C++: What is std::bit_cast (C++20)?

1#include <bit>
2
3float f = 3.14f;
4auto i = std::bit_cast<int>(f);  // reinterpret bits as int
5auto f2 = std::bit_cast<float>(i); // back to float

1// ❌ Undefined behavior
2float* p = reinterpret_cast<float*>(&i);
3
4// ✅ Well-defined
5float f = std::bit_cast<float>(i);