Licensing Question

[graciano]

Ok.
Now let's suppose someone wrote an example, good or bad, and wants to share it.
When using the Open Source version of Qt, de default licenssing mode is, i suppose, LGPL.
If so ... every software created with this version should be LGPL. Right?

[graciano]

Well ... looks i was wrong about the default LGPL.
http://qt.nokia.com/products/licensing

[richardcarl78]

I would have thought that you were right. I guess you learn something every day. The default LGPL can be a tricky thing. Thanks for sharing your insights on this.

[squidge]

Ok.Now let's suppose someone wrote an example, good or bad, and wants to share it.
When using the Open Source version of Qt, de default licenssing mode is, i suppose, LGPL.
If so ... every software created with this version should be LGPL. Right?

I don't see why, if they abided by the license terms of Qt when they wrote that example, they can distribute there example code under whatever license they feel like - commercial, bsd, gpl, beerware... Its only when you change someone elses code you have to keep original license and header as you can't make restrictions (So you can't say your version is only under GPLv3 if the original was GPLv3 or LGPL for example).

[graciano]

Forgetting the Qt examples for a while ...
If you write a piece of code, using your imagination and skills, with the Qt Opesource version, what are your legal obligations?

[squidge]

That depends on how you decide to distribute it. If you distribute as closed source (binary only), then you must comply with LGPL license and so your application must be dynamically linked.
Else you distribute under GPL license and release the source code, which allows static linking.

Either way, any modifications you make to Qt must be made open-source - anyone who wishes to do so must be able to build the exact same DLLs (or static libraries if you use them) as your program requires.

[wysota]

Forgetting the Qt examples for a while ...
If you write a piece of code, using your imagination and skills, with the Qt Opesource version, what are your legal obligations?

Rule of a thumb:
1. You want to release sources for your application -> go for any licence you want but also obey Qt's GPL or LGPL licence.
2. You don't want to release sources for your application -> go for any licence you want but also obey Qt's LGPL licence (i.e. link Qt dynamically).
3. You want total freedom - buy a commercial licence and distribute your application on whatever licence you see fit.

In any case if you wish to modify Qt itself, you have to retain the original licence (or one that is compatible with it - I think) for Qt (not for you app).