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// condition_variable::notify_one
#include <iostream> // std::cout
#include <thread> // std::thread
#include <mutex> // std::mutex, std::unique_lock
#include <condition_variable> // std::condition_variable
std::mutex mtx;
std::condition_variable produce,consume;
int cargo = 0; // shared value by producers and consumers
void consumer () {
std::unique_lock<std::mutex> lck(mtx);
while (cargo==0) consume.wait(lck);
std::cout << cargo << '\n';
cargo=0;
produce.notify_one();
}
void producer (int id) {
std::unique_lock<std::mutex> lck(mtx);
while (cargo!=0) produce.wait(lck);
cargo = id;
consume.notify_one();
}
int main ()
{
std::thread consumers[10],producers[10];
// spawn 10 consumers and 10 producers:
for (int i=0; i<10; ++i) {
consumers[i] = std::thread(consumer);
producers[i] = std::thread(producer,i+1);
}
// join them back:
for (int i=0; i<10; ++i) {
producers[i].join();
consumers[i].join();
}
return 0;
}
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