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 #93
Topic:
ICANON Relevant Sections: 7.1.1.9 lines 246-250 PASC

Clause 7.1.1.9 lines 246-250 conflicts with clause 7.1.2.2 lines 351-352 with respect to the relevance of ICANON to the translation of CR to NL on input. Lines 246-250 state that ICANON must be set as a necessary precondition to the translation of CR to NL on input. Lines 351-352 do not mention ICANON as a precondition for this mapping. Note that historical practice (BSD and System V) agree with 7.1.2.2 lines 351-352. Note also that the definition of ICANON (7.1.2.5 line 434 and lines 450-452) indicates ICANON is associated with erase and kill processing, character echo processing, and line assembly; not with input character mapping.

Ask the relevant committee to recognize, in a future revision of 1003.1, that the mention of ICANON in lines 246-250 is erroneous. State that the conformance of an implementation cannot be affected by its behavior with respect to ICANON having an effect on mapping of CR to NL on input, and that portable applications cannot rely on any such effect.

Interpretation Response
There is no conflict, clause 7.1.1.9 refers to ICANON and the reference is strictly redundant. Existing practise does do the translation when ICANON is turned off.

Rationale for Interpretation
None Forwarded to Interpretations group: 10 Sept 1998 Proposed Interpretation: 26 Oct 1998 Finalised Interpretation: February 17 1999