error LNK2005 "already defined" error

DeepBlack (36)
Hi,

I am trying to include a header file in two source files.
In spite of including a guard for the header I get a linker error in VS2008 saying the class have already been defined.

Error:

Misc_Functions.obj : error LNK2005: "class std::map<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> >,struct std::less<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > >,class std::allocator<struct std::pair<class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const ,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > > > > Board_Pos" (?Board_Pos@@3V?$map@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@U?$less@V?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@2@V?$allocator@U?$pair@$$CBV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@V12@@std@@@2@@std@@A) already defined in Morris_Main.obj


Files:

Global.h
Morris_Main.cpp
Misc_Functions.cpp

Code:

Global.h

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#ifndef _Global_H_
#define _Global_H_


#include <map>
#include <string.h>
#include <iostream>
#include <vector>

using namespace std;

void init_variables(char*);

map<string, string> Board_Pos;
string board_pos_arr[];

vector<string> White_Coins;

vector<string> Black_Coins;

#endif



can someone please help me with this?

Thanks in advance!
vlad from moscow (6539)
Due to the statements

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map<string, string> Board_Pos;
string board_pos_arr[];

vector<string> White_Coins;

vector<string> Black_Coins;

in your header you are define these objects twice.
DeepBlack (36)
Thank you for the response,

I figured that the issue is solved by declaring the classes as extern.


Global.h
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#ifndef _Global_H_
#define _Global_H_


#include <map>
#include <string.h>
#include <iostream>
#include <vector>

using namespace std;

void init_variables(char*);

extern map<string, string> Board_Pos;
extern string board_pos_arr[];

extern vector<string> White_Coins;

extern vector<string> Black_Coins;

#endif


Misc_Functions.cpp

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#include <Global.h>
#include <map>
#include <string.h>
#include <iostream>
#include <vector>
#include <sstream>
#include <fstream>

using namespace std;


map<string, string> Board_Pos;
string board_pos_arr[];

vector<string> White_Coins;

vector<string> Black_Coins;
.....
.....


this solved my problem, if there is any other solutions to this, I'd still like to know.
vlad from moscow (6539)
If an object has external linkage it should be defined only once.
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