void cvSobel(CvArr* src, CvArr* dst, int xorder, int yorder, int aperture_size) {
    void *fptr;

    fptr = dlsym(_Chcv_handle, "cvSobel_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return;
    }
    dlrunfun(fptr, NULL, cvSobel, src, dst, xorder, yorder, aperture_size);
}
