C++11 constexpr function pass parameter

Question

Consider the following code:

static constexpr int make_const(const int i){
    return i;
}

void t1(const int i)
{
    constexpr int ii = make_const(i);  //          


        

Answer 1

Because t1() is not a constexpr function, the parameter i is a runtime variable... which you can't pass to a constexpr function. Constexpr expects the parameter to be known at compile time.