g++ 5.3.0 with argument -std=c++11/14/17 has __cplusplus < 201103L

I'm trying to get some C++ code compiled with compiles&runs fine on ubuntu with

g++ (Ubuntu 5.4.0-6ubuntu1~16.04.5) 5.4.0 20160609

It does not work on

CentOS release 6.5 (Final)

with

g++ (GCC) 5.3.0

It errors out in

bits/c++0x_warning.h:32:2: error: #error This file requires compiler and library support for the ISO C++ 2011 standard.

despite I've used -std=c++11 (and -std=c++14, -std=c++17) -- all of which are accepted....

Anybody any clue?!

The code is using

std::atomic .