int cvSetImageIOFunctions(CvLoadImageFunc _load_image, CvLoadImageMFunc _load_image_m, CvSaveImageFunc _save_image, CvShowImageFunc _show_image) {
    void *fptr;
    int retval;

    fptr = dlsym(_Chcv_handle, "cvSetImageIOFunctions_chdl");
    if(fptr == NULL) {
        fprintf(_stderr, "Error: %s(): dlsym(): %s\n", __func__,  dlerror());
        return -1;
    }
    dlrunfun(fptr, &retval, cvSetImageIOFunctions, _load_image, _load_image_m, _save_image, _show_image);
    return retval;
}
