opencv build failed with xcode

Question

I have a problem with a webcam capturing in opencv.

This can be built successfully:

#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/core/core.hpp"
using namespace cv;

int main() {
//    VideoCapture cap(0);
//    while(true){
//        Mat Webcam;
//        cap.read(Webcam);
//        imshow("Webcam", Webcam);
//    }
}

However, this is not:

#include <iostream>
#include "opencv2/highgui/highgui.hpp"
#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/core/core.hpp"
using namespace cv;

int main() {
    VideoCapture cap(0);
    while(true){
        Mat Webcam;
        cap.read(Webcam);
        imshow("Webcam", Webcam);
    }
}

There is no error or warning message popped out, so I can't solve it by myself.

Any idea is appreciated!

Updates:

Error message

It seems something went wrong when I updated xcode.....

Error message 2

Answer 1

Your code is perfectly ok except following line after imshow:

waitKey(10);

It will provide ui thread to draw the frames. Without this delay ui thread can not be updated or get time slice from cpu.