[ub] Type punning to avoid copying (was: unions and undefined behavior)

Lawrence Crowl Lawrence at Crowl.org
Thu Jul 25 22:56:12 CEST 2013


On 7/25/13, Howard Hinnant <howard.hinnant at gmail.com> wrote:
> It was this SO question that started this thread:
>
> http://stackoverflow.com/q/17789928/576911
>
> I'm curious:  The accepted answer uses memcpy and the claim is that this is
> a correct answer to the question.  That is it does not exhibit undefined
> behavior.  My current understanding is that I agree with this answer.  But I
> wanted to check here.  Do people here agree that:
>
> http://stackoverflow.com/a/17790026/576911
>
> does not break the aliasing rules, or otherwise invoke undefined behavior?

I believe so.

>
> Thanks,
> Howard
>
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-- 
Lawrence Crowl


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