on Fri Jun 15 2012, Mathias Gaunard <mathias.gaunard-AT-ens-lyon.org> wrote:
On 15/06/2012 17:59, Dave Abrahams wrote:
1. How can you tell whether bar failed or the assignment failed, here?
If I know that T::operator= has the strong guarantee,
Big if. That wasn't part of the scenario you framed.
I know that foo will always be in either of two states: either bar() succeeds, and it has the new value returned by bar(), or it failed, and it has the old value.
Yes, by definition.
If overloading were allowed to take foo, half-modify it, then fail, then that wouldn't be true anymore.
2. Do you really write code like that?
Of course, what would be the point of exceptions is not to catch them?
Usually you want to do something with the exception once caught; your code doesn't do that. And code where the catch block doesn't rethrow tends to be incredibly rare. -- Dave Abrahams BoostPro Computing http://www.boostpro.com