Proprietary System and GPL Software


I’m trying to understand the limitations of using GPL software within a proprietary (closed source) software application. According to this you can distribute the GPL software with your proprietary as long as they communicate “at arms length”. What exactly does this mean? If you communicate using a COM server? How about a ROAP server? What about good old fashioned Unix like pipes? What about simply batching jobs to the GPL software?

Can anyone more familiar with the legalese of the GPL shed some light?



The page you linked sez that arm’s length means “that they are not combined in a way that would make them effectively a single program” and then goes on to explain further. This still isn’t a great definition but I would take it to mean that you don’t, for example, take GNU source code or executable and link/bind it into your own executable module. Once installed on a system, could you remove your program and leave the GNU part intact, or vice versa? If yes, then you’re OK (although that’s a seat-of-the-pants test). Any of the examples you gave look fine to me.