I want to make a program that makes use of all threads. I get the cores by:
const auto processorCount = std::thread::hardware_concurrency();
Then I tried to do this:
std::thread threads[processorCount];
for (int i = 0; i < processorCount; i )
{
threads[i] = std::thread(addArray);
}
Then it gave me this error.
g main.cpp -o build
In file included from /usr/include/c /11/thread:43,
from main.cpp:1:
/usr/include/c /11/bits/std_thread.h: In instantiation of ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = int* (&)(int*, int*); _Args = {}; <template-parameter-1-3> = void]’:
main.cpp:62:46: required from here
/usr/include/c /11/bits/std_thread.h:130:72: error: static assertion failed: std::thread arguments must be invocable after conversion to rvalues
130 | typename decay<_Args>::type...>::value,
| ^~~~~
/usr/include/c /11/bits/std_thread.h:130:72: note: ‘std::integral_constant<bool, false>::value’ evaluates to false
/usr/include/c /11/bits/std_thread.h: In instantiation of ‘struct std::thread::_Invoker<std::tuple<int* (*)(int*, int*)> >’:
/usr/include/c /11/bits/std_thread.h:203:13: required from ‘struct std::thread::_State_impl<std::thread::_Invoker<std::tuple<int* (*)(int*, int*)> > >’
/usr/include/c /11/bits/std_thread.h:143:29: required from ‘std::thread::thread(_Callable&&, _Args&& ...) [with _Callable = int* (&)(int*, int*); _Args = {}; <template-parameter-1-3> = void]’
main.cpp:62:46: required from here
/usr/include/c /11/bits/std_thread.h:252:11: error: no type named ‘type’ in ‘struct std::thread::_Invoker<std::tuple<int* (*)(int*, int*)> >::__result<std::tuple<int* (*)(int*, int*)> >’
252 | _M_invoke(_Index_tuple<_Ind...>)
| ^~~~~~~~~
/usr/include/c /11/bits/std_thread.h:256:9: error: no type named ‘type’ in ‘struct std::thread::_Invoker<std::tuple<int* (*)(int*, int*)> >::__result<std::tuple<int* (*)(int*, int*)> >’
256 | operator()()
| ^~~~~~~~
make: *** [Makefile:2: array] Error 1
What do I do now? Is their a simpler way of doing this?
CodePudding user response:
First of all, like in the comments suggested, I would recommend you to use std::vector
as well, for example something like, std::vector<std::thread>
. Here is a small example of how it could look like:
#include <iostream>
#include <vector>
#include <thread>
using namespace std;
void print(int i)
{
std::cout << i << std::endl;
}
int main()
{
std::vector<std::thread> Threads;
for(int i = 0; i<std::thread::hardware_concurrency(); i )
{
Threads.push_back(std::thread(print, i));
}
for(auto& i : Threads)
{
i.join();
}
return 0;
}
I hope this is solves your problem.