If you want to use Qt in commercial closed source product without paying for the license, it’s easy to do when you use LGPL version.<p>1. Do not buy the commercial version.<p>2. Do not change the source code of the Qt library. Use it at it is.<p>3. Provide access to either statically or dynamically linked object files with instructions for linking. Static vs. dynamic linking does not matter with LGPL. LGPL requires access to source code and the ability for the user to modify open source library and link it to your closed source object file to create binary.<p>You compile your commercial code into commercial.o then compile LGPL code into lgpl.o and link them into a single binary.<p><pre><code> ld -o binary lgpl.o commercial.o -lc
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When you deliver the software, you send the binary, provide access to commercial.o and LGPL licensed source code with instructions for linking. User has now the ability to meddle with LGPL version of Qt, compile it into lgpl.o and link it against your commercial.o without having access to your source code.<p>(note: of course you can modify the Qt under LGPL when you release modifications with the LGPL. But then you have to maintain the fork on your own and you don't usually want to do that.)
Slightly off-topic but it's interesting how all of the discussion on this post (right now) is centered around the only other top-level comment rather than the article.