Re: Kernel header changes break glibc build

[Jakub Jelinek <jakub at redhat dot com>]

On Wed, Dec 06, 2006 at 02:07:19PM +0000, David Woodhouse wrote:
> On Wed, 2006-12-06 at 14:59 +0100, Thomas Graf wrote:
> > Are you suggesting that the kernel has to keep macros around which
> > are of no use to the kernel itself just because glibc uses them?
> 
> No, although in fact that _is_ the only reason we use these horrid __uXX
> types rather than proper C datatypes, isn't it?

There are the kernel's own headers and kernel ABI headers for userland use.
Until recently the latter has been maintained by various distributions
and manually occassionally updated to sync a little bit with kernel ABI
additions (new syscalls, etc.)., but now, thanks to David, these are
generated from kernel's own headers.  If the macros were part of
such ABI (I don't think these macros were meant to be #ifdef __KERNEL__
and just by omission exported to userland), then if you change
the kernel headers (which of course you can do, that's kernel private
headers), then you IMNSHO should also add magic to make headers_install
to keep the kernel ABI headers for userland headers stable.
Which in this case would mean if you decide rtnetlink.h shouldn't include
the newly added if_addr.h that you add rules for generating the userland
rtnetlink.h such that it will include linux/if_addr.h and define the
macros you intentionally omitted.

	Jakub