Safe Iterator Framework for the C++ Standard Template Library

The C++ Standard Template Library is the flagship example for libraries based on the generic programming paradigm. The usage of this library is intended to minimize classical C/C++ errors, but does not warrant bug-free programs. Furthermore, many new kinds of errors may arise from the inaccurate use of the generic programming paradigm, like dereferencing invalid iterators or misunderstanding remove-like algorithms. In this paper we present some typical scenarios that may cause undefined or weird behaviour. We present approaches that can be used for developing different safe iterators to avoid run-time errors. Some of these iterators are able to manipulate the container directly, hence they cannot result in undefined behaviour when an algorithm needs to add elements to the container or delete elements from the container. Our iterators are able to indicate if they are invalid. Algorithms’ preconditions are evaluated with our iterators.