Error message when shutdown

问题

When I compile the following code (with Visual C++ 2010 Express) with

cl test.cpp

and run the .exe, and then shutdown Windows 7, I get an error message like:

The instruction 0x00f....9 in explorer.exe cannot access memory at 0x00000000. Memory cannot be read.

I tried lots of modifications in the following code, but cannot solve this issue. Another remark: I'm really sure it's this program which is responsible for the crash: I don't run it, no shutdown error message, if I run it, there is one.

What could be the reason of the crash ?

Source file downloadable here.

#pragma comment(lib, "user32.lib")
#define UNICODE
#include <windows.h>

LRESULT CALLBACK WindowProc(HWND hwnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    return DefWindowProc(hwnd, uMsg, wParam, lParam);
}

int WINAPI wWinMain(HINSTANCE hInstance, HINSTANCE, PWSTR pCmdLine, int nCmdShow)
{
    const wchar_t CLASS_NAME[]  = L"Sample Window Class";
    WNDCLASS wc = { };
    wc.lpfnWndProc   = WindowProc;
    wc.hInstance     = hInstance;
    wc.lpszClassName = CLASS_NAME;
    RegisterClass(&wc);

    HWND hwndMain = CreateWindowEx(WS_EX_TOOLWINDOW | WS_EX_LAYERED, wc.lpszClassName, 0, WS_POPUP | WS_VISIBLE | WS_SYSMENU, 0, 0, 300, 300, 0, 0, 0, 0);
    SetLayeredWindowAttributes(hwndMain, 0, 192, LWA_ALPHA);
    ShowWindow(hwndMain, nCmdShow);

    // without the next 2 lines, no crash at shutdown
    // but these 2 next lines are really important to make the main 
    // window part of the windows' desktop    
    // see comments on http://stackoverflow.com/a/27787003/1422096
    HWND hwndOwner = GetWindow(GetWindow(GetTopWindow(0), GW_HWNDLAST), GW_CHILD);   
    SetWindowLong(hwndMain, GWL_HWNDPARENT, (LONG) hwndOwner);      

    MSG msg = { };
    while (GetMessage(&msg, NULL, 0, 0) > 0)
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

来源：https://stackoverflow.com/questions/27856507/error-message-when-shutdown

标签

c++

winapi

shutdown

explorer