glibc/time/Versions

libc {
  GLIBC_2.0 {
    # global variables
    __timezone; __daylight; __tzname;

    # functions with special/multiple interfaces
    __adjtimex;

    # functions used in other libraries
    __gmtime_r; __gettimeofday;

    # variables in normal name space
    daylight; timezone; tzname;

    # a*
    adjtime; adjtimex; asctime; asctime_r;

    # c*
    clock; ctime; ctime_r;

    # d*
    difftime; dysize;

    # f*
    ftime;

    # g*
    getitimer; gettimeofday; gmtime; gmtime_r;

    # l*
    localtime; localtime_r;

    # m*
    mktime;

    # s*
    setitimer; settimeofday; stime; strftime; strptime;

    # t*
    time; timegm; timelocal; tzset;
  }
  GLIBC_2.1 {
    # variables in normal name space
    getdate_err;

    # g*
    getdate; getdate_r; getitimer;

    # s*
    strfxtime;
  }
}