如何用while循环写一个信号等待程序？

如何用while循环写一个信号等待程序（未接到信号时阻滞，接到信号时继续运行）？
C++的题，老板说涉及Posix和信号量的知识点。
求解答！

使用条件变量std::condition_variable和互斥锁std::mutex mtx，即可实现你的需求
详细参考C++11 多线程编程之条件变量std:: condition_variable、wait()、notify_one()、notify_all()_他人是一面镜子，保持谦虚的态度的博客-CSDN博客_std条件变量

#include<iostream>
using namespace std;
int main()
{
string s;
char c;
while((c=cin.get())!='\n')
s.append(1,c)
cout<<s<<endl;
return 0;
}

类似这样，循环输入，回车跳出循环

#include <atomic>
#include <chrono>
#include <condition_variable>
#include <iostream>
#include <mutex>
#include <queue>
#include <thread>

std::mutex m;
std::condition_variable cv;
std::queue<int> data;
std::atomic_bool processed(false);
std::atomic_bool done(false);

void producer_thread() {
  int n = 0;
  while (1) {
    {
      // prepare data for consumer
      std::unique_lock<std::mutex> lk(m);
      std::cout << "producer: ";
      for (int i = 0; i < 5; i++) {
        data.push(n);
        std::cout << n << " ";
        n++;
      }
      std::cout << '\n';
      processed = false;
    }

    // notify consumer the data is ready for processing
    cv.notify_one();

    // break the loop if there is no more data to send
    if (n >= 20) {
      done = true;
      break;
    }

    // wait for the consumer finishing to process the data
    {
      std::unique_lock<std::mutex> lk(m);
      cv.wait(lk, []() -> bool { return processed; });
    }
  }
}

void consumer_thread() {
  while (!done) {
    // wait for the consumer preparing the data
    {
      std::unique_lock<std::mutex> lk(m);
      cv.wait(lk, []() -> bool { return !data.empty(); });
    }

    // process the data
    {
      std::unique_lock<std::mutex> lk(m);
      std::cout << "consumer: ";
      while (!data.empty()) {
        std::cout << data.front() << " ";
        data.pop();
      }
      std::cout << '\n';
    }

    // notify the producer that the data has been processed
    processed = true;
    cv.notify_one();
  }
}

int main() {
  std::thread t1(producer_thread);
  std::thread t2(consumer_thread);
  t1.join();
  t2.join();
  return 0;
}

$ g++ -Wall main.cpp -lpthread
$ ./a.out
producer: 0 1 2 3 4 
consumer: 0 1 2 3 4 
producer: 5 6 7 8 9 
consumer: 5 6 7 8 9 
producer: 10 11 12 13 14 
consumer: 10 11 12 13 14 
producer: 15 16 17 18 19 
consumer: 15 16 17 18 19