这是显示AVI视频的代码片段，它可以工作。

int main(int argc, char** argv) {

    //    cvNamedWindow(“Example2”, CV_WINDOW_AUTOSIZE);

    CvCapture* capture = cvCreateFileCapture("video.avi");
    IplImage* frame;

    while(1) {
        frame = cvQueryFrame(capture);
        if(!frame)
            break;
        cvShowImage("Example2", frame);
        char c = cvWaitKey(33);
        if(c == 27)
            break;
    }

    cvReleaseCapture(&capture);
    cvDestroyWindow("Example2");

    return 0;
}

但是，当我从第二行删除注解//时，它不起作用。我得到的错误是：

Invoking: GCC C Compiler
gcc -I/usr/include/opencv -O0 -g3 -Wall -c -fmessage-length=0 -MMD -MP -MF"main.d" -MT"main.d" -o"main.o" "../main.c"
../main.c: In function ‘main’:
../main.c:5:5: error: stray ‘\342’ in program
../main.c:5:5: error: stray ‘\200’ in program
../main.c:5:5: error: stray ‘\234’ in program
../main.c:5:5: error: stray ‘\342’ in program
../main.c:5:5: error: stray ‘\200’ in program
../main.c:5:5: error: stray ‘\235’ in program
../main.c:5:23: error: ‘Example2’ undeclared (first use in this function)
../main.c:5:23: note: each undeclared identifier is reported only once for each function it appears in
make: *** [main.o] Error 1

“Example 2”如何未声明？cvNamedwindow不应该做这个工作吗？