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From: walter@hpcllca.HP.COM (Walter Murray)
Newsgroups: comp.std.c
Subject: Re: the "const" qualifier
Message-ID: <16490025@hpcllca.HP.COM>
Date: 9 Aug 90 22:01:23 GMT
References: <1990Aug1.005200.21645@ccu.umanitoba.ca>
Organization: Hewlett Packard Calif. Language Lab
Lines: 29

Larry Jones:

>It seems to me that there used to be a statement in the standard that
>said basically that if an aggregate is qualified, all of the members
>are effectively qualified, and if a member of an aggregate is
>qualified, then the aggregate is effectively qualified.  Now I don't
>seem to be able to find it.  Am I imagining things again, did I miss
>it, or did we remove it?

Doug Gwyn:

>Yeah, I was looking for that too, and I didn't find it either.
>The only thing I found that was at all relevant said that a qualifier
>in an array declaration actually qualifies the elements of the array,
>not the array itself.  However, that's not what we're looking for..
>I have no idea what might have happened to the part<->whole clause.

If you access a member of a struct or union that has qualified type,
using the . operator or the -> operator, the qualifiers of the
struct or union apply to the member.  Section 3.3.2.3.

Going the other way, a struct or union can't be a modifiable lvalue
if it has a member with a const-qualified type.  Section 3.2.2.1.

Taken with the semantics rules in 3.5.3, these seem to provide what
we are looking for.

Walter Murray
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