Dynamic linking, was: Re: Dispelling BSD License Misconceptions

David Woolley david at djwhome.demon.co.uk
Fri Jan 26 07:17:45 UTC 2007

> Always???? So if I write a program to work only on Windows Vista and no
> other system, is my code a derivative work of Windows? 

That's a non-sequitur in the case of the GPL, because there is a specific
exemption in that case.

Also, in general, I think one needs to consider what the purpose of the
linking restrictions are in trying to determine the meaning of the licence.
It is fairly clear that the purpose of the linking requirements are to
prevent someone from creating software that can only realistically be
used in combination with GPLed code, but isn't, itself, free software.

The borderline case occurs when they provide a non-GPLed stub of a
GPLed library.  I think you then have to consider intention.  If the
intention is that most users will use that stub, and all functions of the
non-free code are still accessible without excessive contortions, it would
seem to me that it is legitimate to conform to the API of the GPLed

If they actually use the machine readable GPLed shared library or header
files in building their program, or if their intention is that most users
would replace the stub library with the GPLed one, I would suggest that
they are trying to defeat the intentions of the GPL.

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