Qt Part 1 - licenses and motivation

Qt is a cross-platform application and UI framework primarily aimed at C++ users (although plenty of other bindings exist). In plain English that means we can use it to create GUIs. It can do a ton of other stuff including networking, database access and OpenGL to name a few. It's been around since the early 90s and some of it's concepts pre-date the usage of "modern" C++ (unsurprising since the C++ standard was only ratified in 1998). The history of Qt is quite a read - it took a while for the product to gain momentum, but two events helped it along. First it was chosen by the European Space Agency in 1996 and then it was chosen as the toolkit upon which the fledgling KDE Linux desktop environment was built. From then it was upwards all the way to the present day where we are at v4.5.

In 2008 Trolltech (the original owner and creater of Qt) was bought by Nokia, the telecomms giant. Nokia changed the business plan for Qt. Originally the product was only available under two licenses - commercial (big bucks) or GPL (open source). GPL means any product created with Qt must also be open source. So the only way to create and sell a commercial product was to pay hundreds of dollars. This obviously limited adoption of Qt. Nokia decided that in order to spread the usage of Qt it was necessary to allow people to create commercial software either for free or at least very cheaply. In the end they chose the free option (phew!) and used the LGPL (Lesser GPL ) license. This means it now doesn't cost a penny to create commercial apps with Qt. Of course, you might want to stump up for Visual Studio Professional but that's a different story.

Anyway, next I'll see how easy or difficult it is to get Qt up and running...