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Getting sensible info from CLR-to-SEH exceptions in a mixed mode C++ project

Mixed mode C++ project. Native code is calling managed code. Managed code might throw an exception. I can catch said exception in native mode using a vectored exception handler; I can see its PEXCEPTION_POINTERS. The telling code 0xE0434F4D, meaning it's a CLR exception, is there.

Question: is there any way to get any sensible information (exception class, message, stack trace etc.) from the attendant data? There's one parameter in the ExceptionInformation, and it looks like a pointer to something...

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Seva Alekseyev Avatar asked Nov 05 '22 11:11

Seva Alekseyev


2 Answers

No, that's too late. All you got is the exception code. You might get something in ExceptionInformation if the original managed exception was caused by a processor fault. Like NullReference or AccessViolation. This won't be helpful since you don't know the original SEH exception anymore. Using COM give you a better mouse trap, the CLR implements IErrorInfo. But the managed code you're trying to run is probably not [ComVisible]. Calling the code through a managed stub that catches Exception might be a better angle.

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Willem D'Haeseleer Avatar answered Nov 13 '22 23:11

Willem D'Haeseleer


There is similar answer to this question here:
Catching a CLR exception through unmanaged code

This was resolved in the following manner:

#import <mscorlib.tlb> raw_interfaces_only no_smart_pointers named_guids no_implementation

ATL::CComPtr< IErrorInfo > spErrorInfo;
ATL::CComPtr< mscorlib::_Exception > spCLRException;
ATL::CComPtr< mscorlib::_Exception > spCLRInnerException;

ATL::CComBSTR bstrCLRStackTrace;
ATL::CComBSTR bstrCLRMessage;

GetErrorInfo(0, &spErrorInfo)
spErrorInfo.QueryInterface(&spCLRException)
spCLRException->get_InnerException(&spCLRInnerException)
spCLRInnerException->get_StackTrace(&bstrCLRStackTrace)
spCLRInnerException->get_Message(&bstrCLRMessage)
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lsalamon Avatar answered Nov 13 '22 23:11

lsalamon