Subject: Re: [boost] [containers] Are there flat_map/set and stable_vector proposals at work?
From: Jonathan Wakely (jwakely.boost_at_[hidden])
Date: 2013-10-28 06:23:11
On 28 October 2013 09:04, Rob Stewart wrote:
> On Oct 27, 2013, at 8:32 AM, Jonathan Wakely <jwakely.boost_at_[hidden]> wrote:
>
>> On 25 October 2013 20:44, Rob Stewart wrote:
>>>
>>> A flat_map, backed by std::array, is quite possibly no faster than a normal C++11 map, with a suitable allocator. A C++03 map won't use its allocator for nodes, but IIRC, a C++11 map will.
>>
>> What do you mean by "use"?
>>
>> std::map has always allocated the memory for its nodes using its allocator.
>
> 03's allocator interface means that the element and node allocations were done via different allocator types, which leads to distinct allocations. I don't recall the details, but that prevents using the same memory for both, as I recall.
You're mistaken. The element has always been embedded in the node, so
only the node is allocated.