Contains a symbolic constant (values are given below) that indicates in which part of the year Daylight Saving Time is in force. (Note: its value is constant throughout the year: it does not indicate that DST is in force, it just selects an algorithm.) The daylight saving time algorithms defined are as follows :
DST_NONE - not on dst
DST_USA - USA style dst
DST_AUST - Australian style dst
DST_WET - Western European dst
DST_MET - Middle European dst
DST_EET - Eastern European dst
DST_CAN - Canada
DST_GB - Great Britain and Eire
DST_RUM - Rumania
DST_TUR - Turkey
DST_AUSTALT - Australian style with shift in 1986