title: Why std::sample is not constexpr?
body: <p>I know that c++11 PRNG in <code>&lt;random&gt;</code> such as <code>std::mt19937</code>  are not usable in compile time, but  access the <code>__TIME__</code> preprocessor macro to implement the <code>constexpr</code> version of PRNG is possible, why <a href="https://en.cppreference.com/w/cpp/algorithm/sample" rel="nofollow noreferrer"><code>std::sample</code></a>/<a href="https://en.cppreference.com/w/cpp/algorithm/ranges/sample" rel="nofollow noreferrer"><code>std::ranges::sample</code></a> is not <code>constexpr</code> even in C++20?</p>