Re: [Boost-users] hash<pair<...

Subject: Re: [Boost-users] hash<pair<...
From: John Dlugosz (JDlugosz_at_[hidden])
Date: 2009-09-17 18:24:38

> 
> I think the issue is that TR1 does not (as of yet) require hash for
> pairs.  Boost does have a hash function that works on pairs, in
> Functional/Hash, and that's the default hash used by Boost's unordered
> map, but since they aren't part of TR1, they're not included in the TR1
> namespace. 

The unordered_map is finding it anyway.

> The Functional/Hash documentation links to a working group
> document which mentions this among other issues with TR1 (as then
> proposed).
> 
> http://www.boost.org/doc/libs/1_40_0/doc/html/hash.html
> 
> The document is four years old though.  Someone more up on the C++0x
> development can tell you more, and what the current status is.

That links to N1837 which marks the matter as "closed".  
"The LWG agreed that there are usability problems with the current interface, but thought that this
proposal was too large, and raised too many design issues, for it to be accepted for the TR."
Hopefully, a simpler, acceptable improvement will be provided in the final specification.  The wording there is no vauge to know if there is an issue specifically with a pair form.

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