Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!rutgers!ucsd!ucbvax!agate!violet.berkeley.edu!jerry
From: jerry@violet.berkeley.edu ( Jerry Berkman )
Newsgroups: comp.lang.fortran
Subject: Backspacing across an EOF
Message-ID: <18503@agate.BERKELEY.EDU>
Date: 21 Dec 88 01:55:33 GMT
Sender: usenet@agate.BERKELEY.EDU
Reply-To: jerry@violet.berkeley.edu ( Jerry Berkman )
Organization: University of California, Berkeley
Lines: 47

How many records should be in the file created by:

      do 10 i=1,10
         write(12,8010) i
8010     format(' record ',i5, '.' )
10    continue
      rewind 12
      call skptoend( 12 )
      write(12,8000)
8000  format(' new record at end')
      end

      subroutine skptoend( lunit )
100   continue
      read ( lunit, '()', end=200 )
      go to 100

200   backspace lunit
      end

On our VAX UNIX, Sun UNIX, and IBM CMS systems, the file looks like:

 record     1.
 record     2.
 record     3.
 record     4.
 record     5.
 record     6.
 record     7.
 record     8.
 record     9.
 record    10.
 new record at end

However, on our Cray UNICOS system and a VMS system I tested,
the record "record    10." is missing from the final output.

As I read the standard, section 12.10.4.1 (Backspace):
	"... if the preceding record is an endfile record, the file
	 becomes positioned before the endfile record"
and section 12.6:
	"[if] An endfile record is encountered during [reading]
	the file is positioned after the endfile record."

Does anyone know DEC's or Cray's position on this?
	- Jerry Berkman, U.C. Berkeley
	  jerry@violet.berkeley.edu, (415)642-4804