How to check whether a system is big endian or little endian?

Question

How to check whether a system is big endian or little endian?

Answer 1

In C++20 use std::endian:

#include 
#include 

int main() {
    if constexpr (std::endian::native == std::endian::little)
        std::cout << "little-endian";
    else if constexpr (std::endian::native == std::endian::big)
        std::cout << "big-endian";
    else
        std::cout << "mixed-endian";
}