Input
 tzlen
    Length of the tzname buffer.
 utc
    Binary time.
    Output
 tzname
    Character string that is long enough to hold the time zone label.
 tdf
    Longword with differential in seconds east or west of GMT.
 isdst
    Integer with a value of -1, indicating that no information is
    supplied as to whether it is standard time or daylight saving
    time. A value of -1 is always returned.