Using GPL library in commercial app - confusion

**nish** · 29th June 2009, 09:17

Hi,

So i wanted to make a stupid lame app for myself, and if someone likes it i would like to sell it too one day. I am using a mix of various sources as follows:-

EDIT:- gosh... i forgot to mention the gpl lib in this gpl thread...

... now added it as point (0)

0. One library with GPL license (gpllib.dll)
1. Qt (LGPL) (dynamic linking here.. no problems)
2. Parts of source code from an Artistic license app to build my own lib (say it art.dll)
3. My own GUI and logic code which do not uses or link to any other lib. execpt Qt ( gui.dll ).
4. My main application exe which links to above 0,1,2,3 dlls. (gpllib.dll,qt.dll, art.dll, gui.dll)

I googled and found the following Faq at http://www.gnu.org/licenses/gpl-faq.html#GPLWrapper

I'd like to incorporate GPL-covered software in my proprietary system. Can I do this by putting a â€œwrapperâ€ module, under a GPL-compatible lax permissive license (such as the X11 license) in between the GPL-covered part and the proprietary part?

No. The X11 license is compatible with the GPL, so you can add a module to the GPL-covered program and put it under the X11 license. But if you were to incorporate them both in a larger program, that whole would include the GPL-covered part, so it would have to be licensed as a whole under the GNU GPL.

The fact that proprietary module A communicates with GPL-covered module C only through X11-licensed module B is legally irrelevant; what matters is the fact that module C is included in the whole.

So i was wondering that can i make the 3rd dll(gui.dll) as closed source stating that i purchased this dll from somewhere and release the source code for the rest ? Or i am missing something?

**wysota** · 29th June 2009, 10:44

If none of the components are licenced under pure GPL (remember that GPL and LGPL differ greatly) and the artistic licence allows you to use the component in a closed-source application then the rest of the application (3. and 4.) can be closed-sourced as well.

**nish** · 29th June 2009, 11:23

hi..

thx for reply... i forgot to mention the utmost library... its added as point 0... can u plz reconsider your answer?
my point of interest is the gui.dll can be closed?
thx

**wysota** · 29th June 2009, 13:08

If there is at least one component with a GPL licence, every piece of code the application uses has to be open source (with a GPL-compatible licence).