Availability:built-in
format_time(+Out, 
+Format, +StampOrDateTime, +Locale)Format time given a specified Locale. This predicate is a 
work-around for lacking proper portable and thread-safe time and locale 
handling in current C libraries. In its current implementation the only 
value allowed for Locale is posix, which 
currently only modifies the behaviour of the a, A, b 
and B format specifiers. The predicate is used to be able 
to emit POSIX locale week and month names for emitting standardised 
time-stamps such as RFC1123.