Interpretations

Answering questions that may arise related to the meaning of portions of an IEEE standard concerning specific applications.

IEEE Standards Interpretation for IEEE Std 1003.1™-1990 IEEE Standard for Information Technology--Portable Operating System Interfaces (POSIX®)

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Interpretation Request #41
Topic: streams & file descriptors & impl defined Relevant Sections: 8.1.1 Classification: No change

Section 8.1.1 - Extensions to Time Functions. Line 64 and line 90 are inconsistent within this section. Line 64 uses the terms 'start' and 'end'. On line 90, the term 'date' is used. Beyond this level of inconsistency, line 64 uses the notation for optional parameters. Line 90 does not repeat this notation. It also does not state if the default for no start/end date is unspecified or implementation defined. Finally, the 'rule' section does not indicate what default (or error) is appropriate when start/end dates are omitted and 'dst' is specified.
(reference line 68). (Paul Wanish IBM)

Interpretation Response
Line 64 is the full specification of the expanded format of a time zone that does not have a colon as the first character. Since no ways to determine default values for start/end date are mentioned in IEEE Std 1003.1-1990, the defaults are to be treated as unspecified.

Rationale for Interpretation
The different wording used on line 90 informally re-casts the structure of a time zone specification in a way that illustrates one aspect of the internal logic of the syntax. There is no conflict between the more-specific and the less-specific statements of the syntax.

The wording of this section is being revised, in the interest of clarity, for IEEE Draft Standard P1003.1a.