Function convert_wstring_to_mbstring

dlib/unicode/unicode.cpp:115–130

// ----------------------------------------------------------------------------------------

    const std::string convert_wstring_to_mbstring(const std::wstring &src)
    {
        std::mbstate_t st{};
        const wchar_t* p = src.c_str();

        // Compute length
        size_t n = std::wcsrtombs(nullptr, &p, 0, &st);
        if (n == static_cast<std::size_t>(-1)) throw std::runtime_error("Invalid wide sequence / locale mismatch");

        // Convert
        std::string out(n, '\0');
        st = std::mbstate_t{};
        n  = std::wcsrtombs(&out[0], &p, out.size(), &st);
        if (n == static_cast<std::size_t>(-1)) throw std::runtime_error("Conversion failed");
        return out;
    }

// ----------------------------------------------------------------------------------------