Re: VC++2008 and vector exception - not caught
On Mon, 21 Jul 2008 02:51:21 GMT, jetan@online.microsoft.com ("Jeffrey
Tan[MSFT]") wrote:
Hi Frank,
Thanks for your feedback.
As Doug pointed, the main difference between vector::[] operator and
vector::at() function is that former one will not perform the
range/boundary check or validation. So vector::[] operator will not try to
throw standard C++ exception for invalid index. It will just use it for
referencing which may result in OS/Hardware level exception(such as Access
Violation) which will not be caught by C++ catch(std::exception). For this
type of exception, OS SEH(structured exception handling) is needed.
Just to be clear on the SEH angle, we really do only mean "may result". In
many cases, erroneous indexing will land in accessible memory that is not
part of the vector storage, and the program won't crash right away or
perhaps not at all. You might go on to read some random value, or you might
write to the bogus item and corrupt some other data structure. That said, I
wouldn't want anyone to think I'm arguing for vector::at; in fact, I can't
remember ever using the function.
--
Doug Harrison
Visual C++ MVP