main ()
{
    printf 
    (
        "MSDOS: ", MSDOS, "\n"
        "UNIX: ", UNIX, "\n"
        "unix: ", unix, "\n"
        "LINUX: ", LINUX, "\n"
        "linux: ", linux, "\n"
        "M_UNIX: ", M_UNIX, "\n"
        "M_SYSV: ", M_SYSV, "\n"
        "_POSIX_SOURCE: ", _POSIX_SOURCE, "\n"
        "__hpux: ", __hpux, "\n"
    );
}