IEEE Standards Interpretations for IEEE Std 1003.1c™-1995 IEEE Standard for Information Technology--Portable Operating System Interface (POSIX(R)) - System Application Program Interface (API) Amendment 2: Threads Extension (C Language)
Copyright © 1996 by the Institute of Electrical and Electronics Engineers, Inc. 345 East 47th Street New York, New York 10017 USA All Rights Reserved.
These are interpretations of IEEE Std 1003.1c-1995.
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Interpretation Request #11
Topic: sigpending() Relevant Clauses: 18.104.22.168
Clause 22.214.171.124 states "are pending either for the process or the calling thread". The present wording text allows for implementations that differ severely and impacts application portability. This should be better restated as "the union of signals pending for the process and calling thread". The intent is to return the set of signals which are pending and may be processed by the calling thread, whether pending on the thread or the process (i.e., the union of the process and thread pending signals). By saying "either the process or the calling thread", an implementation is allowed to return one or the other. If system A returns pending signals for the calling thread, and system B returns pending signals for the process, applications will not be portable.
This needs clarification. We believe the wording could be better phrased as "the union of signals pending for the process and calling thread which are blocked from delivery for the calling thread"
This is a duplicate of Interpretation #3, part 12.
Rationale for Interpretation