Path: utzoo!mnetor!uunet!husc6!cmcl2!acf3!pedersen
From: pedersen@acf3.NYU.EDU (paul pedersen)
Newsgroups: comp.lang.c++
Subject: Cfront output (partly) explained
Message-ID: <542@acf3.NYU.EDU>
Date: 23 Feb 88 00:20:58 GMT
Reply-To: pedersen@acf3.UUCP (paul pedersen)
Distribution: na
Organization: New York Univsersity
Lines: 31

Sorry to post this, but megatest.UUCP and riacs.ARPA are both unknown to my
mailer.

In article <275@goofy.megatest.UUCP> you write:
>
>A while back, I asked what bad things would happen if I hacked cfront so
>that it does not prefix automatic variables with au0_, etc.
>Nobody said anything. You may have thought I was jesting.
>I was serious.    Stop me if I'm going to break something. Really.  
>Also cfront changes the field names in structs, prefixing
>the name of the struct.  What if I change it so that it doesn't do that?
>
>Please comment.
>
>
>		Dave Jones
>		ARPA: megatest!djones@riacs.ARPA


The reason for prefixing field names with struct names is to handle old
C compilers, which barf if more than one struct uses a given field name.
When K&R was written, this was standard C behavior, and any variable whatever
could be qualified with the "." operator, followed by any structure member
name whatever.  More modern compilers restrict the use of member names,
allowing them to follow only structures (using ".") or structure pointers
(using "->") of the proper type, and therefore allowing the same member name
to appear in more than one struct.  See K&R page 209 (the C reference manual,
section 14.1).

I can't account for the "au0_" prefixes, but probably the reason is something
similar: handling old C compilers.