Re: [Boost-users] custom allocators Re:pool_alloc

Subject: Re: [Boost-users] custom allocators Re:pool_alloc
From: Eric Whitcombe (ericwsf_at_[hidden])
Date: 2010-03-19 14:02:56

Sorry, if this is a little late to be helpful but I thought I'd add this for 
historical purposes for anyone looking at this thread to deal with their own 
problem. All STL containers use allocators to allocate and initialize the 
memory to store the _elements_ in the container not the node structure. The 
containers definition of the data structures that support the implentation 
details are purely internal. The allocator interface is paramterized on the 
type of the container element.

>
> B Hart wrote:
>> Sorry, I don't get you...as I understand the pool is a singleton, and
>> once out of scope I would assume all the memory for the set is
>> released back to the OS.  Therefore what is the purpose of
>> release_memory()...maybe I don't understand pool.  And then "internal
>> node type"...what is that?
>>
>
> Set is implemented using a binary search tree.  set<int>
> doesn't actually allocate ints, it allocates a struct that probably
> looks something like:
>
> struct Node {
>    int value;
>    int color;
>    Node * left;
>    Node * right;
>    Nonde * parent;
> };
>
> pool_allocator uses separate singleton pools for
> each size of element that it needs to handle.
>
> In Christ,
> Steven Watanabe
>
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