Re: [boost] [spirit] hold_any invalid assignment to destructed object?

Subject: Re: [boost] [spirit] hold_any invalid assignment to destructed object?
From: Hartmut Kaiser (hartmut.kaiser_at_[hidden])
Date: 2013-03-12 18:21:05

> The boost::spirit::hold_any implementation includes the following
> functions defined in the detail sub-namespace:
> 
>     // member of fxns<mpl::true_> specialisation, line 99
>     static void move(void* const* src, void** dest)
>     {
>         reinterpret_cast<T*>(dest)->~T();
>         *reinterpret_cast<T*>(dest) =
>             *reinterpret_cast<T const*>(src);
>     }
> 
>     // member of fxns<mpl::false_> specialisation, line 99
>     static void move(void* const* src, void** dest)
>     {
>         (*reinterpret_cast<T**>(dest))->~T();
>         **reinterpret_cast<T**>(dest) =
>             **reinterpret_cast<T* const*>(src);
>     }
> 
> As I understand it, the object is destroyed _and then assigned to_; does
> it not need to be constructed at this point, i.e. have something like this
> (for the first specialisation):
> 
>         new (reinterpret_cast<T*>(dest)) T(
>             *reinterpret_cast<T const*>(src) );
> 

Yes, your code looks about right. Would you care to submit a patch for me to
apply?

Regards Hartmut
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