The utime function sets the access and modification times of the
    filenamed by the path argument. The file must be openable for
    write-access to use this function.

    If times is a NULL pointer, the access and modification times of
    the file are set to the current time. To use utime in this way,
    the effective user ID of the process must match the owner of the
    file, or the process must have write permission to the file or
    have appropriate privileges.

    If times is not a NULL pointer, it is interpreted as a pointer
    to a utimbuf structure, and the access and modification times
    are set to the values in the specified structure. Only a process
    with an effective user ID equal to the user ID of the file or a
    process with appropriate privileges can use utime this way.

    The utimbuf structure is defined by the <utime.h> header. The
    times in the utimbuf structure are measured in seconds since the
    Epoch.

    Upon successful completion, utime marks the time of the last file
    status change, st_ctime, to be updated. See the <stat.h> header
    file.

                     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, stat and fstat set 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.