c++ - ld : duplicate symbols for architecture x86_64 when defining a global var in a header

Question

如何解决这个问题？

只是得到以下错误:

g++ 输出:

duplicate symbol _game in:
    /var/folders/w6/yqp0s0t92hl5g842hg8tztfr0000gn/T/main-62666f.o
    /var/folders/w6/yqp0s0t92hl5g842hg8tztfr0000gn/T/Game-a5a31d.o
duplicate symbol _game in:
    /var/folders/w6/yqp0s0t92hl5g842hg8tztfr0000gn/T/main-62666f.o
    /var/folders/w6/yqp0s0t92hl5g842hg8tztfr0000gn/T/Write-83f8ee.o

看来问题不在头文件中。

编辑:头文件如下所示:

#ifndef GAME_H
#define GAME_H
#include "Color.h"
#include "Tile.h"

class Game
{
  public:

    Game();
    ~Game();
    Color getActivePlayer();
    void setStarttile(Tile Firststarttile);
    Color togglePlayer();
    void setRunning(bool run);
    char newActiveplayer;
    void run();
    void runsecondmethod();

  private:
    Game(const Game &);
    Color Activeplayer;
    Tile *Starttile;
    bool Running;
}game;

#endif

Answer 1

您在头文件“Game.h”中实例化了一个Game 实例，由于它被包含在多个文件中，您最终会得到多个game 实例在链接时。变化:

class Game
{
  public:

  ...

}game;

到:

class Game
{
  public:

  ...

};

extern Game game;

然后添加:

Game game;

在您的一个 .cpp 文件中。