_com_error::Source
Microsoft Specific
Calls IErrorInfo::GetSource function.
_bstr_t Source() const;
Returns the result of IErrorInfo::GetSource for the IErrorInfo object recorded within the _com_error object. The resulting BSTR is encapsulated in a _bstr_t object. If no IErrorInfo is recorded, it returns an empty _bstr_t.
Any failure while calling the IErrorInfo::GetSource method is ignored.
END Microsoft Specific