Re: [boost] [multiindex] internal scope_guard has changed access from public to protected

Subject: Re: [boost] [multiindex] internal scope_guard has changed access from public to protected
From: joaquin_at_[hidden]
Date: 2010-05-06 06:43:49

Thorsten, any comment on the mail below?

Thanks,

Joaquin M Lopez Munoz escribió:
> Thorsten Ottosen <nesotto <at> cs.aau.dk> writes:
>
>   
>> Joaquin M Lopez Munoz skrev:
>>     
>>> Yep, why can't you just define null guard as
>>>
>>> struct null_guard:boost::multi_index::detail::scope_guard_impl_base{};
>>>       
>> the ?: operator seem to require that the second argument can be 
>> converted to the type of the first argument.
>>     
>
> I might be missing something, but I think tou can simply
> write the following to circumvent the problem:
>
> #define BOOST_AUTO_BUFFER_CONSTRUCTOR_SCOPE_GUARD() \
>   boost::has_nothrow_copy<T>::value ? \
>   static_cast<boost::multi_index::detail::scope_guard>( \
>     boost::auto_buffer_detail::null_guard()) : \
>   static_cast<boost::multi_index::detail::scope_guard>( \
>     boost::multi_index::detail::make_obj_guard( \
>       *this, \
>       &auto_buffer::deallocate, \
>       buffer_, members_.capacity_ ))
>
> Does this work? Additionally, why are you doing the
> guard selection on run time? boost::has_nothrow_copy<T>::value
> is a compile-time value so you can select the exact
> type of the guard (null or otherwise) with some Boost.MPL.
>
>   
>>> Unrelated to your particular problem, is this auto_buffer class
>>> of yours part of Boost or a private project? If the former, we
>>> should think about moving scope_guard to boost/detail/ where
>>> implementation bits common to several libs inhabit.
>>>       
>> That's a good idea. I'm using it for an upcomming library
>> called Boost.AutoBuffer.
>>
>> I'm confident that other boost libs also use it.
>>     
>
> I've just made a global search and the only other lib using
> it is Signals2, inside a detail component of yours (the one you
> intend to promote to official lib status, I presume). I'll
> add this move to boost/detail/ to my todo list.
>
> Joaquín M López Muñoz
> Telefónica, Investigación y Desarrollo
>
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Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo