Chapter 7: Portability - TOC - 7.6 REPRESENTATION CLAUSES AND IMPLEMENTATION-DEPENDENT FEATURES

7.6.8 Unchecked Conversion

guideline

Avoid dependence on Ada.Unchecked_Conversion (see Guideline 5.9.1).

rationale

The unchecked type conversion mechanism is, in effect, a means of bypassing the strong typing facilities in Ada. An implementation is free to limit the types that may be matched and the results that occur when object sizes differ.

exceptions

Unchecked type conversion is useful in implementation-dependent parts of Ada programs where lack of portability is isolated and where low-level programming and foreign language interfacing are the objectives.

If an enumeration representation clause is used, unchecked type conversion is the only language-provided way to retrieve the internal integer code of an enumeration value.