For sequential files, writes an end-of-file record to the file and
  positions the file after this record (the terminal point).  For
  direct access files, truncates the file after the current record.

  Statement format:

     ENDFILE ([UNIT=]io-unit[,ERR=label][,IOSTAT=i-var])
     ENDFILE io-unit

     io-unit   Is the logical unit specifier, optionally prefaced
               by UNIT=.  UNIT= is required if unit is not the first
               I/O specifier.

     label     Is the label of an executable statement that
               receives control if an error occurs, prefaced
               by ERR=.

     i-var     Is an I/O status specifier, prefaced by IOSTAT=.
               (Returns a zero if no error condition exists or
               a positive integer if an error condition exists.)

  If the unit specified in the ENDFILE statement is not open, the
  default file is opened for unformatted output.

  An end-of-file record can be written only to sequential
  organization files that are accessed as formatted sequential files
  or unformatted segmented sequential files.  An ENDFILE statement
  performed on a direct access file always truncates the file.

  An ENDFILE statement must not be specified for a file that is open
  for keyed access.  End-of-file records should not be written in
  files that are read by programs written in a language other than
  Fortran.