static constexpr vs constexpr in function body?

Question

Is there any difference between static constexpr and constexpr when used inside a function's body?

int SomeClass::get(const bool b) 
{
    static constexpr int SOME_CONSTANT = 3;
    constexpr int SOME_OTHER_CONSTANT = 5;

    if(b)
        return SOME_CONSTANT;
    else
        return SOME_OTHER_CONSTANT;
}

Answer 1

The main difference between those two declarations is the lifetime of the objects. When writing the question, I thought that using constexpr instead of const would place that object into the .rodata section. But, I was wrong. The constexpr keyword, here, only provides that the object can be used at compile-time functions. So, the object is actually created in the stack during run-time and destroyed when leaving the function's body. On the other hand, the static constexpr object is an object placed in the .rodata section. It is created at the first time we call the wrapping function. In addition, thanks to the constexpr, it is also available during compile-time.