SetFTime procedure

  DECLARATION:  SetFTime(var F; Time : LongInt);

      PURPOSE:  Sets the date and time a file was last written

         UNIT:  DOS

      REMARKS:  F must be a file variable of any type (typed, untyped or text)
                that has been Assigned and opened.  The parameter, Time, can
                be created by a call to PackTime.

                NOTE:  Errors are reported through DosError, with the only
                       possible error being 6 (Invalid File Handle)

 RESTRICTIONS:  File must be open