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Qt is a cross-platform C++ application and UI framework that abstracts the user interface and presentation from the operating system, allowing you in theory to write applications once and deploy them across many desktop and embedded operating systems without rewriting the source code.

Commercial version

Trolltech the company behind Qt offered a commercial version of Qt that included extended C++ classes, more extensive framework and full technical support, however since the OS/2 version is an independent port the company does not support the software on that platform.

Qt development tools


  • Nov 2005: 3.3.1-rc06
  • Mar 2013: Qt 4 version 4.7.3-2



  • GNU GPL[3] 3, with Qt special exception
  • GNU Lesser General Public License (LGPL v2.1) (Qt open-source version)
  • Qt Commercial License (Qt Commercial version)


  • Trolltech
  • Digia