[PATCH 06/25] Add struct scratch_buffer and its internal helper functions

[Florian Weimer]

On 03/23/2015 07:48 PM, Florian Weimer wrote:
> On 03/23/2015 07:46 PM, Joseph Myers wrote:
>> On Mon, 23 Mar 2015, Florian Weimer wrote:
>>
>>> On 03/23/2015 07:41 PM, Joseph Myers wrote:
>>>
>>>>> Since C allows platforms where pointers and/or floating-point values have
>>>>> alignments stricter than intmax_t, I suggest using 'max (__alignof__
>>>>> (intmax_t), __alignof__ (max_align_t))' along with a comment explaining why
>>>>> you don't trust max_align_t here.
>>>>
>>>> max_align_t was added to stddef.h in GCC 4.7, so we can't rely on it in 
>>>> glibc without appropriate conditionals.
>>>
>>> We compile glibc in -std=gnu99 mode, and max_align_t appears available.
>>>  Suggestions?
>>
>> It's specifically when compiling with GCC 4.6 (the oldest supported 
>> version) that it won't be available.
> 
> Oh, I misread what you wrote.  What I was saying is that we can't get it
> easily with GCC 4.9.2, either.

I proposed a patch for a libc_max_align_t type here:

  <https://sourceware.org/ml/libc-alpha/2015-04/msg00004.html>

As far as I can see, using that instead of intmax_t should address the
only remaining issue with this patch.

-- 
Florian Weimer / Red Hat Product Security