sys/mount.h vs fcntl.h

[DJ Delorie]

Florian Weimer <fweimer@redhat.com> writes:
> I suggest this instead:
>
> #include <bits/cloexec.h>
> #define O_CLOEXEC __O_CLOEXEC
> #define OPEN_TREE_CLOEXEC O_CLOEXEC
>
> So it's identical to the kernel macro definition and no #undef is
> needed.

Do we need an #undef before that first #define, in case it's already
defined?  I assume no, since the definitions would be identical (the
user can include fcntl.h before sys/mount.h), but in case they
aren't (because future kernel header conflicts).

> > +/* Both fcntl.h and sys/mount.h include APIs that need O_CLOEXEC.
> > +
> > +   So, there's an arch-specific header for this constant, just for
> > +   this purpose.  We test that it is defined correctly here, and that
> > +   fcntl.h can use it.  */
> 
> You can include both <bits/cloexec.h> and the kernel header
> <linux/fcntl.h> and use static_assert.

That's not what I was testing.  The test specifically tests user-level
includes to make sure all the changes I made result in a workable
solution.

> Or write a tst-fcntl-consts.py test that checks all constants.  This
> would completely break the build if there's an inconsistency.

I don't think that would be useful for most constants.  It would just
mean "any change has to be made twice" without solving any problems.