[postgis-users] liblwgeom and LGPL?

[Brian H Wilson]

This thread is veering off topic and I feel responsible. I am an ardent 
supporter of GPL, open source, and PostGIS.
I was trying to explain how a "traditional" software company might react 
to a shift in licensing. I promote open source, I contribute to it when 
I can. So far I have not been able to convince my traditional employer 
to open source things I have done for him, but I am getting much closer. 
My attitude is "give back, and help it get even better."

But let's drop that part -- Jim's ORIGINAL question was (in part)

" Which means, that when I want to link lwgeom to another piece of 
software (I'm thinking of spatialite here), this again needs to be GPL 
and when I then want to link spatialite together with e.g. gdal this 
again becomes GPL etc. etc. -- "

MY understanding is that you can use GPL libraries without making your 
derived program GPL -- spatialite or GDAL in this case -- see the "GPL 
licensing exception". This gets into the whole GPL V1/V2/V3 thing. Which 
license covers liblwgeom? It looks like it's GPL V2. Parts are under 
more permissive licenses. (eg GDAL).

 From the wikipedia page: http://en.wikipedia.org/wiki/GPL_linking_exception

" Craig Mundie, Microsoft Senior Vice President has described the GPL as 
being "viral" <http://en.wikipedia.org/wiki/Viral_license>.^[81] 
<http://en.wikipedia.org/wiki/GNU_General_Public_License#cite_note-81> 
Mundie argues that the GPL has a "viral" effect in that it only allows 
the conveyance of whole programs, which means programs that link 
<http://en.wikipedia.org/wiki/GPL_linking_exception> to GPL libraries 
must themselves be under a GPL-compatible license, else they cannot be 
combined and distributed.

In the views of Richard Stallman, Mundie's metaphor of a "virus" is 
wrong as software under the GPL does not "attack" or "infect" other 
software. Stallman believes that comparing the GPL to a virus is an 
extremely unfriendly thing to say, and that a better metaphor for 
software under the GPL would be a spider plant 
<http://en.wikipedia.org/wiki/Chlorophytum_comosum>: If one takes a 
piece of it and puts it somewhere else, it grows there too.^[82] 
<http://en.wikipedia.org/wiki/GNU_General_Public_License#cite_note-82> 
^[83] 
<http://en.wikipedia.org/wiki/GNU_General_Public_License#cite_note-83> 
^[84] 
<http://en.wikipedia.org/wiki/GNU_General_Public_License#cite_note-84>"

Spatialite itself is also GPL V2 _or_ LGPL _or_ Mozilla Public license. 
I consider this a little confusing but I am not worried! They just want 
to make it easy for you to use and prevent it from being locked up or 
patented.

I think the real answer to Jim is "no" -- if you create a work that uses 
spatialite and liblwgeom as libraries then you are working entirely 
within the framework spelled out by GPL V2. Go for it! Is there someone 
(Paul Ramsey? PostGIS foundation?) who can make this unequivocal?  If 
you don't change the library you are free to use it in your own program 
without that program becoming GPL.

When I use open source code in a library and I make a change to the 
library, I always send the change back.

Personally I want people to use the work I do, so my own leaning is 
towards licenses like X/MIT, Apache, BSD and so on that are not 
confusing. As in: "Do anything you want with this. If you break it you 
can keep both pieces."

Gotta go, spouse dragging me away from computer for family dinner, cheers --

Brian





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