C++多线程读写问题

#include <iostream>
#include <thread>
#include <mutex>
#include <unistd.h>
using namespace std;mutex read_write_mutex;void read_handler()
{while(true){read_write_mutex.lock();cout << "A" << endl;read_write_mutex.unlock();sleep(2);}
}void write_handler()
{while(true){read_write_mutex.lock();cout << "B" << endl;read_write_mutex.unlock();sleep(2);}
}int main()
{thread read_thread(read_handler);thread write_thread(write_handler);read_thread.join();write_thread.join();return 0;
}