Config parser requires a custom config::path class for win32.

[evoskuil]

std::filesystem::path{ std::string } treats string (or char*) as ANSI on win32. path needs to be populated from to_utf16(std::string) for proper unicode interpretation. After that it's fine.

[evoskuil]

example

class utf8_path
    {
    public:
        utf8_path() = default;
        utf8_path(const std::filesystem::path& p) : path(p) {}
        operator std::filesystem::path&() { return path; }
        operator const std::filesystem::path&() const { return path; }
        friend std::istream& operator>>(std::istream& in, utf8_path& p)
        {
            std::string value;
            if (!(in >> value) || value.empty()) {
                in.setstate(std::ios::failbit);
                p.path = std::filesystem::path();
                return in;
            }
            #ifdef _WIN32
            p.path = std::filesystem::path(to_utf16(value));
            #else
            p.path = std::filesystem::path(value);
            #endif
            return in;
        }
        friend std::ostream& operator<<(std::ostream& out, const utf8_path& p)
        {
            #ifdef _WIN32
            out << to_utf8(p.path.wstring());
            #else
            out << p.path.string();
            #endif
            return out;
        }
    private:
        std::filesystem::path path;
    };

[evoskuil]

Also look into /Zc:utf8