Path: utzoo!utgpu!watmath!iuvax!ux1.cso.uiuc.edu!ux1.cso.uiuc.edu!uxe.cso.uiuc.edu!hirchert
From: hirchert@uxe.cso.uiuc.edu
Newsgroups: comp.lang.fortran
Subject: Re: Position in file after open?
Message-ID: <50500153@uxe.cso.uiuc.edu>
Date: 20 Oct 89 15:12:00 GMT
References: <1162@atha.AthabascaU.CA>
Lines: 21
Nf-ID: #R:atha.AthabascaU.CA:1162:uxe.cso.uiuc.edu:50500153:000:1151
Nf-From: uxe.cso.uiuc.edu!hirchert    Oct 20 10:12:00 1989


1. The FORTRAN 77 standard does not specify the position of a file after an
   OPEN.  This was done intentionally in order to allow processors the freedom
   to support external prepositioning of files (e.g., the MOD disposition in
   IBM JCL which positions at the end of a file or the way many systems handle
   multi-file tapes).

2. It was the FORTRAN committee's intention that processors that did not
   support prepositioning would position at the beginning.  However, one
   famous family of implementations positions files at the end.  Depending
   on who you ask, the reason for this was
   a. to provide a useful alternative that could not be easily achieved
      otherwise
   b. to prove that there was a hole in the standard

3. The proposed Fortran 8x standard includes a keyword in the OPEN statement
   for specifying initial position.  Contrary to what has been posted earlier,
   the default is 'ASIS', allowing Fortran 8x processors to behave
   consistently with their FORTRAN 77 predecessors.  However, we can still
   hope that processors without prepositioning treat 'ASIS' as synonymous with
   'REWIND' rather than 'APPEND'.