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From Liviu Nicoara <nikko...@hates.ms>
Subject Re: STDCXX-1056 : numpunct fix
Date Tue, 25 Sep 2012 11:41:52 GMT
On 09/24/12 23:50, Stefan Teleman wrote:
> On Mon, Sep 24, 2012 at 10:03 PM, Martin Sebor <msebor@gmail.com> wrote:
>> FWIW, there are race conditions in stdcxx. Some of them are by
>> design and benign on the systems the library runs on (although
>> I acknowledge that some others may be bugs). One such benign
>> date race is:
>>
>>    time    T1      T2
>>      0    x = N
>>      1    x = N   read x
>>
>> where x is a scalar that can be accessed atomically by the CPU
>> and the compiler.
>>
>> I think some of the lazy facet initialization falls under this
>> class. It would be nice to fix them but only if it doesn't slow
>> things down. The others need to be fixed in any case.
>
> The race conditions I am talking about are not benign.

Caching failures aside, we have no failing tests. Before saying they are malign you need to
objectively show a failing program.

>
> It shows the types of race conditions it's reporting: these are
> read/write race conditions, not read/read. The thread analyzer's html
> filter doesn't show the types of races reported as clearly as the
> command-line analyzer which has a windowing GUI.

Martin's example above is a read-write race. In the absence of a failing test case it is quite
unreasonable to modify the current implementation.

Liviu


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