LNK2019 Error under Visual Studio 2010

Question

I have created a sample c++ project under Visual Studio 2010 with following files.

A.h

#ifndef A_H
#define A_H

#include 

void foo();

#         


        

Answer 1

EDIT: Nevermind the original answer (below), I believe what you're looking for may be here: Visual Studio 2010's strange "warning LNK4042"

Original answer (not the problem, but maybe sound advice?): Your header should have guards around it, otherwise it will be defined each time it is called, and cause redefinitions.

#ifndef A_H
#define A_H

#include 

void foo();

#endif //A_H