GPL and closed source

Mahesh T. Pai paivakil at
Fri Jun 3 08:04:54 UTC 2011

Dale said on Fri, Jun 03, 2011 at 09:04:08AM +0300,:

 >    Hi
 >    Can GPLv3 code access functions (with dynamic/runtime linking) of a closed
 >    source .dll (not operating system .dll but an applications' library) which
 >    exposes an API ? Keep in mind that the dll although closed source is free
 >    for use

So, you have A.exe accessing functionality provided by B.dll.

What makes you think that #2, GPL v3 does not apply??

"This License explicitly affirms your unlimited permission to run the
unmodified Program."

 >    1.if you are the copyright holder of the GPL code then you can do that

It does not matter whetehr the work is GPL or not; if I am the owner /
creator, I can do just as I please with it. I am surprised that this
statement was made at all.

 >    2.if you are the copyright holder of the GPL code then you can
 >    do that provided that you add a clause to the GPL license that
 >    your code can be linked against closed source APIs.Although I
 >    find that this mostly should concern 3rd party developers who
 >    want to use your GPL code and link it against closed source APIs

I will rephrase that in slightly lesser words:- "I, as the creator /
owner of the copyrighted work need to grant myself permission to use

I hope I got that I got it correct; if so, I am speechless.

 >    3.If you GPL code uses dynamic/runtime linking rather than static,then it
 >    is ok

If GPL code uses static linking of non-GPL work, you have violated
license terms of the non-GPLed work. (I am assuming the "non-GPLed
work" here is closed source, non-modifiable, work). 

 >    4.If your GPL code accesses another non-GPL but open source library and
 >    this library calls the closed source API then your GPL code uses an
 >    intermediate interface which acts as the communication bridge between them
 >    thus does not access the closed source directly,which is ok.I see some
 >    people describe that as a 'shim'
Why is this shim shim required? 

If the non-free API is in legitimate possession of the user, the GPL
code does not impose any burden on the user. AFAICT, AFAIK. 

I have seen shims in use, but that is mostly to overcome
_distribution_ and/or packaging limitations. 

 >    So if the GPL code cannot access the .dll directly,can it through those

If the GPL'ed code cannot access another library, the only reason
would be technical, not legal or license, IMHO.

 >    libraries?
 >    GPL code <----> non-GPL but (GPL compatible) open source library <---->
 >    closed source. dll

 >    It looks like that GPL is too restricive in a sense

In what sense?

GPL does NOT restrict how you use code covered by the GPL. And, IMHO,
"use" in the GPL's sense includes access of other programs. 

Of course, when things work in other direction, GPL kicks in, and that
is why some people prefer to call GPL a "viral" license. 

I am no longer a lawyer though; and TINLA. 

Mahesh T. Pai   ||
TRUTH,  n.   An   ingenious  compound  of  desirability  and
  appearance.   Discovery of  truth is  the sole  purpose of
  philosophy, which  is the  most ancient occupation  of the
  human  mind  and has  a  fair  prospect  of existing  with
  increasing activity to the end of time.
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