Function select

test/System/Utf.test.cpp:20–27

// one OS or the other.
template <typename T>
auto select(const std::basic_string_view<T>& string16, const std::basic_string_view<T>& string32)
{
    assert(string16 != string32 && "Invalid to select between identical inputs");
    if constexpr (sizeof(wchar_t) == 2)
        return string16;
    else
        return string32;
}
} // namespace

using namespace std::string_view_literals;