将C ++ 11 std :: thread移植到boost :: thread编译问题

Question

我正在尝试使用boost :: thread将C ++ 11 std :: thread代码移植到VC9（VS 2008）。 下面的“等效” C ++ 11代码在msvc12上可以正常编译：

#include <iostream>
#include <thread>
#include <vector>
#include <algorithm>
#include <cassert>

void thFun(int i) 
{
    std::cout << "Hello from thread " << i << " !\n";
}
int main()
{
    std::vector<std::thread> workers;
    for (int i = 0; i < 10; ++i)
    {
        auto th = std::thread(&thFun, i);
        workers.push_back(std::move(th));
        assert(!th.joinable());
    }
    std::cout << "Hello from main!\n";
    std::for_each(workers.begin(), workers.end(), [](std::thread& th)
    {
        assert(th.joinable());
        th.join(); 
    });
    return 0;
}    

我想使用msvc9编译器和Boost 1.55将代码移植到C ++ 03。 如何解决以下编译错误：

#include <iostream>
#include <boost/thread.hpp>
#include <cassert>
#include <boost/foreach.hpp>
#include <boost/container/vector.hpp>

void thFun(int i) 
{
    std::cout << "Hello from thread " << i << " !\n";
}
void foo(boost::thread& th)
{
    assert(th.joinable());
    th.join(); 
}

int main()
{    
    boost::container::vector<boost::thread> workers;
            for (int i = 0; i < 10; ++i)
    {
        BOOST_AUTO(th, boost::thread(&thFun, i));
        workers.push_back(boost::move(th));
        assert(!th.joinable());
    }

    std::cout << "Hello from main!\n";
    BOOST_FOREACH(boost::thread& t, workers)
    {
        foo(t);
    }
    return 0;
}

编译错误是：

d:\program data\boost\boost_1_55_0\boost\preprocessor\iteration\detail\local.hpp(37): error C2770: invalid explicit template argument(s) for '::boost::move_detail::enable_if_c<boost::enable_move_utility_emulation<T>::value&&!boost::move_detail::is_rv<T>::value,const T&>::type boost::forward(const ::boost::move_detail::identity<T>::type &)'
          d:\program data\boost\boost_1_55_0\boost\move\utility.hpp(78) : see declaration of 'boost::forward'
          d:\program data\boost\boost_1_55_0\boost\container\vector.hpp(1797) : see reference to function template instantiation 'void boost::container::allocator_traits<Alloc>::construct<T,T>(Alloc &,T *,const P0 &)' being compiled
          with
          [
              Alloc=std::allocator<boost::thread>,
              T=boost::thread,
              P0=boost::thread
          ]
          d:\program data\boost\boost_1_55_0\boost\container\vector.hpp(1791) : while compiling class template member function 'void boost::container::vector<T>::priv_push_back(const T &)'
          with
          [
              T=boost::thread
          ]
          d:\work\boostthreadscratch\boostthreadscratch\boostthreadscratch.cpp(19) : see reference to class template instantiation 'boost::container::vector<T>' being compiled
          with
          [
              T=boost::thread
          ]

Answer 1

将此放在开头：

#define BOOST_THREAD_USES_MOVE

请参阅此处以供参考。 它启用Boost.Move（ boost::move ）为boost::thread提供的仿真，该仿真默认在Boost.Thread版本2中被禁用（在您的情况下MSVC9可以使用）。