[Insight-developers] Linear algebra licensing and ITK 3.18 Release

Tue Mar 23 13:49:06 EDT 2010

Hi Emmanuel,

We are not questioning the legality of the LGPL license.

It is quite clear that the LGPL license, as well as all the
other licenses approved by the Open Source initiative
are perfectly legal:

              http://www.opensource.org/licenses

What we are discussing is the compatibility of the LGPL
and GPL licenses with the BSD license used by ITK.

The practical reality is that the LGPL and GPL licenses
are not compatible with the BSD license. In the sense
that code licensed under GPL and LGPL can not be
repackaged and redistributed under a BSD license.

This is because the GPL and LGPL licenses include
conditions that are not present in the BSD license.

     Luis

-------------------------------------------------------------------------
On Tue, Mar 23, 2010 at 11:20 AM, Emmanuel Christophe
<emmanuel.christophe at gmail.com> wrote:
> Hi Luis,
>
> Looking at the LGPL license, it doesn't seem so restrictive:
> http://www.gnu.org/licenses/lgpl-3.0-standalone.html
>
> Looking at 4 d) 0), it seems that if you link statically but provide
> the .a and the source of the LGPL library, you enable the user to
> modify the LGPL part and relink the application (without providing
> your source). The final work can be redistributed under the term of
> your choice. Note, you can chose either 4 d) 0) or 4 d) 1).
>
> Not sure if this is practical from a technological point of view, but
> it seems legal.
>
> Best regards,
> Emmanuel
>
>
> On Tue, Mar 23, 2010 at 22:53, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>> Hi Kent,
>>
>>
>> The practical rule with LGPL libraries is the following:
>>
>> 1) If your application links statically to an LGPL library XYZ
>>    then your application is considered a derivative work
>>    of the library XYZ and therefore, if you distribute your
>>    application then you must do so under the LGPL license
>>    as well.
>>
>> 2) If your application links dynamically to an LGPL library,
>>    then your application is not considered to be a derivative
>>    work of the library and therefore the library doesn't impose
>>    further condition on the licensing of your application.
>>
>>
>> Since ITK does not finely control how users build their applications,
>> we are better off by avoiding carrying third party libraries that are
>> covered by the LGPL license.
>>
>>
>>     Luis
>>
>>
>>
>> --------------------------------------------------------------------------------------
>> On Mon, Mar 22, 2010 at 2:12 PM, kent williams
>> <norman-k-williams at uiowa.edu> wrote:
>>> Not to belabor the point but you say 'your summary is correct' and yet you
>>> state LGPL should can't be included, where as I said I thought that it could
>>> be OK.  I don't care one way or another. I don't know of any LGPL code that
>>> ITK needs or wants.
>>>
>>> But I am interested in which LGPL restrictions are incompatible with the ITK
>>> license.
>>>
>>> It's really a global problem. Some people apply licenses to their code
>>> without really understanding what they've done, or they fail to include any
>>> license at all, which is just as dangerous.
>>>
>>> Due to DMCA Copyright rules, EVERYTHING anyone creates is implicitly
>>> copyrighted, so if someone wants to share code, they need to explicitly
>>> state what rights they're willing to grant those who wish to use their code.
>>>
>>> As for GPL, it reflects the absolutist political stance of Richard Stallman,
>>> and like all absolutist opinions, it is by definition unreasonable. It's
>>> like abstinence-only sex education: being unwilling to accomodate real world
>>> conditions, it ends up sabotaging its own goals.
>>>
>>> But that's probably not an arugment to get into here ;-)
>>>
>>> On 3/22/10 11:36 AM, "Luis Ibanez" <luis.ibanez at kitware.com> wrote:
>>>
>>>> Hi Kent,
>>>>
>>>>
>>>> Your summary is correct.
>>>>
>>>>
>>>> 1) Yes, ITK's BDS license has minimal conditions and it is one of the
>>>>     most permissive licenses approved by the Open Source Initiative.
>>>>
>>>> 2) Code covered by the GPL license can not be incorporated into ITK.
>>>>
>>>> 3) Code covered by the LGPL license can not be incorporated into ITK.
>>>>
>>>> 4) Yes, code incorporated into ITK must be under a BSD license or
>>>>     under a license that has less restrictions than the BSD license.
>>>>     The ACM license is very restrictive, therefore we must replace
>>>>     any code in ITK that is subject to that license.
>>>>
>>>> 5) Yes, in extremely useful cases we carry code that may facilitate
>>>>     to interface to GPL and/or LGPL code. Such adaptor classes are
>>>>     to be enabled by the user, via a CMake flag.  It is then up to the
>>>>     users to deal with the consequences of their applications becoming
>>>>     subject to the GPL license.
>>>>
>>>>
>>>>
>>>>        Luis
>>>>
>>>>
>>>> ------------------------------------------------------------------------------
>>>> ----------
>>>> On Fri, Mar 19, 2010 at 11:34 AM, kent williams
>>>> <norman-k-williams at uiowa.edu> wrote:
>>>>> Correct me if I'm wrong but here's my executive overview of ITK licensing.
>>>>>
>>>>> 1. ITK itself is released with a BSD-like license, meaning that it's truly
>>>>> Free software, in that anyone can use it any way they want to --
>>>>> incorporating it into both open- and closed-source applications.
>>>>>
>>>>> 2. GPL has the 'viral hook' disadvantage, in that it forces anything
>>>>> incorporating GPL-licensed software to also be GPL licensed.  This is
>>>>> incompatible with ITK's license, so ITK doesn't incorporate GPL-licensed
>>>>> software.
>>>>>
>>>>> 3. The Lesser GPL (LGPL) license is GPL minus the 'viral hook.' GLIBC is
>>>>> released under GPL; otherwise no closed-source program would be legal on
>>>>> Linux, or OSX.  LGPL libraries could potentially be incorporated into ITK.
>>>>>
>>>>> 4. Anything incorporated into ITK has to have an unambiguous software
>>>>> license compatible with the ITK license.  Thus the current search to replace
>>>>> the linear algebra stuff apparently under ACM license restrictions.
>>>>>
>>>>> 5. In extraordinary cases, (FFTW being the prime example), ITK will include
>>>>> classes that depend on GPL-licensed libraries, but without including the
>>>>> library as part of ITK. It's up to the ITK user to resolve their own
>>>>> licensing questions if they configure ITK to use these GPL-licensed
>>>>> libraries.
>>>>>
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>> _______________________________________________
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>>
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>>
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>>
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