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From: ngo@tammy.harvard.edu (Tom Ngo)
Newsgroups: comp.lang.c++
Subject: What is the cv-qualifier of a reference?
Message-ID: <NGO.91Apr2153525@tammy.harvard.edu>
Date: 2 Apr 91 20:35:25 GMT
Sender: news@husc6.harvard.edu
Distribution: comp
Organization: Harvard Chemistry Department
Lines: 79


On March 25 I posted a question to which nobody replied.  Here it is
again, in shorter form:

[What I do understand]     A pointer can have a cv-qualifier, e.g.

                               int *const p;

                           here the cv-qualifier is "const" and it refers
                           to the pointer, NOT to the object pointed to.

[What I don't understand]  A reference can have a cv-qualifier, e.g.

                               int &const j;

                           What does const mean in this case?  What
                           restrictions are placed on j?

My original post, which I feel was more precisely worded, is included below.

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From: ngo@tammy.harvard.edu (Tom Ngo)
Newsgroups: comp.lang.c++
Subject: What?  A reference can have cv-qualifiers?
Date: 25 Mar 91 15:13:59 GMT
Distribution: comp
Organization: Harvard Chemistry Department


I'm confused.  I just read in ARM 8.2.2 [References]:

    In a declaration T D where D has the form

        & cv-qualifier-list-opt D1

    the type of the contained identifier is "... cv-qualifier-list
    reference to T."

I cannot imagine what the cv-qualifiers do!  In the case of a pointer,
we read ARM 8.2.1 [Pointers]:

    In a declaration T D where D has the form

        * cv-qualifer-list-opt D1

    the type of the contained identifier is "... cv-qualifer-list
    pointer to T."  The cv-qualifiers apply to the pointer and not to
    the object pointed to.

and of course that makes total sense.  But how could cv-qualifiers
apply to a reference?

    const int& i;       // reference to const int
    int &const j;       // const reference to int?

What restrictions are there on j?  We already know that j cannot be
made to refer to a different object since in ARM 8.4.3 [References] we
have 

    A variable declared to be a T& ... must be initialized .... A
    reference cannot be changed to refer to another object after
    initialization. 

I would appreciate responses by email, and I will summarize.  No doubt
I will be flooded by replies that say "No, no, you are totally
misunderstanding references!"

Thanks in advance...

--
  Tom Ngo
  ngo@harvard.harvard.edu
  617/495-1768 lab number, leave message
--
  Tom Ngo
  ngo@harvard.harvard.edu
  617/495-1768 lab number, leave message