Re: [boost] [review] Fast track review of Boost.Utility/Singleton begins today

From: Martin Bonner (Martin.Bonner_at_[hidden])
Date: 2008-01-17 09:07:26

From: Tobias Schwinger
> Johan Nilsson wrote:
>> Tobias Schwinger wrote:
>>> Edson Tadeu wrote:
>>>>   Does it support a single singleton across multiple DLL's? I.e.,
>>>> singleton S is accessed the first time by DLL A (and is created),
>>>> then it is accessed by DLL B. Does DLL B create a new instance of
>>>> singleton S for it, or can it use the one created by DLL A as a
>>>> truly global singleton?
>>> Yes. See the documentation for details.
>> 
>> Unless you have updated the documentation since the announcement, I
>> think it would be a good idea to explain this in better detail. An
>> 'implementation details' section would be a great addition to the
>> document. 
> 
> OK, I'll take this as the "how does it work"-question :-).
> 
> It's actually quite easy: The macros introduce a member function that
> is defined in compiled code and used to access the Singleton. This 
> way, all code to manage a Singleton's lifetime is in one place.

I haven't looked at the library, but I don't understand how that works
on Windows.  Won't both DLLs have their own copy of the compiled code,
and hence won't they both have their own copy of the singleton?
-- 
Martin Bonner
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