我正在创建一个简单的窗口但是当我看到窗口被创建并关闭它时，不会得到WM_QUIT消息。这是一些代码：
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR cmdLine, int cmdShow)
{
cWindowApplication app(hInstance);
const long width = 1024L;
const long height = 768L;
if (app.CreateWindowApplication(width, height) == false)
{
MessageBox(NULL, "Unable to create OpenGL Window", "An error occurred", MB_ICONERROR | MB_OK);
app.DestroyWindowApplication();
return 1;
}
return app.MainLoop();
}
这里是CreateWindowApplication（int，int）函数：
bool cWindowApplication::CreateWindowApplication(long width, long height, bool full_screen /*= false*/)
{
DWORD dwExStyle; // Window Extended Style
DWORD dwStyle; // Window Style
mWindowRect.left = 0L; // Set Left Value To 0
mWindowRect.right = width; // Set Right Value To Requested Width
mWindowRect.top = 0L; // Set Top Value To 0
mWindowRect.bottom = height; // Set Bottom Value To Requested Height
mFullScreen = full_screen;
// fill out the window class structure
const char* class_name = "MyClass";
mWindowClass.cbSize = sizeof(WNDCLASSEX);
mWindowClass.style = CS_HREDRAW | CS_VREDRAW;
mWindowClass.lpfnWndProc = cWindowApplication::StaticWindowsProcessCallback;
mWindowClass.cbClsExtra = 0;
mWindowClass.cbWndExtra = 0;
mWindowClass.hInstance = mhInstance;
mWindowClass.hIcon = LoadIcon(NULL, IDI_APPLICATION); // default icon
mWindowClass.hCursor = LoadCursor(NULL, IDC_ARROW); // default arrow
mWindowClass.hbrBackground = NULL; // don't need background
mWindowClass.lpszMenuName = NULL; // no menu
mWindowClass.lpszClassName = class_name;
mWindowClass.hIconSm = LoadIcon(NULL, IDI_WINLOGO); // windows logo small icon
// register the windows class
if (!RegisterClassEx(&mWindowClass))
{
return false;
}
if (mFullScreen == true) //If we are Full Screen, we need to change the display mode
{
DEVMODE dmScreenSettings; // device mode
memset(&dmScreenSettings, 0, sizeof(dmScreenSettings));
dmScreenSettings.dmSize = sizeof(dmScreenSettings);
dmScreenSettings.dmPelsWidth = width; // screen width
dmScreenSettings.dmPelsHeight = height; // screen height
dmScreenSettings.dmBitsPerPel = BITS_PER_PIXEL; // bits per pixel
dmScreenSettings.dmFields = DM_BITSPERPEL | DM_PELSWIDTH | DM_PELSHEIGHT;
if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
{
// setting display mode failed, switch to windowed
MessageBox(NULL, "Display mode failed", NULL, MB_OK);
mFullScreen = false;
}
}
if (mFullScreen == true) // Are We Still In Full Screen Mode?
{
dwExStyle = WS_EX_APPWINDOW; // Window Extended Style
dwStyle = WS_POPUP; // Windows Style
//ShowCursor(false); // Hide Mouse Pointer
}
else
{
dwExStyle = WS_EX_APPWINDOW | WS_EX_WINDOWEDGE; // Window Extended Style
dwStyle = WS_OVERLAPPEDWINDOW; // Windows Style
}
AdjustWindowRectEx(&mWindowRect, dwStyle, false, dwExStyle); // Adjust Window To True Requested Size
// class registered, and create our window
mHWND = CreateWindowEx(NULL, // extended style
class_name, // class name
"My Windows", // application name
dwStyle | WS_CLIPCHILDREN | WS_CLIPSIBLINGS,
0, 0, // x,y coordinate
mWindowRect.right - mWindowRect.left,
mWindowRect.bottom - mWindowRect.top, // width, height
NULL, // handle to parent
NULL, // handle to menu
mhInstance, // application instance
this); // this pointer to call member functions
