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Subject: Re: [boost] [functional/hash] Interface-breaking changes to hash_combine
From: Daniel James (dnljms_at_[hidden])
Date: 2014-07-28 18:50:09


On 27 July 2014 17:07, Joaquin M Lopez Munoz <joaquin_at_[hidden]> wrote:
> Hi,
>
> There's been a number of internal changes to the implementation of
> boost::hash_combine during this year, with the result that the
> documented procedure:
>
> http://www.boost.org/doc/html/hash/reference.html#boost.hash_combine
>
> namely, seed ^= hash_value(v) + 0x9e3779b9 + (seed << 6) + (seed >> 2),
> is no longer followed in all cases.
>
> This is a backwards compatibility breach --at the very least I think it
> should be documented.

That algorithm should never have been specified in the documentation.
I guess I overestimated myself and assumed I wouldn't do such a thing.
I've removed it now, and added some notes.


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