QCustomPlot Discussion and Comments

If i use QCustomPlot to develop a commercial application,then do i have to publish source code of my application?.I am bit confuse of these licensing.
I am not changing anything in QCustomPlot Source code.

Hi Nikesh,

Yes, with the default GPL license of QCustomPlot you will have to publish your source code also under the GPL. However, for closed-source developers I also offer commercial licenses. If you or your company is interested, just contact me.

just a quick followup question on this.
Do I need to publically make the source available or only to those who purchases my software?
Do I need to always deliver source with the software or deliver source upon request from the customer who bought the software?

I'm not the developer, but my understanding of the FSF's documents on this is that you only have to provide it on request. You cannot release GPL'd code under a non-disclosure agreement (see http://www.gnu.org/licenses/gpl-faq.html#DoesTheGPLAllowNDA), so the code they receive will still be GPL'd, which gives them the right to modify it as they please, redistribute the source code, and to release binaries they have compiled without your permission. If you don't want to pay Mr. Eichhammer then you cannot profit from his work by releasing proprietary software that links with QCP.

If I would like to publish my application which has a non-modified QCustomPlot as part of the application under a GPLv3 license.
Should I share the source code only the part related to QCustomPlot or should I share the whole project? Provided that I have a Qt license.


If you are including QCustomPlot in your application, which is licensed under GPLv3, then the entire application must also be licensed under the GPLv3. This means that you must provide access to the complete source code of the application, not just the parts that are related to QCustomPlot.

If you have a Qt license, it is possible that your application includes proprietary code that you do not wish to share under an open-source license. In this case, you license QCP under the commercial license (please get in contact via the support email address in this case), which allows you to keep your code proprietary.

However, if you want to distribute your application under GPLv3, then you must provide access to the complete source code of the application. This includes any modifications that you have made to QCustomPlot, as well as any other code that is part of the application.

I hope this answers your questions, let me know if anything is unclear.
Best Regards