I know that this is probably a stupid question :\ but I am stupid...
I am getting 1>angledCollision.obj : error LNK2001: unresolved external symbol "protected: static class angledCollision * Singleton<class angledCollision>::ms_Singleton" (?ms_Singleton@?$Singleton@VangledCollision@@@@1PAVangledCollision@@A) 1>spawningArea.obj : error LNK2001: unresolved external symbol "protected: static class angledCollision * Singleton<class angledCollision>::ms_Singleton" (?ms_Singleton@?$Singleton@VangledCollision@@@@1PAVangledCollision@@A) I know the problem is that a source file wasn't found, but I can't see where...

Singleton hedder(theres no .cpp implementation):

#ifdef _MSVC
  // Turn off warnings generated by this singleton implementation
  #pragma warning (disable : 4311)
  #pragma warning (disable : 4312)
#endif
#ifndef SINGLETON_H
#define SINGLETON_H

#include <assert.h>

  template <typename T> class Singleton
  {
  protected:

    static T* ms_Singleton;

  public:

    Singleton()
    {
      assert( !ms_Singleton );
      int offset = (int)(T*)1 - (int)(Singleton <T>*)(T*)1;
      ms_Singleton = (T*)((int)this + offset);
    }
    ~Singleton(){ assert( ms_Singleton ); ms_Singleton = 0; }
      
    static T* getSingleton() { return ms_Singleton; }

  };
#endif

here is where I declared that angledCollision is a child of singleton

class angledCollision : public Singleton<angledCollision>

and finally, here are my #include's for both linking error files:
angledCollision:

#include <vector>
#include <math.h>
#include <glut.h>
#include "aCNode.h"
#include "Singleton.h"

spawningArea:

#include <math.h>
#include <iostream>
#include "render.h"
#include "loadTex.h"
#include <gl/glut.h>
#include "TextureLoader.h"
#include "Vector3D.h"
...
class spawningArea : public render // thus ill also show you render's #include's

render:

#include "texturedPolygons.h"
#include "angledCollision.h"

I did try #include'ing "angledCollision.h" inside of spawningArea, it changed nothing

so why am I still getting linking errors? if you need any more source just ask, decided not to dump everything because I don't think the internet is big enough :P


btw, If you see my history, I haven't answered any questions, Ive been trying to answer un-solved questions, but my solutions are always overly complex and may be hard to understand, so I don't bother, so I am trying to help the comunity, not just leach.


###EDIT###
oh, btw, before I make anything using angledCollision, i have spcified:

//initiates angledCollision singleton
	new angledCollision;

Edited 5 Years Ago by falconmick: n/a

I know that this is probably a stupid question :\ but I am stupid...
I am getting 1>angledCollision.obj : error LNK2001: unresolved external symbol "protected: static class angledCollision * Singleton<class angledCollision>::ms_Singleton" (?ms_Singleton@?$Singleton@VangledCollision@@@@1PAVangledCollision@@A) 1>spawningArea.obj : error LNK2001: unresolved external symbol "protected: static class angledCollision * Singleton<class angledCollision>::ms_Singleton" (?ms_Singleton@?$Singleton@VangledCollision@@@@1PAVangledCollision@@A) I know the problem is that a source file wasn't found, but I can't see where...

Singleton hedder(theres no .cpp implementation):

#ifdef _MSVC
  // Turn off warnings generated by this singleton implementation
  #pragma warning (disable : 4311)
  #pragma warning (disable : 4312)
#endif
#ifndef SINGLETON_H
#define SINGLETON_H

#include <assert.h>

  template <typename T> class Singleton
  {
  protected:

    static T* ms_Singleton;

  public:

    Singleton()
    {
      assert( !ms_Singleton );
      int offset = (int)(T*)1 - (int)(Singleton <T>*)(T*)1;
      ms_Singleton = (T*)((int)this + offset);
    }
    ~Singleton(){ assert( ms_Singleton ); ms_Singleton = 0; }
      
    static T* getSingleton() { return ms_Singleton; }

  };
#endif

here is where I declared that angledCollision is a child of singleton

class angledCollision : public Singleton<angledCollision>

and finally, here are my #include's for both linking error files:
angledCollision:

#include <vector>
#include <math.h>
#include <glut.h>
#include "aCNode.h"
#include "Singleton.h"

spawningArea:

#include <math.h>
#include <iostream>
#include "render.h"
#include "loadTex.h"
#include <gl/glut.h>
#include "TextureLoader.h"
#include "Vector3D.h"
...
class spawningArea : public render // thus ill also show you render's #include's

render:

#include "texturedPolygons.h"
#include "angledCollision.h"

I did try #include'ing "angledCollision.h" inside of spawningArea, it changed nothing

so why am I still getting linking errors? if you need any more source just ask, decided not to dump everything because I don't think the internet is big enough :P


btw, If you see my history, I haven't answered any questions, Ive been trying to answer un-solved questions, but my solutions are always overly complex and may be hard to understand, so I don't bother, so I am trying to help the comunity, not just leach.


###EDIT###
oh, btw, before I make anything using angledCollision, i have spcified:

//initiates angledCollision singleton
	new angledCollision;

Hey, this is not my area of expertise. Does this quote from cplusplus.com help any?

Templates and multiple-file projects
From the point of view of the compiler, templates are not normal functions or classes. They are compiled on demand, meaning that the code of a template function is not compiled until an instantiation with specific template arguments is required. At that moment, when an instantiation is required, the compiler generates a function specifically for those arguments from the template.

When projects grow it is usual to split the code of a program in different source code files. In these cases, the interface and implementation are generally separated. Taking a library of functions as example, the interface generally consists of declarations of the prototypes of all the functions that can be called. These are generally declared in a "header file" with a .h extension, and the implementation (the definition of these functions) is in an independent file with c++ code.

Because templates are compiled when required, this forces a restriction for multi-file projects: the implementation (definition) of a template class or function must be in the same file as its declaration. That means that we cannot separate the interface in a separate header file, and that we must include both interface and implementation in any file that uses the templates.

Since no code is generated until a template is instantiated when required, compilers are prepared to allow the inclusion more than once of the same template file with both declarations and definitions in a project without generating linkage errors.

I decided that the strain it was causing me + the time restraints I had, I couldn't follow that path, so I made the class angledCollision a singleton, rather than making it's parent a singleton, it's working now, thanks anyway :) if I ever try the singleton again Ill keep you'r advice in mind, thank you very much

:| sorry I couldn't stick around long enough to see if I could fix problem so others could

Edited 5 Years Ago by falconmick: n/a

This question has already been answered. Start a new discussion instead.