[Consult] g++: About "-Wunused-variable" for constant variable in header file

[Chen Gang <gang.chen.5i5j@xxxxxxxxx>]

Hello All:

At present, I met one warning issue about gcc 5.0.0.

 - For "const float a = 3.4 - 2.1 / 3;", if it is unused, gcc5 will not
   report warning.

 - "const char n() {return 1;}; const a = n();", if 'a' is unused, gcc5
   will report warning.

For gcc old version (e.g. gcc4), it will not report warning. Is it the
new feature for gcc5, or just a gcc5's bug?

Welcome any ideas, suggestions or completions.

Thanks.
-- 
Chen Gang

Open share and attitude like air water and life which God blessed