windows下的错误代码处理

看了下《windows核心编程》的错误代码处理部分。我这才知道错误代码处理的重要性，以前的时候有错误就埋头苦调，现在发现当初好傻。埋头苦调根本就是又费力又费时，而且错误代码还不一定能调的出来。以后就用Windows下面的错误代码处理额···

下面是一个例子

#include <windows.h>


DWORD GetLastErrorBox(HWND hWnd, LPSTR lpTitle);
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);


LPSTR szAppName = "Curves";
LPSTR szTitle = "Curves Application";


int WINAPI WinMain(
				   HINSTANCE hInstance,
				   HINSTANCE hPrevInstance,
				   LPSTR lpCmdLine,
				   int nCmdShow)
{
	MSG msg;
	HWND hWnd;
	WNDCLASS wc;
	
	// 注册窗口类
	wc.style = CS_OWNDC; 
	wc.lpfnWndProc = (WNDPROC)WndProc; 
	wc.cbClsExtra = 0; 
	wc.cbWndExtra = 0; 
	wc.hInstance = hInstance;
	wc.hIcon = NULL; 
	wc.hCursor = LoadCursor(NULL, IDC_ARROW);
	wc.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
	wc.lpszMenuName = NULL;
	wc.lpszClassName = szAppName; 
	
	if (!RegisterClass(&wc))
	{
		GetLastErrorBox(NULL, "Error in RegisterClass");
		return (FALSE);
	}
	// 创建窗口
	hWnd = CreateWindow(
		szAppName, 
		szTitle, 
		WS_OVERLAPPEDWINDOW,
		CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, 
		NULL, 
		NULL,
		hInstance, 
		NULL 
		);
	
	if (!hWnd)
	{
		GetLastErrorBox(hWnd, "Error in CreateWindow");
		return (FALSE);
	}
	// 显示更新
	ShowWindow(hWnd, nCmdShow); 
	UpdateWindow(hWnd); 
	// 消息循环
	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	
	return (int)(msg.wParam);
	
	UNREFERENCED_PARAMETER(lpCmdLine); 
}


LRESULT CALLBACK WndProc(
						 HWND hWnd, 
						 UINT message, 
						 WPARAM uParam, 
						 LPARAM lParam)
{
	switch (message)
	{
	case WM_CREATE:
		{
			SetWindowLong(hWnd,GWL_EXSTYLE,NULL);//SetWindowLong(NULL,GWL_EXSTYLE,NULL);

		}
		GetLastErrorBox(hWnd, "Error in WM_CREATE");
		break;


	case WM_DESTROY: 


		PostQuitMessage(0);
		break;


	default: 
		return (DefWindowProc(hWnd, message, uParam, lParam));
	}
	return (0);
}


// 显示错误信息
DWORD GetLastErrorBox(HWND hWnd, LPSTR lpTitle)
{
	LPVOID lpv;
	DWORD dwRv;
	
	if (GetLastError() == 0) return 0;
	
	dwRv = FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER |
		FORMAT_MESSAGE_FROM_SYSTEM,
		NULL,
		GetLastError(),
		MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US),
		(LPSTR)&lpv,
		0,
		NULL);
	
	MessageBox(hWnd, (LPCSTR)lpv, lpTitle, MB_OK);
	
	if(dwRv)
		LocalFree(lpv);
	
	SetLastError(0);
	return dwRv;
}

在WM_CREATE的时候若是我在函数SetWindowLong(hWnd,GWL_EXSTYLE,NULL);第一个参数传入NULL，此时其实窗口还没生成，又何来句柄，然后就会出现错误消息，

我们自己写个函数把错误代码转化成我们能看得懂的东西。运行上面修改后的程序，就会弹出错误的框，内容是"Invalid window Handle"，这下就错误一目了然了额····

上面这个错误错里就当作模版处理，记在博客上面····