Hands-On Design Patterns with C++

Chapter 11

• What is an error-safe, or exception-safe, program?

An error-safe program maintains a well-defined state (a set of invariants) even if it encounters an error. Exception safety is a particular kind of error safety; it assumes that errors are signaled by throwing expressions. The program must not enter an undefined state when an (allowed) expression is thrown. An exception-safe program may require that certain operations do not throw exceptions.

• How can we make a routine that performs several related actions in an error-safe manner?

If a consistent state must be maintained across several actions, each of which may fail, then the prior actions must be undone if a subsequent action fails. This often requires that the actions do ...