| Re: Anyone link GSL into IDL? [message #59633] |
Fri, 04 April 2008 09:08  |
Brian Larsen
Messages: 270
Registered: June 2006
|
Senior Member |
|
|
> I think what we probably agree on is that this newsgroup is far too
> friendly to go down this particular road and it's a topic best left to
> other fora.
>
Allan,
that I agree with 100 fold
Cheers,
Brian
------------------------------------------------------------ --------------
Brian Larsen
Boston University
Center for Space Physics
http://people.bu.edu/balarsen/Home/IDL/IDL.html
|
|
|
|
| Re: Anyone link GSL into IDL? [message #59634 is a reply to message #59633] |
Fri, 04 April 2008 09:02  |
Foldy Lajos
Messages: 268
Registered: October 2001
|
Senior Member |
|
|
On Fri, 4 Apr 2008, Allan Whiteford wrote:
>> I am working on the DLM support for FL and my example program is FFTW3.
>> I plan to release the DLM source under GPL. Is this enough? What is your
>> opinion?
>
> Some people would certainly assert that that would make all of FL GPL but
> that's not to say they'd be right (although I think within open source
> software circles they will be in the majority).
>
Now I see why GPL is called viral: a few dozen lines long interface can
infect a 200,000 lines program :-)
> My personal opinion and understanding of the GPL would be that this would be
> a violation but I'm not an expert on these things by any stretch of the
> imagination.
>
> I would be very cautious about releasing a FFTW3 plug-in for FL.
>
OK, to be on the safe side. I will drop FFTW3, it was meant as a useful
example program only. I will choose an other library with a more friendly
licence. And probably FL users will write their own FFTW3 DLM, they can
not infect FL :-)
> You can always write to the FSF for advice and/or contact the FFTW3 people to
> see if they'll make an exception for FL.
>
The FSF advice would be to release FL under GPL. And after reading the
FFTW pages I think the chance of obtaining an exception is exactly 0%.
So, I will not use FFTW.
thanks,
lajos
> Thanks,
>
> Allan
>
|
|
|
|
|
|
|
|
| Re: Anyone link GSL into IDL? [message #59640 is a reply to message #59638] |
Fri, 04 April 2008 08:25 |
Allan Whiteford
Messages: 117
Registered: June 2006
|
Senior Member |
|
|
Lajos,
F�LDY Lajos wrote:
>
> On Fri, 4 Apr 2008, Allan Whiteford wrote:
>
>>
>> Brian,
>>
>> Even if they had, it would probably[1] be in violation of the GPL to
>> distribute such code.
>>
>
> There is an FFTW3 DLM on the ITTVIS website. FFTW3 is GPL and ITTVIS
> distributes this DLM (binary only). So, is ITTVIS violating GPL?
>
Once again, IANAL. I note that you can buy a non-GPL version of FFTW3,
maybe ITTVIS did this in which case discussions are academic.
The whole argument comes down to the difference between linking code and
aggregating code and exactly how two pieces of code communicate. It has
been discussed ad-nauseum by thousands of people and I'm not really in a
position to give a more informed opinion than anyone else. Debian legal
discussions are a good place to look for technical discussions rather
than just flamewars.
The FSF and GPL seem to draw the line somewhere between a SO/DLM/DLL
approach and using a fork and exec. My understanding is that if you have
a GPL library then you couldn't distribute a program which links against
it (either statically or dynamically) without that program becoming GPL.
See this:
http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
which seems fairly definitive and this:
http://www.gnu.org/licenses/gpl-faq.html#GPLPluginsInNF
which is coming from the opposite point of view but would still suggest
that a non-free main program can't have a GPL plug-in without special
permission from the plug-in author. I think plug-in could be considered
to mean something called via linkimage, call_external in the context of IDL.
> Actually, IDL is not linked against the DLM, IDL is a standalone
> executable. The user links in (loads) the DLM at run-time using the
> DLM hook provided by IDL. Is this the same as build-time linking?
>
I think the FSF and GPL don't see a difference (see last link above).
