Re: [Boost-users] [Thread] Constructing a move-only object asyncronously

Le 19/03/13 19:40, Alexander Lamaison a écrit :

I'm trying to create a move-only object asyncronously using Boost.Thread unique_future but I'm running into trouble:

error C2248: 'A::A' : cannot access private member declared in class 'A' c:\users\awl03\documents\visual studio 2005\projects\boost_1_51_0\boost\thread\future.hpp 493

I've tried all sorts of ways to work around this but always end up with some variation or other of this error message. What am I doing wrong?

The code is below. The setup is: Visual Studio 2005 Boost 1.51

Thanks, Alex

#include #include #include #include

using namespace boost;

class A : public noncopyable { BOOST_MOVABLE_BUT_NOT_COPYABLE(A)

public: A(int i) {}

A(BOOST_RV_REF(A) other) {}

A& operator=(BOOST_RV_REF(A) other) {}

};

A create_a() { return A(42); }

unique_future<A> async_create_a() { packaged_task<A> task(create_a); unique_future<A> result = task.get_future(); thread(move(task)).detach(); return move(result); }

int main() { A a = async_create_a().get(); return 0; }

Hi, you need to use version 4 to got this functionality. I have modified your example to use boost::future (*) and use packaged_task with a signature parameter (**). With this change it to works for the following toolsets. bjam toolset=darwin,darwin-4.6.2,darwin-4.7.1,clang-3.1,clang-3.2,darwin-latest,darwin-4.7.2 -l 300 variant=debug -j6 bjam toolset=darwin,darwin-4.6.2,darwin-4.7.1,clang-3.1,clang-3.2,darwin-latest,darwin-4.7.2 -l 300 variant=debug -j6 ts_ iMac-de-Vicente-Botet-Escriba:test viboes$ Best, Vicente #define BOOST_THREAD_VERSION 4 #include #include #include #include using namespace boost; class A : public noncopyable { BOOST_MOVABLE_BUT_NOT_COPYABLE(A) public: A(int ) {} A(BOOST_RV_REF(A) ) {} A& operator=(BOOST_RV_REF(A) ) { return *this;} }; A create_a() { return A(42); } future<A> async_create_a() //* { packaged_task task(create_a); // ** future<A> result = task.get_future(); //* thread(move(task)).detach(); return move(result); } int main() { A a = async_create_a().get(); return 0; }