CvSeq* cvConvexityDefects(CvArr* contour, CvArr* convexhull, CvMemStorage* storage) {
    void *fptr;
    CvSeq*retval;

    fptr = dlsym(_Chcv_handle, "cvConvexityDefects_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return NULL;
    }
    dlrunfun(fptr, &retval, cvConvexityDefects, contour, convexhull, storage);
    return retval;
}
