Re: [Boost-bugs] [Boost C++ Libraries] #11818: future.then will be blocked if promise is set after the invocation of then

Subject: Re: [Boost-bugs] [Boost C++ Libraries] #11818: future.then will be blocked if promise is set after the invocation of then
From: Boost C++ Libraries (noreply_at_[hidden])
Date: 2015-11-24 17:28:47

#11818: future.then will be blocked if promise is set after the invocation of then
---------------------------------------------+----------------------
  Reporter:  Xiaoshuang LU <luxiaoshuang@…>  |      Owner:  viboes
      Type:  Bugs                            |     Status:  assigned
 Milestone:  To Be Determined                |  Component:  thread
   Version:  Boost 1.59.0                    |   Severity:  Problem
Resolution:                                  |   Keywords:
---------------------------------------------+----------------------
Changes (by viboes):

 * owner:  anthonyw => viboes
 * status:  new => assigned


Old description:

> int function()
> {
>     boost::promise<int> promise;
>     boost::future<int> future = promise.get_future();
>
>     boost::future<int> result =
>     future.then
>     (
>         boost::launch::deferred,
>         [](boost::future<int> && f)
>         {
>             std::cout << std::this_thread::get_id() << ": callback" <<
> std::endl;
>             std::cout << "The value is: " << f.get() << std::endl;
>             return f.get();
>         }
>     );
>
>     // We could not reach here.
>     std::cout << std::this_thread::get_id() << ": function" << std::endl;
>
>     promise.set_value(0);
>
>     return 0;
> }

New description:

 {{{
 int function()
 {
     boost::promise<int> promise;
     boost::future<int> future = promise.get_future();

     boost::future<int> result =
     future.then
     (
         boost::launch::deferred,
         [](boost::future<int> && f)
         {
             std::cout << std::this_thread::get_id() << ": callback" <<
 std::endl;
             std::cout << "The value is: " << f.get() << std::endl;
             return f.get();
         }
     );

     // We could not reach here.
     std::cout << std::this_thread::get_id() << ": function" << std::endl;

     promise.set_value(0);

     return 0;
 }
 }}}

--
-- 
Ticket URL: <https://svn.boost.org/trac/boost/ticket/11818#comment:2>
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