c++ - Unable to read memory while using std::shared_ptr

Question

I have a class that has a std::shared_ptr as a member, which is later initialised in a function. However, I don't believe it's working correctly as when I debug it and inspect the layout of the shared_ptr object, it shows <Unable to read memory>when I try to view the inner pointer (the class the shared_ptr is pointing to).

The first three file snippets below are from a DLL project that a second project references. The IGLSLProgram.h file is included in this second project so that the exported class defined in the DLL can be used.

---

IGLSLProgram.h (Interface in the DLL)

class IGLSLProgram;
typedef IGLSLProgram *GLSLProgramHandle;
typedef shared_ptr<IGLSLProgram> IGLSLProgramPtr;
extern "C" COMMON_API GLSLProgramHandle APIENTRY getGLSLProgram();

class IGLSLProgram {
public:
    IGLSLProgram() {}
    ~IGLSLProgram() {}

    // ...

    virtual void release() = 0;
};

---

GLSLProgram.h (Implements IGLSLProgram)

#include "IGLSLProgram.h"

class GLSLProgram : public IGLSLProgram {
public:
    GLSLProgram() {}
    ~GLSLProgram() {}

    // ...

    void release();
};

---

GLSLProgram.cpp (Defines GLSLProgram implementation)

#include "GLSLProgram.h"

COMMON_API GLSLProgramHandle APIENTRY getGLSLProgram() {
    return new GLSLProgram;
}

// ...

---

Program.h (Program that uses the DLL)

#include "Common\IProgram.h"
#include "Common\IGLSLProgram.h"

class Program : public IProgram {
protected:
    IGLSLProgramPtr shaderProgram;
public:
    Program() {}
    ~program() {}

    void createShaderProgram();

    // ...
};

---

Program.cpp (Defines class declared in Program.h)

#include "Program.h"
#include "Common\IGLSLProgram.h"

// ...

void Program::createShaderProgram() {
    shaderProgram = IGLSLProgramPtr(getGLSLProgram(), mem_fn(&IGLSLProgram::release));

    // ...

}

---

When inspecting the last line in the Program.cpp snippet, I see that shaderProgram has the following layout: http://i.stack.imgur.com/VZrkF.jpg

Any help with this issue would be greatly appreciated.

Answer 1

我通过IGLSLProgram shaderProgram;在Program.h中设置静态来解决了这个问题。这对我的目的来说很好，因为 Program 类应该只有一个实例。

---

Program.h（已解决）

#include "Common\IProgram.h"
#include "Common\IGLSLProgram.h"

class Program : public IProgram {
protected:
    static IGLSLProgramPtr shaderProgram;
public:
    Program() {}
    ~program() {}

    void createShaderProgram();

    // ...
};

---

我不确定的是为什么这会有所帮助以及为什么 astd::shared_ptr不能成为类中的非静态成员。如果有人能解释这一点，我将不胜感激。