Description

   The utimes function sets the access and modification times of the
   file pointed to by the path argument to the value of the times
   argument. The utimes function allows time specifications accurate
   to the microsecond.

   If the times argument is a NULL pointer, the access and
   modification times of the file are set to the current time. The
   effective user ID of the process must be the same as the owner
   of the file, or must have write access to the file or appropriate
   privileges to use this call in this manner.

   Upon completion, utimes marks the time of the last file status
   change, st_ctime, for update.

                    NOTE (Integrity servers, Alpha)

      On OpenVMS Alpha and Integrity server systems, the stat,
      fstat, utime, and utimes functions have been enhanced to
      take advantage of the new file-system support for POSIX
      compliant file timestamps.

      This support is available only on ODS-5 devices on OpenVMS
      Alpha systems beginning with a version of OpenVMS Alpha
      after Version 7.3.

      Before this change, the stat and fstat functions were
      setting the values of the st_ctime, st_mtime, and st_atime
      fields based on the following file attributes:

         st_ctime - ATR$C_CREDATE (file creation time)
         st_mtime - ATR$C_REVDATE (file revision time)
         st_atime - was always set to st_mtime because no support
         for file access time was available

      Also, for the file-modification time, utime and utimes were
      modifying the ATR$C_REVDATE file attribute, and ignoring the
      file-access-time argument.

      After the change, for a file on an ODS-5 device, the stat
      and fstat functions set the values of the st_ctime, st_
      mtime, and st_atime fields based on the following new file
      attributes:

         st_ctime - ATR$C_ATTDATE (last attribute modification
         time)
         st_mtime - ATR$C_MODDATE (last data modification time)
         st_atime - ATR$C_ACCDATE (last access time)

      If ATR$C_ACCDATE is 0, as on an ODS-2 device, the stat and
      fstat functions set st_atime to st_mtime.

      For the file-modification time, the utime and utimes
      functions modify both the ATR$C_REVDATE and ATR$C_MODDATE
      file attributes. For the file-access time, these functions
      modify the ATR$C_ACCDATE file attribute. Setting the ATR$C_
      MODDATE and ATR$C_ACCDATE file attributes on an ODS-2 device
      has no effect.

      For compatibility, the old behavior of stat, fstat, utime,
      and utimes remains the default, regardless of the kind of
      device.

      The new behavior must be explicitly enabled by defining the
      DECC$EFS_FILE_TIMESTAMPS logical name to "ENABLE" before
      invoking the application. Setting this logical does not
      affect the behavior of stat, fstat, utime, and utimes for
      files on an ODS-2 device.