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// { dg-options "-std=gnu++2a -pthread" }
// { dg-do run { target c++2a } }
// { dg-require-effective-target pthread }
// { dg-require-gthreads "" }
// { dg-add-options libatomic }
#include <iostream>
#include <sstream>
#include <thread>
#include <semaphore>
#include <mutex>
#include <chrono>
#include <vector>
std::counting_semaphore<4> semaphore{6};
std::mutex mtx;
std::vector<std::string> results;
void thread_main(size_t x)
{
semaphore.acquire();
std::this_thread::sleep_for(std::chrono::milliseconds(100));
semaphore.release();
{
std::ostringstream stm;
stm << "Thread " << x << " finished.";
std::lock_guard g{ mtx };
results.push_back(stm.str());
}
}
int main()
{
constexpr auto nthreads = 10;
std::vector<std::thread> threads(nthreads);
size_t counter{0};
for(auto& t : threads)
{
t = std::thread(thread_main, counter++);
}
for(auto& t : threads)
{
t.join();
{
std::lock_guard g{ mtx };
for (auto&& r : results)
std::cout << r << '\n';
std::cout.flush();
results.clear();
}
}
}
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