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Is that true? My understanding is that so long as you clearly segregate GPL and non-GPL code by using wrapper classes and linking (rather than copypasta), the

by sheetjs 12y ago

Is that true? My understanding is that so long as you clearly segregate GPL and non-GPL code by using wrapper classes and linking (rather than copypasta), the core application can remain non-GPL.

lbradstreet 12y ago
I don't think that's correct as it is most of the point of the LGPL. I think it's how QT was able to sell licenses to closed source software despite being GPL'd as well (dual license).
hugs 12y ago
Usually, the litmus test is: Does the software work at all without the GPL'd parts? If not, it doesn't matter how segregated you think it is, because it's still dependent on that GPL'd code.
- sheetjs 12y ago
  As an example, consider a video player with a codec plugin system. The player ships with a noop plugin, a proprietary plugin for MPEG-1 video, and a general plugin that leverages GPL code. It is my understanding that the video player can still be non-GPL, but that wrapper to the GPL code must be GPL
  - vertex-four 12y ago
    If you're distributing them all together, all of it would have to be under the GPL. If you're distributing them separately, otoh, only the GPLed bits would have to be under the GPL.
  - geofft 12y ago
    This seems exactly analogous to the CLISP/libreadline example I just linked in another comment, where it was agreed that CLISP needs to be under the GPL. The situation is, probably, a bit different if the video player authors have no intention of using GPL code and just develop an interface, and someone else unrelated comes along and writes a GPL plugin. But if the app's authors ship the GPL plugin or worse write it, they're on shaky ground. (This gets you into some slightly silly situations where author A writes GPL software A linking software B, software B can make use of a GPL-incompatible library C, all of A, B, and C can legally redistribute their software on their own, but Debian has to make sure A doesn't link C because they're shipping the whole thing.)
vertex-four 12y ago
> Is that true? My understanding is that so long as you clearly segregate GPL and non-GPL code by using wrapper classes and linking (rather than copypasta), the core application can remain non-GPL. Sort of. If you license your main source code under, say, the MIT license, you can distribute that source code, and any object code compiled from it, under the terms of the MIT license. However, once you distribute a binary containing that source code and some GPLed source code linked together, you have to distribute all that source code (including any other libraries) under GPL-compatible licenses, such that the user can compile and distribute the application themselves. The LGPL allows you to keep your main source code closed-source while using an LGPLed shared library, so long as a user can replace the shared library with their own version.
geofft 12y ago
Except for OS libraries and similar, distributing two components intended to be runtime-linked together is generally not sufficient separation to be considered "mere aggregation". I would personally not even patch a GPL app to expose a custom API with the intention of using it from a separate non-GPL process; that also seems like it's more than "mere aggregation". (Using an existing / common API seems fine.) See the discussion of libnoreadline.a in this email exchange: http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-CLISP-is-under-GPL http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-... and specifically Steve Jobs asking Richard Stallman if he could avoid having the Objective-C compiler be under GPL: I say this based on discussions I had with our lawyer long ago. The issue first arose when NeXT proposed to distribute a modified GCC in two parts and let the user link them. Jobs asked me whether this was lawful. It seemed to me at the time that it was, following reasoning like what you are using; but since the result was very undesirable for free software, I said I would have to ask the lawyer. What the lawyer said surprised me; he said that judges would consider such schemes to be "subterfuges" and would be very harsh toward them. He said a judge would ask whether it is "really" one program, rather than how it is labeled. I am personally not a fan of that answer, but between recent caselaw like Oracle v. Google and some clarifications in GPLv3 around "Standard Interfaces" and the aggregation clause, it seems like betting on any other answer is a bad plan.

by sheetjs 12y ago

Is that true? My understanding is that so long as you clearly segregate GPL and non-GPL code by using wrapper classes and linking (rather than copypasta), the core application can remain non-GPL.

lbradstreet 12y ago

I don't think that's correct as it is most of the point of the LGPL. I think it's how QT was able to sell licenses to closed source software despite being GPL'd as well (dual license).

hugs 12y ago

Usually, the litmus test is: Does the software work at all without the GPL'd parts? If not, it doesn't matter how segregated you think it is, because it's still dependent on that GPL'd code.

sheetjs 12y ago
As an example, consider a video player with a codec plugin system. The player ships with a noop plugin, a proprietary plugin for MPEG-1 video, and a general plugin that leverages GPL code. It is my understanding that the video player can still be non-GPL, but that wrapper to the GPL code must be GPL
- vertex-four 12y ago
  If you're distributing them all together, all of it would have to be under the GPL. If you're distributing them separately, otoh, only the GPLed bits would have to be under the GPL.
- geofft 12y ago
  This seems exactly analogous to the CLISP/libreadline example I just linked in another comment, where it was agreed that CLISP needs to be under the GPL. The situation is, probably, a bit different if the video player authors have no intention of using GPL code and just develop an interface, and someone else unrelated comes along and writes a GPL plugin. But if the app's authors ship the GPL plugin or worse write it, they're on shaky ground. (This gets you into some slightly silly situations where author A writes GPL software A linking software B, software B can make use of a GPL-incompatible library C, all of A, B, and C can legally redistribute their software on their own, but Debian has to make sure A doesn't link C because they're shipping the whole thing.)

vertex-four 12y ago

> Is that true? My understanding is that so long as you clearly segregate GPL and non-GPL code by using wrapper classes and linking (rather than copypasta), the core application can remain non-GPL. Sort of. If you license your main source code under, say, the MIT license, you can distribute that source code, and any object code compiled from it, under the terms of the MIT license. However, once you distribute a binary containing that source code and some GPLed source code linked together, you have to distribute all that source code (including any other libraries) under GPL-compatible licenses, such that the user can compile and distribute the application themselves. The LGPL allows you to keep your main source code closed-source while using an LGPLed shared library, so long as a user can replace the shared library with their own version.

geofft 12y ago

Except for OS libraries and similar, distributing two components intended to be runtime-linked together is generally not sufficient separation to be considered "mere aggregation". I would personally not even patch a GPL app to expose a custom API with the intention of using it from a separate non-GPL process; that also seems like it's more than "mere aggregation". (Using an existing / common API seems fine.) See the discussion of libnoreadline.a in this email exchange: http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-CLISP-is-under-GPL http://clisp.cvs.sourceforge.net/viewvc/clisp/clisp/doc/Why-... and specifically Steve Jobs asking Richard Stallman if he could avoid having the Objective-C compiler be under GPL: I say this based on discussions I had with our lawyer long ago. The issue first arose when NeXT proposed to distribute a modified GCC in two parts and let the user link them. Jobs asked me whether this was lawful. It seemed to me at the time that it was, following reasoning like what you are using; but since the result was very undesirable for free software, I said I would have to ask the lawyer. What the lawyer said surprised me; he said that judges would consider such schemes to be "subterfuges" and would be very harsh toward them. He said a judge would ask whether it is "really" one program, rather than how it is labeled. I am personally not a fan of that answer, but between recent caselaw like Oracle v. Google and some clarifications in GPLv3 around "Standard Interfaces" and the aggregation clause, it seems like betting on any other answer is a bad plan.