std:::is_constant_evaluated

Örnek

Açıklaması şöyle

There are 3 kinds of functions in C++, and is_constant_evaluated only makes sense in one of them.

Şöyle yaparız

// a strictly run-time function
int foo(int arg) 
{
    if (std::is_constant_evaluated()) // pointless: always false
        // ...
}

// a strictly compile time function
consteval int foo(int arg) 
{
    if (std::is_constant_evaluated())  // pointless: always true
        // ...
}

// both run-time and compile-time
constexpr int foo(int arg) 
{
    if (std::is_constant_evaluated())  // ok: depends on context in 
                                       // which `foo` is evaluated
        // ...
}