kdelibs and the GPL

[Rolf Magnus]

On Thursday 20 June 2002 14:44, Rob Kaper wrote:

> The fun part is that you can easily make proprietary applications using
> GPLed libraries/cores. Use IPC/DCOP tricks. I can't link to your code? No
> problem, I'll just add another (IPC) interface to your code, GPL that
> interface (which does link to your code) and make my proprietary app on top
> of the interface.
>
> Probably one of the bigger loopholes in the GPL.

Where exactly does the GPL make a difference between calling functions 
directly and calling them through IPC mechanisms?

There is something about this in the FAQ, too:
http://www.gnu.org/licenses/gpl-faq.html#MereAggregation

===============================================================================
What constitutes combining two parts into one program? This is a legal 
question, which ultimately judges will decide. We believe that a proper 
criterion depends both on the mechanism of communication (exec, pipes, rpc, 
function calls within a shared address space, etc.) and the semantics of the 
communication (what kinds of information are interchanged). 

...

By contrast, pipes, sockets and command-line arguments are communication 
mechanisms normally used between two separate programs. So when they are used 
for communication, the modules normally are separate programs. But if the 
semantics of the communication are intimate enough, exchanging complex 
internal data structures, that too could be a basis to consider the two parts 
as combined into a larger program. 
===============================================================================

What you describe sounds like it falls into the category "intimate enough".