Re: [Boost-users] problems with Boost.Thread on VS10

Subject: Re: [Boost-users] problems with Boost.Thread on VS10
From: John M. Dlugosz (mpbecey7gu_at_[hidden])
Date: 2012-04-06 02:04:13

On 4/5/2012 2:32 AM, Igor R wrote:
> Can you provide a trivial example that reproduces the issue?
>

#include "boost/test/unit_test.hpp"
#include "boost/thread/future.hpp"
#include "boost/utility/result_of.hpp"
#include <functional>

struct async_func {
        virtual ~async_func() { }
        virtual void run() =0;
        };

template <typename Ret>
class async_func_pt : public async_func {
        boost::packaged_task<Ret> f;
public:
        void run() override { f(); }
        async_func_pt (boost::packaged_task<Ret>&& f) : f(std::move(f)) {}
        ~async_func_pt() { }
        boost::unique_future<Ret> get_future()  { return f.get_future(); }
        };

void async_core (async_func* p);

template <typename F>
boost::unique_future<typename boost::result_of< F() >::type>
async (F&& f)
  {
  typedef typename boost::result_of< F() >::type RetType;
  async_func_pt<RetType>* p= new  async_func_pt<RetType> (boost::packaged_task<RetType>(f));
  boost::unique_future<RetType> future_result= p->get_future();
  async_core (p);
  return std::move(future_result);
  }

template <typename F, typename A1>
boost::unique_future<typename boost::result_of< F(A1) >::type>
async (F&& f, A1&& a1)
  {
// This should be all it needs.  But get a funny error deep inside Boost.
// problem overloading with && ?
  return async (std::tr1::bind(f,a1));
  }

BOOST_AUTO_TEST_SUITE(thread_pool_tests)

int calculate_the_answer_to_life_the_universe_and_everything()
{
     return 42;
}

size_t foo (const std::string& s)
  {
  return s.size();
  }

BOOST_AUTO_TEST_CASE( async_test )
{
// this one works
        // most fundimental form:
        boost::unique_future<int> fi= async 
(&calculate_the_answer_to_life_the_universe_and_everything);
        int i= fi.get();
        BOOST_CHECK_EQUAL (i, 42);

// This one chokes at compile time
        boost::unique_future<size_t> fut_1= async (&foo, "Life");

        BOOST_CHECK_EQUAL (fut_1.get(), 4);
}

BOOST_AUTO_TEST_SUITE_END()