Get relative path from two absolute paths

With C++17 and its std::filesystem::relative, which evolved from boost, this is a no-brainer:

#include <filesystem>
#include <iostream>
namespace fs = std::filesystem;
int main()
{
    const fs::path base("/is/the/speed/of/light/absolute");
    const fs::path p("/is/the/speed/of/light/absolute/or/is/it/relative/to/the/observer");
    const fs::path p2("/little/light/races/in/orbit/of/a/rogue/planet");
    std::cout << "Base is base: " << fs::relative(p, base).generic_string() << '\n'
              << "Base is deeper: " << fs::relative(base, p).generic_string() << '\n'
              << "Base is orthogonal: " << fs::relative(p2, base).generic_string();
    // Omitting exception handling/error code usage for simplicity.
}

Output (second parameter is base)

Base is base: or/is/it/relative/to/the/observer
Base is deeper: ../../../../../../..
Base is orthogonal: ../../../../../../little/light/races/in/orbit/of/a/rogue/planet

It uses std::filesystem::path::lexically_relative for comparison.
The difference to the pure lexical function is, that std::filesystem::relative resolves symlinks and normalizes both paths using
std::filesystem::weakly_canonical (which was introduced for relative) before comparison.