On Wed, Feb 01, 2006 at 06:08:23PM +0100, Christian Weckmueller wrote:
> Hello dear gcc-helper,
>
> I have a program without problems compiling with 3.3.5 but don't work with
> 4.0.2. So here is the question: are there big differences in templates
> combined with inheritance between these versions?
>
> I give you a part of the code:
>
> template<typename T> class Vector{
>
> protected:
> T *vectorPtr;
> size_type dim; <<<<<
> unsigned short coutwidth;
> ...
> };
>
> template<typename T> class NumericVector : public Vector<T>{
>
> public:
> NumericVector() : Vector<T>(){}
> NumericVector(size_type dim) : Vector<T>(dim){}
> NumericVector(size_type dim, T initVal) : Vector<T>(dim,
initVal){}
> NumericVector( const Vector<T> &src );
>
> void makeHilb();
> };
>
> template<typename T> NumericVector<T>::NumericVector( const Vector<T> &src )
{
>
> dim = src.length();
<<<<<<<
> vectorPtr = NULL;
> unsigned short counter = 3;
> ...
> }
>
> in the program i use NumericVector. the compiler 4.0.2 says he don't know
> dim
> in the convertconstructor of NumericVector
>
> the older one is fine with this program.
>
> Can anybody explain why there is a problem?
>
> Thanks, cris
Hi,
g++ 4.0.2 is right, your code is incorrect:
since class template NumericVector uses a *dependant* base class Vector<T>,
members of this base class must be qualified. So to get access to dim
in that constructor, you need to call it
Vector<T>::dim
or
this -> dim.
(A using declaration
using Vector<T>::dim;
also does the job.)
Oliver
P.S. Search for "dependant names" in the index of
@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.}
}
