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From: ravi@earth.ce.nwu.edu (Ravi Sinha)
Newsgroups: comp.lang.fortran
Subject: File handling in Fortran 77
Message-ID: <11191@accuvax.nwu.edu>
Date: 22 Aug 90 21:28:47 GMT
Sender: news@accuvax.nwu.edu
Reply-To: ravi@earth.ce.nwu.edu (Ravi Sinha)
Organization: Civil Engineering Dept., Northwestern University
Lines: 34

Hi,

I have been wondering for a while about how certain aspects of
file handling are supposed to be in Fortran 77 standard.  Maybe
someone can shed some light on it.

(i)  If you open an OLD file using status=UNKNOWN and write
     less no. of lines to it than is already there, should the
     new file have only the stuff written when it was opened
     last.  Or should the write statement just overwrite
     the old file, thereby leaving rest of the old contents
     untouched.  I have seen implementations of compilers
     which do either and I am not sure which is the expected
     behavior.
			    
(ii) Can you open a file with status=NEW if the file already
     exists.  Again I have seen implementations which don't
     allow this (most unix), and others which allow you
     to open existing files with status=NEW (vax/vms).
						    
(iii) (i) if an old file is opened with status=NEW qualifier.
						     
(iv) Are any of these issues dependent on whether your
     file is binary or ASCII.  I remember that there were
     some discussions a few months ago about how to change
     only portions of an existing file through selective 
     read/write.  I can't recall the details, though.

Thanks.

---------------------------------------------------------------------
Ravi Sinha			|  As usual, the opinions here 
Northwestern University		|  are mine, and only mine.
ravi@earth.ce.nwu.edu		|  Who'd want to claim these anyway?