简单的多线程听键盘

Question

让多个线程听键盘最简单的技巧是什么？
我希望简单的r-key一次记录多个凸轮。
这是我的简化单线程代码（实际是多线程）。

#include <iostream>
#include <thread>
#include <opencv2/opencv.hpp>
using namespace std;
using namespace cv;
void videoWindow0(){
    VideoCapture capture(0); // use webcam
    //VideoCapture capture("input.mpg"); // use input file
    Mat frame;

    if(capture.isOpened()) {
        // if using webcam:
        int fps = 30;
        // if using input file:
        //int fps = capture.get(CV_CAP_PROP_FPS);

        int width = capture.get(CV_CAP_PROP_FRAME_WIDTH);
        int height = capture.get(CV_CAP_PROP_FRAME_HEIGHT);
        cout << "FPS: " << fps << ", width: " << width << ", height: " << height << endl;

        VideoWriter writer("output0.mpg",
                           CV_FOURCC('P','I','M','1'),
                           fps, cvSize(width, height), 0); // 0 means gray, 1 means color

        if(writer.isOpened()) {
            while(true) {
                capture >> frame;

                if(!frame.empty()) {
                    imshow("Video0", frame);
                }

                Mat frame_gray = frame.clone();
                cvtColor(frame, frame_gray, CV_RGB2GRAY);
                writer << frame_gray;

                int key = waitKey(10);
                if((char)key == 'q') { break; }
            }
        }
    }
}
int main(){
    std::thread t0(videoWindow0)
    t0.join();
    return 0;
}

问题：
如何让我的线程听取r-key键盘按钮？