真怪,调用CreateWindowEx返回NULL,但错误码为0
代码如下:
//主窗口消息处理函数
LRESULT CALLBACK WinProc( HWND hWnd, UINT message,
WPARAM wParam, LPARAM lParam )
{
return 0;
}
//创建主窗口
HWND InitWindow(HINSTANCE hInstance, int nCmdShow)
{
HWND l_hWnd; //创建窗口的临时句柄
WNDCLASS wc; //用来注册的窗口类
//填充窗口类结构
wc.style = CS_HREDRAW | CS_VREDRAW; //窗口类型
wc.lpfnWndProc = WinProc; //消息处理的回调函数
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = LoadIcon( hInstance, IDI_APPLICATION );
wc.hCursor = LoadCursor( NULL, IDC_ARROW );
wc.hbrBackground = (HBRUSH )GetStockObject(BLACK_BRUSH);
wc.lpszMenuName = NULL;
wc.lpszClassName = GameTitle;
//注册窗口类
if (0 == ::RegisterClass(&wc))
MessageBox(NULL, "Register class fail!", "Error!", MB_OK);
//创建窗口
l_hWnd = ::CreateWindowEx(WS_EX_TOPMOST, GameTitle,
GameTitle, WS_BORDER, 0, 0, GetSystemMetrics(SM_CXSCREEN), GetSystemMetrics(SM_CYSCREEN),
NULL, NULL, hInstance, NULL);
if ( NULL == l_hWnd )
{
long lError = ::GetLastError();
char ErrorStr[50];
::sprintf(ErrorStr, "%s%d",
"Create window fail! ErrCode = ", lErrorStr );
MessageBox(NULL, ErrorStr, "Error!", MB_OK);
return 0;
}
}
会显示出"Create window fail! ErrorCode = 0"的对话框。
就觉得奇怪了,既然失败返回NULL了,为什么取错误码会是0呢?0的解释是执行成功。