typedef HANDLE (_stdcall* BOUNDARYDESCRIPTOR)(LPTSTR, DWORD);
BOUNDARYDESCRIPTOR CreateBoundaryDescriptor;

typedef BOOL (_stdcall* ADDSIDTOBOUNDARYDESCRIPTOR)(HANDLE *, PSID);
ADDSIDTOBOUNDARYDESCRIPTOR AddSIDToBoundaryDescriptor;

typedef HANDLE (_stdcall *CREATEPRIVATENAMESPACE)(LPSECURITY_ATTRIBUTES, LPVOID, LPCSTR);
CREATEPRIVATENAMESPACE CreatePrivateNamespace;

typedef HANDLE (_stdcall* OPENPRIVATENAMESPACE)(PVOID, LPCSTR);
OPENPRIVATENAMESPACE OpenPrivateNamespace;

void CSingletonDlg::CheckInstances()
{
    HMODULE hKernel = LoadLibrary("Kernel32.dll");

    if (hKernel)
    {
        CreateBoundaryDescriptor = (BOUNDARYDESCRIPTOR)GetProcAddress(hKernel, "CreateBoundaryDescriptorA");
        // 注意函数名AddSIDToBoundaryDescriptor后面没带'A'
        AddSIDToBoundaryDescriptor = (ADDSIDTOBOUNDARYDESCRIPTOR)GetProcAddress(hKernel, "AddSIDToBoundaryDescriptor"); 

        CreatePrivateNamespace = (CREATEPRIVATENAMESPACE)GetProcAddress(hKernel, "CreatePrivateNamespaceA");
        OpenPrivateNamespace = (OPENPRIVATENAMESPACE)GetProcAddress(hKernel, "OpenPrivateNamespaceA");
    }

    );

    if (NULL == m_hBoundaryDescriptor)
    {
        // 创建边界描述符失败
        return;
    }

    // 为边界描述符关联一个SID
    BYTE localAdminSID[SECURITY_MAX_SID_SIZE];
    PSID pLocalAdminSID = &localAdminSID;
    DWORD cbSID = sizeof(localAdminSID);
    if (!CreateWellKnownSid(WinBuiltinAdministratorsSid, NULL, pLocalAdminSID, &cbSID))
    {
        // 创建SID失败
        return;
    }

    if (!AddSIDToBoundaryDescriptor(&m_hBoundaryDescriptor, pLocalAdminSID))
    {
        // 链接边界描述符失败
        return;
    }

    SECURITY_ATTRIBUTES sa;
    sa.nLength = sizeof(sa);
    sa.bInheritHandle = FALSE;
    if (!ConvertStringSecurityDescriptorToSecurityDescriptor(
        TEXT("D:(A;;GA;;;BA)"), SDDL_REVISION_1, &sa.lpSecurityDescriptor, NULL))
    {
            return;
    }

    // 创建命名空间
    /*HANDLE */m_hPrivateNameSpace = CreatePrivateNamespace(&sa, m_hBoundaryDescriptor, "3-Namespace");
    LocalFree(sa.lpSecurityDescriptor);

    // 检查已创建的命名空间：看是否有权限访问ERROR_ACCESS_DENIED和该命名空间是否存在ERROR_ALREADY_EXISTS
    DWORD dwLastErro = GetLastError();
    if (m_hPrivateNameSpace == NULL)
    {
        if (ERROR_ACCESS_DENIED == dwLastErro)
        {
            return;
        }
        else if (ERROR_ALREADY_EXISTS == dwLastErro)
        {
            m_hPrivateNameSpace = OpenPrivateNamespace(m_hBoundaryDescriptor, "3-Namespace");

            if (NULL == m_hPrivateNameSpace)
            {
                return;
            }
        }
    }

    // 创建互斥对象
    };
    StringCchPrintf(cMutexName, sizeof(MAX_PATH), "%s\\%s", "3-Namespace", "Single");
    g_hSingleton = CreateMutex(NULL, FALSE, cMutexName);

    if (GetLastError() == ERROR_ALREADY_EXISTS)
    {
        AddText(TEXT("Another instance of Singleton is running:\r\n"));
        AddText(TEXT("--> Impossible to access application features.\r\n"));
    } else
    {
        AddText(TEXT("First instance of Singleton:\r\n"));
        AddText(TEXT("--> Access application features now.\r\n"));
    }

    FreeLibrary(hKernel);
}