Chapter 7: Portability - TOC - 7.5 EXCEPTIONS

7.5.1 Predefined and User-Defined Exceptions

guideline

Do not depend on the exact locations at which predefined exceptions are raised.

Do not rely on the behavior of Ada.Exceptions beyond the minimum defined in the language.

rationale

The Ada Reference Manual (1995, §11) states that, among implementations, a predefined exception for the same cause may be raised from different locations. You will not be able to discriminate between the exceptions. Further, each of the predefined exceptions is associated with a variety of conditions. Any exception handler written for a predefined exception must be prepared to deal with any of these conditions.

Guideline 5.6.9 discusses the use of blocks to define local exception handlers that can catch exceptions close to their point of origin.