Defect Report #401

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Submitter: Batty
Submission Date: 2011-10-14
Source: WG 14
Reference Document: N1584
Version: 1.1
Date: February 2012
Subject: "happens before" can not be cyclic

Summary

C++11 forbids "happens before" from being cyclic, but this change has not made its way into C11. In order to fix this, the following sentence (taken from C++ N3291, 1.10p12) should be added to 5.1.2.4p18:

The implementation shall ensure that no program execution demonstrates a cycle in the "happens before" relation.

NOTE: This cycle would otherwise be possible only through the use of consume operations.

Suggested Technical Corrigendum
See above.


Oct 2011 meeting

Committee Discussion

Feb 2012 meeting

Proposed Technical Corrigendum

Add to 5.1.2.4p18:
The implementation shall ensure that no program execution demonstrates a cycle in the "happens before" relation.

NOTE: This cycle would otherwise be possible only through the use of consume operations.
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