how to declare a vector of thread

问题

i'm new in c++ programing and need some help to use a thread library with vector library...

first I follow this tutorial

but the compiler (visual studio 2013) show me errors and I don't know how correct it:

first declaration of function

void Fractal::calcIterThread(vector<vector<iterc>> &matriz, int desdePos, int hastaPos, int idThread){
   ...
}

in main loop

vector<vector<iterc>> res;
res.resize(altoPantalla);

for (int i = 0; i < altoPantalla; i++){
   res[i].resize(anchoPantalla);
}

int numThreads = 10;
vector<thread> workers(numThreads);

for (int i = 0; i < numThreads; i++){ //here diferent try
   thread workers[i] (calcIterThread, ref(res), inicio, fin, i)); // error: expresion must have a constant value
   workers[i] = thread(calcIterThread, ref(res), inicio, fin, i)); // error: no instance of constructor "std::thread::thread" matches the argument list
}

...rest of code...

thanks for any help to clarify

回答1:

Try this:

#include <functional>
#include <thread>
#include <vector>

// ...

int numThreads = 10;
std::vector<std::thread> workers;

for (int i = 0; i != numThreads; ++i)
{
    workers.emplace_back(calcIterThread, std::ref(res), inicia, fin, i);
}

for (auto & t : workers)
{
    t.join(); 
}

回答2:

finally I can solve the problem with this change in my code...

workers.emplace_back(thread{ [&]() {
    calcIterThread(ref(res), inicio, fin, i);
}});

来源：https://stackoverflow.com/questions/32872202/how-to-declare-a-vector-of-thread

标签

c++

multithreading

vector

declaration