On 14 October 2014 22:57, Chen Gang <gang.chen.5i5j@xxxxxxxxx> wrote:
> 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.
Because there is no cost to initializing the variable.
> - "const char n() {return 1;}; const a = n();", if 'a' is unused, gcc5
> will report warning.
Because it requires dynamic initialization, running a function at
startup, which has a cost. If you don't use the variable then you
might not want to run the initialization code at startup, so you get a
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?
I think this behaviour is intended and is not a bug.
