A little background: I have a library project which I put under the LGPL v2.1. However, I have two applications inside the project tree using the library. It would be somewhat inconvenient to make these two small applications have their own license, so I figured I could just use the LGPL for all the code in the tree, including those applications.

Does it make sense to have an application under the LGPL? What would change when compared to, e.g., the GPL?

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    to whoever voted down this question: could you elaborate why? this looks to me as a bona fide question to ask. – Philippe Ombredanne May 15 '16 at 9:03
  • Do you have a link to your project? – Philippe Ombredanne May 15 '16 at 9:04
  • @PhilippeOmbredanne Yes. I've edited the description. – Romário May 15 '16 at 14:42
  • You've provided your own reason why it makes sense in the question itself! – curiousdannii May 16 '16 at 1:18
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    @PhilippeOmbredanne I completely agree. I'm struggling to see what's wrong with the question, if anything. There's a clear statement, and a clear background - a perfect question, is it not? – Zizouz212 May 16 '16 at 1:57

The LGPL v2.1 is specifically designed for libraries; in particular, it allows distribution of modified versions of the library only in certain circumstances (section 2), including

The modified work must itself be a software library.

However, you can distribute your library and its associated programs under the LGPL, because section 3 of the LGPL allows it to be upgraded to standard GPL (version 2 or later). Thus a recipient making changes and wishing to redistribute them can do so either under the LGPL or the GPL, whichever is appropriate. (After distribution occurs under the GPL though, further distribution of modified works on top of that can only use the GPL.)

Having said all that, using two licenses within your source code isn't all that complex: all you need to do is include both the LGPL and the GPL, and make sure the source files' headers indicate which license applies to them (as explained at the end of the license documentation).

  • What version of the GPL can a program under the LGPL be upgraded to, exactly? I'm guessing GPL v2+, but I might be wrong. – Romário May 15 '16 at 14:44
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    Section 3 says "To do this, you must alter all the notices that refer to this License, so that they refer to the ordinary GNU General Public License, version 2, instead of to this License. (If a newer version than version 2 of the ordinary GNU General Public License has appeared, then you can specify that version instead if you wish.) Do not make any other change in these notices." So LGPL 2.1 becomes GPL 2, or later. – Stephen Kitt May 15 '16 at 15:00

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