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From: mattd@Apple.COM (Matt Deatherage)
Newsgroups: comp.sys.apple2
Subject: Re: Parent pointers
Message-ID: <44582@apple.Apple.COM>
Date: 6 Sep 90 20:16:45 GMT
References: <5928366@ub.cc.umich.edu>
Organization: Apple Computer Inc., Cupertino, CA
Lines: 24

In article <5928366@ub.cc.umich.edu> Tabakal@UB.CC.UMICH.EDU writes:
>Do standard ProDOS subdirectories have a pointer to their parent 
>directory?  Or do they have to scan from root to find it?  It seems
>that noone implements the equivalent of a .. parameter when they
>implement a change directory command (with the exception of APW).
>I've never understood why.  It's very useful when you're hopping
>from children to parent to sibling directories.
> 
It's not there for application use, generally -- it's there for the file
system's use.  If you OPEN and READ a directory, you won't ever see the
parent pointers - only if you do block access will you see them, and that
makes you incompatible with AppleShare.

Davex implements a .. directory walking command (which as Doug Gwyn points
out can be done by simply stripping off the last part of any prefix), but
it doesn't work multiply.  (for example, "cd .." works but "cd ../.." doesn't.)


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Matt Deatherage, Apple Computer, Inc. | "The opinions represented here are
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