C++11 多线程，通过引用传递

c++11 multithread, passing by reference

本文关键字：引用 多线程 C++11      更新时间：2023-10-16
void _function_(std::vector<long long>& results){
results.push_back(10);
return ;
}

int main(){
std::vector<std::thread> threads;
std::vector<std::vector<long long>> results_array;
for(int i=1;i<=N;i++){
results_array[i]=std::vector<long long>();
threads.push_back(std::thread(&_function_,results_array[i]));
}
for(auto& th : threads){
th.join();
}
return 0;
}

这是 c++ 代码。我想使用std::vector<long long>来保留每个线程的结果。所以我初始化了一个 每个线程std::vector<std::vecotor<long long>>。但是，在通过results_array[i]时，我遇到了以下错误：

In file included from /usr/include/c++/5/thread:39:0,
from multi-thread.cc:3:
/usr/include/c++/5/functional: In instantiation of ‘struct std::_Bind_simple<void (*(std::vector<long long int>))(std::vector<long long int>&)>’:
/usr/include/c++/5/thread:137:59:   required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = void (*)(std::vector<long long int>&); _Args = {std::vector<long long int, std::allocator<long long int> >&}]’
multi-thread.cc:21:60:   required from here
/usr/include/c++/5/functional:1505:61: error: no type named ‘type’ in ‘class std::result_of<void (*(std::vector<long long int>))(std::vector<long long int>&)>’
typedef typename result_of<_Callable(_Args...)>::type result_type;
^
/usr/include/c++/5/functional:1526:9: error: no type named ‘type’ in ‘class std::result_of<void (*(std::vector<long long int>))(std::vector<long long int>&)>’
_M_invoke(_Index_tuple<_Indices...>)

我也尝试std::ref(results_array[i])，但有恶化错误。

任何人都可以在这个问题上帮助我吗？谢谢！

这里有正确的代码：

void _function_(std::vector<long long>& results){
results.push_back(10);
return ;
}


int main(){
int N = 10;
std::vector<std::thread> threads;
std::vector<std::vector<long long>> results_array;
for(int i=0;i<N;i++){
results_array.push_back(std::vector<long long>());
threads.push_back(std::thread(&_function_, std::ref(results_array[i])));
}
for(auto& th : threads){
th.join();
}
return 0;
}

您的问题出在以下行：

threads.push_back(std::thread(&_function_, std::ref(results_array[i])));

你没有得到results_array的参考。 哟也必须像这里一样纠正

results_array.push_back(std::vector<long long>());

相关文章：