Re: [boost] Stack-based vector container

Subject: Re: [boost] Stack-based vector container
From: Howard Hinnant (howard.hinnant_at_[hidden])
Date: 2010-12-29 09:55:40

On Dec 28, 2010, at 11:41 PM, Frank Mori Hess wrote:

> On Tuesday 28 December 2010, Howard Hinnant wrote:
>>> Yeah, an allocator with some internal storage that falls back to the
>>> heap when it's exausted would allow std::vector's to essentially use
>>> the "small string optimization."
>> 
>> For example:
>> 
>> http://home.roadrunner.com/~hinnant/stack_alloc.html
> 
> That page talks about the allocator working with c++03 containers, but what 
> about 20.1.5 paragraph 4?  Quote:
> 
> "Implementations of containers described in this International Standard are 
> permitted to assume that their
> Allocator template parameter meets the following two additional 
> requirements beyond those in Table 32.
> 
> — All instances of a given allocator type are required to be 
> interchangeable and always compare equal to
>  each other..."
> 
> And then I also see there is an allocator copy constructor postcondition 
> which it does not fulfill:
> X a(b);                                       post: Y(a) == b

I've changed my documentation to make it clear that the C++03 compatibility part of the design is based on actual C++03 implementations of standard containers as opposed to strictly following the C++03 specification.

-Howard