Re: [boost] Review Request: Singularity

Subject: Re: [boost] Review Request: Singularity
From: Klaim - Joël Lamotte (mjklaim_at_[hidden])
Date: 2011-08-15 04:17:46

Hi,

On Sun, Aug 14, 2011 at 23:20, Ben Robinson <icaretaker_at_[hidden]> wrote:

> The documentation, implementation and Boost unittests are available on
> GitHub at https://github.com/icaretaker/Singularity.
>

> I will now include an excerpt of the documentation file "singularity.htm"
> which is part of the GitHub download:
>
>
Could you provide an online page that we can read in a browser without
downloading the package?

>
>  Introduction<file:///C:/home/ben/workspace_boost/boost/source/common/libs/singularity/singularity.htm#singularity.introduction>
>
>
>  Motivation<file:///C:/home/ben/workspace_boost/boost/source/common/libs/singularity/singularity.htm#singularity.motivation>
>
>
Those links are obviously wrong :)

> Like Singleton, Singularity restricts a class to a single instance. However
> Singularity does not suffer from lifetime, scoping and initialization
> problems. The following are the advantages of Singularity over Singleton:
>
>   1. The lifetime of the single object is bounded by calls to create() and
>   destroy(). This lifetime is managed similiarly to objects bounded by
> calls
>   to new() and delete().
>   2. Singularity does not force global access to the instance. If global
>   access is required, then a globally accessible get_global() function can
> be
>   enabled upon creation of the instance.
>   3. Singularities of objects can be created using any available
>   constructor for that object.
>
>
>
Just a quick question : what about having a "singularity" in separate
modules, like dlls?

I've seen several singleton implementation ask the user to define manually
the static instance because without doing it there would be problems with
multiple dlls/so not using the same instance in case of extensions (dll/so
loaded at runtime via os-specific API (or boost::extension) ).

I'm not sure about the details of this potential problem, but did you try to
use singularity in this kind of configuration?

Joël Lamotte