[boost] [serialization] exception-safety of container-serialization

Dear All, I have just added serialization to Boost.Ptr container. I briefly discussed an issue with Robert, namely that the current implementation calls clear() before reading the new values. The alternative is to provide roll-back guarantee by default by creating a local container and swap() in the end. By default this would temporarily use more memory. IMO we should go for the strong guarantee. Any thoughts? -Thorsten