Path: utzoo!attcan!uunet!ginosko!gem.mps.ohio-state.edu!apple!dlyons
From: dlyons@Apple.COM (David Lyons)
Newsgroups: comp.sys.apple
Subject: Re: System Error $1101
Message-ID: <35074@apple.Apple.COM>
Date: 27 Sep 89 23:39:11 GMT
References: <1989Sep27.225746.23189@polyslo.CalPoly.EDU>
Organization: Apple Computer Inc, Cupertino, CA
Lines: 32

In article <1989Sep27.225746.23189@polyslo.CalPoly.EDU> jearls@polyslo.CalPoly.EDU (  Stupid  ) writes:
>Now you've got me confused -- what is a class 0 and class 1 pathname?

A class-0 pathname has one byte at the beginning indicating how long the
pathname is.  ProDOS 8 uses this kind of string, and so do all the "class 0"
GS/OS calls (the ones that are there for ProDOS 16 compatibility).

The class 1 GS/OS calls (in the $20xx range) use class 1 strings, which
have *two* bytes at the beginning indicating the length.  If you use a
class 0 string by mistake, GS/OS interprets the first character of your
string as the high-order byte of the length.  For example, "AB" as a
class 0 string is $01 $41 $42; as a class 1 string it's $01 $00 $41 $42.
If you feed GS/OS the first one when it's expecting the second, it sees
a string $4101 bytes long--the first character is "B", and the other
16640 are whatever happens to be in memory following that.

>> --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
>>   America--Apple Edition: DAVE.LYONS        |   P.O. Box 875
     ^^^^^^^^^^^^^^^^^^^^^^

Dang...I caught that a few minutes ago.  It can't be all my fault... :)
somebody must have distracted me yesterday while I was editing my
signature file (changing AppleLink--Personal Edition to America Online).
-- 

 --Dave Lyons, Apple Computer, Inc.          |   DAL Systems
   AppleLink--Apple Edition: DAVE.LYONS      |   P.O. Box 875
   America Online: Dave Lyons                |   Cupertino, CA 95015-0875
   GEnie: D.LYONS2 or DAVE.LYONS         CompuServe: 72177,3233
   Internet/BITNET:  dlyons@apple.com    UUCP:  ...!ames!apple!dlyons

   My opinions are my own, not Apple's.