Undefined reference to foo::bar static ofstream

Question

I've been trying to compile a program I've spent the past three days building, and I can't figure out how to get it to stop throwing an error. I keep getting the compile error "undefined reference to Foo::bar" where "bar" is a static ofstream declared in the Foo.h file.

Foo.h

Class Foo
{
    public:
          <insert methods>
    private:
          static ofstream& bar;
 }

Foo.cpp

#include <iostream>
#include <fstream>
#include <sstream>
#include "EventReport.h"
using namespace std;

Foo::Foo()
{
   bar.open("foobar.txt");
}

I keep getting the error message on the "bar" in Foo.cpp (there are multiple in the file). Any ideas on why?

score 0 · Answer 1 · answered Mar 08 '13 at 01:05

0

undefined reference to Foo::bar

That error means that you told the compiler this object exists...

class Foo {
      static ofstream& bar;
};

...and the compiler decided to use it.

But you never defined it. It's undefined.

Add this to Foo.cpp:

ofstream& Foo::bar = (something);

answered Mar 08 '13 at 01:05

Drew Dormann

59,987
13
123
180

... I should write a macro. :) – Drew Dormann Mar 08 '13 at 01:06
What type should 'something' be? I'm still trying to learn C++ concepts. – johwiltb Mar 08 '13 at 01:09
@johwiltb, It should refer to an existing `ofstream` object. – chris Mar 08 '13 at 01:11

Undefined reference to foo::bar static ofstream

1 Answers1