How to read EXCEPINFO tuple in win32 error messages?

Question

I am writing an app that interacts with Excel. However, I'm hitting an error that I can't track down. My traceback says:

pywintypes.com_error: (-2147352567, 'Exception occurred.', (0, None, None, None, 0, -2147352565), None)

Using the com_error documentation, I can figure out most of this. However, I can't figure out how to read the interior tuple. The docs refer to this as an (optional) excepinfo tuple, but they don't describe what the contents of it are.

what is your expected output? You want to get access to the tuple objects? or the meaning of the errors? — Jean-François Fabre, May 04 '17 at 19:11
I'd like to know the meaning of the error so I can fix whatever is causing it. — indigochild, May 04 '17 at 19:12

score 3 · Answer 1 · answered Sep 08 '17 at 16:47

From https://msdn.microsoft.com/en-us/library/windows/desktop/ms221133(v=vs.85).aspx

typedef struct tagEXCEPINFO {
  WORD    wCode;
  WORD    wReserved;
  BSTR    bstrSource;
  BSTR    bstrDescription;
  BSTR    bstrHelpFile;
  DWORD   dwHelpContext;
  PVOID   pvReserved;
  HRESULT (__stdcall *pfnDeferredFillIn)(struct tagEXCEPINFO*);
  SCODE   scode;
} EXCEPINFO, *LPEXCEPINFO;

Examining a com_error output that was generated by one of my applications, I would think that the excepinfo tuple maps to (wCode, bstrSource, bstrDescription, bstrHelpFile, dwHelpContext, scode)

Admittedly, I didn't bother to go hunting in pywin32 sources to find where the tuple is constructed.

`pywin32` sources for `PyCom_PyObjectFromExcepInfo` [here](https://github.com/mhammond/pywin32/blob/cacb1ab5fbddaf1a275e741a76d987170c3504f5/com/win32com/src/ErrorUtils.cpp#L680-L686) confirm that you are right paulluap. The tuple does indeed map to `(wCode, bstrSource, bstrDescription, bstrHelpFile, dwHelpContext, scode)` — Day, Dec 18 '17 at 21:57

How to read EXCEPINFO tuple in win32 error messages?

1 Answers1