Peter Hosey (comments): YYYY and yyyy are Unicode date format patterns. These offer quite a bit more flexibility than the old str[fp]time(3) formats, particularly in choosing different representations of the same value (e.g., “September” vs “Sep” vs “09” vs “9”). YYYY is defined as the “year for week-of-year”: that is, the year for ISO week … Continue reading Unicode Date Formats, YYYY?!