Distributing desktop apps

[nicodasiko]

hey i want to get into qt but i want to distribute my apps. What is the whole licensing thing do i have to buy a license?

[JKSH]

http://qt-project.org/forums/viewthread/42820

[mcosta]

Hi,

read "here":http://qt-project.org/doc/qt-5/licensing.html to find information about Qt Licensing.

[nicodasiko]

So what if i want to make an app with qt and then distribute it for free without buying a license can i do that.

[mcosta]

Hi,

depends to what do you mean for "distribute for free".
If you want distribute your software under GPL or LGPL licence you can use GPL or LGPL Qt Licence (this means you have not to buy Commercial Licence).
For other kind of licence (for example if you don't want distribute your code) you MUST buy Commercial Licence.

[MuldeR]

[quote author="mcosta" date="1401101650"]Hi,
For other kind of licence (for example if you don't want distribute your code) you MUST buy Commercial Licence.[/quote]

Not necessarily. The LGPL explicitely does allow linking the LGPL'ed library against a ClosedSource program, as long as that is done dynamically, i.e. as a shared library. At least that's the commonly accepted interpretation of the LGPL. So, as long as he doesn't need to link Qt as a static library, he can stick with the LGPL-version of Qt and still he will not be required to distribute the sources of his "main" program. That's the important difference between the LGPL and the GPL. With the LGPL, he only will be required to distribute the sources of the LGPL'ed library (Qt in this case), if it has been modified.

Some people even say that statically linking LGPL'ed code with proprietary code is fine, as long as the individual object code files are distributed. This way the user has a chance to link the program himself and, optionally, replace the LGPL'ed library with a different version. So the LGPL requirement is satisfied.

[mcosta]

Sorry, you're right!

Using LGPL Licence you could also (with some exceptions) develop and distribute Closed Source Software