Dual licensing is a business model for free and open source software. There is usually one copyleft community license such as GNU GPL and a commercial proprietary license sold for companies who do not want to release their source-code of the application derived from it.
EiffelStudio is an IDE for the Eiffel programming language (ECMA-367, ISO/IEC 25436, and ACM Software System Award 2006).
It includes:Eiffel generates C or CLI for .NET or Mono. Eiffel applies O-O principles and Design by Contract for high-quality software.
Many libraries are included: ADT, network, GUI, database, parsing (including an Eiffel parser), XML, Web, COM, and more.
The popular and extensible open source telephone system in the world, offering flexibility, functionality and features not available in advanced, high-end (high-cost) proprietary business systems. Asterisk® is a hybrid TDM and packet VOIP voice PBX (Private Branch eXchange) and IVR platform with ACD functionality.
Qt is a toolkit for software developers. It simplifies the task of writing and maintaining GUI (graphical user interface) applications.
qt
gui
Development
License:GPL
cross-platform
toolkit
C++
desktop
Programming
dual-license
Qtopia (former Qt Palmtop Environment) is a platform for linux-based PDAs, Webpads and mobile-phones developed by Trolltech.
As most Trolltech products Qtopia is dual licensed under the free License:GPL or closed-source which requires a licensing fee then.