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From: Maciej Sobczak <see.my.homepage@gmail.com>
Newsgroups: comp.lang.ada
Subject: Re: Ada containers and custom allocators
Date: Mon, 7 Jan 2008 23:59:34 -0800 (PST)
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Date: 2008-01-07T23:59:34-08:00
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On 8 Sty, 02:54, "Randy Brukardt" <ra...@rrsoftware.com> wrote:

> > Is it possible to set up a custom allocator for use with any given Ada
> > container?
>
> If you mean an allocator for the private data of the container (which
> includes all of the elements and is the bulk of the container), the answer
> is no.

This is exactly what I mean. It is not uncommon for a program to have
a majority of its dynamic memory managed by containers.

> The standard Ada containers do not provide any mechanism to control
> how/were the container allocates memory.

This limitation prevents programmers from doing many interesting
optimizations. Even if we put performance issues aside, I might want
to control the memory allocation for reliability.

[...]
> (or, the
> storage pool passed would have to be completely general, allowing any size
> allocation, which would eliminate the vast majority of interesting things
> that you can do with storage pools).

There are ways to overcome this problem, at least for some container
types. Node-based containers could use fixed-size allocators, but of
course it is the container which would then instantiate the allocator
with the proper node size. It was possible in C++.

--
Maciej Sobczak * www.msobczak.com * www.inspirel.com