Re: [Boost-users] custom allocators, pool_alloc release_memory() seems to be broken

Subject: Re: [Boost-users] custom allocators, pool_alloc release_memory() seems to be broken
From: B Hart (bhartsb_at_[hidden])
Date: 2010-03-18 18:47:02

So, I see likewise that 20 is the number per uint...I guess I missed
it earlier.  So, once I determine that I guess I can safely use 20?

Another question:  If I don't release but the set is destroyed then
that pool's memory will get re-used if I create another set?  I assume
yes, but confirming.

A comment: I strongly encourage whoever keeps up the documentation put
in some additional notes about this behavior, and update the author's
contact e-mail.  It is difficult when it is new and one already has
one's own code to deal with...e.g. while trying to figure this out I
had another issue with MSVS 2008 not showing local variables in the
debugger under Windows 7 64-bit.  The VS issue only reared it's ugly
head in my pool_alloc test program.  And running into multiple issues
at once is typical in my experience.

On Thu, Mar 18, 2010 at 3:23 PM, Steven Watanabe <watanabesj_at_[hidden]> wrote:
> AMDG
>
> B Hart wrote:
>>
>> nope, continued upwards and release_memory() always returns false.
>>
>
> I stepped though
>
> #include <boost/pool/pool_alloc.hpp>
> #include <set>
>
> int main() {
>   {
>       std::set<int, std::less<int>, boost::pool_allocator<int> > s;
>       for(int i = 0; i < 100; ++i) {
>           s.insert(i);
>       }
>   }
>   boost::singleton_pool<boost::pool_allocator_tag, 20>::release_memory();
> }
>
> and the call to release memory does seem to work.
>
>> Also, I would say that release_memory is broken, or needing revision,
>> if one has to guess what the pool size is.
>>
>
> It isn't broken.  release_memory works fine if you can
> find the right pool.  Because std::set does not expose the type
> that it actually allocates there is no portable way to do so.
>
> In Christ,
> Steven Watanabe
>
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