} catch (overflowexception) { webid = guid.empty; I think that this only works if you raise and then catch the exception, but not if you try getting the traceback before raising an exception object that. How does this help catch multiple exceptions in one line as the question requires?
Los Angeles Clippers NBA's Hottest Team on a NineGame Winning Streak
Note that most crashes are not caused by exceptions in c++. } catch (formatexception) { webid = guid.empty; You can catch all exceptions, but that won't prevent many crashes.
Try { webid = new guid(querystring[web]);
