[Boost-users] (Newbie) Embedded programming, memory pools, and allocate_shared()

Subject: [Boost-users] (Newbie) Embedded programming, memory pools, and allocate_shared()
From: Steven Boswell II (ulatekh_at_[hidden])
Date: 2017-12-05 21:18:57

I apologize for bothering the mailing-list with this newbie question, but after searching the Net for several days, I still can't find the answers I'm looking for.

I am considering using Boost for a project I'm doing on an embedded system.I can't seem to find a lot of discussion on the particulars of Boost in embedded systems, just a few here and there.The biggest relevant limitation in embedded programming is on dynamic memory allocation -- the usual pattern is to allocate all necessary memory in "startup" phases, e.g. launching the program, loading the next playing-field in a game application, etc.
I believe I can do what I want with allocate_shared() and fixed-size memory pools.The first big issue I have is trying to figure out the size of the objects that'll be allocated from the pool.I don't want to just allocate a raw block of memory; I want to allocate a block with space for a certain number of objects of a homogeneous type.But an object_pool for a type T doesn't accurately reflect what allocate_shared() is going to try to create.From much digging around, it looks like it's actually creating a subclass of boost::detail::sp_counted_base, e.g. boost::detail::sp_counted_impl_pd<P,D>, boost::detail::sp_counted_impl_pda<P,D,A>, etc.It seems like I'm not supposed to refer to that class directly, but I don't know how else to get the size of individual objects for my pool-allocator.Also, navigating all the template-parameters needed by these classes is proving to be mind-twisting. Probably just because I'm seeing it for the first time.

Another example of where I need to track down the implementation class is with async-operation handlers in Boost::ASIO, e.g. completion handlers for socket's async_read_some(), generic handlers passed to io_service::post(), and so on. In the case of socket::async_read_some(), there's an example in boost/doc/html/boost_asio/example/cpp03/allocation/server.cpp which shows how to allocate completion-handlers from a pool, but not how to get the size of the necessary completion-handler class. It appears the class is boost::asio::detail::reactive_socket_recv_op<>. Again, this doesn't seem to be a public class, nor can I find a nice public typedef for it.
Can anyone advise me on how to use Boost in this way?All of the Boost memory-pools I've seen so far either just allocate chunks of raw memory, or they allocate non-shared variants of objects.A memory-pool with a given number of spaces for the final object type seems like a defensible, traditional solution, but it doesn't seem that Boost makes that easy.Am I way off base here?
Thanks for any help.
-Steven