Programming Language?
It's a toolkit & GUI API for C++ and other languages, not a language itself.
From Trolltech to Nokia and Nokia to Digia, the application framework Qt has had a challenging corporate life even though it retained fans among developers. Now, the language's next phase of life has begun in earnest, spun out of Digia into a separate subsidiary tasked with bringing the commercial and open source Qts back into …
It's a nice alternative to Java GUI classes/libraries to have a cross platform framework, but can be faster due to underlying C++ and other languages. You can in theory do a lot of GUI without using the real programming languages. But I doubt you'd do a real application in QT without the underlying design in C++ or something. It's a wonderful way to do the GUI part of any application.
It was a pity that Nokia didn't adopt it earlier to produce a new GUI for Symbian instead of S60 GUI, they should have just outsourced that to Trolltech instead of buying the company. By 2002 Nokia could no longer manage software.
"But I doubt you'd do a real application in QT without the underlying design in C++ or something"
Err... What? Qt is C++. I think you're referring to QML which is designed as a GUI-specific DSL based on JS - it is not designed to replace backend functionality (unless it is very simple).
But it did make it onto the N900 and N9.
I have only built a few Qt applications. This is because I am using KDE and it is also built on Qt.
The really neat about Qt (and GTK apparently) is that the Gui can be exported to HTML5, making it far easier to produce a desktop and browser version.
Something about that flexibility makes sense.
P.