C ++链接器错误

Question

因此，我试图将我的游戏分成多个文件。 我得到这些错误：

1>item.obj : error LNK2005: "private: static class sf::Image ctile::itile" (?itile@ctile@@0VImage@sf@@A) already defined in character.obj
1>item.obj : error LNK2005: "class cmap maps" (?maps@@3Vcmap@@A) already defined in character.obj
1>item.obj : error LNK2005: "class cmainchar mainch" (?mainch@@3Vcmainchar@@A) already defined in character.obj
1>item.obj : error LNK2005: "class citemmanager itemmanager" (?itemmanager@@3Vcitemmanager@@A) already defined in character.obj
1>item.obj : error LNK2005: "private: static class sf::Image citem::iitem" (?iitem@citem@@0VImage@sf@@A) already defined in character.obj
1>item.obj : error LNK2005: "private: static class sf::Image cspell::ispell" (?ispell@cspell@@0VImage@sf@@A) already defined in character.obj
1>item.obj : error LNK2005: "class sf::RenderWindow App" (?App@@3VRenderWindow@sf@@A) already defined in character.obj
1>item.obj : error LNK2005: "class sf::View View" (?View@@3V0sf@@A) already defined in character.obj
1>main.obj : error LNK2005: "private: static class sf::Image ctile::itile" (?itile@ctile@@0VImage@sf@@A) already defined in character.obj
1>main.obj : error LNK2005: "class cmap maps" (?maps@@3Vcmap@@A) already defined in character.obj
1>main.obj : error LNK2005: "class cmainchar mainch" (?mainch@@3Vcmainchar@@A) already defined in character.obj
1>main.obj : error LNK2005: "class citemmanager itemmanager" (?itemmanager@@3Vcitemmanager@@A) already defined in character.obj
1>main.obj : error LNK2005: "private: static class sf::Image citem::iitem" (?iitem@citem@@0VImage@sf@@A) already defined in character.obj
1>main.obj : error LNK2005: "private: static class sf::Image cspell::ispell" (?ispell@cspell@@0VImage@sf@@A) already defined in character.obj
1>main.obj : error LNK2005: "class sf::RenderWindow App" (?App@@3VRenderWindow@sf@@A) already defined in character.obj
1>main.obj : error LNK2005: "class sf::View View" (?View@@3V0sf@@A) already defined in character.obj
1>map.obj : error LNK2005: "private: static class sf::Image ctile::itile" (?itile@ctile@@0VImage@sf@@A) already defined in character.obj
1>map.obj : error LNK2005: "class cmap maps" (?maps@@3Vcmap@@A) already defined in character.obj
1>map.obj : error LNK2005: "class cmainchar mainch" (?mainch@@3Vcmainchar@@A) already defined in character.obj
1>map.obj : error LNK2005: "class citemmanager itemmanager" (?itemmanager@@3Vcitemmanager@@A) already defined in character.obj
1>map.obj : error LNK2005: "private: static class sf::Image citem::iitem" (?iitem@citem@@0VImage@sf@@A) already defined in character.obj
1>map.obj : error LNK2005: "private: static class sf::Image cspell::ispell" (?ispell@cspell@@0VImage@sf@@A) already defined in character.obj
1>map.obj : error LNK2005: "class sf::RenderWindow App" (?App@@3VRenderWindow@sf@@A) already defined in character.obj
1>map.obj : error LNK2005: "class sf::View View" (?View@@3V0sf@@A) already defined in character.obj
1>spell.obj : error LNK2005: "private: static class sf::Image ctile::itile" (?itile@ctile@@0VImage@sf@@A) already defined in character.obj
1>spell.obj : error LNK2005: "class cmap maps" (?maps@@3Vcmap@@A) already defined in character.obj
1>spell.obj : error LNK2005: "class cmainchar mainch" (?mainch@@3Vcmainchar@@A) already defined in character.obj
1>spell.obj : error LNK2005: "class citemmanager itemmanager" (?itemmanager@@3Vcitemmanager@@A) already defined in character.obj
1>spell.obj : error LNK2005: "private: static class sf::Image citem::iitem" (?iitem@citem@@0VImage@sf@@A) already defined in character.obj
1>spell.obj : error LNK2005: "private: static class sf::Image cspell::ispell" (?ispell@cspell@@0VImage@sf@@A) already defined in character.obj
1>spell.obj : error LNK2005: "class sf::RenderWindow App" (?App@@3VRenderWindow@sf@@A) already defined in character.obj
1>spell.obj : error LNK2005: "class sf::View View" (?View@@3V0sf@@A) already defined in character.obj

Answer 1

您可能在.h文件中有方法定义。 结果，您的单个定义中有许多副本

将声明包含在.h文件中，并包含include防护：

#ifndef SOMETHING_H_
#define SOMETHING_H_

class Something {
public:
    int foo();
};

#endif // SOMETHING_H_

以及.cpp文件中的方法定义：

#include "Something.h" 

int Something::foo() {
    return 5;
}

Answer 2

问题在于类成员函数的定义放在头文件中。 因此，相同的定义用于不同的翻译单元。

另外，在头文件中使用include防护 。