4 Documentation requirements

When it is impossible or infeasible for a system or program to define a particular behavior itself, it is permissible to state that the behavior is unspecifiable and to explain the circumstances and reasons why this is so.

4.1 System documentation

4.1.1 Implementation-defined options

The implementation-defined items in the following list represent characteristics and choices left to the discretion of the implementor, provided that the requirements of this standard are met. A system shall document the values for, or behaviors of, each item.

4.1.2 Ambiguous conditions

A system shall document the system action taken upon each of the general or specific ambiguous conditions identified in this standard. See 3.4.4 Possible actions on an ambiguous condition.

The following general ambiguous conditions could occur because of a combination of factors:

The following specific ambiguous conditions are noted in the glossary entries of the relevant words:

4.1.3 Other system documentation

A system shall provide the following information:

4.2 Program documentation

4.2.1 Environmental dependencies

A program shall document the following environmental dependencies, where they apply, and should document other known environmental dependencies:

4.2.2 Other program documentation

A program shall also document: