with Qt Quick 2.|
|Qt Image Formats||All||Plugins for additional image formats: TIFF, MNG, TGA, WBMP.|
|Qt OpenGL||OpenGL support classes.|
Note: Provided to ease porting from Qt 4.x. Please use the QOpenGL classes in QtGui for new code.
|Qt Print Support||All||Classes to make printing easier and more portable.|
|Qt Declarative||All||Qt Declarative is provided for Qt 4 compatibility. The documentation is available through the Qt 4.8 Qt Quick documentation.|
|Qt Script||All||Classes 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 Tools||All||Additional components for applications that use Qt Script.|
|Qt SVG||All||Classes for displaying the contents of SVG files.|
|Qt XML||C++ implementations of SAX and DOM.|
|Qt XML Patterns||Support for XPath, XQuery, XSLT and XML schema validation.|
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 Designer||Classes for extending Qt Designer.|
|Qt Help||Classes for online help.|
|Qt UI Tools||Classes for UI tools.|
See also Class and Function Documentation.
Lists and Indexes of classes, functions, and types.