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

Subject: Re: [Boost-users] custom allocators Re:pool_alloc
From: Steven Watanabe (watanabesj_at_[hidden])
Date: 2010-03-17 14:21:49

AMDG

B Hart wrote:
> I am not understanding the use of pool with std::set.  i.e. the
> release_memory() function referenced in last example shown on:
> http://www.boost.org/doc/libs/1_42_0/libs/pool/doc/interfaces.html
> seems to do nothing.
>
> I call GetProcessMemoryInfo() and don't see any change after the set
> has gone out of scope.
>
> maybe someone could relate what happens to the allocated memory when
> set goes out of scope and
> release_memory() isn't called versus what happens when set goes out of scope and
> release_memory() is called.
>
> I want to do something like:
>
> 1.std::set<unsigned int, std::less<unsigned int>,
> boost::pool_allocator<unsigned int>> v;
> 2. for(int i=0; i<(K); i++)
>        {
>                v.insert(i);
>
>        }
> 3. use v
> 4. release_memory() on v //dump all set elements in one action. Note,
> without custom allocator this is very slow for large sets.
> 5. repeat 1-4 with a new set
>   

std::set rebinds the allocator to its internal node type.  Thus,
the allocator actually used by the set is using a different underlying
pool than v.

In Christ,
Steven Watanabe