I'm working on a piece of software that'll be released as a dll under LGPL. The software interfaces with hardware from a small company that has provided me with the needed libraries and some code to use them correctly (not only headers but its all in a separate file). As far as i know, the same code is used in their proprietary software that they don't intend to open source but they'd be fine releasing the piece of code they've given me.

Now here's the question:

What license could be used on the code I got from the company? I guess using GPL or LGPL would make them violate GPL when using the same code in their other software.

Is MIT a good idea? Is it ok to just include a file with MIT license on it in my otherwise LGPL:ed project?

Since I'm not the copyright holder, I'd have to ask the company to apply the license obviously but that shouldn't be a problem.



  • 1
    You need to call an attorney instead of posting here.
    – bmargulies
    Mar 12, 2011 at 19:09
  • If you are redistributing someone else's libraries, headers, or anything else, make sure that they are aware of it. Redistribution won't necessarily impact them but it could cause some legal discomfort for you.
    – D.Shawley
    Mar 12, 2011 at 19:16

3 Answers 3


Companies are allowed to double license their code. If they allow you to take the parts and release them as LGPL, everything should be fine.



This really depends on the rights they have given you to their code in the how they have licensed the code to you. You can only do to their code what they allow you to.

If your code can written and distributed in a way that doesn't require their code to be included then you probably can release your code and run run-time linking to their code. If you can then you will need to negotiate with them (the copyright owner) to release the code in a compatible (see WhatIsCompatible) open-source license.

Put simply you cannot license/sub-license code you do not own the copyright to or have been conferred the right to sub-license.

As stated in other answers the copyright owner can release the same code in GPL/LGPL/MIT/whatever license and a proprietary license and they own the copyright. The GPL doesnt place constraints on the owner of the code, only on the distribution of the code.

The concept is explained briefly in this faq from the GNU "I would like to release a program I wrote under the GNU GPL, but I would like to use the same code in non-free programs.".


The licence of you software including the donated piece of code has no impact of the company proprietary software licence

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