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From: dr@ski.UUCP (David Robins)
Newsgroups: net.micro.apple
Subject: Re: Help with DOS 3.3 write end of file
Message-ID: <225@ski.UUCP>
Date: Sat, 1-Feb-86 19:12:57 EST
Article-I.D.: ski.225
Posted: Sat Feb  1 19:12:57 1986
Date-Received: Wed, 5-Feb-86 01:44:54 EST
References: <189@noscvax.UUCP> > >  Help! since my
Lines: 46

2 Feb 86 00:12:57 GMT
Distribution: usa
Organization: Smith-Kettlewell Institute, S.F., CA.
Lines: 41

> 				 Ted
> 				 milnet address "medin@nosc-shark"
Although you didn't specify, I assume you are dealing with a
SEQUENTIAL text file.

If you look in the Apple DOS Programmer's Manual, page 66, the answer
is right there.  

"This section gives you a new use for OPEN.  Suppose your program
routinely replaces an old text file with a new one with the same name.
When the new one is shorter than the old one, the new one will have
part of the old file hanging on the the end unless the program first
deletes the old one.  If you don't want this extra text at the end of
the file, delete the old file before writing to the new one.  The next 
program shows you how to delete a file and open it for new data,
whether or not the file already exists."
	....................................
	40  PRINT D$;"OPEN ";FILE$
	50  PRINT D$;"DELETE ";FILE$
	60  PRINT D$;"OPEN ";FILE$


		WRITE

	160 PRINT D$;"CLOSE ";FILE$

I believe the EOF marker is a 00, (see Beneath Apple DOS) which I THINK
is placed there by the CLOSEing of a file. 
I don't know why overwriting a sequential text
file and ending it in a 00 won't stop the extra text from getting in
the way.  In any case, most users follow the OPEN, DELETE, OPEN
business to keep things straight.
-- 
====================================================================
David Robins, M.D. 
Smith-Kettlewell Institute of Visual Sciences
2232 Webster St; San Francisco CA 94115
415/561-1705
			{ihnp4,qantel,dual}!ptsfa!ski!dr

The opinions expressed herein do not reflect the opinion of the Institute!