Linking error: undefined reference within the same class

Question

I am getting the following error with g++ 4.9:

basis.cpp:16: undefined reference to `Basis::foo(int, int)'

This is the header file:

#ifndef BASIS_H
#define BASIS_H


#include "common.h"
#include <math.h>
#include "xdouble.h"

using namespace std;

class Basis {

private:

    int rank;
    int dim;



public:

    Basis(); //Empty constructor

    Basis(int r, int d); //Default constructor

    void foo(int a, int b);
    void bar(int a, int b);
};

#endif

The basis.cpp file is the following:

#include "basis.h"

Basis::Basis()
{
    rank = 0;
    dim = 0;
}

Basis::Basis(int r, int d) // Default constructor
{
    rank = r;
    dim = d;

}

void Basis::bar(int a, int b)
{
    void foo(int a, int b);
}

void Basis::foo(int a, int b)
{

}

Even though I'm including the basis.h file I get the undefined reference error and I can't understand why this is happening. What am I doing wrong?

Thanks

You probably missed to link `basis.cpp` with your executable. — πάντα ῥεῖ, May 15 '15 at 07:40
@πάνταῥεῖ this seems like a compile time error though, from looking at the error message. But it is not reproducible from the code above, even removing the `foo` function declaration in `Basis::bar()` and replacing it by a function call. — vsoftco, May 15 '15 at 07:44
Are you getting a compile time error or a linker error? From your error message it looks like a compile time error, but in the title you say linker error. — vsoftco, May 15 '15 at 07:55
All files are compiled. Only at the end when the executable is to be created I get this error. So, I assume that this is a linker error — fc67, May 15 '15 at 08:38

score 1 · Answer 1 · edited May 22 '15 at 13:10

1

It looks like a copy and paste error. Try this:

void Basis::bar(int a, int b)
{
  foo(a, b);
}

You made a mistake because you copied and pasted the definition of the function foo in the place where you wanted to call this function.

edited May 22 '15 at 13:10

Uyghur Lives Matter

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answered May 15 '15 at 11:23

Ahemski

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Adding a simple explaination about when you removed within your answer would be helpful. – Uyghur Lives Matter May 15 '15 at 12:59
I don't know what can I write... fc67 made a mistake, because he (or she) copied and pasted definition of function foo in place where he wants to call this function. – Ahemski May 20 '15 at 07:45
That would be useful to include in your answer – Uyghur Lives Matter May 20 '15 at 19:39

Linking error: undefined reference within the same class

1 Answers1