Re: Use of GPL'd code with proprietary programs

[Isaac]

On 11 Jul 2004 01:28:24 +0200, David Kastrup <dak@gnu.org> wrote:
> I thought that copyright cases were dealt with under the civil code?
> But there is a fine line between calling dlopen and dynamically
> linking a program: in the latter case, symbol addresses are resolved
> and scattered through the caller.  The calling code is adapted to the
> called library and can't call a different one after linking.

There are some criminal provisions associated with copyright 
infringement.  Distributing someone's work for financial gain
can trigger criminal penalties.  (See 17 USC 506)

> In contrast, just using dlopen and dlsym does not merge the
> code of the dynamically linked library and the caller.
> 
> I doubt, however, that the technical difference between dlopen/dlsym
> and dynamic linking would matter at all to a judge and jury, much like
> I doubt that the difference between dynamic and static linking would
> matter much: the point is that two non-functional entities are
> combined into one that can do the job.

I think you are right about the technical differences between the
modes of linking.  They probably would not matter much.  But facts
closely associated with the technical differences could matter.  A 
jury might be impressed with the fact that a program using dynamic
linking cannot even load and run without the library being present,
while the program using dlopen does run although in some alternate
and possibly more limited function.

Similarly a jury might find it relevant that programs using dlopen
or dynamic linking were distributed to people who had already
permission to use the library while a statically linked executable
involved distribution of the library without permission.

One issue that is unique where the GPL is involved is that the 
copyright holder cannot complain about the end users actions
of linking to the library because those actions are permitted by
the GPL.  Thus infringement actions based on contributory or
vicarious infringement are not viable.  The copyright holder must
claim that the distributor of a linking program is directly
infringing and not that some he has caused some final infringing
entity to be made by a user.

Isaac