Initializing constexpr with const: Different treatment for int and double [duplicate]

Answer 1

Shafik Yaghmour already provided a link explaining the background.

Since I have to maintain code which has to compile with different standards, I use the following macro:

#if __cplusplus <= 199711L  // lower than C++11
  #define MY_CONST const
#else // C++11 and above
  #define MY_CONST constexpr
#endif