未解决的外部

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问题描述

我有一个未解决的外部符号错误，这驱使我坚果。总之，我有一个包装类SDL_Surfaces（'DgSurface'）和一个类加载和存储DgSurfaces（'DgSurfaceList'）。尝试在我的项目中包括DgSurfaceList文件时，会出现链接问题。这是我的类：

I have an unresolved external symbol error that's driving me nuts. In short, I have a wrapper class for SDL_Surfaces ('DgSurface') and a class to load and store DgSurfaces ('DgSurfaceList'). The link issue arises when trying to include the DgSurfaceList files in my project. Here are my classes:

头文件DgSurface.h包含DgSurface类声明：

The header file "DgSurface.h" contains the DgSurface class declaration:

    #ifndef DGSURFACE_H
    #define DGSURFACE_H

    #include "SDL.h"
    #include <string>

    class DgSurface
    {
    public:

        //Constructor/destructor
        DgSurface(std::string N, SDL_Surface* I): image(I), name(N) {}
        DgSurface() {name = ""; image = NULL;}
        ~DgSurface();

        //Copy operations
        DgSurface(const DgSurface&);
        DgSurface& operator= (const DgSurface&);

        //Data members
        std::string name;       //The name of the image
        SDL_Surface* image;     //The image
    };

    #endif

cpp文件DgSurface.cppcontatins DgSurface定义：

The cpp file "DgSurface.cpp" contatins DgSurface definitions:

#include "DgSurface.h"
#include "SDL.h"

//--------------------------------------------------------------------------------
//        Constructor
//--------------------------------------------------------------------------------
DgSurface::DgSurface(const DgSurface& other)
{
    //Copy name
    name = other.name;

    //Create new SDL_Surface
    image = SDL_ConvertSurface(other.image, other.image->format, 0);
}


//--------------------------------------------------------------------------------
//        Destructor
//--------------------------------------------------------------------------------
DgSurface::~DgSurface()
{
    SDL_FreeSurface(image);
}


//--------------------------------------------------------------------------------
//        Assignment operator
//--------------------------------------------------------------------------------
DgSurface& DgSurface::operator= (const DgSurface& other)
{
    // if same object
    if ( this == &other )
        return *this;

    //Copy name
    name = other.name;

    //Create new SDL_Surface
    image = SDL_ConvertSurface(other.image, other.image->format, 0);

    return *this;
}

这个类似乎工作得很好，我开放反馈:)。

This class seems to work fine and performs as expected (however, as always, am open to feedback :).

DgSurfaceList.h包含DgSurfaceList类声明：

"DgSurfaceList.h" contains DgSurfaceList class declarations:

#ifndef DGSURFACELIST_H
#define DGSURFACELIST_H

#include "SDL.h"
#include <list>
#include <string>
#include "DgSurface.h"


class DgSurfaceList
{
    public:
        //Constructors/destructor
        DgSurfaceList() {}
        ~DgSurfaceList() {}

        //Functions
        bool AddImage(std::string location, std::string name);

        //Return Functions
        SDL_Surface* GetImage(std::string S) const;

    private:
        //Data members
        std::list<DgSurface> imlist;    //The list of DgSurfaces

        //Functions
        SDL_Surface* LoadImage( std::string filename );
};


#endif

最后是DgSurfaceList.cpp包含DgSurfaceList定义：

and finally "DgSurfaceList.cpp" contains DgSurfaceList definitions:

#include "SDL.h"
#include "SDL_image.h"
#include <list>
#include <string>
#include "DgSurface.h"
#include "DgSurfaceList.h"


//--------------------------------------------------------------------------------
//      Load an image from file
//--------------------------------------------------------------------------------
SDL_Surface* DgSurfaceList::LoadImage( std::string filename )
{
    //Loads an image from file, returns SDL_surface*
    ...

}   //End:DgSurfaceList::LoadImage()


//--------------------------------------------------------------------------------
//      Add a DgSurface to the list
//--------------------------------------------------------------------------------
bool DgSurfaceList::AddImage(std::string location, std::string name)
{
    //Load the image
    DgSurface temp(name,LoadImage(location));

    //If there was an error in loading the image
    if( temp.image == NULL )
        return false;

    //If everything loaded fine, place a copy into imlist
    imlist.push_back(temp);

    return true;

}   //End: DgSurfaceList::AddImage();


//--------------------------------------------------------------------------------
//      Searches imlist for an image, returns a pointer to a SDL_Surface
//--------------------------------------------------------------------------------
SDL_Surface* DgSurfaceList::GetImage(std::string S) const
{
    std::list<DgSurface>::const_iterator i;

    //Search imlist for DgSurface of the same name
    for (i = imlist.begin(); i != imlist.end(); i++)
    {
        if (S.compare((*i).name) == 0)
            return (*i).image;
    }

    //Return Null if name not found
    return NULL;

}   //End:DgSurfaceList::GetImage()

如果我在cpp文件中注释掉DgSurfaceList :: GetImage（）定义，DgSurfaceList似乎工作正常，并存储图像正确。更具体地说，当我在上述函数中包括for循环时，链路错误才出现。

Now, if I comment out the DgSurfaceList::GetImage() definition in the cpp file, DgSurfaceList seems to work fine and store images correctly. More specifically, the link error only arises when I include the for loop in the above function. What could it be?

其他资讯：

错误：

unresolved external symbol __imp___CrtDbgReportW referenced in function "public: class
DgSurface const & __thiscall std::_List_const_iterator<class std::_List_val<class
DgSurface,class std::allocator<class DgSurface> > >::operator*(void)const "

编码环境：
Visual C ++ express 2010

Coding environment:Visual C++ express 2010

DgSurfaceList

问题描述

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