vc，mfc，GetLastError 错误代码 ，FormatMessage 显示错误信息

DWORD dwError = GetLastError(hwnd, IDC_ERRORCODE, NULL, FALSE); HLOCAL hlocal = NULL; // Buffer that gets the error message string // Get the error code's textual description BOOL fOk = FormatMessage( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER, NULL, dwError, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US), (PTSTR) &hlocal, 0, NULL); if (!fOk) { // Is it a network-related error? HMODULE hDll = LoadLibraryEx(TEXT("netmsg.dll"), NULL, DONT_RESOLVE_DLL_REFERENCES); if (hDll != NULL) { FormatMessage( FORMAT_MESSAGE_FROM_HMODULE | FORMAT_MESSAGE_FROM_SYSTEM, hDll, dwError, MAKELANGID(LANG_ENGLISH, SUBLANG_ENGLISH_US), (PTSTR) &hlocal, 0, NULL); FreeLibrary(hDll); } } if (hlocal != NULL) { SetDlgItemText(hwnd, IDC_ERRORTEXT, (PCTSTR) LocalLock(hlocal)); LocalFree(hlocal); } else { SetDlgItemText(hwnd, IDC_ERRORTEXT, TEXT("Error number not found.")); }

 

1.FormatMessage函数在内部分配一块内存，并返回指向这块内存的句柄，即参数hlocal。故调用LocalFree(hlocal);释放资源

2.FORMAT_MESSAGE_FROM_SYSTEM ：获取系统自定义的错误代码对应的字符串

3.FORMAT_MESSAGE_ALLOCATE_BUFFER：要求函数分配一块足以容纳错误文本描述的内存。

 

 

  书本中有FORMAT_MESSAGE_IGNORE_INSERTS：允许活得含有%占位符的消息。此代码中无

 

注：FindWindow，参数1：class name； 参数2：window name.