If the current locale does not have language information defined,
    the function returns information from the C locale. The program
    should not modify the string returned by the function. This
    string might be overwritten by subsequent calls to nl_langinfo.

    If the setlocale function is called after a call to nl_langinfo,
    then the pointer returned by the previous call to nl_langinfo
    will be unspecified. In this case, the nl_langinfo function
    should be called again.