Questions specifically for version 5.x of the Qt library. If your question applies to other versions of Qt, use the tag [tag:qt4] or [tag:qt3]. It is recommended to use with the tag [tag:qt].
Qt (pronounced officially as cute (/kyut/) though commonly pronounced as (/ˈkyu ti/)) is a cross-platform application development framework widely used for the development of GUI programs (in which case it is known as a widget toolkit), and also used for developing non-GUI programs such as console tools and servers. wikipedia
Qt is developed and maintained by The Qt Company which is subsidiary of Digia.
Qt also provides an integrated development environment named Qt Creator. Though it mainly aims at creating Qt applications, it can be used to create regular C++ applications too.
Resources:
Official documentation - covers all classes, in addition to tutorials and examples. You will often see these tutorials and examples referenced in the questions and answers on this site.
Tagging recommendation:
You will often see questions tagged specifically as qt3,qt4 or qt5 to indicate that the user experiences the problem in Qt 3.x, 4.x or 5.x, respectively. The default when version information is lacking is to assume version 5.x of the API.
