Re: [boost] [config] gcc and <unordered_set> vs <ext/hash_set>

Subject: Re: [boost] [config] gcc and <unordered_set> vs <ext/hash_set>
From: David Abrahams (dave_at_[hidden])
Date: 2008-12-16 16:24:33

on Tue Dec 16 2008, "Robert Ramey" <ramey-AT-rrsd.com> wrote:

> John Maddock wrote:
>> Folks, Dave A. asked for a config macro to detect the presence of std
>> conforming <unordered_set> and <unordered_map>.
>>
>> However, I've run into an unexpected issue: it appears that with
>> gcc-4.3.x you cannot include both <unordered_set> and <ext/hash_set>
>> as attempting to do so leads to endless errors inside the <ext/*>
>> headers :-(
>> Including either one of the headers is just fine though.
>>
>> So... how should we handled this?  Not define BOOST_HAS_HASH when
>> <unordered_set> *is* available?
>
> That would make it impossible to read archives which contain hashed
> pointers under the current system.  

Are you sure?  I'd be a bit surprised if hash_set<T>'s serialized data
couldn't be read into an unordered_set<T>.

-- 
Dave Abrahams
BoostPro Computing
http://www.boostpro.com