据此,没有办法将HRESULT错误代码转换为Win32错误代码。 因此(至less对我的理解),我使用FormatMessage为了生成错误消息(即
std::wstring Exception::GetWideMessage() const { using std::tr1::shared_ptr; shared_ptr<void> buff; LPWSTR buffPtr; DWORD bufferLength = FormatMessageW( FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, GetErrorCode(), 0, reinterpret_cast<LPWSTR>(&buffPtr), 0, NULL); buff.reset(buffPtr, LocalFreeHelper()); return std::wstring(buffPtr, bufferLength); }
)不适用于HRESULT。
如何为HRESULT生成这些types的系统特定的错误string?
这个答案包含了Raymond Chen的想法,正确地识别了传入的HRESULT,并使用正确的工具返回错误字符串以获取错误消息:
///////////////////////////// // ComException CString FormatMessage(HRESULT result) { CString strMessage; WORD facility = HRESULT_FACILITY(result); CComPtr<IErrorInfo> iei; if (S_OK == GetErrorInfo(0, &iei) && iei) { // get the error description from the IErrorInfo BSTR bstr = NULL; if (SUCCEEDED(iei->GetDescription(&bstr))) { // append the description to our label strMessage.Append(bstr); // done with BSTR, do manual cleanup SysFreeString(bstr); } } else if (facility == FACILITY_ITF) { // interface specific - no standard mapping available strMessage.Append(_T("FACILITY_ITF - This error is interface specific. No further information is available.")); } else { // attempt to treat as a standard, system error, and ask FormatMessage to explain it CString error; CErrorMessage::FormatMessage(error, result); // <- This is just a wrapper for ::FormatMessage, left to reader as an exercise :) if (!error.IsEmpty()) strMessage.Append(error); } return strMessage; }