Re: [AMBER-Developers] PBSA license

From: Jason Swails <>
Date: Fri, 17 Mar 2017 23:11:48 -0400

On Fri, Mar 17, 2017 at 10:19 PM, David Case <> wrote:

> On Fri, Mar 17, 2017, Hai Nguyen wrote:
> > So non-GPL license programs are not allowed to to link to libsander.
> Above is not true. The whole point of making libsander LGPL is to allow
> non-GPL programs to link to it. (Certain restrictions apply, but the LGPL
> license is designed to encourage such connections.)

​Actually Hai's assessment here is accurate. The GPL is the Midas license
-- everything it touches turns to GPL. The problem in this case is that
sander -- and by extension libsander -- is by definition "based on" PBSA.​
 This is detailed explicitly in the GPL FAQ here:

So the issue here is that by licensing libsander as LGPL, we violate the
terms of PBSA's GPL license. So in this case we have two options:

1. License PBSA as L-GPL
2. License libsander as GPL

Also note that making libsander L-GPL would effectively strip GPL
protections from PBSA -- since all of PBSA's symbols are compiled into
libsander, you could always replace "-lFpbsa" with "-lsander". The GPL
would have no power if it were so easily sidestepped...

There's a reason the corporate world stays as far away from GPL-licensed
libraries as they can for commercial tools (this has been in several of my
recent trainings).

All the best,

Jason M. Swails
AMBER-Developers mailing list
Received on Fri Mar 17 2017 - 20:30:02 PDT
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