boost::gil::make_scanline_reader

template<
    typename String,
    typename FormatTag>
get_scanline_reader<String, FormatTag>::type
make_scanline_reader(
    String const& file_name,
    FormatTag const&)
requires mp11::mp_and
        <
            detail::is_supported_path_spec<String>,
            is_format_tag<FormatTag>
        >::value;