Re: [boost] [Review.Coroutine] Some comments

Subject: Re: [boost] [Review.Coroutine] Some comments
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2012-09-09 03:24:50

Le 08/09/12 22:15, Oliver Kowalke a écrit :
> Am 08.09.2012 21:57, schrieb Vicente J. Botet Escriba:
>>
>> The suggested Allocator is just there to responds to your need 
>> (predictability) :)
> Vicente - I looked at packaged_task as you suggested. I found 
> following code:
>
> packaged_task() : {
> typedef typename Allocator::template rebind<detail::task_object<R,FR> 
> >::other A2;
> A2 a2(a); // allocated on the stack, after return from ctor destroyed
> typedef thread_detail::allocator_destructor<A2> D;
> task = task_ptr(::new(a2.allocate(1)) detail::task_object<R,FR>(f), 
> D(a2, 1) ); // a2 passed to allocator_destructor
> }
>
> template <class _Alloc>
>    class allocator_destructor
>     {
>       ...
>       _Alloc& alloc_; // reference to A2
>       size_type s_;
>     public:
>       allocator_destructor(_Alloc& a, size_type s)BOOST_NOEXCEPT
>       : alloc_(a), s_(s)
>       {}
>       ...
>     };
>
> allocator_destructor hold only a reference to the allocator A2 but the 
> instance was allocated on the stack.
> Doesn't this mean that the alloc_ member of allocator_destructor will 
> point to a non-existing object?
>

Yes, you are right. The code is using something not very clean that 
works only for stateless allocators.
I guess that storing the allocator on allocator_destructor should solve 
the issue.
Please could you create a ticket to track the issue?

Best,
Vicente