- set-file-times! FILE #!optional MTIME ATIMEprocedure
Sets the time of last modification MTIME and/or time of last access ATIME (in seconds) for FILE. FILE may be a filename, a file-descriptor or a file-backed port. If the file does not exist, an error is signaled.
If neither MTIME nor ATIME is supplied, the current time is used. If only MTIME is supplied, ATIME will be set to the same value. If an argument is #f, it will not be changed.
Consequently, if only MTIME is passed and it is #f, ATIME is assumed to be #f as well and neither will be changed.