If dst is missing, no summer time applies to this locale. Jn, n, and Mm.n.d. By default, the value will be right justifieid with space padding on the left. If - is specified, it will be left justified with space padding on the right. If 0 is specified, it will be right justified and padded with zeros on the left.
Case is ignored when matching date and time names.
If the conversion fails, the contents of tm are undefined. These conversion specifiers are formed by prepending either E or O to a select list of conversion specifiers. A format specifier. X format specifier. Ex format specifier.