Ada '83 Language Reference Manual

Copyright 1980, 1982, 1983 owned by the United States Government. Direct reproduction and usage requests to the Ada Information Clearinghouse.

F. Implementation-Dependent Characteristics

This appendix is not part of the standard definition of the Ada programming language.

The Ada language definition allows for certain machine-dependences in a controlled manner. No machine-dependent syntax or semantic extensions or restrictions are allowed. The only allowed implementation-dependences correspond to implementation-dependent pragmas and attributes, certain machine-dependent conventions as mentioned in chapter 13, and certain allowed restrictions on representation clauses.

The reference manual of each Ada implementation must include an appendix (called Appendix F) that describes all implementation-dependent characteristics. The appendix F for a given implementation must list in particular:

1. The form, allowed places, and effect of every implementation-dependent pragma.
2. The name and the type of every implementation-dependent attribute.
3. The specification of the package SYSTEM.
4. The list of all restrictions on representation clauses (see 13.1)
5. The conventions used for any implementation-generated name denoting implementation-dependent components (see 13.4).
6. The interpretation of expressions that appear in address clauses, including those for interrupts (see 13.5).
7. Any restriction on unchecked conversions (see 13.10.2).
8. Any implementation-dependent characteristics of the input-output packages (see 14).

Style Guide references: 4.1.1 Separate Compilation Capabilities, 5.4.1 Heterogeneous Data, 7.1.1 Global Assumptions, 7.1.2 Actual Limits, 7.1.3 Comments, 7.1.5 Encapsulating Implementation Dependencies, 7.1.6 Implementation-Added Features, 7.2.1 Predefined Numeric Types, 7.2.4 Accuracy Constraints, 7.4.3 Package Calendar, Type Duration, and System.Tick, 7.6.2 Package System, 7.6.3 Machine Code Inserts, 7.6.5 Implementation-Defined Pragmas and Attributes, 7.6.8 Run Time Dependencies

Address any questions or comments to adainfo@sw-eng.falls-church.va.us.