Visual Studio 2003 linker error LNK2005

[ivan]

I have one small problem with my project. Let's say thah I am creating new console win32 aplication, and I am using precompiled headers ["stdafx.h"]. Now I create an additional header file with all the data tables I'll be using in my classes called for example "data.h", where I put :

char _race_names[3][20]={"Human","Ghoul","Mutant"};

and this file I am including in stdafx.h [#include "data.h" etc ]
Then I create first class called "foo" [using wizard]. VS created two files : "foo.h" and "foo.cpp". Now I modify a bit these files and finaly :

main.cpp

#include "stdafx.h"
#include "foo.h"
int main(int argc, char *argv[]) {
foo tmp;
tmp.show();
return 0;
}

stdafx.h

#pragma once
#define WIN32_LEAN_AND_MEAN
#include <iostream>
#include "data.h"
#include <tchar.h>

stdafx.cpp

#include "stdafx.h"

foo.h

#pragma once
using namespace std;
class foo {
public :
foo(void);
show(void);
~foo(void);
}

foo.cpp

#include "stdafx.h"
#include "foo.h"
foo::foo(void){
}
foo::show(void){
cout <<_race_names[0];
}
foo::~foo(void){
}

and that is enough for Visual to throw linker error LNK2005 which says that :

foo.obj : error LNK2005: "char (* _race_names)[20]" (?_race_name@@3PAY0P@DA) already defined in stdafx.obj
D:\Projects\Fallout\Debug\main.exe : fatal error LNK1169: one or more multiply defined symbols found

any idea how to solve it ? of course this is just an example ... real data.h contains a lot of "const int N_sht", "char _some_name_tables[x][y]", "enum enum_types {bla1,bla2}" etc ...
Why not to implement it in foo.h file ? because in my project are few classes that uses this data so i thougt it should be stored in some external file and then just include it whenewer I need it ... I know that this idea could be crappy then please tell me how can I do it more efficiently

IvaN

 

[Voral]

See RTFM - it's rulles.
Quote from MSDN (about error LNK2005):

A header file declared and defined a variable. Possible solutions include:

* Declare the variable in .h: extern BOOL MyBool; and then assign to it in a .c or .cpp file: BOOL MyBool = FALSE;.

Your sample:

data.h

extern char _race_names[3][20];

data.cpp

char _race_names[3][20]={"Human","Ghoul","Mutant"};

 

[pavan_2804]

1 ) The method "show()" is missing prototype, you should have declared it as
"void show()" and is not necessary to use (void) as C++ doesn differentiate.

2) Please do "clean" and then "Build".

3) "Voral" has the right suggestion, you cannot use the variable directly just because you have included the file. The variable you have declared has a file scope which you cannot gain access in your "foo" file.