How to do it...

• To control the alignment of a type (both at the class level or data member level) or an object, use the alignas specifier:

        struct alignas(4) foo 
        { 
          char a; 
          char b; 
        }; 
        struct bar 
        { 
          alignas(2) char a; 
          alignas(8) int  b; 
        }; 
        alignas(8)   int a; 
        alignas(256) long b[4];

• To query the alignment of a type, use the alignof operator:

        auto align = alignof(foo);