NS libraries on Mac OS X

[julius guzy]

Hi,
i've been struggling to determine which bits of objective c code on 
mac OS X are free for me to use under gnu without having to obtain a 
licence from apple. I have been directed by numerous people to the 
darwin developer pages, foundation pages etc but none of these makes 
the issue clear.

Initial investigations at apple developer site appear to indicate 
that all of the routines prefixed by NS belong to apple..... but...
I see in your site documentation plentiful references to objects 
frefixed NS e.g.
http://www.gnustep.org/resources/documentation/gnustep-base_2.html#SEC2 and
http://www.gnustep.it/nicola/Tutorials/BasicClasses/
to name but two.

Are you able to shed any light in the situation, i.e. is it the case 
that all of the objects prefixed by NS (e.g NSObject) mentioned on 
this site are in fact available under gnu licence even when sited on 
apple OS X machines?

Thanking you in advance
Julius