Re: linking to GPL'd libraries WAS Re: One unclear point in the Vim license
Hamish Moffatt <hamish@debian.org> writes:
> Don't dismiss this as completely obvious. It's not uncontroversial.
>
> For example, the kernel is GPLed but will load and run programs
> with incompatible licenses. Those programs make syscalls to
> the kernel to perform system work; how is this permitted?
Because the kernel is not one program together with the applications
it runs.
> It is so different from an incompatibly-licensed program linking
> to a GPLed library?
Yes, it is different. One is a program making callouts to a different
entity, the kernel. The case we were talking about is that of library
linking.
> The ldso license is interesting (/usr/doc/ldso/copyright, possibly
> only on potato or earlier systems). The commentary implies that
> ld.so deliberately uses the BSD license because the GPL is too
> strict. It also has the following paragraph:
The ldso people don't have any ability to change the licenses of the
actual authors of the libraries in question.
There are lots of different cases. A great deal of difficulty is
caused by people asserting that totally different cases must all be
treated the same way. Post one case at a time, and not a giant spew
of a jillion examples, as if they all argued for one single point.
Each separate case is a separate discussion.
Many of the examples you cited are cases where it is not very
important whether the combined thing is a single derived work or not,
because the licenses are more permissive than the GPL. Other cases
involve explicit declarations by the authors of the programs about how
they intend the license to be interpreted. Many involve things like
the kernel that are not libraries at all.
> Getting off-topic a bit, there's an interesting clause in the
> license for libio, in /usr/doc/libc6/copyright (on potato anyway).
>
> As a special exception, if you link this library with files
> compiled with a GNU compiler to produce an executable, this does
> not cause the resulting executable to be covered by the GNU General
> Public License. This exception does not however invalidate any
> other reasons why the executable file might be covered by the GNU
> General Public License.
>
> Why does the license require you to use a GNU compiler? Bizarre.
I have no idea. But what on earth does it have to do with the present
conversation?
Why do you think that "getting off-topic a bit", in a post which
already contained so much that is off-topic, has any hope of doing any
good for the conversation?
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