Am 08.09.2012 21:57, schrieb Vicente J. Botet Escriba:
Le 08/09/12 20:05, Christopher Kormanyos a écrit :
Am 08.09.2012 16:25, schrieb Vicente J. Botet Escriba:
> On solution could be to make coroutine non-copyable, Is coroutine copyable? moveable-only - I mean to derive from boost::noncopyable I'm lost. How this can help here? I was thinking about to make coroutine deriving from boost::noncopyable and not moveable-only. Then I could refactor coroutine that it does not need to allocate memory for inner classes. The user can decide if the coroutine instance is allocated on the stack or in the freestore and which technique is used. Well, if it were my design, I would make coroutine non-copyable and simply forget about all the related troubles of copy semantics. Furthermore, I would entirely avoid the use of dynamically allocated resources and a coroutine allocator.
But, of course, I am predominantly interested in using coroutine in embedded systems that lack a heap and benefit from the predictability of statically allocated resources. As you already mentioned in various communications, though, we can work on a lightweight embedded version in the future.
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? Oliver