Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!wuarchive!usc!ucsd!ucbvax!hplabs!hpfcso!hpldola!hp-lsd!bae
From: bae@hp-lsd.COS.HP.COM (Bruce Erickson)
Newsgroups: comp.sys.hp
Subject: Re: DIRECTORY (3C) strangeness
Message-ID: <8250016@hp-lsd.COS.HP.COM>
Date: 25 Nov 89 19:13:54 GMT
References: <616@mmlai.UUCP>
Organization: HP Logic Systems Division - ColoSpgs, CO
Lines: 24

>While trying out the C DIRECTORY(3C) routines, I noticed
>some very strange behavior.  When you do a readdir,
>the files are returned in what seems to be random
>order.  At first it appeared that they return in the
>order that the files are created, but new files pop
>up where ever.

I'm not an expert, but I believe that 'readdir' returns the files in the
order that they are in the directory inode, which I think is essentially
an array of file names, which are placed in the first unused slot.  So, when
a directory is first created the files are in first-come first-slot basis;
after a file is removed, however, I believe that the next created file gets
the slot freed up by the removed file.

(I am remembering this from an O/S class 8 years ago, so I may be mis-
remembering this!)

If you need the files in alphabetical order, read them in but stick them
in a binary tree (use bsearch(3C) for ease of implementation) then read
them back from the binary tree....


                              Bruce Erickson
                              hp-lsd!bae