Linking problems in Visual Studio

Hallo,

I have been stuggeling for a while now to get my project to work. I tried to add my Vector2D class to one of the others, but that turned out to create a lot of unforeseen problems.

I have #ifndef in front of all by header files, but this still happens. Any ideas on what I am doing wrong?

Here is what the evil compiler screams at me:

Quote:

---

>Linking...
1>Object.obj : error LNK2005: "int __cdecl Dot(class Vector2D,class Vector2D)" (?Dot@@YAHVVector2D@@0@Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(int,int,int,int)" (??0BoundingBox@@QAE@HHHH@Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(void)" (??0BoundingBox@@QAE@XZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: int __thiscall BoundingBox::getWidth(void)" (?getWidth@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: int __thiscall BoundingBox::getHeight(void)" (?getHeight@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: int __thiscall BoundingBox::getXpos(void)" (?getXpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: int __thiscall BoundingBox::getYpos(void)" (?getYpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: struct vertex __thiscall BoundingBox::getVertex(int)" (?getVertex@BoundingBox@@QAE?AUvertex@@H@Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: void __thiscall BoundingBox::rotate(int)" (?rotate@BoundingBox@@QAEXH@Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: void __thiscall BoundingBox::move(int,int)" (?move@BoundingBox@@QAEXHH@Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: class BoundingBox __thiscall BoundingBox::allignToAxis(void)" (?allignToAxis@BoundingBox@@QAE?AV1@XZ) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: bool __thiscall BoundingBox::pointIntersection(struct vertex &)" (?pointIntersection@BoundingBox@@QAE_NAAUvertex@@@ Z) already defined in BulletMgr.obj
1>Object.obj : error LNK2005: "public: class Rectangle2D __thiscall BoundingBox::convertToRec(void)" (?convertToRec@BoundingBox@@QAE?AVRectangle2D@@XZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "int __cdecl Dot(class Vector2D,class Vector2D)" (?Dot@@YAHVVector2D@@0@Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(int,int,int,int)" (??0BoundingBox@@QAE@HHHH@Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(void)" (??0BoundingBox@@QAE@XZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: int __thiscall BoundingBox::getWidth(void)" (?getWidth@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: int __thiscall BoundingBox::getHeight(void)" (?getHeight@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: int __thiscall BoundingBox::getXpos(void)" (?getXpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: int __thiscall BoundingBox::getYpos(void)" (?getYpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: struct vertex __thiscall BoundingBox::getVertex(int)" (?getVertex@BoundingBox@@QAE?AUvertex@@H@Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: void __thiscall BoundingBox::rotate(int)" (?rotate@BoundingBox@@QAEXH@Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: void __thiscall BoundingBox::move(int,int)" (?move@BoundingBox@@QAEXHH@Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: class BoundingBox __thiscall BoundingBox::allignToAxis(void)" (?allignToAxis@BoundingBox@@QAE?AV1@XZ) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: bool __thiscall BoundingBox::pointIntersection(struct vertex &)" (?pointIntersection@BoundingBox@@QAE_NAAUvertex@@@ Z) already defined in BulletMgr.obj
1>Sprite.obj : error LNK2005: "public: class Rectangle2D __thiscall BoundingBox::convertToRec(void)" (?convertToRec@BoundingBox@@QAE?AVRectangle2D@@XZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "int __cdecl Dot(class Vector2D,class Vector2D)" (?Dot@@YAHVVector2D@@0@Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(int,int,int,int)" (??0BoundingBox@@QAE@HHHH@Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(void)" (??0BoundingBox@@QAE@XZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: int __thiscall BoundingBox::getWidth(void)" (?getWidth@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: int __thiscall BoundingBox::getHeight(void)" (?getHeight@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: int __thiscall BoundingBox::getXpos(void)" (?getXpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: int __thiscall BoundingBox::getYpos(void)" (?getYpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: struct vertex __thiscall BoundingBox::getVertex(int)" (?getVertex@BoundingBox@@QAE?AUvertex@@H@Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: void __thiscall BoundingBox::rotate(int)" (?rotate@BoundingBox@@QAEXH@Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: void __thiscall BoundingBox::move(int,int)" (?move@BoundingBox@@QAEXHH@Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: class BoundingBox __thiscall BoundingBox::allignToAxis(void)" (?allignToAxis@BoundingBox@@QAE?AV1@XZ) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: bool __thiscall BoundingBox::pointIntersection(struct vertex &)" (?pointIntersection@BoundingBox@@QAE_NAAUvertex@@@ Z) already defined in BulletMgr.obj
1>Visualisation.obj : error LNK2005: "public: class Rectangle2D __thiscall BoundingBox::convertToRec(void)" (?convertToRec@BoundingBox@@QAE?AVRectangle2D@@XZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "int __cdecl Dot(class Vector2D,class Vector2D)" (?Dot@@YAHVVector2D@@0@Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(int,int,int,int)" (??0BoundingBox@@QAE@HHHH@Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: __thiscall BoundingBox::BoundingBox(void)" (??0BoundingBox@@QAE@XZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: int __thiscall BoundingBox::getWidth(void)" (?getWidth@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: int __thiscall BoundingBox::getHeight(void)" (?getHeight@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: int __thiscall BoundingBox::getXpos(void)" (?getXpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: int __thiscall BoundingBox::getYpos(void)" (?getYpos@BoundingBox@@QAEHXZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: struct vertex __thiscall BoundingBox::getVertex(int)" (?getVertex@BoundingBox@@QAE?AUvertex@@H@Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: void __thiscall BoundingBox::rotate(int)" (?rotate@BoundingBox@@QAEXH@Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: void __thiscall BoundingBox::move(int,int)" (?move@BoundingBox@@QAEXHH@Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: class BoundingBox __thiscall BoundingBox::allignToAxis(void)" (?allignToAxis@BoundingBox@@QAE?AV1@XZ) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: bool __thiscall BoundingBox::pointIntersection(struct vertex &)" (?pointIntersection@BoundingBox@@QAE_NAAUvertex@@@ Z) already defined in BulletMgr.obj
1>main.obj : error LNK2005: "public: class Rectangle2D __thiscall BoundingBox::convertToRec(void)" (?convertToRec@BoundingBox@@QAE?AVRectangle2D@@XZ) already defined in BulletMgr.obj
1>Debug/HelloWorld.exe : fatal error LNK1169: one or more multiply defined symbols found

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Does the header file containing "BoundingBox" have include guards? If so, do they look like this?

Code:

---

#ifndef MY_HEADER_H
#define MY_HEADER_H
...
#endif

---

Let's see what BoundingBox::getWidth() looks like in the header.

gg

I suggest posting the smallest and simplest code that demonstrates the error. Look out for things like class templates: did you try and separate the class template definition from its implementation?

These are double definition errors. The problem is probably that you didn't separate class definition from method implementation. In other words, I bet your header file is full of

Code:

---

return_type BoundingBox::methodName()
{
  foo!
}

---

Alternatively, did you #include a .cpp file?

Thanks for the replies.

CornedBee and LaserLight, you were right(as always) separating it into a .h and a .cpp file fixed the problem.

EDIT:
I used the same math class for several projects and it worked fine. Any ideas on why it blew up in my face now?

If you have a single source file project of some kind and #include another source file then your code should still link fine. The problem typically comes in when you have multiple source files (as you do) that all #include that source file. In this case, each individually compiled object file winds up with copies of the functions that were in the #included file. When the linker tries to combine all of these object files into a single executable, the matching bits of code cause the "already defined" problems you are seeing.