std::atomic_fetch_or, std::atomic_fetch_or_explicit

#include <atomic>
#include <chrono>
#include <functional>
#include <iostream>
#include <thread>
 
// Binary semaphore for demonstrative purposes only.
// This is a simple yet meaningful example: atomic operations
// are unnecessary without threads. 
class Semaphore
{
 std::atomic_char m_signaled;
public:
 Semaphore(bool initial = false)
 {
 m_signaled = initial;
 }
 // Block until semaphore is signaled
 void take() 
 {
 while (!std::atomic_fetch_and (&m_signaled, false))
 {
 std::this_thread::sleep_for (std::chrono::milliseconds (10));
 }
 }
 
 void put() 
 {
 std::atomic_fetch_or(&m_signaled, true);
 }
};
 
class ThreadedCounter
{
 static const int N = 100;
 static const int REPORT_INTERVAL = 10;
 int m_count;
 bool m_done;
 Semaphore m_count_sem;
 Semaphore m_print_sem;
 
 void count_up() 
 {
 for (m_count = 1; m_count <= N; ++m_count)
 if (m_count % REPORT_INTERVAL == 0)
 {
 if (m_count == N)
 m_done = true;
 m_print_sem.put(); // signal printing to occur
 m_count_sem.take(); // wait until printing is complete proceeding
 }
 std::cout << "count_up() done\n";
 m_done = true;
 m_print_sem.put();
 }
 
 void print_count() 
 {
 do
 {
 m_print_sem.take();
 std::cout << m_count << '\n';
 m_count_sem.put();
 }
 while (!m_done);
 std::cout << "print_count() done\n";
 }
 
public:
 ThreadedCounter() : m_done(false) {}
 void run() 
 {
 auto print_thread = std::thread (&ThreadedCounter::print_count, this);
 auto count_thread = std::thread (&ThreadedCounter::count_up, this);
 print_thread.join();
 count_thread.join();
 }
};
 
int main() 
{
 ThreadedCounter m_counter;
 m_counter.run();
}

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print_count() done
count_up() done