Re: [PATCH] binutils/nm.c: Skip sbrk() under Darwin when _POSIX_C_SOURCE not defined

[Chen Gang <gang dot chen dot 5i5j at gmail dot com>]

On 9/15/14 21:54, Tristan Gingold wrote:
> 
> On 15 Sep 2014, at 15:31, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>> On 9/15/14 21:21, Tristan Gingold wrote:
>>> Hello,
>>>
>>> On 15 Sep 2014, at 15:20, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>>> [...]
>>>> --- a/binutils/nm.c
>>>> +++ b/binutils/nm.c
>>>> @@ -1698,6 +1698,7 @@ main (int argc, char **argv)
>>>>  END_PROGRESS (program_name);
>>>>
>>>> #ifdef HAVE_SBRK
>>>> +#if !defined (__DARWIN_C_LEVEL) || defined (_POSIX_C_SOURCE)
>>>>  if (show_stats)
>>>>    {
>>>>      char *lim = (char *) sbrk (0);
>>>> @@ -1705,6 +1706,7 @@ main (int argc, char **argv)
>>>>      non_fatal (_("data size %ld"), (long) (lim - (char *) &environ));
>>>>    }
>>>> #endif
>>>> +#endif
>>>
>>> Enable code on machine specific macro is not recommended by the GNU standard.
>>> Also note that sbrk is also used by gas.
>>>
>>> Maybe the test of sbrk in configure should be done using warnings flags.
>>>
>>> (the work-around is to configure using --disable-werror).
>>>
>>
>> Originally, I really tried to do that, but I found that HAVE_SBRK really
>> need be true under Darwin, but may report warning.
> 
> Can you clarify that ?  IIRC, the only use of sbrk within binutils is to
> compute the amount of memory used.
> 

Yeah, in "binutils/binutils", what you said is reasonable to me.

But in "bintuils" (include as, ld, gdb ...), most of sub-systems content
"HAVE_SBRK", and some of them not enable 'Werror'.

Originally I tried "binutils/binutils" in "binutils/binutils/configure"
(but not send patch). But after I thought of again, for me:

 - 'HAVE_SBRK' express whether have sbrk(), do not care about warnings.

 - Multiple sub-systems use 'HAVE_SBRK', some can bare the warnings.

 - If the sub-systems can not bare warnings, it needs additional trying
   (e.g binutils/binutils), and still keep the standard checking for
   'HAVE_SBRK' in related configure.


Thanks.
-- 
Chen Gang

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