undefined reference to `cvCreateCameraCapture'

[musa_yilmaz]

hi, i am new at qt, i installed opencv, and i want to make i simple example like capturing a frame from webcam. i wrote the first line but it gave error. so i cant continue.

codes in my main class is :
#include <QtGui/QApplication>
#include "mainwindow.h"
#include "opencv/cv.h"
#include "opencv/highgui.h"
#include "opencv/cxcore.h"

CvCapture* myCap;
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
myCap = cvCaptureFromCAM(0);
return a.exec();
}
it gives everytime same error what should i do ?
"undefined reference to `cvCreateCameraCapture'"