Query and set POSIX time attributes of a file. Both OldTimes 
and
NewTimes are lists of option-terms. Times are represented in 
SWI-Prolog's standard floating point numbers. New times may be specified 
as now to indicate the current time. Defined options are:
- access(Time)
- Describes the time of last access of the file. This value can be read 
and written.
- modified(Time)
- Describes the time the contents of the file was last modified. This 
value can be read and written.
- changed(Time)
- Describes the time the file-structure itself was changed by adding (link()) 
or removing (unlink()) names.
Below are some example queries. The first retrieves the access-time, 
while the second sets the last-modified time to the current time.
?- set_time_file(foo, [access(Access)], []).
?- set_time_file(foo, [], [modified(now)]).