[RFC] DT_WHT

[Ben Hutchings]

On Wed, 2018-02-21 at 02:16 -0800, Rical Jasan wrote:
> There is one undocumented DT_* macro in manual/filesys.texi: DT_WHT.  It
> is defined in dirent/dirent.h and appears to be used once in io/fts.c:
> 
> #if defined FTS_WHITEOUT && 0
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â if (dp->d_type == DT_WHT)
> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â p->fts_flags |= FTS_ISW;
> #endif
> 
> For an entry in the manual, I was thinking something along the lines of:
> 
> "This macro is obsolete and has no effect.  It was used to..."
> 
> but I'm not sure what to say about what it was used for.
[...]
> Lastly, I can't find a reference to it in any of the standards I've
> managed to obtain so far (not to say that's exhaustive at all).  Is this
> also BSD?

Some Linux filesystems support white-out directory entries for use with
union filesystems.  At least the coda and xfs implementations of
getdents() appear to be capable of setting d_type to DT_WHT.

Ben.

-- 
Ben Hutchings
Software Developer, Codethink Ltd.