Tornado and Grand Central Dispatch: a quick look [LWN.net]

Tornado and Grand Central Dispatch: a quick look

Posted Sep 16, 2009 21:08 UTC (Wed) by nteon (guest, #53899)
Parent article: Tornado and Grand Central Dispatch: a quick look

As Apple's changes to their kernel have to do with KQueue, I doubt we will
see any 'Apple code' looking for inclusion in the Linux kernel.

It might also be worth noting that some enterprising fellows have GCD running
on FreeBSD already. For the Linux 'port' there is talk of using libevent
(which abstracts kqueue and epoll).

I've been interested in working on this, but am somewhat put off by the fact
that it is Apache licensed (knowing that no matter how well it works, license
restrictions will prevent people from playing with it). Are there guides or
advice on how to start a similar project that would be API compatible but
legally under the GPL? Would this even be possible if I've looked through
the source for GCD (which I have)?

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Tornado and Grand Central Dispatch: a quick look

Posted Sep 16, 2009 21:44 UTC (Wed) by MathFox (guest, #6104) [Link]

Are there guides or advice on how to start a similar project that would be API compatible but legally under the GPL? Would this even be possible if I've looked through the source for GCD (which I have)?

In general, one can independently re-implement a public interface without any obligation to the original designer of the interface. The keyword is independently and that's why in professional re-implementation settings one uses a clean-room methodology. (See http://en.wikipedia.org/wiki/Clean_room_design).

If you have read the source code it's better that you stay on the specification side of things and avoid implementing... OTOH, I think that Apple in this case will only object to very obvious code lifting, as they Open Sourced the code already. (IIRC under a GPLv3 compatible license)

Tornado and Grand Central Dispatch: a quick look

Posted Oct 6, 2009 9:56 UTC (Tue) by trasz (guest, #45786) [Link] (1 responses)

Actually, Apache license is not a problem - it's a liberal, Open Source license, and since libdispatch
is a system library, there is nothing preventing its use by programs under any kind of license,
including GPL.

Tornado and Grand Central Dispatch: a quick look

Posted Oct 6, 2009 14:11 UTC (Tue) by nix (subscriber, #2304) [Link]

Unfortunately the system library exception is not practically usable by
Linux distributors, which means it'll remain unused by Linux distributions
(because what's the point of a system library that you can't link to GPLed
code?).

It should just have been unencumbered BSD, dammit.