Re: [boost] 'const T & const' and C++98

From: Matthew Towler (towler_at_[hidden])
Date: 2003-04-16 09:42:39

Reece Dunn wrote:

> If I understand the ISO/IEC C++98 standard correctly:
>
> [1] const T & ref;
> means that the data type referred to by ref is constant (i.e. you 
> cannot modify its internal state).
>
> [2] T & const ref;
> means that the *reference* is constant.

No, I don't think you do understand the standard correctly.

This form [2] does not mean anything different from [1], references are 
implicitly constant in that you cannot 'reseat' them. e.g.

int a, c;
int& b = a;
b = c; // error, as attempting to reseat the reference.

This means that VC++7 is correct in warning "anacronism used : 
disregarding additional qualifiers".  It also means form [3] is 
pointless as well.

If you want something you can reseat, and that does have the 3 forms you 
describe, then you need to use pointers.

Matt