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

Subject: Re: [Boost-users] custom allocators Re:pool_alloc
From: Kenny Riddile (kfriddile_at_[hidden])
Date: 2010-03-17 16:27:24

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.

If you mean when the std::set goes out of scope, then no.

> And then "internal node type"...what is that?

Some STL containers (std::list, std::set, etc.) don't directly store 
elements of the type you specify.  For example, a std::list would likely 
store list nodes that contain the data element itself as well as 
pointers to the previous and next nodes.  In that case, a std::list< 
Foo, boost::pool_allocator<Foo> > doesn't allocate via 
boost::singleton_pool<boost::pool_allocator_tag, sizeof(Foo)>.  It 
allocates via boost::singleton_pool<boost::pool_allocator_tag, 
sizeof(SomeUnknownInternalNodeType)>.