Re: [boost] Incorporating N2308 into boost::function

From: Marco (mrcekets_at_[hidden])
Date: 2007-11-02 18:44:21

On Thu, 01 Nov 2007 22:38:00 +0100, Emil Dotchevski  
<emil_at_[hidden]> wrote:

>> Would this not break all code currently using the templated allocator
>> version of boost::function? I would call that not at all appropriate  
>> for a
>> dot release, and should be avoided outright if possible.
>
> I apologize I meant 1.35 but now I see that it was naive to think it
> could happen that soon. My understanding is that Doug himself wanted
> the new allocator semantics for boost::function merged into Boost, but
> perhaps we should have a discussion first.
>
> About breaking user code -- yes, it's a breaking change but I think
> that most people will not be affected, because using allocators with
> boost::function is not very practical with the legacy allocator
> semantics, and switching to the new allocator semantics is trivial.
>
> It is also possible to introduce a macro that switches the legacy
> allocator semantics on (the allocator change affects only 2 hpp
> files.)
>

This sounds as a good news! So it will be possible
for boost overload to pass a (shared) user-defined allocator
to the embedded boost function objects. At present the only solution,
to allow to specify an allocator type as template argument, would be
to wrap all the supported signatures inside a tuple. This new semantic
remove such a need, providing a transparent solution to the problem. :-)

Marco

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