What’s in include/uapi of kernel source project

The uapi folder is supposed to contain the user space API of the kernel. Then upon kernel installation, the uapi include files become the top level /usr/include/linux/ files. (I’m not entirely clear on what exceptions remain.)

The other headers in theory are then private to the kernel. This allow clean separation of the user-visible and kernel-only structures which previously were intermingled in a single header file.

The best discussion I have seen of this is located at a Linux Weekly News article that predates the patch landing.

The UAPI patch itself landed with kernel 3.7. Linus’s quick and dirty summary is:

  • the “uapi” include file cleanups. The idea is that the stuff
    exported to user space should now be found under include/uapi and

    Let’s hope it actually works. Because otherwise this was just a
    totally pointless pain in the *ss. And regardless, I’m definitely done
    with these kinds of “let’s do massive cleanup of the include files”

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