It might be worth looking into the organisation of the Linux HAL - but
that's a GPL main program with proprietary plug-ins rather than the
other way around.
> I am working on the DLM support for FL and my example program is FFTW3.
> I plan to release the DLM source under GPL. Is this enough? What is your
> opinion?
Some people would certainly assert that that would make all of FL GPL
but that's not to say they'd be right (although I think within open
source software circles they will be in the majority).
My personal opinion and understanding of the GPL would be that this
would be a violation but I'm not an expert on these things by any
stretch of the imagination.
I would be very cautious about releasing a FFTW3 plug-in for FL.
You can always write to the FSF for advice and/or contact the FFTW3
people to see if they'll make an exception for FL.
Thanks,
Allan
|
|
|
|
| Re: Anyone link GSL into IDL? [message #59643 is a reply to message #59640] |
Fri, 04 April 2008 07:43 |
Foldy Lajos
Messages: 268
Registered: October 2001
|
Senior Member |
|
|
On Fri, 4 Apr 2008, Allan Whiteford wrote:
> Brian Larsen wrote:
>> In the realm of crazy TLAs has anyone ever linked the GNU scientific
>> library (GSL) into IDL. This is probably a case where I need to use a
>> DLM. Before I expend a bunch of effort reinventing the wheel I just
>> want to make sure that others have not done this.
>>
>>
>>
>> Cheers,
>>
>> Brian
>>
>> ------------------------------------------------------------ --------------
>> Brian Larsen
>> Boston University
>> Center for Space Physics
>
> Brian,
>
> Even if they had, it would probably[1] be in violation of the GPL to
> distribute such code.
>
There is an FFTW3 DLM on the ITTVIS website. FFTW3 is GPL and ITTVIS
distributes this DLM (binary only). So, is ITTVIS violating GPL?
Actually, IDL is not linked against the DLM, IDL is a standalone
executable. The user links in (loads) the DLM at run-time using the
DLM hook provided by IDL. Is this the same as build-time linking?
I am working on the DLM support for FL and my example program is FFTW3.
I plan to release the DLM source under GPL. Is this enough? What is your
opinion?
thanks,
lajos
> GSL is GPL and opposed to LGPL. This broadly means[2] you can't distribute a
> derivative work which links IDL and GSL.
>
> See the "licensing" section here:
>
> http://www.gnu.org/software/gsl/
>
> where the GPL has been explicitly chosen over the LGPL.
>
> See also:
>
> http://www.gnu.org/licenses/why-not-lgpl.html
>
> http://www.gnu.org/licenses/gpl-faq.html#IfLibraryIsGPL
>
> http://www.gnu.org/licenses/gpl-faq.html#GPLInProprietarySys tem
>
> http://www.gnu.org/licenses/gpl-faq.html#MoneyGuzzlerInc
>
> You can, of course, link IDL and GSL but then you're not allowed[2] to
> distribute that work.
>
> Of course, IANAL, and this is just my understanding of things. I am also not
> advocating anything in particular - just pointing out the situation as I see
> it.
>
> Thanks,
>
> Allan
>
> [1] You can get non-GPL versions of GSL but I'll work on the assumption
> you're talking about the free version you can just download.
>
> [2] i.e. is the general understanding of what the GPL means.
>
|
|
|
|
|
|
| Re: Anyone link GSL into IDL? [message #59719 is a reply to message #59633] |
Fri, 04 April 2008 20:48 |
Robbie
Messages: 165
Registered: February 2006
|
Senior Member |
|
|
Hi there,
I think that the only thing which is questionable is that you would
distributing GPL software which refers to idl_export.h, which is not
open source.
If Bwian made his source for a GSL DLM available under GPL, then there
is nothing anyone could or would do about it.
The purpose of GPL is to stop another party repackaging it as a binary
product, for example ITT might package it as another pricey add on.
The downside of GPL is that you loose the right to distribute
derivative works under anything but a GPL license. It's a simple trade
off.
I'd say go for it mate.
Robbie
|
|
|
|
comp.lang.idl-pvwave archive
Members
Search
Help
Login
Home
