std.datetime.date.DateTimeException if isAD is true.
import std.datetime.date : DateTime; assert(SysTime(DateTime(0, 1, 1, 12, 30, 33)).yearBC == 1); assert(SysTime(DateTime(-1, 1, 1, 10, 7, 2)).yearBC == 2); assert(SysTime(DateTime(-100, 1, 1, 4, 59, 0)).yearBC == 101);
Year B.C. of the Gregorian Calendar counting year 0 as 1 B.C.