OpenCV的waitKey()应该返回-1，但没有 [英] OpenCV waitKey() should return -1 but didn't

问题描述

在 doc 中，它说

它返回按下的键的代码；如果在指定的时间之前没有按下任何键，则返回-1.

It returns the code of the pressed key or -1 if no key was pressed before the specified time had elapsed.

但是在我的 Ubuntu 14.04 设备上没有按任何键时，它将返回255而不是-1.为什么会这样?

But it returns 255 instead of -1 when no key is pressed on my Ubuntu 14.04 device. Why is that?

代码示例:

#include <opencv/cv.hpp>
#include <iostream>

using namespace cv;

int main(void) {
    Mat image = Mat::zeros(100, 100, CV_8UC3);
    char window_name[] = "waitKey() example";
    imshow(window_name, image);

    const int DELAY = 50;
    int c = waitKey(DELAY);
    std::cout << c << std::endl;
}

推荐答案

最近在cv::waitKey()上进行了一些代码修改，并且有一个

recently some code modification has made on cv::waitKey() and there is a fix about this issue not merged yet.

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