Ben Bucksch wrote: > Ian Hickson wrote: > >> The term (as used by the FSF) is extremely well defined. The GPL is a >> license that ensures two things: >> >> a. Code covered by the GPL will be free. >> b. Code covered by the GPL won't be used with code that is not free. >> > Not exactly. Code covered under the GPL can't be used with code that is > not the *GPL* (or a subset of it). Otherwise, the list of licenses > compatible with teh GPL would be identical to the list of Free Software > licenses. It isn't, and the MPL unfortunately happens to fall in the > category "Free Software, but incompatible with the GPL". That's exactly > what causes all this headache. That's why I think that the GPL is not at > all "extremely well defined".
I'll let the lawyers quibble with whether the GPL is "well defined", but you can't knock it on the above grounds. The GPL *must* limit combinations to licenses whose restrictions are a strict subset of its own, or else sneaky people could craft a license with which they could violate copyleft by putting impossible-to-meet extra restrictions on a critical file or two. It is probably legally impossible to define what kinds of "additional restrictions" would be acceptable and which aren't while still guaranteeing the goals of the GPL are met. Thus a large number of "free" licenses are incompatible with the restrictive GPL. -Dan Veditz
