Improve exception safety with smart pointers

[elfring]

Would you like to wrap any pointer data members with the class template “std::unique_ptr”?

[rserban]

I assume you are talking about private data members in which case I am not so sure it is worth using unique_ptr. For data members that are made public (e.g., through accessors), it's almost always the case that a shared_ptr is needed (unless you found a case where that's not true?). Having said that, there are still places in Chrono where raw pointers are exposed to the user -- we fix these as we go along whenever we find the time.

[elfring]

I suggest to achieve safe resource management.