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SubjectRe: x32 and width of blksize_t, suseconds_t
On Fri, 16 Mar 2012, H. Peter Anvin wrote:

> On 03/16/2012 01:19 AM, Paul Eggert wrote:
> > Come to think of it, the proposed x32 patch may have issues
> > with blksize_t and suseconds_t as well. POSIX says that an x32
> > implementation must support at least one programming environment
> > (presumably settable via a feature test macro) where blksize_t
> > and suseconds_t are no wider than 'long'; see
> > <http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/sys_types.h.html>.
> > But if I understand things correctly, x32 glibc would
> > define these to be 'long long'. This issue affects system
> > calls such as 'stat' and 'select'.
>
> That's just not going to happen, sorry. Why on Earth is this a
> requirement? It makes no sense whatsoever.

It's probably to support code written for C90. Note that it's the
POSIX-conforming system as a whole that is to support such an environment
- but it might be an environment that uses the traditional 32-bit or
64-bit ABIs, it needn't be one using the x32 ABI. "getconf
POSIX_V7_WIDTH_RESTRICTED_ENVS" must print the names of the environments
meeting this requirement; if one is "POSIX_V7_ILP32_OFF32", for example,
then "getconf POSIX_V7_ILP32_OFF32_CFLAGS" will print the flags (maybe
-m32) and likewise for _LDFLAGS and _LIBS. In glibc this means defining
appropriate macros in bits/environment.h to give the right flags - and
also probably changing posix/confstr.c which has comments saying
"Currently this means all environment which the system allows." (the x32
patch series may need to adjust this in some way).

--
Joseph S. Myers
joseph@codesourcery.com


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