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 #40
Topic: streams & file descriptors & impl defined Relevant Sections: 8.2.3 Classification: No change

Interactions of Other File-Type C Functions (section 8.2.3) specifies 'single file description can be accessed both through streams and through file descriptors.' Section 2.2.2.57 (pathname) 'A pathname that begins with two successive slashes may be interpreted in an implementation-defined manner.' Does this mean that the stream functions can behave in an implementation-defined manner? If all the S_IS* functions return false, are there any requirements on using the referenced file?

Interpretation Response
The implementation-defined semantics allowed by the text quoted from 2.2.2.57 apply to the process of pathname resolution. Functions that use objects of type FILE * do their pathname resolution in an implementation-defined manner for pathnames that begin with two slashes followed by non-slash characters. 2.2.2.57 does not apply to behavior other than that required for pathname resolution.

The behavior of file types that cannot be identified with the S_IS* macros (5.6.1.1) is beyond the scope of IEEE Std 1003.1-1990.

Rationale for Interpretation
None.