GPL shared library usage in Proprietary code

[Nicolas Salles]

Le mardi 07 juillet 2009 à 17:04 +0530, Karthik Venkateswaran a écrit : 
> Greetings all,
> 
> I have been using GPL code for eternity but always wanted to know how 
> proprietary products are working around without violating GPL. 
> 
> 1. If there is a proprietary program using uClibc or libc (which is GPLv2) 
> does it automatically be part of GPL?

As far as I know, uClibc and libc are licensed under LGPL which may be
linked with proprietary code. LGPL is not GPL, it's LesserGPL.
As far as you don't modify or make any static link with it, you can use
it within a proprietary program.
So you may use uClibc and libc libraries as you take care that the
library remain accessible (code+source) to the user.

> 2. Would using libdbus (Part of both AFL and GPL) in a proprietary code 
> violate the GPL ? (libdbus is a socket communication interface mainly used 
> for IPC)

In fact, libdbus is only GPL or AFL. If you choose the GPL licence you
are not allowed to use it into a proprietary program if you intend to
distribute it, as you will be forced to gain access to whole code to
your users. What concerns AFL, I have no clue.

> 3. In a GPL code like Linux kernel if I add a kernel module part of GPLv3 
> would it automatically move on to version 3 of GPL?

On that part, I assume that you can't modify the licence an author gave
on his own code. So only the part your provide will be GPLv3, other
parts will remain available under their own licence.
It doesn't seem to be a problem to distribute a kernel with a mixed of
licences modules as there are not incompatible.

-- 
Nicolas Salles

"The man who trades freedom for security does not deserve nor will he
ever receive either." Benjamin Franklin