Except for Exception Handling ...

Exception handling in Ada has a number of well-known problems. It allows for the propagation of unhandled and anonymous exceptions, it is error-prone and it is inappropriate for some language features including tasking and tagged types. Ada programs with exceptions are difficult to understand, develop, modify or analyse, and the exception handling features can be misused in a number of ways. In this paper we introduce the requirements for good exception handling features. We classify the problems with Ada exception handling into two subsets: serious conceptual problems that require an improvement of the language features, and problems attributable to the misuse of the existing features. Problems in the second category can be solved by improving programmers' understanding of the features and ways of using them.