How to initialize unmanaged static pointer in C++/CLI code?

Question

Hi all, thanks for checking my problem:)

I'm not able to initialize a static native pointer inside a managed class.

Here's the detail: I created a C++/CLI console project and declared a static unmanaged pointer inside. However I can't initialize the static pointer with any means (but if I put the pointer into an anonymous namespace, there's no problem, demoed in the code). Did u meet similar situations and got solutions for it?

Code here:

class MyTask
{
public:
    int m_index;
    MyTask()
    {
        m_index = 0;
    }
};

namespace
{
    static MyTask* s_pTask;
}

public ref class MyApplication
{
public:
    static MyTask* sm_pTask;

    static void InitizlizeStaticMembers(MyTask* pTask)
    {
        sm_pTask = pTask;
    }

    void AddTask()
    {
        sm_pTask = new MyTask();
    }
};

void main()
{
    MyApplication^ app = gcnew MyApplication();

    // 1st, doesn't work (sm_pTask is still null after the execution)
    MyApplication::sm_pTask = new MyTask();
    // 2nd, doesn't work (pTask can be initialized correctly, sm_pTask is still null after the execution)
    MyTask* pTask = new MyTask();
    MyApplication::InitizlizeStaticMembers(pTask);
    // 3rd, doesn't work (sm_pTask is still null after the execution)
    app->AddTask();
    // 4th, work(s_pTask can be initialized correctly)
    s_pTask = new MyTask();
}

Answer 1

I don't see any issue with the code and it works fine for me. The anonymous namespace is not needed.

#include "stdafx.h"
#include <iostream>

class MyTask
{
public:
    int m_index;
    MyTask()
    {
        m_index = 0;
    }
};

static MyTask* s_pTask;

public ref class MyApplication
{
public:
    static MyTask* sm_pTask = NULL;

    static void InitizlizeStaticMembers(MyTask* pTask)
    {
        sm_pTask = pTask;
    }

    void AddTask()
    {
        sm_pTask = new MyTask();
    }
};

void main()
{
    MyApplication^ app = gcnew MyApplication();

    // 1st, doesn't work (sm_pTask is still null after the execution)
    std::cout << "MyApplication::sm_pTask before new " << MyApplication::sm_pTask << '\n'; // 0
    MyApplication::sm_pTask = new MyTask();
    std::cout << "MyApplication::sm_pTask after new " << MyApplication::sm_pTask << '\n'; // 003B8170

    MyTask* pTask = new MyTask();
    std::cout << "pTask= " << pTask << '\n'; // 003B81A0
    MyApplication::InitizlizeStaticMembers(pTask);
    std::cout << "MyApplication::sm_pTask = " << MyApplication::sm_pTask << '\n'; // 003B81A0

    app->AddTask();    
    s_pTask = new MyTask();
}

Answer 2

I found that (with VS2005) the debugger confirms what you said - the value of the pointer doesn't change as it gets updated. But the code is actually working if you make it output something.

I believe this is a bug in the debugger.

Answer 3

Thank Vijay and Drew! You're both correct, I dumped the values out and found they are correct. And on my colleague's machine, the VS works well (can get the correct value by the watching window or by hovering the mouse on). By the way, I'm using VS 2008 Pro with SP1 installed, the same configuration for my colleague.