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From: mjv@objects.mv.com (Michael J. Vilot)
Newsgroups: comp.lang.c++
Subject: re: Exception handling
Message-ID: <965@zinn.MV.COM>
Date: 10 Oct 90 20:53:40 GMT
Sender: nuucp@zinn.MV.COM
Lines: 27

David Masterson asks:

> Would it be valid to add a call to another function (say myf()) at the end of
> main() ... Point is, is it valid to reset how exceptions are processed?

The short answer is: Yes.
Handlers for the same exception attached to different blocks are distinct.
So, a handler for catching X's thrown from one block need not do the same
thing as a handler for catching them in some other context.

Note, however, two points:

  1.  For the set of handlers attached to the _same_ block, ``control is transferred
  to the nearest handler of an appropriate type ... the handlers for a try-block are 
  tried in order of appearance.  It is an error to place a handler for a base class
  ahead of a handler for its derived class since that would ensure that the handler
  for the derived class would never be invoked.'' [E&S, Ch 15]
  
  2.  ``An exception is considered handled upon entry to a handler.'' That is, it
  takes an explicit action to throw (or re-throw) in order to propagate an exception
  beyond a matching handler.
  
Hope this helps,

--
Mike Vilot,  ObjectWare Inc, Nashua NH
mjv@objects.mv.com  (UUCP:  ...!decvax!zinn!objects!mjv)