Linux distros share a kernel -- the Linux kernel. Maybe different versions, maybe a few different patches here and there -- but unquestionably the same kernel.

Linux distros share a kernel -- the Linux kernel. Maybe different versions, maybe a few different patches here and there -- but unquestionably the same kernel. In BSD world they're completely separate OSes. Their kernels have evolved differently. They may have similar ancestry. You can't just copy and paste code from one to another and expect it to work.