Templates and Inheritance

[karbau]

Hi,
I got a problem I cannot solve and would be most grateful if someone could give me a hint:

under g++ Version 3.2.2 and icc Version 8.0
this code compiles perfectly:

-------------------------------------------------
template<class C>
class A {
public:
C c;
double a;
};

template<class C>
class B : public A<C> {
public:
void init() {
a = 1.0;
};
};
-------------------------------------------------

if I go now to a machine with g++ Version 3.4.x I get
an error message
"error: `a' undeclared (first use this function)"


Thanks so much!

[vmohanaraj]

Although it is really confusing behaviour between two versions of g++, I know a workaround for this. Just qualifying the member with its class name avoids the compilation error. May be some expert can give an explanation and better solution.

The following will compile without error.

template<class C>
class A {

public:
C c;
double a;
};

template<class C>
class B : public A<C> {
public:
void init() {
A<C>::a = 1.0;
}
};

[GazzaH]

actually that's just a syntax error - you've got
a semicolon after the function definition on the second last line:
};
remove it and wallah!

[edam]

actually that's just a syntax error - you've got
a semicolon after the function definition on the second last line:
};
remove it and wallah!

Not the case! Using GCC 3.4.4 the original code (with extra semi-colon removed) doesn't compile. The error message is:

test.cc:12: In member function `void B<C>::init()':
test.cc:12: error: `a' undeclared (first use this function)

[anonymous]

I noticed the same thing using the mingw compiler (port of gcc) version 3.4.2.
I would also like to find a better alternative than specifying the scope of the variable...