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### 1151. Behavior of the library in the presence of threads is incompletely specified

Section: 16 [library] Status: Resolved Submitter: LWG Opened: 2009-06-28 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

Addresses US 63

Description

The behavior of the library in the presence of threads is incompletely specified.

For example, if thread 1 assigns to `X`, then writes data to file `f`, which is read by thread 2, and then accesses variable `X`, is thread 2 guaranteed to be able to see the value assigned to `X` by thread 1? In other words, does the write of the data "happen before" the read?

Another example: does simultaneous access using `operator at()` to different characters in the same non-const string really introduce a data race?

Suggestion

Notes

17 SG: should go to threads group; misclassified in document

Concurrency SG: Create an issue. Hans will look into it.

[ 2009 Santa Cruz: ]

> Move to "Open". Hans and the rest of the concurrency working group will study this. We can't make progress without a thorough review and a paper.

[ 2010 Pittsburgh: Moved to NAD Editorial. Rationale added below. ]

Rationale:

Solved by N3069.

Proposed resolution: