void cvDrawContours(CvArr *img, CvSeq* contour, CvScalar external_color, CvScalar hole_color, int max_level, int thickness, int line_type, CvPoint offset) {
    void *fptr;

    fptr = dlsym(_Chcv_handle, "cvDrawContours_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return;
    }
    dlrunfun(fptr, NULL, cvDrawContours, img, contour, external_color, hole_color, max_level, thickness, line_type, offset);
}
