multithreading - C++11 std::thread accepting function with rvalue parameter -

i have homework, , have troubles understanding, (probably) how passing parameters std::thread constructor works.

assume following code (i deleted unneeded parts)

template<typename t, typename task> class scheduler {     private:         typedef std::unordered_map<std::size_t, t> results;         class solver         {             public:             solver(task&& task) : m_thread(&solver::thread_function, std::move(task))             {                 m_thread.detach();             }              solver(solver&& solver) = default; // required vector::emplace_back             ~solver() = default;              private:             void thread_function(task&& task)             {                 task();             }             std::thread m_thread;         };      public:         scheduler() = default;         ~scheduler() = default;          void add_task(task&& task)         {             m_solvers.emplace_back(std::move(task));         }      private:         std::vector<solver> m_solvers; };  template<typename t> struct ftor {     explicit ftor(const t& t) : data(t) { }     t operator()() { std::cout << "computed" << std::endl; return data; }     t data; };  int main() {     scheduler<int, ftor<int>> scheduler_ftor;     scheduler<int, std::function<int(void)>> scheduler_lambda;     ftor<int> s(5);     scheduler_ftor.add_task(std::move(s));     scheduler_lambda.add_task([](){ std::cout << "computed" << std::endl; return 1; }); } 

why doesn't compile? mvs2015 complaining about

functional(1195): error c2064: term not evaluate function taking 1 arguments functional(1195): note: class not define 'operator()' or user defined conversion operator pointer-to-function or reference-to-function takes appropriate number of arguments
note: while compiling class template member function 'scheduler<int,ftor<int> >::solver::solver(task &&)'

while g++ 4.9.2

functional: in instantiation of ‘struct std::_bind_simple<std::_mem_fn<void (scheduler<int, ftor<int> >::solver::*)(ftor<int>&&)>(ftor<int>)>’:
required ‘void scheduler<t, task>::add_task(task&&) [with t = int; task = ftor<int>]’

functional:1665:61: error: no type named ‘type’ in ‘class std::result_of<std::_mem_fn<void (scheduler<int, ftor<int> >::solver::*)(ftor<int>&&)>(ftor<int>)>’ typedef typename result_of<_callable(_args...)>::type result_type;

i suppose there problems std::moving std::thread.

if use member function first thread argument, second argument supposed pointer, pointing object member function called to

update

good discussion here

start thread member function