int cvTrackFace(CvFaceTracker* pFaceTracker, IplImage* imgGray, CvRect* pRects, int nRects, CvPoint* ptRotate, double* dbAngleRotate) {
    void *fptr;
    int retval;

    fptr = dlsym(_Chcv_handle, "cvTrackFace_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return -1;
    }
    dlrunfun(fptr, &retval, cvTrackFace, pFaceTracker, imgGray, pRects, nRects, ptRotate, dbAngleRotate);
    return retval;
}
