How to ensure constexpr function never called at runtime?

Question

Lets say that you have a function which generates some security token for your application, such as some hash salt, or maybe a symetric or asymetric key.

Now lets sa

Answer 1

In the upcoming C++20 there will be consteval specifier.

consteval - specifies that a function is an immediate function, that is, every call to the function must produce a compile-time constant