Mastering C++ Multithreading

Example

In this example using atomic_fetch_sub, an indexed container is processed by multiple threads concurrently, without the use of locks:

 #include <string> #include <thread> #include <vector> #include <iostream> #include <atomic> #include <numeric> const int N = 10000; std::atomic<int> cnt; std::vector<int> data(N); void reader(int id) { for (;;) { int idx = atomic_fetch_sub_explicit(&cnt, 1, std::memory_order_relaxed); if (idx >= 0) { std::cout << "reader " << std::to_string(id) << " processed item " << std::to_string(data[idx]) << '\n'; } else { std::cout << "reader " << std::to_string(id) << " done.\n"; break; } } } int main() { std::iota(data.begin(), data.end(), 1); cnt = data.size() - 1; std::vector<std::thread> v; for (int n = ...