// check if window creation failed (hwnd would equal NULL)
if (mHWND == false)
{
return false;
}
mHDC = GetDC(mHWND);
ShowWindow(mHWND, SW_SHOW); // display the window
UpdateWindow(mHWND); // update the window
return true;
}
基本上在这个函数调用之后，CreateWindowEx（）函数将调用如下所示的StaticWindowProcessCallback（）：
LRESULT cWindowApplication::StaticWindowsProcessCallback(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
cWindowApplication* win_app = NULL;
if (msg == WM_CREATE)
{
//Creation event
//Get the pointer we pass during CreateWindowApplication() call
win_app = (cWindowApplication*)((LPCREATESTRUCT)lParam)->lpCreateParams;
//Associate window pointer with the hwnd for the other events to access
SetWindowLongPtr(wnd, GWLP_USERDATA, (LONG_PTR)win_app);
}
else
{
//Non-creation event
win_app = (cWindowApplication*)GetWindowLongPtr(wnd, GWLP_USERDATA);
if (win_app != NULL)
{
return DefWindowProc(wnd, msg, wParam, lParam);
}
}
//call member
return win_app->WindowsProcessCallback(wnd, msg, wParam, lParam);
}
最后，此函数的最后一行调用如下所示的成员函数WindowProcessCallback（）：
LRESULT cWindowApplication::WindowsProcessCallback(HWND wnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
case WM_CREATE:
{
mHDC = GetDC(wnd);
SetupPixelFormat();
//Set the version that we want, in this case 3.0
int attribs[] = { WGL_CONTEXT_MAJOR_VERSION_ARB, 3, WGL_CONTEXT_MINOR_VERSION_ARB, 0, 0 }; //zero indicates the end of the array
//Create temporary context so we can get a pointer to the function
HGLRC tmp_context = wglCreateContext(mHDC);
//Make it current
wglMakeCurrent(mHDC, tmp_context);
PFNWGLCREATECONTEXTATTRIBSARBPROC wglCreateContextAttribsARB = NULL;
wglCreateContextAttribsARB = (PFNWGLCREATECONTEXTATTRIBSARBPROC)wglGetProcAddress("wglCreateContextAttribsARB");
if (wglCreateContextAttribsARB == NULL)
{
//No OpenGL 3.0, back to 2.0
mHGLRC = tmp_context;
}
else
{
//Create OpenGL 3.0
mHGLRC = wglCreateContextAttribsARB(mHDC, 0, attribs);
//Delete the temp context
wglDeleteContext(tmp_context);
}
//Make OpenGL 3.0
wglMakeCurrent(mHDC, mHGLRC);
mIsRunning = true;
}
break;
case WM_QUIT:
case WM_DESTROY:
case WM_CLOSE:
wglMakeCurrent(mHDC, NULL);
wglDeleteContext(mHGLRC);
mIsRunning = false;
PostQuitMessage(0); //Send a WM_QUIT message
return 0;
default:
break;
}
return DefWindowProc(wnd, msg, wParam, lParam);
}
正如您所看到的，那里有一些消息处理代码......但除了WM_CREATE之外，没有其他案例被击中。发送WM_CREATE消息后，正在调用函数MainLoop（），如下所示：
int cWindowApplication::MainLoop()
{
while (mIsRunning == true)
{
ProcessWindowsMessages();
}
DestroyWindowApplication();
return 0;
}
基本上，ProcessWindowsMessages（）函数在窗口关闭后没有得到任何消息......我必须按停止VS来运行才能终止进程。 ProcessWindowsMessages（）函数如下所示：
void cWindowApplication::ProcessWindowsMessages()
{
MSG msg;
if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
答案 0 :(得分：2)
StaticWindowsProcessCallback中的这个逻辑向后看：
if (win_app != NULL)
{
return DefWindowProc(wnd, msg, wParam, lParam);
}
如果您没有指向窗口包装器对象的指针，则需要调用DefWindowProc。所以这应该发生if (win_app == NULL)。这是为了处理在WM_CREATE之前发送的少量消息。因此，您的代码在WM_CREATE之前处理的邮件上具有未定义的行为，并在WM_CREATE之后丢弃（通过应用默认处理）所有邮件。
但是，使用WM_NCCREATE设置链接会更好。同样，win_app也不是一个非常好的名称，可能win_obj或其他。
您也不应该在窗口过程中处理WM_QUIT，因为它不会被发送到窗口。 WM_CLOSE的默认行为应该没问题，它会调用DestroyWindow来触发WM_DESTROY。
但是第一个，未能将WM_CREATE之后的任何消息转发到您的窗口过程，可能会解释您在主消息循环中缺少WM_QUIT。