f_owner_ex vs. POSIX

[Rich Felker]

On Mon, Sep 02, 2019 at 03:44:53PM +0200, Florian Weimer wrote:
> * Michael Kerrisk:
> 
> > I do not know what the rationale was for the addition of the 'enum',
> > and it wouldn't surprise me if there was no public discussion about
> > it. The use of an 'enum' strikes me as a slightly odd decision (given
> > that the kernel uses 'int') but, related to your point below, there
> > is precedent in, for example, the use of an 'enum' for 'idtype_t' in
> > waitid() inside glibc, while the kernel type for the argument in
> > the underlying system call is 'int'.
> 
> There is also the issue of -fshort-enum.  Some people probably expect
> that they can use that option and still use glibc headers.
> 
> I do not have any inside knowledge why things are like they are.
> Presumably we can switch the type member to int.

I'm strongly in favor of switch to int. enum types are an
ABI/compatibility nightmare and have little purpose (unlike enum
constants which are actually useful).

Rich