Re: [boost] Re: Re: basic guarantees in variant

From: E. Gladyshev (egladysh_at_[hidden])
Date: 2003-10-09 01:00:07

--- Rainer Deyke <rainerd_at_[hidden]> wrote:

> I can think of at least one degenerate case where your trick fails.
> 
> class A;
> 
> A* the_A = 0;
> 
> class A {
>   A() { the_A = this; }
>   ~A() { the_A = 0; }
> };
> 
> class B {
>   B() { if (the_A) do_something_with(the_A); }
> };
> 
> variant<A, B> v(A());
> v = B();
> 

It'll fail as soon as you use placement 'new' 
regadless of this trick.
The current boost::variant uses placement 
'new' all the time.

Eugene

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