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Conference turris::c_plus_plus

Title:C++
Notice:Read 1.* and use keywords (e.g. SHOW KEY/FULL KIT_CXX_VAX_VMS)
Moderator:DECCXX::AMARTIN
Created:Fri Nov 06 1987
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:3604
Total number of notes:18242

3463.0. "%CXX-E-REFENCLOSING" by MOIRA::FAIMAN (Wandrer, du M�der, du bist zu Haus) Mon Feb 24 1997 17:09

/* When compiled, this program yields the error

                friend class _iset;     // (2)
        ...............^
    %CXX-E-REFENCLOSING, In this declaration, "_iset" has a declaration in an
     enclosing scope, and this class declaration contains a reference to that
     declaration.

If you delete the lines marked (1) (i.e., make it an ordinary class instead of a
template class), it compiles successfully.  Also, if you interchange the lines
marked (2), it compiles successfully.

Explanation, please?

	-Neil
*/

template <class Key>            // (1)
class _iset {
public:
    class iterator {
        const _iset* set;       // (2)
        friend class _iset;     // (2)
    };
};

void main()
{
    _iset
        <int>                   // (1)
            x;
}
T.RTitleUserPersonal
Name		DateLines
3463.1SPECXN::DERAMODan D&#039;EramoMon Feb 24 1997 17:3312
        It will probably work if you change
        
        	friend class _iset;
        
        to
        
        	friend class _iset<Key>;
        
        Don't know whether the latest draft of the standard-to-be
        requires the <Key> to be there.
        
        Dan
3463.2I think it's a bug...DECC::J_WARDTue Feb 25 1997 09:038

Section 14.6.1 of the standard:

"Within the scope of a class template, the name of
the template, when not followed by <, is equivalent
to the name of the template followed by the template-parameters
enclosed in <>.
3463.3a related problem: %CXX-E-INACCESSIBLEMOIRA::FAIMANWandrer, du M�der, du bist zu HausTue Feb 25 1997 14:3033
/*
In .0, I stated that interchanging the two lines marked (2) allowed the test
program to compile successfully.  It appears from the following that it was only
partially successful.  I have interchanged those two lines, but added code in
the _iset class which invokes the private constructor of the iterator class. 
_iset ought to be a friend of iterator now; but compiling this program yields

            void foo(float k) {iterator i(k);}
        .................................^
%CXX-E-INACCESSIBLE, In this declaration, "_iset<int >::iterator::iterator" is
 not accessible.

As before, removing the lines marked (1) (i.e., making _iset an ordinary class
rather than a template class) eliminates the problem.
*/

template <class Key>            // (1)
class _iset {
public:
    class iterator {
        friend class _iset;     // (2)
        const _iset* set;       // (2)
        iterator(float);
    };
    void foo(float k) {iterator i(k);}
};

void main()
{
    _iset
        <int>                   // (1)
            x;
}
3463.4MOIRA::FAIMANWandrer, du M�der, du bist zu HausTue Feb 25 1997 14:366
The problem reports in .0 and .3 were based on DEC C++ V5.4 on VAX/VMS.  I just
confirmed that the problem in .0 occurs with V5.5 on Alpha/VMS and on
Alpha/Unix.  Oddly enough, the problem in .3 occurs with V5.5 on Alpha/Unix, but
*not* with V5.5 on Alpha/VMS.

	-Neil