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


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/
> 

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


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