##### Field Width, Fill Character and Adjustment

    boost::cnv::charconv cnv;

    string s01 = convert<string>( 12, cnv(arg::width = 4)).value();
    string s02 = convert<string>( 12, cnv(arg::width = 5)
                                         (arg::fill = '*')).value();
    string s03 = convert<string>( 12, cnv(arg::width = 5)
                                         (arg::fill = 'x')
                                         (arg::adjust = cnv::adjust::left)).value();
    string s04 = convert<string>(-98, cnv(arg::width = 6)
                                         (arg::fill = 'Z')
                                         (arg::adjust = cnv::adjust::right)).value();

    string s05 = convert<string>(-12.3451, cnv(arg::precision = 2)
                                              (arg::width = 10)
                                              (arg::fill = '*')
                                              (arg::adjust = cnv::adjust::left)).value();
    string s06 = convert<string>(-12.3450, cnv(arg::adjust = cnv::adjust::right)).value();
    string s07 = convert<string>(-12.3450, cnv(arg::adjust = cnv::adjust::center)).value();

    BOOST_TEST(s01 == "  12");
    BOOST_TEST(s02 == "***12");
    BOOST_TEST(s03 == "12xxx");
    BOOST_TEST(s04 == "ZZZ-98");
    BOOST_TEST(s05 == "-12.35****");
    BOOST_TEST(s06 == "****-12.35");
    BOOST_TEST(s07 == "**-12.35**");