Interpretations

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

IEEE Standards Interpretations for IEEE Std 1003.1™-2001 IEEE Standard for Information Technology - Portable Operating System Interface (POSIX®)

Copyright © 2006 by the Institute of Electrical and Electronics Engineers, Inc. 3 Park Avenue New York, New York 10016-5997 USA All Rights Reserved.

Interpretations are issued to explain and clarify the intent of a standard and do not constitute an alteration to the original standard. In addition, interpretations are not intended to supply consulting information. Permission is hereby granted to download and print one copy of this document. Individuals seeking permission to reproduce and/or distribute this document in its entirety or portions of this document must contact the IEEE Standards Department for the appropriate license. Use of the information contained in this document is at your own risk.

IEEE Standards Department Copyrights and Permissions 445 Hoes Lane, Piscataway, New Jersey 08855-1331, USA

Interpretation Request #33
Topic: key_t arithemetic type Relevant Sections: XBD <sys/types.h> key_t

In XBD <sys/types.h> we find the following the statment that key_t need not be an arithmetic type: 13068 All of the types shall be defined as arithmetic types of an appropriate length, with the following 13069 exceptions: 13070 XSI key_t But in the description of "Data Types" in XSH (Section 2.12), we find the following contradictory statement: 3363 key_t Arithmetic type used for XSI interprocess communication. Since ftok() returns (key_t)-1 on error, if it is not an arithmetic type then the only other thing it could be is a pointer. Remove line 13070 "XSI key_t" from <sys/types.h>

Interpretation Response
The standard is inconsistent on this issue, and no conformance distinction can be made between alternative implementations based on this. This is being referred to the sponsor.

Rationale for Interpretation
The standard developers agreed that key_t should be an arithmetic type.