Re: [Consult] g++: About "-Wunused-variable" for constant variable initialized by function

[Jonathan Wakely <jwakely dot gcc at gmail dot com>]

On 22 October 2014 02:46, Chen Gang <gang.chen.5i5j@gmail.com> wrote:
>
>
> On 10/15/14 18:07, Chen Gang wrote:
>> On 10/13/14 21:18, Chen Gang wrote:
>>> On 10/13/14 18:53, Jason Merrill wrote:
>>>> On 10/12/2014 10:32 AM, Chen Gang wrote:
>>>>>    [root@localhost qemu_cc]# cat test.cc
>>>>>    const char n() { return 1; }
>>>>>    const char c =  n();
>>>>>    [root@localhost qemu_cc]# /usr/local/bin/g++ -Wall -O0 -c -o test.o test.cc
>>>>>    [root@localhost qemu_cc]# /usr/local/bin/g++ -Wall -O2 -c -o test.o test.cc
>>>>>    test.cc:2:12: warning: 'c' defined but not used [-Wunused-variable]
>>>>>     const char c =  n();
>>>>>                ^
>>>>
>>>> The warning is correct (and new).  Please submit bug reports via the website; see https://gcc.gnu.org/bugs/
>>>>
>
> Aftr trying, I can not make a new account for gcc bugzilla.
>
>  - Before file a bug, it is mandatory to have an acount.
>
>  - I try to register a new account on the website, it said that need
>    send mail to overseers@gcc.gnu.org.
>
>  - I sent related mail to overseers@gcc.gnu.org, but get no response.
>
> Need I wait for some days? or could any member help to file this bug to
> gcc bugzilla?
>
> And whether it is OK or not, I shall try to analyze this issue directly,
> I should try to finish it within 2014-10-31 (although I am really not
> quite sure about it).

I thought we'd established this is not a bug.



>
> Thanks.
>
>>
>> Thank Jason Merrill, again. At present, I have got enough confirmation
>> from you and other members (excuse me, I am not quite familiar with C++,
>> for me, it is a complex language, so need several members confirmation).
>>
>> And if no additional reply within this week, I shall submit bug reports,
>> and try to fix it within this month (although I am really not quite
>> sure).
>>
>> I am not quite familiar with C++, so if any members worry about me: feel
>> that I am not quite suitable to report bug and fix it, please let me
>> know within this week.
>>
>> Thanks.
>>
>>>
>>> OK, thanks. After finish this consult, I shall report bugs, and shall
>>> try to fix it (I got it from Qemu which in my current focus border).
>>> Hope I can finish within this month.
>>>
>>> And one another consult: if the constant variable is defined in header
>>> file, and never be used, need our g++ still report warning about
>>> [-Wunused-variable] too (for me, I guess, not)?
>>>
>>>
>>> Thanks.
>>>
>>
>
> --
> Chen Gang
>
> Open, share, and attitude like air, water, and life which God blessed