RE: Template base class: name lookup bug?

RE: Template base class: name lookup bug?

[Kaz Kylheku]

 Kaz Kylheku wrote:
> #include <cstdio>
> 
> template <class T>
> class Base {
>     protected:
>         int numberBase;
> };
> 
> template <class T>
> class Derived : public Base<T> {
> public:
>     void print()
>     {
>         printf("bn = %d\n", numberBase);
>     }
> };
> 
> int main()
> {
>     Derived<int> d;
>     d.print();
>     return 0;
> }


New discovery: simply changing it to ``this->numberBase'' gets rid of
the error.

I forgot to mention that the latest version with which I reproduced this
is GCC 4.1.1.

Re: Template base class: name lookup bug?

[Ian Lance Taylor]

"Kaz Kylheku" <kaz@zeugmasystems.com> writes:

> New discovery: simply changing it to ``this->numberBase'' gets rid of
> the error.

Look for documentation on two-phase lookup.

Ian

Template base class: name lookup bug?

[Kaz Kylheku]

In this example program class Derived<T> inherits from Base<T>. Yet an
unqualified name lookup of a base class member fails within
Derived<T>::print. If the identifier is qualified (Base<T>::numberBase)
then it works.

foo.cc: In member function `void Derived<T>::print()':
foo.cc:16: error: `numberBase' was not declared in this scope

#include <cstdio>

template <class T>
class Base {
    protected:
        int numberBase;
};

template <class T>
class Derived : public Base<T> {
public:
    void print()
    {
        printf("bn = %d\n", numberBase);
    }
};

int main()
{
    Derived<int> d;
    d.print();
    return 0;
}