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3249. There are no 'pointers' in §[atomics.lockfree]

Section: 31.5 [atomics.lockfree] Status: WP Submitter: Billy O'Neal III Opened: 2019-08-03 Last modified: 2020-11-15

Priority: 4

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Discussion:

According to SG1 experts, the requirement in [atomics.lockfree]/2 is intended to require that the answer for is_lock_free() be the same for a given T for a given run of the program. The wording does not achieve that because it's described in terms of 'pointers', but there are no pointers in an atomic<int>.

[2020-02 Status to Ready on Thursday morning in Prague.]

[2020-11-09 Approved In November virtual meeting. Status changed: Ready → WP.]

Proposed resolution:

This wording is relative to N4830.

  1. Modify 31.5 [atomics.lockfree] as indicated:

    -2- The functions atomic<T>::is_lock_free, and atomic_is_lock_free (31.8.2 [atomics.types.operations]) indicates whether the object is lock-free. In any given program execution, the result of the lock-free query is the same for all atomic objects shall be consistent for all pointers of the same type.