(.bss+0x0): multiple definition of `player';

Question

I am creating a game in ray lib and have a player header file with a struct of player to keep things organised. I get this error saying that there is multiple definition of the struct 'player'.

Error:

/usr/bin/ld: main.o:(.bss+0x0): multiple definition of `player'; player.o:(.bss+0x0): first defined here collect2: error: ld returned 1 exit status

player.cpp:

#include <raylib.h>
#include "player.h"

void InitPlayer() {

    player.x = 0;
    player.y = 0;

    player.tint = (Color)RAYWHITE;
    player.Frame = 0;
    player.FrameWidth = 16;
    player.MaxFrames = 3;
    player.animation_number = 0;
    player.timer = 0.0f;    

    player.flip = 1;

    //Load Texture2D
    player.playerTexture = LoadTexture("Sprites/PlayerAll.png");

}

void UpdatePlayer() {

player.timer += GetFrameTime();
    
if(player.timer >= 0.2f){
    
        player.timer = 0.0f;
        player.Frame += 1;  
}

if(IsKeyDown(KEY_S)) {
        player.animation_number = 16;   
        player.y += 1;  
    }else if(IsKeyUp(KEY_S)){
        player.animation_number = 0;
    }
    
    
    if(IsKeyDown(KEY_W)){
        player.animation_number = 32;
        player.y -= 1;
    }
    
    if(IsKeyDown(KEY_A)){
        player.animation_number = 48;
        player.x -= 1;'''
    }
        
    if(IsKeyDown(KEY_D)){
        player.animation_number = 48;
        player.x += 1;
        player.flip = -1;
    } else {
        player.flip = 1;
    }
    
    //Clamp frame value
    player.Frame = player.Frame % player.MaxFrames;

}

void DrawPlayer() {
    
DrawTexturePro(player.playerTexture,
        Rectangle{player.FrameWidth*player.Frame,(float)player.animation_number,(float)player.flip*16,16},
        Rectangle{(float)player.x,(float)player.y,16,16},
        Vector2{0,0},0,player.tint);
}

void UnloadPlayer() {
    
    UnloadTexture(player.playerTexture);
}

Player.cpp:

#ifndef PLAYER_H
#define PLAYER_H

typedef struct Player{
    
    int x, y;
    Color tint; 

    int Frame;
    int FrameWidth;
    int MaxFrames;
    int animation_number;   
    float timer;    

    int flip;   
    Texture2D playerTexture;
        
}Player;

Player player;


void UnloadPlayer();
void InitPlayer();
void UpdatePlayer();
void DrawPlayer();
#endif

Main: The main.cpp' file basically calls the functions from the 'player.h' file. And I have included 'player.h' in 'main.cpp'

Just for some extra information if needed: I have tried using 'extern' on 'player' but it requires me to compile the cpp files in a strange order. After compiling and linking both object 'player.o' and 'main.o', I change 'player.cpp' to have 'extern' on struct global variable 'player' and compile 'player.cpp' only without compiling 'main.cpp' and link both objects files with the 'main.o' being the old one.

Why are you doing that strange way of compiling? Instead of that try declaring the global `player` properly in either player.cpp or main.cpp - just one or the other, not both. You really should show us a minimal example including a minimal player.cpp - can't really tell what's going on without the declaration of the global variable. (Note: if you have to edit your source and recompile a file in order to link you're doing something wrong already to require that.) — davidbak, Nov 06 '20 at 18:13
P.S. you definition of the struct `Player` is awfully C-like. Shouldn't hurt that way, but instead just declare it directly in the C++ style: `struct Player { ... };`. — davidbak, Nov 06 '20 at 18:16
I thought a second ago I saw an `extern` in front of `Player player` in the header? Not there now? It should be. — davidbak, Nov 06 '20 at 18:17
Global objects? Global functions to work on that global object? Not very C++. Please get [a few good books](https://stackoverflow.com/questions/388242/the-definitive-c-book-guide-and-list/388282#388282) to learn C++ "properly", including how to use classes and member functions. — Some programmer dude, Nov 06 '20 at 18:18
@davidbak I'm sorry I may have misinterpreted what I did as global variable. The 'player' is declared in the header file as 'Player player;'. — Shahroz, Nov 07 '20 at 02:37
The header file is included in multiple source files. Therefore every global declared in a header must be declared `extern`. Then you pick _one_ source file and declare it there _without_ the `extern`. That'll become the real instance - the _only_ instance - of that global in your program. The `extern` (in the header) says the global _will exist somewhere_ without actually declaring it. If the global in the header does _not_ have `extern` then it will exist in _each_ source file that includes it: that's multiple definition of the same thing and not allowed. — davidbak, Nov 07 '20 at 05:58

(.bss+0x0): multiple definition of `player';

0 Answers0