Re: [PATCH 1/2] Add --with-ilp32-large-off_t

["H.J. Lu" <hjl dot tools at gmail dot com>]

On Fri, Jul 6, 2012 at 8:09 AM, Andreas Jaeger <aj@suse.com> wrote:
> On 07/06/2012 05:02 PM, H.J. Lu wrote:
>>
>> On Fri, Jul 6, 2012 at 7:54 AM, Andreas Jaeger <aj@suse.com> wrote:
>>>
>>> On 07/06/2012 04:32 PM, H.J. Lu wrote:
>>>>
>>>>
>>>> On Fri, Jul 6, 2012 at 7:15 AM, Andreas Jaeger <aj@suse.com> wrote:
>>>>>
>>>>>
>>>>> On 07/06/2012 04:05 PM, H.J. Lu wrote:
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hi,
>>>>>>
>>>>>> On x86-64, ILP32 with large off_t (64-bit) can be either -mx32 or -m32
>>>>>> with "-D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64".  This patch adds
>>>>>> a configure time option to choose which one to use for ILP32_OFFBIG.
>>>>>> Any comments?
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> I'm not sure what you're doing, this sounds really wrong to me and I
>>>>> smell
>>>>> an ABI breakage. So, please help me to understand the problem you're
>>>>> trying
>>>>> to solve.
>>>>>
>>>>> Could you show a short example program that has a problem and explain
>>>>> the
>>>>> problem a bit more?
>>>>>
>>>>
>>>> See:
>>>>
>>>> http://sourceware.org/ml/libc-alpha/2012-05/msg02093.html
>>>
>>>
>>>
>>>
>>> Thanks, I see the problem. We surely should not make this the default
>>> since
>>> I expect slow adoption of the new ABI - and most people won't have a full
>>> development environment for it but will have on for x86 (-m32).
>>
>>
>> By default, nothing is changed, except for x32 glibc, which will use -mx32
>> for ILP32_OFFBIG.
>
>
> But you only install headers from the 64-bit library, so you need the
> configure option for the 64-bit build - correct?

You need to use --with-ilp32-large-off_t=mx32 to configure both -m64
and -m32 glibc build to enable -mx32 for ILP32_OFFBIG.


-- 
H.J.