Re: [boost] [container] Implemented Polymorphic Memory Resources

Subject: Re: [boost] [container] Implemented Polymorphic Memory Resources
From: Andrey Semashev (andrey.semashev_at_[hidden])
Date: 2015-09-08 07:26:26

On 07.09.2015 23:23, Ion Gaztañaga wrote:
> Hi to all,
>
> In case anyone is interested, I just committed to the develop branch the
> implementation of the proposal "N3916 Polymorphic Memory Resources - r2"
> that was included in the TS "C++ Extensions for Library Fundamentals".
> The library continues to support C++03 compilers.
>
> It basically introduces in namespace boost::container::pmr and the path
> boost/container/pmr/:
>
> - memory_resource
> - synchronized_pool_resource
> - unsynchronized_pool_resource
> - monotonic_buffer_resource
> - polymorphic_allocator
> - resource_adaptor
> - new_delete_resource / null_memory_resource / get_default_resource /
> set_default_resource
> - Aliases for all containers, using the polymorphic_allocator.
>
> As default resource, new_delete_resource and null_memory_resource are
> required to be globals, they are implemented in the separately compiled
> boost.container library that was used to implement the DLMalloc-based
> extended allocator.
>
> It seems that many users dislike building Boost libraries, but I felt
> this was the correct way to implement it. We could change or make it
> optionally header-only if there is demand. To avoid dependencies to some
> users, I made sure that memory_resource and resource_adaptor, which
> don't depend on the global default memory resource, can be used without
> linking the library.
>
> Some logic was refactored from scoped_allocator_adaptor to avoid
> repeating the complicated template and preprocessor machinery in the
> polymorphic_allocator. I hope this does not cause any problem to scoped
> allocator users.
>
> Any suggestion or bug report is welcome. Best,

I see that new_delete_resource and null_memory_resource instances have 
static storage duration. I suppose, it means that containers using these 
resources cannot be used in global constructors/destructors (including 
the global variables of their type)? This is a serious limitation IMO, 
as people often use strings and containers globally.