VC获取错误消息

CString GetSystemErrorMessage(){CString strRet;LPVOID lpMsgBuf;DWORD dw = GetLastError();FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER|FORMAT_MESSAGE_FROM_SYSTEM,NULL,dw,GetSystemDefaultLangID(),(LPTSTR) &lpMsgBuf,0, NULL );strRet.Format(TEXT("Error Code: %d\nError Message: %s"),dw,lpMsgBuf);LocalFree(lpMsgBuf);return strRet;}