With DECC$EFS_FILE_TIMESTAMPS enabled, stat and fstat report
    new ODS-5 access time (st_atime), attribute revision time
    (st_ctime) and modification time (st_mtime) for files on ODS-5
    volumes that have the extended file times enabled using SET
    VOLUME/VOLUME=ACCESS_DATES.

    If DECC$EFS_FILE_TIMESTAMPS is disabled, or the volume is not
    ODS-5, or the volume does not have support for these additional
    times enabled, st_ctime continues to be the file creation time
    and st_atime the same as the st_mtime.

    The utime and utimes functions support these ODS-5 times in the
    same way as stat.