Choosing a license

Bruce Alspaugh compulinkltd at
Fri May 11 18:20:50 UTC 2007

Matthew Flaschen wrote:
> Bruce Alspaugh wrote:
>> I thought about the MPL, but then I read there is a complicating factor
>> that MPL and GPL code cannot legally be linked together.  We need to be
>> able to link with LGPL code as well.
> I am not a lawyer, but I believe MPL can link with LGPL, but not GPL.
So what this all means is that if an MPL project attempts to link to a 
GPL library, the GPL will apply to the entire combined work due to the 
"viral" nature of the GPL.  However, the terms and conditions the GPL 
imposes on the MPL code are incompatible with the terms and conditions 
of the MPL license.  Thus, the combined work can never be released 
without an alternative GPL-compatible license being offered.

On the other hand, if LGPL code links to GPL code or is copied into GPL 
code, the terms and conditions of the GPL would apply to the entire 
combined work, but the license terms and conditions are otherwise 
compatible.  However, we could not combine the enhancements back into 
the LGPL library.

So theoretically the Mozilla Foundation and the FSF could work together 
to make their respective licenses compatible. Sort of like the 
negotiations underway to allow Apache code to be linked or copied into a 
GPLv3 codebase.


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