Re: Strange template behaviour with gcc 3.4 (20030813 and 20031001)

[Mihnea Balta <dark_lkml at mymail dot ro>]

Thank you, I had already noticed that this->first works, but I had to go 
through some code that's not mine, correcting the issue (KDE headers, to be 
more exact). I'll try to get that book to see why this restriction is A Good 
Thing (tm) :)

On Monday 06 October 2003 13:40, Oliver Kullmann wrote:
> > Hello,
> >
> > I'd like to know if this is a bug in the experimental gcc I'm using or if
> > I'm doing something wrong:
> >
> > template<class A, class B>
> > struct pair_t{
> >     A   first;
> >     B   second;
> > };
> >
> > template<class A, class B>
> > class something_t : public pair_t<A, B>{
> > public:
> >     void strange(A i){
> >         first = i;
> >     }
> > };
> >
> > int main(){
> >     return 0;
> > }
>
> Hi,
>
> the above code is incorrect, since non-dependent names like "first" are
> bound at the point of *definition* of the template (*not* its
> instantiation), and they are not looked up in dependent base classes (like
> "pair_t<A,B>", which depends on the template parameters A and B),
>
> This issue is discussed in depth in
>
> @Book{JV2002,
>   author =         {David Vandevoorde and Nicolai M. Josuttis},
>   title =          {C++ Templates: The Complete Guide},
>   publisher =          {Addison-Wesley},
>   year =          2002,
>   address =         {Boston},
>   month =         {November},
>   note =         {ISBN 0-201-73484-2; QA76.73.C153 V37 2003},
>   annote =         {Vorhanden.}
> }
>
> The solution is to make the name "first" dependent. Two solutions:
>
> 1) Use this -> first
>
> 2) Use pair_t<A,B>::first
>
> instead of "first".
>
> According to JV2000 the first solution in general is preferable.
>
> Oliver
>
> P.S. I'm happy to hear that now g++ is handling is issue correctly!!
>
>