[numbsafari]

Why not just write the license in such a way that linking against the stable ABI requires your code to also be GPL licensed?

Is there a legal reason why the requirement can only apply to the original source code and not the compiled source code? Don't the "proprietary binary" people exert some kind of license over their proprietary binaries?

And why can't the Linux Kernel have a versioned ABI? I don't know enough about it, but does it really get revised that often and by that much? I mean, Apple and Microsoft seem to be able to make this work, and everyone seems to think they aren't very capable compared to the Linux Kernel crew. The argument about "having to support old things" also doesn't seem to hold water, because one of the big reasons people use Open Source software is to leverage older, outdated hardware or to have access to older, outdated software and data that the proprietary vendors leave behind.

[dragonwriter]

> Why not just write the license in such a way that linking against the stable ABI requires your code to also be GPL licensed?

Well, for one thing, its dubious than ABI's are copyrightable (for much the same reasons as that is true for API's, see Oracle v. Google), so work derived from an existing products ABI quite likely doesn't need a copyright license, so therefore is unlikely to be effectively restrictable by way of a gratuitous copyright license.