Path: utzoo!attcan!uunet!wuarchive!decwrl!elroy.jpl.nasa.gov!jato!jdickson
From: jdickson@jato.jpl.nasa.gov (Jeff Dickson)
Newsgroups: comp.sys.amiga.tech
Subject: Re: Files larger than available memory.
Message-ID: <1990Oct3.172801.26802@jato.jpl.nasa.gov>
Date: 3 Oct 90 17:28:01 GMT
References: <924@ucsvc.ucs.unimelb.edu.au> <1990Sep23.174736.16118@lavaca.uh.edu> <83986@tut.cis.ohio-state.edu> <14646@cbmvax.commodore.com> <MWM.90Sep25180852@raven.pa.dec.com> <14669@cbmvax.commodore.com>
Reply-To: jdickson@jato.Jpl.Nasa.Gov (Jeff Dickson)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 79

Newsgroups: comp.sys.amiga.tech
Subject: Indicating end of file
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	Hi all.

	During late last year and then again some this year I wrote a
serial I/O handler. It inserts itself as a DOS device. At first I had
to perform my own DOS packet interchange with it, because it was not
DOS compatible in the least bit. Recently, I changed it so that it
would be DOS compatible. Now it works with such Amiga commands as copy,
echo, filenote, etc. 

	The problem I am having comes when I am copying from my 
handler to a file.

	copy SID:2400,1,8,N,031 sidout
             |_| |____________|
             |         |
	   DOS device  |
	    name       |
		       |
		  communication
		  parameters

	If the file exists, Copy concludes by printing the message,
"Error during writing - sidout removed". Otherwise, copy doesn't
print an error, but I can't Type the file because (I guess) the 
end of file (^J ?) has been obscured. Funny thing is according to
the List command, the file contains the same number of bytes as
the characters I typed on the terminal.

	The sequence of DOS packets is as follows:

		ACTION_LOCATE_OBJECT
		ACTION_EXAMINE_OBJECT
			...so that the whatever is inputing from
			the SID doesn't give up because there is
			nothing to read, I block the DOS packet
			until something does become available.

		        When the DOS request can be satisfied, I
			insert the number of bytes available in
			the 'fib_Size' field and the number of
			blocks in the 'fib_NumBlocks' field (usally
			zero). I have no idea what to initialize
			the 'fib_DiskKey' field as. I've tried -1
			and 0.
		ACTION_FIND_INPUT
		ACTION_READ
			.
			.
	           and so forth
			.
			.
		ACTION_END

	I have a rather old Transactor magazine that includes an article
on AmigaDOS. It says on end of file that the 'RES1' field of the DOS packet
is to contain a -1 (DOSFALSE) and that the 'RES2' is to contain the end of
file indication (in my case zero). I tried that, but it didn't work. So
now, I just put zero in the 'RES1' field when end of file occurs.

	Any comments on what I could be doing wrong? I am using MANX 'C'
compiler v3.4a. Please don't inundate me with things along the lines of 
INTs VS LONGs. Think I could have gotton this far if I didn't know the
implications of each?

						Jeff

---------------------------------------------------------------------------
Jeff S. Dickson                                 jdickson@zook.jpl.nasa.gov