(C++) Linking with namespaces causes duplicate symbol error
- by user577072
Hello.
For the past few days, I have been trying to figure out how to link the files for a CLI gaming project I have been working on. There are two halves of the project, the Client and the Server code.
The client needs two libraries I've made. The first is a general purpose game board. This is split between GameEngine.h and GameEngine.cpp. The header file looks something like this
namespace gfdGaming {
// struct sqr_size {
// Index x;
// Index y;
// };
typedef struct { Index x, y; } sqr_size;
const sqr_size sPos = {1, 1};
sqr_size sqr(Index x, Index y);
sqr_size ePos;
class board
{
// Prototypes / declarations for the class
}
}
And the CPP file is just giving everything content
#include "GameEngine.h"
type gfdGaming::board::functions
The client also has game-specific code (in this case, TicTacToe) split into declarations and definitions (TTT.h, Client.cpp). TTT.h is basically
#include "GameEngine.h"
#define TTTtar "localhost"
#define TTTport 2886
using namespace gfdGaming;
void* turnHandler(void*);
namespace nsTicTacToe
{
GFDCON gfd;
const char X = 'X';
const char O = 'O';
string MPhostname, mySID;
board TTTboard;
bool PlayerIsX = true, isMyTurn;
char Player = X, Player2 = O;
int recon(string* datHolder = NULL, bool force = false);
void initMP(bool create = false, string hn = TTTtar);
void init();
bool isTie();
int turnPlayer(Index loc, char lSym = Player);
bool checkWin(char sym = Player);
int mainloop();
int mainloopMP();
}; // NS
I made the decision to put this in a namespace to group it instead of a class because there are some parts that would not work well in OOP, and it's much easier to implement later on.
I have had trouble linking the client in the past, but this setup seems to work.
My server is also split into two files, Server.h and Server.cpp.
Server.h contains exactly:
#include "../TicTacToe/TTT.h" // Server needs a full copy of TicTacToe code
class TTTserv;
struct TTTachievement_requirement {
Index id;
Index loc;
bool inUse;
};
struct TTTachievement_t {
Index id;
bool achieved;
bool AND, inSameGame;
bool inUse;
bool (*lHandler)(TTTserv*);
char mustBeSym;
int mustBePlayer;
string name, description;
TTTachievement_requirement steps[safearray(8*8)];
};
class achievement_core_t : public GfdOogleTech {
public: // May be shifted to private
TTTachievement_t list[safearray(8*8)];
public:
achievement_core_t();
int insert(string name, string d, bool samegame, bool lAnd, int lSteps[8*8], int mbP=0, char mbS=0);
};
struct TTTplayer_t {
Index id;
bool inUse;
string ip, sessionID;
char sym;
int desc;
TTTachievement_t Ding[8*8];
};
struct TTTgame_t {
TTTplayer_t Player[safearray(2)];
TTTplayer_t Spectator;
achievement_core_t achievement_core;
Index cTurn, players;
port_t roomLoc;
bool inGame, Xused, Oused, newEvent;
};
class TTTserv : public gSserver {
TTTgame_t Game;
TTTplayer_t *cPlayer;
port_t conPort;
public:
achievement_core_t *achiev;
thread threads[8];
int parseit(string tDat, string tsIP);
Index conCount;
int parseit(string tDat, int tlUser, TTTplayer_t** retval);
private:
int parseProto(string dat, string sIP);
int parseProto(string dat, int lUser);
int cycleTurn();
void setup(port_t lPort = 0, bool complete = false);
public:
int newEvent;
TTTserv(port_t tlPort = TTTport, bool tcomplete = true);
TTTplayer_t* userDC(Index id, Index force = false);
int sendToPlayers(string dat, bool asMSG = false);
int mainLoop(volatile bool *play);
};
// Other
void* userHandler(void*);
void* handleUser(void*);
And in the CPP file I include Server.h and provide main() and the contents of all functions previously declared.
Now to the problem at hand
I am having issues when linking my server. More specifically, I get a duplicate symbol error for every variable in nsTicTacToe (and possibly in gfdGaming as well). Since I need the TicTacToe functions, I link Client.cpp ( without main() ) when building the server
ld: duplicate symbol nsTicTacToe::PlayerIsX in Client.o and Server.o
collect2: ld returned 1 exit status
Command /Developer/usr/bin/g++-4.2 failed with exit code 1
It stops once a problem is encountered, but if PlayerIsX is removed / changed temporarily than another variable causes an error
Essentially, I am looking for any advice on how to better organize my code to hopefully fix these errors.
Disclaimers:
-I apologize in advance if I provided too much or too little information, as it is my first time posting
-I have tried using static and extern to fix these problems, but apparently those are not what I need
Thank you to anyone who takes the time to read all of this and respond =)
