|NoExceptions (const OptionalExceptions &a)|
Disable exceptions in an object derived from OptionalExceptions.
This class was designed to be created on the stack, taking a reference to a subclass of OptionalExceptions. (We call that our "associate" object.) On creation, we save that object's current exception state, and disable exceptions. On destruction, we restore our associate's previous state.
Takes a reference to an OptionalExceptions derivative, saves that object's current exception state, and disables exceptions.
Restores our associate object's previous exception state.