[boost] Re: name clash

From: Joerg Walter (jhr.walter_at_[hidden])
Date: 2002-08-23 06:15:41

Gabriel Dos Reis wrote:

> Some days ago, someone was wondering on this list (sorry, I can't find
> the message off hand)

I believe you mean Peter Schmitteckert, who wrote:

<cite>
Dear all,

ibm xlC visual age 6.0 complains on following typedefs in ublas:

        typedef reverse_iterator1<iterator1> reverse_iterator1;
        typedef reverse_iterator2<const_iterator2> const_reverse_iterator2;

"/.../boost/numeric/ublas/hermitian.hpp", line 364.46: 1540-0416 (S)
 "reverse_iterator1" cannot be declared because its name has already been
used.

Is xlC v6.0 correct, or are these typedefs allowed?

Thanks in advance,
best wishes,
Peter
</cite>

> whether the following construct
>
>    typedef reverse_iterator<T> reverse_iterator;
>
> were valid or not and reported that one of his compiler rejected it.
>
> His compiler was right; somewhere, the standard says
>
> 3.3/4
>    Given a set of declarations in a single declarative region, each of
>    which specifies the same unqualified name,
>
>      --- they shall all refer to the same entity, or all refer to
>          functions and function templates; or
>
>      --- exactly one declaration shall declare a class name or
>          enumeration name that is not a typedef name and the other
>          declarations shall all refer to the same object or
>          enumerator, or all refer to functions and func-tion
>          templates; in this case the class name or enumeration name is
>          hidden (3.3.7). [Note: a namespace name or a class template
>          name must be unique in its declarative region (7.3.2, clause
>          14). ]
>
> Hope that helps,

Yes. If I understand that correctly, than we'll either have to change the
typedefs from

        typedef reverse_iterator1<iterator1> reverse_iterator1;

to

        typedef boost::numeric::ublas::reverse_iterator1<iterator1>
reverse_iterator1;

(ugly) or to rename the referenced reverse_iterator1 class to get something
like

        typedef reverse_iterator1_base<iterator1> reverse_iterator1;

(also ugly ;-)

BTW, the IBM compiler is the first of a couple of compilers to complain
about this.

Thanks for your help

Joerg