Re: Incorrect use of USE_XATTR in coreutils-8.4

[Pádraig Brady]

On 17/01/10 08:03, Jim Meyering wrote:
> Thanks!
> That would fix it, but please retain the 0/1 semantics, in case
> we ever want to use USE_XATTR in a C (as opposed to cpp) expression.
>
>      # Map yes,no to 1,0.
>      AC_DEFINE_UNQUOTED([USE_XATTR],
>                         [`test $use_xattr = yes&&  echo 1 || echo 0`],
>                         [Define if you want extended attribute support.])
>
> I know this is not the norm for USE_* variables e.g., in gnulib,
> but I have come to appreciate being able to use 0/1 cpp symbols
> in C code (albeit not often), for readability.

Also if all variables were defined to something then
we could enable -Wundef which would catch this case:

#define USE_XATTR yes
#if XATTR
...

cheers,
Pádraig.