Function assign

extern/boost/boost/system/detail/error_code.hpp:175–178

    }

    void assign( int val, const error_category & cat, source_location const * loc ) BOOST_NOEXCEPT
    {
        *this = error_code( val, cat, loc );
    }

    template<typename ErrorCodeEnum>
        BOOST_SYSTEM_CONSTEXPR typename detail::enable_if<is_error_code_enum<ErrorCodeEnum>::value, error_code>::type &