Creating a private in-house application with Qt

Question

I want to create an application using the Qt framework, but can not at all afford a commercial license. While looking at the licensing comparison table, I noticed that the LGPLV3 license said this:

Possible to keep your application private with dynamic linking

I understand what dynamic linking and static linking are, but I don't understand the implications of this. Does this mean I must use, for example, DLLs in my program rather than static libraries?

Also, should I just bite the bullet and make the program open source to be safe and use GPL (which seems to have better features according to this chart), or should I stick with LGPL and avoid static linking?

Answer 1

Use of a software internally is not considered a conveyance by the GPL, so you wouldn't have to give source code to anyone.

The moment you decide to distribute your software to any third party, then you'll have to follow the terms of the (L)GPL or pony up for a commercial QT license.

As for static vs dynamic linking, you can static link with an (L)GPL libray, but you must provide the means for a third-party recipient to replace it with a modified version if they desire.

This is all covered in the GPL FAQ https://www.gnu.org/licenses/gpl-faq.en.html