On Tue, 2006-01-17 at 20:57 -0700, David G. Miller (aka DaveAtFraud) wrote: > jdow@xxxxxxxxxxxxx wrote: > > > From: "Jeff Vian" <jvian10@xxxxxxxxxxx> > > > >> On Tue, 2006-01-17 at 21:40 +0000, Andy Green wrote: > >> > Up until recently I worked for a company that developed and marketed a > closed source, Linux based, network monitoring product > (http://www.vericept.com). The company lawyers saw no problem with us > building and selling a closed source product that included calls to a > variety of GPLed and LGPLed libraries. As has been extensively > discussed over at Groklaw (http://www.groklaw.net) and elsewhere on the > 'net, headers and interfaces are *not* protectable elements under > copyright law. The only way the GPL kicks (via copyright law) in is if > you actually modify executable GPLed code for your product. At worst, > you would then need to make only these changes to the GPLed code > available as source (there's also nothing that says the maintainer has > to accept your changes; just publishing them is sufficient). The GPL kicks in if you distribute your product. If your program needs a GPL library the program is a derived work from that library and so if you distribute that program you have to distribute it in a GPL compatible way (for example by putting the program under the GPL). If you have a LGPL library the use of that library is not seen as a derived work and hence you are free to choose the license for your program. > What's good enough for the goose is good enough for the gander so the > GPL zealots can't have it both ways. Either implementing libraries that > are compatible with existing Unix(tm) headers and interfaces violates > someone's (say SCO's) copyrights or using GPLed headers and interfaces > to GPLed libraries in proprietary code is legal. That being said, the > open source folks have a lot more to lose if headers and interfaces are > suddenly found to be subject to copyright protection. > That headers aren't protected by copyright doesn't mean the implementation of the logic behind those headers isn't protected by copyright. If you have a GPL library, copyright doesn't prevent you from rewriting (from scratch) that library with compatible headers. Copyright does however prevents you from using that GPL library in a way that is not compatible with its license. So GPL zealots, as you call them, can implement libraries that are compatible with other libraries, without violating anybodies copyright. And they can put libraries under the GPL and force you to follow that GPL when you use their libraries. You, of course, can reimplement those libraries too if you want and put them under a different license. - Erwin
