使用指針向量創建線程

Question

好的新嘗試，

我將代碼從常規vector<Individual>更改為vector<shared_ptr<Individual>> 。 從那以后，我的線程代碼不起作用，而且我不知道如何解決它。 Start（）是Individual的無效成員，但是如果僅存在指向這些成員的指針，我該怎么稱呼它？

std::vector<thread> threads;
for (int i=0;i<(Individuals.size()-howManyChampions-howManyMutations);i++) {
    threads.push_back(thread(&Individual::start,&Individuals.at(i)));
    if (threads.size() % 5 == 0) {
        for(auto& thread : threads){
            thread.join();
        }
        threads.clear();
    }
}
for(auto& thread : threads){
    thread.join();
}

當我將其更改回vector和非並行版本時，它將起作用：

 for (int i=0;i<(int)Individuals.size();i++) {
    Individuals.at(i)->start();
}

就像魅力一樣。 所以我認為線程push_back有問題嗎？ 錯誤消息（大致翻譯為）是：

 instance created from »_Res std::_Mem_fn<_Res (_Class::*)(_ArgTypes ...)>::operator()(_Tp&, _ArgTypes ...) const [mit _Tp = std::shared_ptr<Individual>*, _Res = void, _Class = Individual, _ArgTypes = {}]«|
 instance created from »void std::_Bind_result<_Result, _Functor(_Bound_args ...)>::__call(std::tuple<_Args ...>&&, std::_Index_tuple<_Indexes ...>, typename std::_Bind_result<_Result, _Functor(_Bound_args ...)>::__enable_if_void<_Res>::type) [mit _Res = void, _Args = {}, int ..._Indexes = {0}, _Result = void, _Functor = std::_Mem_fn<void (Individual::*)()>, _Bound_args = {std::shared_ptr<Individual>*}, typename std::_Bind_result<_Result, _Functor(_Bound_args ...)>::__enable_if_void<_Res>::type = int]«|
 instance created from »std::_Bind_result<_Result, _Functor(_Bound_args ...)>::result_type std::_Bind_result<_Result, _Functor(_Bound_args ...)>::operator()(_Args&& ...) [mit _Args = {}, _Result = void, _Functor = std::_Mem_fn<void (Individual::*)()>, _Bound_args = {std::shared_ptr<Individual>*}, std::_Bind_result<_Result, _Functor(_Bound_args ...)>::result_type = void]«|
 instance created from »void std::thread::_Impl<_Callable>::_M_run() [mit _Callable = std::_Bind_result<void, std::_Mem_fn<void (Individual::*)()>(std::shared_ptr<Individual>*)>]«|
 instanziiert von hier|
 Pointer to element type »void (Individual::)()« with Objecttype »std::shared_ptr<Individual>« incompatible
 Return-Command with value in »void« returning Function [-fpermissive]

多謝你們

Answer 1

嘗試這個 ：

threads.push_back(thread(&Individual::start,Individuals.at(i).get()));

您可以使用get方法訪問shared_ptr持有的指針。 但是，您應該確保在加入所有線程之前不要丟棄此shared_ptr所有實例，否則它們將具有懸垂的Individual指針。